GAS EXPLORATION & DEVELOPMENT DRILLING DEPARTMENT
East Admin. Building, R-3270, Udhailiyah
Phone: 576-6467 Fax: 576-6459
July 6, 2008
GE&DDED/127/08 DRILLING PROGRAM
HADBA WELL No. 1 (WC)
PRE-KHUFF EXPLORATION
CHARGE No. 75-08557-0001
EPA No. 79422
WELL MENU: KD-2
TARGET DAYS: 228 days
EXECUTIVE DIRECTOR
DRILLING AND WORKOVER
DHAHRAN
Attached for your consideration and approval is the proposed Drilling Program for HADBA-1. It is proposed to drill the subject well, vertically, to a total depth of 18,000’ (± 750’ into Sarah Formation).
It is estimated to require 251 days to drill the subject well to T.D, cut seven cores, conduct one bare foot test across the Unayzah Formation, install a 7” liner on the base of Qusaiba drill and log a 5-7/8” hole across Sarah, abandon the 5-7/8”, perform one cased hole test across the Jilh formation, and suspend/abandon the well. HADBA-1 will be drilled utilizing a KD-2 casing menu. This casing program will achieve all objectives as specified in the Exploration Requirement Letter, dated May 18, 2008.
The primary objectives of HADBA-1 are gas in the Jilh, Sudair and Unayzah A reservoirs. The secondary targets are the Khuff B, Khuff C and Sarah reservoirs.
RIG ADC-23 880-5010/11 880-5017 (FAX)
SURFACE LOCATION N 2,817,481.54
Lat: 25 26’ 40.3959” E: 796,054.32
Long: 47 56’ 36.9255” UTM ZONE 38
DISTANCE 391 KM FROM DHAHRAN MAIN GATE
215 KM FROM UDHAILIYAH MAIN GATE
ELEVATIONS 1467’ GL (EST) 1506’ DF (EST)
TOTAL DEPTH 18,000’ (± 750’ into Sarah Formation)
SUPERINTENDENT Karl L. Hilthon 576-6359 (Off) 0506826196 (Mob.)
DRILLING FOREMEN Kenny Cavender Martin Barclay 880-5010 or 5011
880-5017 (Fax)
DRILLING ENGINEER Juan P. Montana
577-8362 (Office)
055-450-1054 (Mob.)
EXPLORATION GEOLOGIST Abdullah Al Zahrani 873-8245 (Office) 050-386-0714 (Mob)
RMD ENGINEER Meftah Tiss 873-7681 (Office) 878-6649 (Home)
055-178-3808 (mob.)
RDD ENGINEER Nhedal Musharfi 873-0246 (Office) 055-812-0021 (Mob.)
GENERAL DRILLING INFORMATION AND GUIDELINES:
A. HYDROCARBON POTENTIAL:
1. Primary Objective: Gas in the Jilh, Sudair and Unayzah A reservoirs.
2. Secondary Objective: Gas in Khuff B, Khuff C and Sarah reservoirs.
B. SAMPLING:
1. Collect a one-gallon sample of any fluid flow for geochemical analysis and estimate the flow rate. Send the sample to Lab R&D Center, Bldg. 136, Dhahran, and send results to the Hydrology Division (B-3105E, R-60).
2. Collect two bags of ditch samples every 10 feet from surface to T.D., wherever circulation is maintained. Additional samples may be required at the discretion of the wellsite Geologist.
3. In addition to normal sampling, a one-gallon sample of any fluid recovered on drill stem tests should be taken by the Wellsite Geologist for special analysis. Sample any other fluid flows and estimate flow rate.
4. Collect two one-gallon mud samples from the flow line immediately prior to pulling out of the hole for logging, one sample to be given to the logging engineer and the other sent to the Lab in the R&D Center for measurement of mud and mud filtrate resistivities. Results are to be sent to RDD (X-7570).
5. Catch samples of all produced fluids, water or oil, and estimate rates. Report all influx on the Morning Report.
6. Collect a one-gallon of all coring mud on circulation before cores.
C. WELLSITE GEOLOGY:
A wellsite Geologist is required to:
1. Describe samples to TD and pick all key formation tops
2. Pick core points and test points
3. Pick All casing points
4. Report all formation tops on the Morning Report.
D. WELL CONTROL CONSIDERATIONS:
1. Have TIW and Inside BOP valves with the necessary crossovers for each string of drill pipe and drill collars on the rig floor at all times. The foreman should ensure that the valves are in operating condition and should be pressure tested during routine BOP tests. A wrench for IBOP should be located on driller’s console for accessibility.
2. Record pipe displacements on all trips using the trip tank. Report calculated and actual fill up volumes on the morning report and IADC report. The annulus pressure should not be allowed to drop more than 100 psi before filling, while tripping.
3. Kill rates and circulating pressures should be taken at the following times: (Two kill rates should be taken, first rate approximately one half of normal circulating and another approximately ¼ of normal rate.)
a. When on bottom with a new bit after setting the 24" casing.
b. When the mud weight changes by 4 pcf or more.
c. Each tour change after setting casing above the Arabs. Report kill rates and pressures on the morning report and the IADC Report daily.
4. All gas encountered, while drilling, should be checked for the presence of H2S and safety measures taken immediately, if required. ALL GAS SHOULD BE ASSUMED SOUR UNTIL PROVEN OTHERWISE.
5. Keep the hole full at all times. If loss circulation is encountered, attempt to fill annulus with mud and/or water. Do not use water or brine across Wasia. If necessary, drill with an 80 - 85 pcf mud cap to prevent wetting the Wasia.
6. Drill 3’ of any drilling break, in a possible producing reservoir, and check for flow. Do not drill more than 10’ of any break without circulating bottoms up.
REPORT KILL RATES, PRESSURES AND ALL DRILLING BREAKS ON THE MORNING REPORT
E. CASING INSPECTION:
1. The rig crews should inspect all casing and tubing after shipment as follows:
a. Clean all threads and visually inspect.
b. Run API full length drift.
c. Visually inspect for overall damage.
2. All casing and tubing (13-3/8" and smaller) should be inspected by VETCO before shipment to the rig as follows:
a. Clean all threads and visually inspect.
b. Visually inspect for overall damage.
c. Electromagnetic inspection (4 functions);
- Longitudinal
- Transverse,
- Wall thickness,
- Grade verification.
3. No FBE casing is required for this well.
F. CEMENTING: (Halliburton)
1. Collect wet and dry cement samples for each cement job.
2. Forward dry cement samples and mix water samples to the Dhahran Laboratory and HOWCO for pilot testing.
3. Final cement volumes and additives will be adjusted following lab tests and evaluation of open hole caliper log.
4. Final confirmation testing will be done in the Dhahran Lab on the 13 3/8” casing, 9-5/8” casing, 7” liner, and 4 1/2” liner cement jobs.
5. Report part number of all DV Tools on the morning report following each casing job.
6. Report volume of cement received on location.
G. LOGGING: (Schlumberger)
1. Prior to pulling out of the hole to log, collect a one gallon sample of drilling fluid for resistivity determination by the logging Engineer. This sample should be taken during the last 50 bbl of circulation.
2. All logging runs should provide a 100' overlap and should be tied depth wise to the previous logging run. Request Integrated Caliper with the programmed log runs.
3. CPI (Computer Processing Interpretation) will be run on request for any logged interval.
4. Suggested logging scales are:
a. Gamma Ray: Surface to Khuff formation 0-100
Pre-Khuff Khuff Clastics 0-200
b. DSI: All runs 104-44
c. Resistivity: All runs Logarithmic Scale
5. Additional data requirements are:
a. Record the time circulation stopped, prior to POH for logging.
b. Record the time logging began off bottom for each log.
c. Record the maximum BHT of each logging run using two thermometers.
H. FORMATION CORING:
Programmed conventional coring is recommended as follows:
a) Arab D Reservoir: Cut 60 ft core if hydrocarbon shows are encountered, coring should continue until the base of the reservoir or hydrocarbon zone penetrated.
b) Lower Jilh Dolomite Reservoir: Cut 120 ft core if hydrocarbon shows are encountered, coring should continue until the base of the reservoir or hydrocarbon zone penetrated.
c) Lower Sudair Dolomite Reservoir: Cut 60 ft core if hydrocarbon shows are encountered, coring should continue until the base of the reservoir or hydrocarbon zone penetrated.
d) Khuff B Reservoir: Cut 60 ft core if hydrocarbon shows are encountered, coring should continue until the base of the reservoir or hydrocarbon zone penetrated.
e) Khuff C Reservoir: Cut 60 ft core if hydrocarbon shows are encountered, coring should continue until the base of the reservoir or hydrocarbon zone penetrated.
f) Unayzah A Reservoir: Cut 120 ft core if hydrocarbon shows and/or porosity are encountered, coring should continue until the base of the reservoir or hydrocarbon zone penetrated.
g) Hot Qusaiba Shale and Sarah sandstone reservoir: Cut 60 ft core if hydrocarbon shows and/or porosity are encountered. Coring should be started above the Sarah in order to catch some of the Base Qusaiba “Hot Shale". The coring should continue until the base of the reservoir or hydrocarbon zone penetrated.
I. FORMATION TESTING:
Should hydrocarbon shows be encountered in any potential reservoir, open-hole drill stem tests may be requested, depending upon hole conditions. If hydrocarbon flows to surface, sampling will be required. Flow rate is to be reported. In the event where open-hole drill stem tests is not possible, a program for any cased-hole testing will be issued following formation evaluation utilizing wireline logs, core, and sample data. Initial tests in all zones should be made with minimal cushion. (Refer to “Requirement for casing program” section for the proposed production test zones).
J. MUD LOGGING REQUIREMENTS ( Datalog )
Full Mud Logging Services are required from the beginning of drilling until TD.
K. DRILLING RAT & MOUSE HOLES.
Drill the mouse and rat holes with spud mud to avoid washing out the cellar.
34” HOLE SECTION
Drill a 34” hole to a depth of 120’, below RT. Circulate the hole clean and spot a Hi-Vis pill in preparation to run conductor. Run and cement a 30” conductor to case off any shallow unconsolidated surface sand and marl.
Note:
Drill this section with mud, NOT water.
POTENTIAL HOLE PROBLEMS
Incompetent sand and marl in the Neogene.
Well Name
Distance DESCRIPTION
HRUR-2
2005 47.4 km NW Drilled 34” hole to 115’ with 64 pcf mud. 100% circulation. Ran and cemented 30” casing w/o problems.
HRUR-1
1978 46.9 km NW The 30” casing stood up twice @ 45’ and 48’. Opened 34” hole to 42”, successfully run pipe to CP @ 137’. Cemented casing w/o problems.
KHRS-82 1996 44.9 km SE Drilled 24” pilot hole with 65 pcf spud mud and 100% circulation to 114’. Opened pilot hole to 34”. Ran and cemented 30” casing w/o problems. Good cement to surface, no fall back.
KHRS-4 1958 38.4 km SE Drilled 17-1/2" pilot hole w/ water and 100% circulation to 35'. Opened hole to 34”. Ran and cemented 26" conductor w/o problems.
KHRS-1 1957 41.9 km SE Drilled 17-1/2” hole to 109’ with gel-water and opened to 26” w/ reamer. Had 100% circulation. Ran and cemented 18-5/8” conductor @ 108’w/o problems.
HUDB-1 1984 4.5 km SW Drilled 24" hole to 115' with 100% circulation. The 18-5/8" conductor was run to 110' and cemented without problems.
KHRS-627 2007 26.9 km SE Drilled 22” hole from surface to 60’ w/ 64 pcf mud. Had 100% circulation. Ran and cemented 18-5/8” conductor w/o problems. Good cement to surface.
DRILLING FLUID Drill the 34” hole with 63 pcf spud mud made up of pre-hydrated bentonite flocculated with lime. Maintain funnel viscosity 60-80 while drilling. Attempt to drill with mud to CP even if returns are lost; otherwise, switch over to water and gel slip if returns are lost. Spot a Hi-Vis pill on bottom prior to running the 30" conductor.
Refer to Attached Drilling Fluids Program for specific details. MUDLOGGING:
Mud logging is required from surface to well TD.
CONDUCTOR DETAILS
Casing Type Shoe Depth
30" 0.75” wt, X-42, JV-LW
BARE [SAP# 10-000-319-62] 120'
*Note: If JV-LW is not available at the tool house, then order casing with “R” Connectors.
CEMENT REQUIREMENTS
330 Sacks Class “G” + 0.015 gps D-Air 3000 L
Slurry wt. 118 pcf
Yield 1.18
ft3/sk
Mix Water 5.0 gps
Thickening Time (EST) 2-3 hrs
• Pump 50 bbls. of fresh water ahead of the cement.
• Calculations include 100% excess in the open hole, and 30' of cement left inside the 30" conductor.
• Perform top job, as required, with Class "G" + 2% CaCl2 mixed at 118 pcf. BOP REQUIREMENTS
1. Center and brace the 30" conductor prior to cementing.
2. No BOPE is required for the next interval. None of the offset wells required BOP at this stage.
CASING/SHOE TEST
Hydro-test the 30" conductor prior to drilling out the shoe.
28” HOLE SECTION
Drill the 28" hole from +/-115’ to a depth of ± 2,130' (± 400’ into Wasia Formation). Run and cement the 24" “Bare” casing using the ISC method.
Note: The UER water level is dry and the Wasia static water level is 670’ below Rotary Table.
POTENTIAL HOLE PROBLEMS
• Total loss of circulation across the Umm Er Radhuma, and Aruma Formations.
• Possible tight hole in the Aruma shales.
• Possible bit balling due to soft clays.
Well Name
Distance DESCRIPTION
HRUR-2
2005 47.4 km NW Drilled 22” hole with 64 pcf mud to 200’ (UER), where 100% returns were lost. Pumped two LCM pills to regain circulation without success, switched to W&GS and drilled to casing point @ 2,820’ (390’ into Wasia). Ran and cemented casing without returns. Three top jobs were necessary to get cement on surface.
HRUR-1
1978 46.9 km NW Encountered 100% lost circ in UER @ 145’ while drilling 26” hole w/ spud mud. Switched to water and gel slip and continued drilling w/o returns to CP @ 2580’. Had to stop drilling and wait on water several times. While RIH 20” casing @ 1160’, the string parted. Fished OK, performed wiper trip and re-ran casing & cement without problems. Required 1 top job.
KHRS-82 1996 44.9 km SE Drilled 28” hole with 65 pcf mud to 174’, where total losses were encountered. Continued drilling to CP @ 1115’ with water and GS. Waited on water several times. Ran 24” casing to 1108’ (48’ into Wasia); however, could not stab in ISC. Cemented casing conventionally without plug. Performed 1 top job and had to place cement plug across shoe to repair leak.
KHRS-4 1958 38.4 km SE Drilled 17-1/2” hole with water to 190’, where 100% losses were encountered. Continued drilling with water and gel slip to CP @ 1033’ (214’ into Wasia). Opened hole to 24”, ran and cemented 18-5/8” casing without problems. Performed 1 top job.
KHRS-1 1957 41.9 km SE Drilled with gel water to 127’, where total losses were observed. Continued drilling with water and gel slips to CP @ 820’. Tried to run logs w/o success, as these stopped @ 340’. Ran 13-3/8” casing to 818’(16’ into Wasia) and cemented same without returns. Performed two top jobs.
HUDB-1 1984 4.5 km SW Drilled 17-1/2” hole with spud mud to 165’, where total losses were observed. Continued drilling to CP @ 1945’ w/ water and gel slip. Ran 13-3/8” casing to 1,944’ (178’ into Wasia) and cemented same without returns. Performed 1 top job.
KHRS-627 2007 26.9 km SE Drilled 16” hole with 64 pcf mud to 106’, where 100% losses were observed. Continued drilling to 1,658’ (100’ into Wasia ) with water and gel slip. Ran and cemented 13-3/8” casing without problems. Performed 1 top job.
DRILLING FLUID PROGRAM
Drill the 28" hole with 64-65 pcf spud mud utilizing mud from previous hole section. Switch to water/gel slip if returns are lost; however, switch back to spud mud to drill into the Wasia. Do not drill the Wasia with water and gel slips. Sweep the hole with hi-vis pills as required. Spot a weighted hi-vis pill on bottom prior to running the 24" casing.
If water/gel slips are used, treat water with (1) ppb lime to increase pH and reduce corrosion. The water should be treated in the tanks and not while being pumped from the suction. If drilling with water and GS, maintain 75 pcf mud cap on the backside from the top of the Wasia to CP. Spot a high vis pill on bottom prior to POH for running 24” casing.
In case circulation is maintained, add small concentration of starch to reduce fluid loss across Aruma for inhibition.
DIRECTIONAL SURVEYS
If hole conditions permit, drop a Totco Survey on bit trips and prior to POH at the 24" casing point.
CASING DETAILS
Casing Type Shoe Depth
24" 176#, X-42, RL-4S
BARE [SAP# 10-000-319-18] ± 2,130'
( 400' into Wasia Formation)
1. Rig up and run 24” casing as follows:
Quantity Length Description SAP #
1 ea. 3’ 24" Weatherford Float Shoe (welded) 10-000-259-91
1 jt. 40' 24" 176# X-42, RL-4S BARE casing 10-000-319-18
1 ea. 3’ 24" Weatherford Float Collar (w/ISC) 10-000-228-85
53 jts. +2,090' 24" 176# X-42 RL-4S BARE casing 10-000-319-18
• Use Weatherford DP Latch-Down Plug to displace the cement.
• Ensure the appropriate stab-in stinger is used in conjunction with the supplied float collar along with the DP latch-in plug (stab-in stingers are supplied on a rental basis by Weatherford).
2. Make-up torque is 26,000 ft-lbs for RL-4S and 1/4 turn connection.
3. Install 24" cement baskets [SAP# 10-000-225-86] with stop collars [SAP# 10-000-228-13] as follows,
-One at 40' above the LC zone, -One at 80' above the LC zone. -One at 60' above the 30" casing shoe. Consider loading the baskets with a mixture of wet Bentonite paste and dry CaCl2 to accelerate the cement TT. Note: Adjust the basket positions, as required, based on losses. Total = 3 baskets. Centralize [SAP# 10-000-226-62] every joint for the first 5 joints and then every 3rd joint back to surface. Place additional centralizers above and below the baskets. Total = ± 26. Use stop collars [SAP# 10-000-228-13] and install in the middle of each joint. Total = ± 52.
CEMENT PROGRAM
• Circulate the casing capacity and reciprocate the casing string.
• Record PU and SO hook loads.
• Position the casing @ neutral string weight for cementing.
• Pump 50 bbls of fresh water ahead of the Lead Slurry.
If full circulation is maintained while drilling, cement with:
Lead –
1900 Sx Class "G" + 6.6 ppb pre-hydrated Bentonite + 0.03 gps D-Air 3000L
Slurry wt. 101 pcf
Yield 1.69 ft3/sk
Mix Water 8.96 gps
BHCT/BHST (Est) 105/95 0F
Thickening Time 6-7 Hrs
Tail –
1000 Sx Class "G" + 0.015 gps D-Air 3000L
Slurry wt. 118 pcf
Yield 1.15
ft3/sk
Mix Water 5.0 gps
BHCT/BHST (EST) 105/95 0F
Thickening Time 4 Hrs.
NOTE:
• Cement calculations assume 75% excess in the open hole, 10% excess in cased hole, 50' of cement left inside the 24" casing and 500’ rise of tail cement in the open hole.
• If circulation is lost during drilling, cement with:
LEAD: 101 pcf slurry, as above, to bring TOC to point of LC w/ 50% OH excess.
TAIL: 1000 Sx Class "G" Neat, mixed to 118 pcf.
• The actual thickening time will be decided prior to any pilot test in agreement with the foreman and drilling engineer.
Inner String Cementer (ISC) Procedure
a. If LC, note static fluid level when POH to run 24" casing. Adjust the maximum DPCP based on this fluid level.
b. Cut and remove flowline. Rough cut the 30" casing at 11.5' (138") BGL and LD before running the 24" casing.
c. With casing on bottom, center and brace the 24" casing with wedges/shims in the 30" casing. Cut off any excess casing stick-up, as required.
d. Double elevator in hole to FC with ISC drill pipe adaptor.
e. Fill DP/csg annulus with 90-pcf mud and ensure level holds. Sting into FC,
f. Establish circulation down DP with water and note pressure at 5-7 BPM.
g. Begin pumping lead slurry and note pressure at 5-7 BPM.
h. Mix and pump tail if lead slurry returns are noted early
i. Watch for indications of bridging while pumping cement. Be prepared to abort job and allow cement to U-tube, -if hole starts bridging off.
j. DO NOT EXCEED 470 psi DP circulating pressure while pumping and displacing tail cement. (Formula: (0.80 X Csg. Collapse Resistance) - ((Cement Wt. – Mud Wt.)/144 X Depth))
Example: (0.80 X 1110) - ((118-90)/144 X 2130)) = 473 psi.
k. Always displace inner string cement job using pumping unit.
l. Be prepared to abort job and allow cement to U-tube if hole starts bridging off during the job i.e. in case there is a doubt between plug bumping and bridging, consider it as bridging and abort the job immediately.
m. Pump 5 bbl cement on top of the WFD DP Latch-Down Plug and displace same with mud. Bump dart @ 1 BPM to ensure it has momentum to pass through the stinger and latch into the float collar. Apply 1000 psi over the final circulating/pumping pressure.
n. Bleed off pressure to check that float equipment is holding.
o. Pressure up on the drill pipe between 750 and 800 psi. Slowly pull the ISC stinger out of the shoe while maintaining this pressure on the drill pipe. (This is to ensure that the ISC dart stays in place as the stinger is removed ).
p. Sting out leaving 10-bbl of cement (± 12’) above the FS. Pick up and clear DP. POH with DP and LD ISC.
q. Perform top job(s), as required, with Class "G" + 2% CaCl2 at 118 pcf.
WELLHEAD and BOP REQUIREMENTS
1. Rough cut the 24" casing at ±10' (120") BGL. Measure and final cut the 30" casing stub at 12' (144") BGL. Dress the 30” casing stub.
Note: Check the actual height measurements of 24” sow casing head & socket.
2. Fill 24" x 30" annulus void with cement level to the top of the 30" final cut line. The level and cured cement pad, along with the 30" stub will provide the support for the lower 1" thick x 40" O.D. base plate.
3. Install the Casing Head Support Unit around the 24" casing and set it on the 30" stub. Check the CHSU to insure it is setting level on the 30" stub. If required, lift the CHSU and dress the 30" casing stub level. Re-install the CHSU and check the top plate for a level fit.
4. Measure the required stick-up of the 24" casing stub inside the 24" SOW casing head to the beveled ‘NO-GO’ shoulder (4") and add 1/8".
*NOTE: MEASUREMENTS VARY AMONG MANUFACTURERS. HAVE A CAMERON OR GRAY REPRESENTATIVE
ASSIST AND VERIFY ALL MEASUREMENTS TO BE MADE. Example: THE CHSU HEIGHT IS 10" + THE REQUIRED 24" STICK-UP OF (4-3/8") + 1/8" = 14-1/2".
THEREFORE, THE FINAL CUT FOR THE 24" IS DETERMINED TO BE AT (144-14-1/2 = 1291/2")
BELOW GL. IT SHOULD ALSO BE 4-1/2" ABOVE THE TOP PLATE OF THE CHSU.
5. Mark and make the 24" final cut and grind “level”, as required.
6. If available, use HOT HED installation services to cut the 24” casing, weld and pressure test the 24” SOW CH.
7. Install 24" SOW casing head on the 24" stub. Check fit and level the head. Tack weld into position.
8. With grinder, cut out the gusset member tacks and remove the gussets (6). Lower the top plate down.
9. Pre-heat and weld the 24" CIW SOW x 26-3/4" 3M casing head. Follow procedures outlined in DMD Welding Procedure WRS-602 [7 May, 1996]. After cool down, PT the weld using water to 880 psi [80% of 24" collapse pressure]. (Refer to the attached wellhead sketch).
Note: If the HOT HED N2 pressure test is applied, cooling down prior to testing is NOT required.
10. Raise the 1" thick x 35" O.D. top plate up directly under the casing head. Insert and weld into place six (6) x 2" thick support gussets and three (3) anti-sway stiffeners to complete the gusseted landing base support system which is designed to distribute future casing loads back to 30" conductor pad. Do not weld the 24" casing head to the gusset support system.
11. Install (2) 3" -3M gate valves on casing head outlets.
12. NU the 26-3/4" -3M Class 'A' BOP Stack.
13. Pressure test as per Aramco Requirements.
CASING/SHOE TEST
Pressure test the casing to 500 psi with water prior to drilling out the 24” FC & FS.
22” HOLE SECTION
Drill 22” hole from +/- 2,130’ to 5,203’ ( 100’ into the Hith formation). Circulate hole clean, Drop survey. POH and Run the open hole logs. Run and cement the 18-5/8" casing.
NOTES:
1. Ensure all solids control equipment is in good operating condition prior to drilling the 24” shoe.
1. Attempt to maintain MW as low as possible while drilling the Wasia and Shu’aiba. Dump sand trap regularly. Circulate bottoms up prior to drilling into Shu’aiba and pre-treat with LCM.
POTENTIAL HOLE PROBLEMS
1. Possible loss of circulation in the Wasia and Shu’aiba Formation, though seen severe only in one of the offset wells.
2. Possible tight spots across Biyadh and Buwaib formations.
3. Excessive string vibrations that could lead to drillstring failure as seen in HRUR-1.
4. Possible occurrence of pyrite as seen in KHRS-82. Monitor drilling parameters to avoid losing bit cones.
Well Name
Distance DESCRIPTION
HRUR-2
2005 47.4 km NW Started 22” hole section w/ 65 pcf mud and reached casing point with 67 pcf and 100% circulation. Tight hole observed from 4,070’ to 4,963’. Ran casing freely to CP @ 6,165’ (110’ into Hith ) and cemented same w/o problems. Required 3 top jobs.
HRUR-1
1978 46.9 km NW Experienced lost circulation while drilling 17-1/2” hole from shoe at 2,580’ to 2,780’, then losses healed and had 100% circulation through out to CP. Observed excessive vibrations from 5,316’. Drill string twisted off @ 5,316’, 5,480’ and 5,548’. Ran 13-3/8” casing freely to bottom and cemented in place. No cement above DV and none to surface.
KHRS-82 1996 44.9 km SE Started 22” hole section with 59 pcf (20/80 OWR ) emulsion mud. Observed 80% losses from 1,320’ to 1,496’. Control drilled w/ reduced pump rate to 1,572’, losses healed and continued drilling to CP @ 4205’ w/ 98% to 100% circulation. Excessive torque seen @ 2,364’ ( Biyadh) caused the bit to lose 3 cones in the hole. Pyrite samples were observed in the lower part of Biyadh. Ran 18-5/8” casing to 4,195’ (56’ into Hith) and cemented casing without problems. Did not see cement above DV and had good cement returns to surface on second stage.
KHRS-4 1958 38.4 km SE Started 17-1/2” hole section with 64 pcf mud. Weight drifted to 74 pcf at 2,582’, but was cut down and CP was reached w/ 64 pcf. The drillstring twisted off while drilling @ 2,650’ (Buwaib formation). Ran 13-3/8” casing to 2,781’ ( 157’ into Buwaib ) and cemented same without problems.
KHRS-1 1957 41.9 km SE Drilled with 74 pcf mud to 1,555’ ( Top of Shu’aiba ), where total losses were observed. Tried to cure losses with several cement plugs, LCM pills, bentonite-diesel plugs, etc w/o success. Continued drilling with aerated mud. ( 66 pcf mud + injecting 10 – 25 cu/ft air/bbl to give +/-56 pcf). Drilled to 3,575’ and string became stuck. Recovered all the fish by alternating several times - backing off string, washing over and fishing. Ran 9-5/8” casing to 3,565’ (185’ above the Hith ) and cemented same with partial returns. Performed one top job.
HUDB-1 1984 4.5 km SW Drilled 12-1/4” hole section with 59 pcf water based mud / oil emulsion ( 40/60 OWR ). Ran and cemented casing w/o problems. Did not observe cement above DV and observed good cement returns on second stage.
KHRS-627 2007 26.9 km SE Drilled 12-1/4” section with 58 pcf water based mud / oil emulsion ( 45/55 OWR ) to 3,653’ (100’ into Buwaib). Observed 100% circ. Ran 9-5/8” casing and cemented same. Lost returns while displacing first stage, did not observe cement above DV, observed good cement returns on second stage.
DRILLING FLUID
Use the mud left from the previous section and maintain mud density at 58 pcf. Circulate bottoms up before entering Wasia, Shu’aiba and Biyadh. Pre-treat mud with 5-10 lb/bbl sized CaCO3 medium & coarse along with 5-10 lb/bbl mica prior to drilling potential loss circulation zones (Wasia, Shu’aiba). Attempt to maintain circulation while drilling these formations. Use all solids control equipment, dump sand traps and maintain proper mud weight.
Loss of circulation and water flow may be encountered while drilling this section. Drilling may continue applying the following:
• Sweep the hole prior to making connections with 25 - 50 bbls high viscosity mud.
• Drill with weighted spud mud with controlled filtration (Filtrate, cc /30min, API = 8) by adding starch @ 1-2 lbs/bbl especially when drilling thru Biyadh Formation.
Refer to the Drilling Fluid Program Attachment for recommended mud properties and formulation.
If loss circulation is encountered in the Wasia, raise viscosity to 100 cp and continue drilling 100’ - 200’, cuttings may help seal off the loss zone, attempt to regain circulation with 2 – LCM pills each 600 bbl and with LCM material concentration of 140 ppb. If attempts to regain circulation have failed, continue drilling ahead with mud and 80 – 85 pcf mud cap to the specified casing point. Add mud to the backside at regular intervals to keep the floating mud cap across the sensitive Wasia sand-shale section. Do Not Drill the Wasia with brine or water.
If loss circulation occurs while drilling the Shu'aiba, drill ahead a short distance with mud, to allow cuttings to help seal off the loss zone. Attempt to regain circulation with LCM pills (mica fine + coarse and ground marble medium). In event of massive LC, where attempts to regain circulation with LCM appear futile, drill ahead with water/gel sweeps using 80 - 85-pcf mud cap (with 2-4 lbs/bbl Soltex added) to protect the interbedded shales and sands, in the Wasia, from becoming water wet and sloughing. Add mud cap to the backside at regular intervals to keep the floating mud cap across the sensitive Wasia sand-shale section. It is important to attempt to maintain full returns through this section, if possible.
NOTES
a. Use all available mud cleaning equipment to minimize solids loading in the annulus.
b. Trip slowly through the Wasia sands to prevent excessive swab/surge pressures.
c. Prior to penetrating Shu’aiba, reduce flow rate to minimize ECD. Have LCM ready in the slug pit. Continue adding LCM through the hopper at the suction pit while drilling Shu'aiba.
d. Monitor mud weight-in and mud weight-out continuously while drilling.
e. Circulate hole clean and spot a hi-vis pill on bottom and treat the mud as per CasingGo recommendations in the appendix prior to POH for running the 18-5/8" casing.
DIRECTIONAL SURVEYS
If hole conditions permit, drop a TOTCO survey prior to POH on bits trip and at the 18-5/8" casing point.
CASING AND CEMENTING DETAILS
CASING TYPE SHOE DEPTH DV DEPTH
18-5/8" 115#, K-55, BTC
BARE - (SAP# 10-000-319-15) ± 5,203
(± 100' into Hith Formation) ± 1,830'
(± 300' above 24" shoe)
1. Prior to running the casing (and all subsequent strings), verify the following:
a) Threads cleaned and visually inspected.
b) Run full-length API drift.
c) Visually inspect tubes for damage.
2. The running order is as follows:
Quantity Length Description SAP#
1 ea. 2’ 18-5/8" Float Shoe, BTC 10-000-259-19
1 jt. 40' 18-5/8" 115#, K-55, BTC, BARE casing 10-000-319-15
1 ea. 2’ 18-5/8" Float Collar, BTC 10-000-228-83
2 jt. 80' 18-5/8" 115#, K-55, BTC, BARE casing 10-000-319-15
1 ea. 2’ 18-5/8" Shut-Off Baffle
± 81 jts 3,247' 18-5/8" 115#, K-55, BTC, BARE casing 10-000-319-15
1 ea. 10' 18-5/8" DV @ ± 2355'
± 46 jts 1,820' 18-5/8" 115#, K-55, BTC bare casing 10-000-319-15
3. Centralize the first five joints, then every 3rd joint to surface, and across the DV. Use stop collars and install centralizers in the middle of the joint. Total = 45centralizers [SAP# 10-000-226-61] and ± 90 stop collars [SAP# 10-000-228-12]
4. Make up each joint to the base of the triangle.
5. It is recommended that high pressure modified thread compound, as specified in API 5A2 be used.
6. If tight hole is experienced while running casing, pull (2) jts, above last free casing, before picking up cement head.
CEMENT PROGRAM - Circulate the casing capacity and reciprocate the casing string. - Record the casing PU and SO hook loads. - Position the casing @ neutral string weight for cementing.
- Pump 100-bbls of fresh water ahead of the First Stage cement slurry.
- Mix and Pump the 1st Stage slurry –
1st STAGE
Lead
2100 Sx Class G + 6.6 ppb Bentonite + 0.03 gps D-Air 3000L + 0.75% Halad-22A + 0.15% CFR-3
Slurry wt. 101 Pcf
Yield 1.69
ft3/sk
Mix Water 8.96 Gps
BHST /BHCT (est.) 142/109 F
Thickening Time 7:00 Hrs
Tail
750 Sx Class G + 0.015 gps D-Air-3000L + 0.50% Halad-22A + 0.45% CFR-3
Slurry wt. 118 Pcf
Yield 1.15
ft3/sk
Mix Water 5.0 Gps
BHST (est.) 142/109 F
Thickening Time 6:00 Hrs:Min.
NOTES
a. Calculations include 50% OH excess, 500’ rise of tail cement, 300' rise above DV, 125' shoe track, and 10-bbls cement behind plug.
b. Cement additives will be revised, if required, after lab testing.
c. The actual thickening time will be decided prior to any pilot test in agreement with the foreman and drilling engineer.
d. Kick off the shut-off plug with + 10-bbls cement and displace with mud.
e. Monitor & record cement volume returns.
f. If lost circulation is encountered, cement with: LEAD 101 pcf slurry, as above, to bring TOC to above LC zone Tailed by 750 Sx at 118 pcf slurry as above.
g. Drop free fall bomb, inflate DV and open ports. Continue circulating at a reduced rate above the DV. Monitor and record quantity and quality of cement returns, if any.
h. Continue circulating above the DV and WOC to allow the First Stage cement to set before raising the BOP stack to set the slips.
i. Monitor cement samples and the fluid level. Center the 18-5/8" casing Raise BOP stack.
j. Install the 18-5/8” casing slips and land casing (record landing weight, excluding the blocks). Re-set the BOP stack.
k. If DV fails to inflate properly, circulate annular capacity. WOC 4-6 hrs. Continue with 2nd/ Stage.
l. The DV should be inflated slowly, 2-3, BPM to ensure bladder inflates properly.
2nd STAGE (18-5/8" DV @ 1,830') Pump 50-bbls of fresh water ahead of the 2nd Stage cement slurry:
Lead
800 Sx Class G +6.6 ppb pre-hydrated Bentonite + 0.03 gps D-Air-3000L
Slurry wt. 101 Pcf
Yield 1.69
ft3/sk
Mix Water 8.96 Gps
BHST/BHCT 102/95 °F
Thickening Time 5 Hrs
Tail
500 Sx Class G + 0.015 gps D-Air-3000L
Slurry wt. 118 Pcf
Yield 1.15
ft3/sk
Mix Water 5.0 Gps
BHST/BHCT 102/95 °F
Thickening Time 4-5 Hrs
• Cement calculations include 10% excess in cased hole and 500’ of tail slurry.
• Kick off the DV Closing Plug with 10-bbls cement.
• Bump Plug and close DV sleeve.
BOP REQUIREMENTS
1. Lift the BOP stack and rough cut 18 5/8” casing.
2. Final cut and dress the 18 5/8" casing stub.
3. Install a 26 ¾” 3M X 26 ¾” 3M DSDPO (for 18 5/8" casing).
4. Energize and test lower cavity to 853 psi (80% of collapse resistance reduced for slip crushing force and biaxial tension assuming a hook load of 576840 lbf ) or as prescribed by wellhead representative.
5. Pressure Test between the DSDPO seals to 1200 psi (80% casing collapse).
6. Install a 26 ¾” 3M x 20 ¾” 3M Casing Spool and install (2 ea.) 3", 3M Gate Valves on side outlets.
7. Energize the casing head secondary seal and test between this seal and DSDPO top seal to 1200 psi (80% of collapse resistance).
8. Install a 20 ¾” 3M x 26 ¾” 3M DSA.
9. NU the 26 ¾”, 3M Class 'A' BOP Stack., remove the 30” annular and install a 21-1/4” 2M one.
10. Test BOPE as per Saudi Aramco requirements.
CASING/SHOE TEST
1. Clean out cement and DV. RIH to TOC.
2. Clean out cement to 20’ above the shoe and pressure test casing to 1500 psi with water.
16" HOLE SECTION
Drill 16” hole from 5,203’ to ± 12,276’ (± 30’ into Base Jilh Dolomite). Perform Gyro survey, run open hole logs. Run and cement the 13-3/8" casing. First run with mill tooth bit and junk subs to clean out, followed by PDC bit and 12-3/4” motor. Note: A 60’ core will be cut across the Arab D if hydrocarbon shows are encountered.
POTENTIAL HOLE PROBLEMS
Possible loss of circulation or HC flow in the Arab D.
H2S may be encountered in the Arabs, ensure all monitors are functioning properly.
Well Name
Distance DESCRIPTION
HRUR-2
2005 47.4 km NW Started 16” hole section with 68 pcf mud. Had the following mud weights as the section was drilled: 74 pcf @ 13,584’, 80 pcf @ 14,171’, and reached CP w/ 100% circ. @ 14,385’ ( 15’ above Base Jilh Dolomite) with 88 pcf. The mud weight increases due to tight hole. Had two stuck pipe incidents at 14,171’ and 14,184’ ( 45-60’ above Jilh Dolomite ). Logged well w/ 90 pcf and ran 13-3/8” casing w/ 95 pcf. Cemented casing w/o problems. Little cement above DV and plenty at surface from second stage.
HRUR-1
1978 46.9 km NW Drilled 12-1/4” hole with 66-73 pcf mud. Increase in MW was due to tight hole. Maintained 100% circ thru-out to CP @ 13,575’. String twisted off while drilling @ 6,833’ and 9,344’. Core bbl broke @ 9,056’ while RIH. Ran 9-5/8” casing to bottom w/o problem. Cemented string having no cement above DV and plenty to surface after second stage.
KHRS-82 1996 44.9 km SE Started 17-1/2” hole section with 62 pcf mud. Had following MWs throughout section: 66 pcf @ 5,667’, 72 pcf @ 10,000’, 80 pcf @ 10,055’ and reached CP @ 10,155’ ( 44’ into Jilh ) with 82 pcf. Ran 13-3/8” casing and cemented same w/o problems. Contaminated cement above DV, and good cement returns of second stage.
KHRS-4 1958 38.4 km SE Started section w/ 64 pcf. While drilling with 72 pcf @ 6,450’ experienced 20-25 BPH losses, cut MW to 63 pcf using bentonite – crude oil emulsion. Regained 100% circ by 6,500’. Cont drilling to CP w/ following MWs: 70 pcf @ 7,362’, 73 pcf @ 9,611’, and reached CP @ 10,245’ ( 17’ into BJD ) w/ 74 pcf. Ran 9-5/8” casing and cemented same without problems.
KHRS-1 1957 41.9 km SE Started 8-5/8” hole section w/ 67.5 pcf mud. Reached CP with 73 pcf @ 9,524’. Had 100% circ throughout entire interval, except 6bpd losses observed @ 4,335’, which healed by 4,600’. Ran 7” casing to 9,520 ( 215’ above Jilh ) and cemented same without problems.
HUDB-1 1984 4.5 km SW Started drilling w/ 64 pcf mud. Cut cores @ 6,215’ and 6,253’, drilled ahead with 66 pcf mud, experienced differentially stuck pipe @ 6,445’, displaced hole to water and freed pipe, continued drilling ahead w/ 64 pcf mud ( w/ 10% diesel in mud ) to TD @ 8,402’ ( 87’ below Base Lower Jilh Reservoir. Logged open hole and P & A same.
DRILLING FLUID Drill this section with the same mud used in the previous section, have the density at 64 pcf LSND mud. Increase the mud weight as hole conditions dictate. As indicated from the offset wells, mud weight may go up to 72-74 pcf.
• Flow-check the well at each potential reservoir.
• Use the finest shaker screens available and all solids removal equipment to remove drill solids in order to optimize drilling performance.
• Prior to POH for casing, pump hi-visc sweep and circulate the hole capacity and treat the mud as per the CasingGo formulation in the drilling fluids attachment.
Refer to the Drilling Fluid Attachment for recommended mud properties and formulation.
CORING PROGRAM
If hydrocarbon shows are encountered in the Arab D Reservoir, cut a 60’ core conventionally. Coring should continue until the base of the reservoir or hydrocarbon zone is penetrated. Note that a geologist should be on site to pick the coring point(s).
DIRECTIONAL SURVEYS
If hole condition permits, drop TOTCO survey prior to POH each bit trip and at the 13-3/8” casing point.
LOGGING PROGRAM (Schlumberger):
Run the following open hole logs from 13-3/8” Casing point to 100ft above the Arab-D Reservoir:
Run 1: AIT-Sonic
Continue with Sonic-GR-PPC to surface 100ft above the 24” casing shoe.
Run 2: TLD-MCFL-CNL-GR-PPC(short axis kit for density)
Run 3: FMI
Run 4: ECS-CMR
Run 5: MDT on standby
NOTE: Report the maximum - BHT for each run with the elapsed time (ΔT) after circulation, from the open-hole logs.
CASING AND CEMENTING DETAILS
SIZE
WT
GRADE
THREAD MAKE-UP TORQUE (FT-LBS)
MINIMUM OPTIMUM MAXIMUM
13-3/8” 86 # VM-95 HC VAM TOP 20850 23150 25450
13-3/8” 72# VM-95HC VAM TOP 20850 23150 25450
Casing Type Interval DV
13-3/8” 86#, VM-95 HC, VAM TOP
12,276’ - 8500’ ±4,903’
(±300’ ABOVE 18-5/8” CSG SHOE)
72#, VM-95 HC, VAM TOP
8,500 - 4,903’
72#, VM-95 HC, VAM TOP
4,903’ - 400’
86#, VM-95 HC, VAM TOP 400’ - 0’
Use all bare casing.
Note: If mud weight exceeds 85 pcf, consider using displacement type DV plug set.
RUNNING DETAILS
The running order is as follows –
Quantity Length Description SAP#
1 ea. 2’ 13-3/8" Float Shoe 10-006-248-31
2 jts. 80' 13-3/8" 86#, VM95HC, Vam Top casing
1 ea. 2’ 13-3/8" Float Collar 10-006-248-15
2 jts. 80' 13-3/8" 86#, VM95HC, Vam Top casing
1 ea. 2’ 13-3/8" Shut-off Baffle
± 90 jts. ± 3,610' 13-3/8" 86#, VM95HC, Vam Top casing
± 90 jts. ± 3,587' 13-3/8" 72#, VM95HC, Vam Top casing 10-005-896-48
1 ea. 10’ 13-3/8" DV @ ± 4719’ (± 300’ above 18-5/8” casing shoe) with Free-fall type Plug Set 10-000-248-90
± 108 jts. 4,503’ 444444444444444444,503’ c444,503’ 13-3/8" 72#, VM95HC, Vam Top casing 10-005-896-48
± 10 jts ± 400’ 13-3/8" 86#, VM95HC, Vam Top casing
NOTE: Use all BARE casing from CP to surface.
1. * Check the availability of this casing with Vam Top connection. If this casing is available with NK3SB connection, appropriate crossover joints are required.
2. Centralize (SAP# 10-000-226-60) the first five joints, then every 3rd joint to surface, and across the DV. Total = ± 97. Use stop collars (SAP# 10-000-228-11) and install centralizers in the middle of the joint. Total = ± 194.
3. Use cleaning solvent (DO NOT use diesel oil) when cleaning premium threads. Wipe out and blow out excess solvents from the thread roots. A thin even coat of API Modified Thread Compound (API 5A3) should be applied on BOTH the premium casing coupling and pin connections with a nylon brush (DO NOT use wire brush). Thread compounds that contain Teflon should not be used. A stabbing guide should also be used when running premium connections.
4. Depending upon the final MW used during drilling, a 3-stage cementation job may be required. A detailed program for this cement job will be conveyed later.
5. Make-up Torque Values if Vam Top casing is not available:
Size/ Wt. Casing Grade Connection Minimum Optimum Maximum
(ft-lbs) (ft-lbs) (ft-lbs)
13-3/8”, 72# NKHC95 NK-3SB 16,000 20,000 24,000
CEMENT REQUIREMENTS
- Reciprocate the casing string while circulating casing capacity.
- Record PU and SO hook loads.
- Position the casing @ neutral string weight for cementing.
- Pump 75 bbls of Aramco Spacer ahead of 1st stage cement slurry. Spacer weight will be decided afterwards depending on actual mud weight used.
1st STAGE
3400 Sx Class G + 35% SSA-1 + 0.015 gps D-Air-3000L + 0.75% Halad-22A + 0.75% CFR-3 + 0.85% HR-5
Slurry wt. 118 Pcf
Yield 1.52 ft3/sk
Fresh Water 6.2 Gps
BHST /BHCT(est.) 2228/178 °F
Thickening Time 10:00 Hrs
NOTE
• Calculations include 50% excess in OH, 10% excess inside casing, 300' rise above DV, 10 bbls behind the plug and 165' shoe track.
• Actual cement volume will be determined based on open hole caliper log.
• Cement additives may be revised after final confirmation testing.
• The actual thickening time will be decided prior to any pilot test in agreement with the foreman and drilling engineer.
• Add Biocide to the mix water prior to mixing chemicals and at regular intervals.
• Kick off the shut-off plug with 10 bbl cement and displace with mud.
• Drop free fall bomb. Inflate DV and open ports.
• Circulate out casing annular volume above DV.
• Monitor and record cement volume returns. WOC and monitor surface samples while circulating at a reduced rate.
• Center 13-3/8" casing and lift the BOP stack. Install 13-3/8" slips and land the casing. Set “full” string weight on slips. Record weight.
2nd STAGE (13-3/8" DV @ 4,903')
Pump 75 bbls of fresh water spacer ahead of the 2nd Stage slurry -
2450 Sx Class G + 35% SSA-1 + 0.015 gps D-Air-3000L + 0.25% CFR-3 + 0.55% HR-4
Slurry wt. 118 Pcf
Yield 1.52
ft3/sk
Fresh Water 6.20 Gps
BHST/BHCT (est.) 140/107 °F
Thickening Time 6 Hrs
Add biocide prior to mixing the chemicals.
• Calculation includes 10% excess in cased hole.
• Cement additives may be revised after final confirmation testing.
• Kick off the Closing Plug with 10-bbls of cement. Displace with mud and close the DV sleeve.
BOP REQUIREMENTS
1. Lift the BOP stack and rough cut 13 3/8” casing.
2. ND the 26-3/4" BOP stack and the 20 ¾” 3M x 26 ¾” 3M DSA.
3. Final cut and dress the 13-3/8" casing stub.
4. Install a 20-3/4" 3M x 16-3/4" 5M DSDPO (for 13 3/8” casing).
5. Energize the seal and test the void between DSDPO and 13 3/8” slips/seal to 3,000 psi (test pressure reduced for slip crushing force and biaxial tension assuming a hook load of 942,336 lbf ) or limited to flange rating as prescribed by wellhead representative.
6. Install the 16-3/4" 5M x 13-5/8" 10M Casing Spool and install (2 ea.) 3", 10M Gate Valves on side outlets. Energize and test the void between the DSDPO top seal and casing spool secondary seal to 5,000 psi (80% casing collapse or limited by flange rating).
7. N/U a 13-5/8” - 10M Class A BOP stack.
8. Test BOPE as per Saudi Aramco requirements.
CASING/SHOE TEST
1. RIH Tricone (Mill Tooth) bit and clean out cement and DV. RIH to TOC.
2. Clean out cement to 20’ above the shoe, circulate hole clean.
3. Displace wellbore to 100 pcf mud and condition same to balance mud wt in & out.
4. Pressure test casing to EMW 150 pcf (4,300 psi surface applied pressure with 100 pcf mud).
5. Continue drilling out shoe track + 10’ of new formation.
6. Test the formation integrity with mud to 150 pcf EMW (4,300 psi surface applied pressure with 100 pcf mud) or to leak-off.
7. Drill ahead 12” hole until bit quits or ROP drops below 30 fph. POH for PDC and motor.
Note: The possibility of drilling out with PDC bit will be evaluated.
12" HOLE SECTION
Drill 12” hole to the casing point @ 16,097’ ( 450’ into Khuff D Anhydrite Formation). Run open-hole logs. Run and cement the 9-5/8" casing. As it can be seen from offset wells, there is a high possibility of encountering high pressure in the lower Jilh; therefore, if this happens, the contingency plan is to set the 9 5/8” casing ± 15’ into the Khuff formation. In case the contingency plan occurs, a supplement will be issued describing the required changes to the program. Note: A 120’ core will be cut across the Lower Jilh Dolomite Reservoir or 60’ cores will be cut across the Lower Sudair Dolomite, Khuff B or Khuff C reservoirs if hydrocarbon shows are encountered.
POTENTIAL HOLE PROBLEMS
• Possible high pressure and gas and/or salt water flow from the Jilh. The offset wells KHRS-1 and HRUR-2 HRUR-2 required 150 and 125 pcf MW respectively, to control flow from the lower Jilh.
• Possible hole instability across the Sudair shales.
• Probable Possible flow (H2S / CO2) and loss of circulation in the Khuff Reservoirs.
• Possible differential sticking due to high overbalance across the Khuff if high pressure Jilh is encountered.
Well Name
Distance DESCRIPTION
HRUR-2
2005 47.4 km NW Started drilling 12” section with 110 pcf mud. While drilling @ 16,000’, encountered abnormal pressures across the lower Jilh. The well flowed gas and salt water. Controlled well with 125 pcf and continued drilling to CP with 125 pcf mud. Ran 9-5/8” csg to 17,432’ (8’ above Khuff formation) and cemented same without problems.
HRUR-1
1978 46.9 km NW Drilled 8-3/8” hole. No Jilh flow. Severe hole stability problems. Pipe stuck @ 14,165’ (freed ok) and the at 14,170’, where sidetrack was necessary. In both cases the string torqued up while drilling w/ 90 pcf mud and consequently became stuck. Tight hole on trip out for bit f/ 14,580’ – 14,575’. Increased MW to 100 pcf and drilled ahead ok to 15,125’, where it was decided to change to Invermul OBM to combat salt stringers. POH to shoe while mix Invermul mud. RIH to 14,580’, ream to 14,629’. Observed lots of cuttings and filter cake over shakers. String torqued up while reaming. Unable to free string. Backed off and attempted to sidetrack. Made four attempts to sidetrack, no success, kick off assembly would follow old hole. Abandoned well.
KHRS-82 1996 44.9 km SE Drilled out with 85.5 pcf mud. Continued drilling 12” hole increasing MW as follows: 95 pcf @ 10,208’, 109 pcf @ 10,502’, 140 pcf @ 10,799’. Observed 10 bph losses, gradually decreased MW to 100 pcf @ 11,790’. Continued drilling w/ 100 pcf to CP @ 13,965’ ( 384’ into Khuff D Anhydrite ). Did not see overpressures across Jilh. Ran 9-5/8” casing to 13,960’ and cement without problems.
KHRS-4 1958 38.4 km SE Drilled out with 70 pcf. Displaced to 155 pcf @ 10,350’ and lost complete returns @ 10,964’. Set packer 23’ above shoe and squeezed cement RIH, cleaned out cement, adjusted MW to 145 pcf and continued drilling reducing MW to 140 pcf. Reached CP @ 11,530’ (85’ above Khuff) with 140 pcf. Ran 7” casing and cemented same w/o problems.
KHRS-1 1957 41.9 km SE Started 6” hole with 88 pcf mud. Raised MW to 90 pcf. Observed salt contamination in mud @ 10,440 and 10,552 and while drilling @ 10,621’ observed well flowing. Was able to bridge off flow by squeezing pills of heavy mud ( 120 to 150 pcf ). Performed bit trip cleaned bridges on way in and well began flowing again. Tried to kill well by pumping heavy through annulus w/o success. Attempted to reverse circulate heavy mud, took 43 bbl gain. Shut in well and recorded 3000 psi on DP and 1500 psi on annulus. Finally was able to kill flow by circulating 150 pcf mud. P & A well.
DRILLING FLUID
Refer to the Drilling Fluid Attachment for recommended mud properties and formulation.
Drill out of the 13-3/8” casing shoe with 100 pcf mud. Mud from the previous 16" hole section can be used for make-up. Add KCl to the mud maintaining at least 7% in the system prior to penetrating the Sudair formation. Also 2 ppb of Soltex should be added and maintained in the mud system prior to penetrating the Sudair to improve the filter cake and reduce filtration loss.
If mechanical hole instability becomes a problem, increase mud wt as required to stabilize the wellbore.
Prior to POH for logging, treat the mud as per the recommendations in the drilling fluids attachment
Refer to the Drilling Fluid Attachment for recommended mud properties and formulation.
CORING PROGRAM
If hydrocarbon shows are encountered in the Lower Jilh Dolomite , Lower Sudair Dolomite, Khuff B or Khuff C Reservoirs, cut a 120’ core conventionally on the first and 60’ on the latter. Coring should continue until the base of the reservoirs or hydrocarbon zones are penetrated. Note that a geologist should be on site to pick the coring point(s).
DIRECTIONAL SURVEY
1. If hole conditions permit, drop Totco Survey prior to POH for bit trips.
2. At 9-5/8” casing point, drop Gyro Multi-Shot and survey at 100' stations while POH from 9-5/8” casing point to surface. If gyro cannot be run before running pipe, run gyro inside casing prior to drilling out 9-5/8" float shoe.
LOGGING PROGRAM (Schlumberger)
Run the following borehole logs to 100 feet above the 13 3/8-inch casing shoe:
Run 1: AIT-Sonic
Run 2: TLD-MCFL-CNL-GR-PPC(short axis kit for density)
Run 3: FMI
Run 4: ECS-CMR
Run 5: MDT on standby
NOTE: Report the maximum - BHT for each run with the elapsed time (ΔT) after circulation, from the open-hole logs.
After completing logging operations, carry out wiper trip and properly circulate hole clean and condition the mud as per the CasingGo recommendations (see drilling fluids attachment). Ensure hole is in good condition before POH to run casing.
CASING AND CEMENT DETAILS
Casing Type Depth Length DV
9-5/8” 58.4#, NKHC110, NK-3SB 16,097’- 11,976’
and 400 -Surface 4,121’
400’ +11,976’
(±300’ above
13-3/8” csg. shoe)
53.5#, NKAC-95ST, NK-3SB 11,976’ – 400’ 11,576’
1. Running order as follows:
QTY Length Description SAP#
1 ea. 2’ 9-5/8" 58.4# Float Shoe, NK-3SB 10-000-259-12
2 jts. 80' 9-5/8" 58.4#, NKHC-110, NK-3SB 10-000-315-93
1 ea. 2’ 9-5/8" 58.4#, Float Collar, NK-3SB 10-000-228-59
2 jts. 80' 9-5/8" 58.4#, NKHC-110, NK-3SB 10-000-315-93
1 ea. 2’ 9-5/8" 58.4#,Float Collar w/ By-pass Baffle, NK-3SB
99 jts. jts. 3,945' 9-5/8" 58.4#, NKHC-110, NK-3SB casing 10-000-315-93
1 10' Weatherford 9-5/8” POST stage cement DV tool @ 10,916’ w/ 2-stage Displacement type Plug Set
290 jts. 11,576’ 9-5/8" 53.5#, NKAC-95ST, NK3SB 10-000-315-55
10 400 9-5/8" 58.4#, NKHC-110, NK-3SB 10-000-315-93
Notes:
a) Crossover joints, if required, will be made locally.
b) Prior to running the casing (and all subsequent strings), perform all required field inspections plus API drift.
c) No FBE pipe is required in this well.
d) Use cleaning solvent (DO NOT use diesel oil) when cleaning premium threads. Wipe out and blow out excess solvents from the thread roots. A thin even coat of API Modified Thread Compound (API 5A3) should be applied on BOTH the premium casing coupling and pin connections with a nylon brush (DO NOT use wire brush). Thread compounds that contain Teflon should not be used. A stabbing guide should also be used when running premium connections.
2. Centralize the first five joints, then every 3rd joint to surface, and six (6) across DV as follows:
a. One immediately above and below the DV.
b. One midway on the joint above and below the DV.
c. One at the end of the joint above and below the DV.
Use stop collars (Total= 260 SAP# 10-000-228-10) and install centralizers (SAP# 10-000-226-39) in the middle of the joint. Total = ± 130. Also install centralizers across the wash out sections (as per caliper log).
3. Make-up torque: (from Drilling Manual)
SAUDI ARAMCO
PREMIUM CASING and TUBING Minimum
(ft-lb.)
Optimum
(ft-lb.) Maximum
(ft-lb.)
9-5/8” 53.5#, NKAC-95T, NK-3SB 13,200 16,500 19,800
9-5/8” 58.4#, NKHC-110, NK-3SB 14,400 18,000 21,600
NOTES:
• Break circulation at intervals while RIH. At shoe, circulate 1 complete btms up prior to entering the open hole.
• If obstruction is encountered while RIH, carefully break the gels (reciprocate pipe) and kick in the pumps to wash through the obstruction. Circulate to lift the debris into the cased hole while reciprocating the pipe prior to continuing to run in hole.
• Wash down last few joints to bottom. On bottom, circulate 120% casing capacity while reciprocating the string. Record PU and SO hook loads.
• Rig up for cementing.
CEMENT REQUIREMENTS
Verify efficiency of rig pumps prior to this cement job.
Notes applicable to both stages:
• Apply recommended cementing best practice (See scorecard on ATTACHMENT # 8)
• Cement additives may be revised, following lab testing.
• Confirmation tests required from BOTH Aramco and Halliburton labs for all cement slurries.
• Use pressurized mud balance to measure spacer & cement weight.
• Add Biocide @ 1 gal/50 bbls mix water to the bottom of the tank prior to mixing chemicals and also at regular intervals.
FIRST STAGE:
Pump 75 bbls. of Halliburton weighted Spacer (spacer weight will be decided afterwards depending upon actual MW used) ahead of the cement slurry.
1750 Sx Class G + 35% SSA-1 + 1% MB-HT + 0.015 gps D-Air-3000L + 0.55% Halad-413 + 0.25% Halad-344 + 1.20% HR-12
Slurry Weight 118 Pcf
Yield 1.53 ft3/sx
Mix Water 6.3 Gps
Thickening Time 9:00 Hrs:Min
BHST (Est.) / BHCT (Est.) 275/225 °F
Notes:
a. Cement volume is based on 50% excess in the open hole, 10% excess inside casing, 165' casing shoe track and 300' rise above DV.
b. Actual cement volumes will be adjusted based on OH caliper log volume.
c. Cement additives will be revised, as required, following lab testing.
d. The actual thickening time will be decided prior to any pilot test in agreement with the foreman and drilling engineer.
e. Use Displacement type plug set.
f. Release By-pass plug immediately behind the 1st stage slurry and load opening plug. Kick off the By-pass plug with 10 bbl cement behind. Displace with mud.
g. Switch to rig pumps and continue displacement by pumping theoretical volume between the by-pass baffle and DV minus 20 bbl short displacement minus 10 bbl slurry.
h. Drop the ‘Displacement type’ Opening plug and continue displacement to land same on DV tool. (volume between DV & cement head). Bump the plug on DV, release pressure to ensure floats are holding, inflate packer, and open DV as per DV tool operator’s instructions. Circulate out casing annular volume above DV.
i. Monitor and record cement volume returns.
j. Continue circulating above the DV (at a reduced rate) and WOC to allow the 1st stage to set before raising the BOP stack to set the slips.
k. Center the 9-5/8" casing. Raise BOP stack. Install the casing slips.
l. Land casing (record weight, excluding blocks). Re-set the BOP stack.
SECOND STAGE: (9-5/8” DV @ ± 11,976')
Pump 75 bbls. of weighted Aramco spacer ahead of 2nd stage cement slurry. The spacer weight will be decided afterwards based on the final mud weight.
3,600 Sx Class G + 35% SSA-1 + 1.0% MB-HT + 0.015 gps D-Air-3000L + 0.25% CFR-3 + 0.75% HR-5
Slurry Weight 118 Pcf
Yield 1.53 ft3/sx
Mix Water 6.3 Gps
Thickening Time 6:30 Hrs:Min
BHST (Est.) / BHCT (Est.) 225/175 °F
• Calculation includes 10% excess in cased hole.
• Release DV closing plug and kick off with 5 bbl cement and 10 bbls of water. Displace with mud.
• Monitor and record cement volume returns.
• Bump plug. Close DV.
BOP REQUIREMENTS
1. PU 13-5/8" 10M BOPE, set slips ( manually activated packoff ), and cut and dress the 9-5/8"casing.
2. Install 13-5/8" 10M x 13-5/8" 10M DSDPO (P.O for 9-5/8" casing); SAP # 1000027390. Energize and test lower seals/void to a maximum of 5,500 psi, based the biaxial effect of tension on collapse with the full weight of the 9-5/8” casing (883,293 lb) set on the slips or as prescribed by wellhead representative.
3. Install 13-5/8" 10M X 11" 10M Tubing Spool and four 3", 10M gate valves. Energize and test lower seals/void to 8,000 psi (lowest between 80% collapse of 58.4# or 80% of flange rating).
4. NU the 13-5/8" 10M Class "A" BOP Stack.
5. Test BOPE as per Saudi Aramco requirements.
6. Install gauge on annulus to monitor pressure.
CASING/SHOE TEST
1. PU and RIH w/ 8-3/8" BHA and TCI bit to TOC. Clean out cement and DV with MW that used to displace cement.
2. RIH to TOC. After drilling the Baffle, Float Collar and cement to 20' above Float Shoe. Circulate hole clean and pressure test casing to 130 pcf EMW (3400 Psi with 100 pcf mud) at 9-5/8” shoe.
3. Drill out the 9-5/8" shoe and 10' of new formation. Test the casing shoe formation integrity with 3400 psi with 100 pcf mud (130 pcf EMW) or to leak-off.
4. Pull back into the casing and displace wellbore to 86 pcf inhibitive KCl-Polymer mud. Drill ahead 8-3/8” hole.
8-3/8" HOLE SECTION
Drill the 8-3/8" hole to the core point and conventionally core 120’ in the Unayzah A reservoir as instructed by the Wellsite geologist. If there is any hydrocarbon show, a barefoot test may be requested. Continue drilling ahead to the liner point @ 16,891’ ( 200 ft into Qusaiba Formation). Run the required open hole logs. Run and cement a 7" liner as outlined in the program.
POTENTIAL HOLE PROBLEMS
• Possible tight / tectonically stressed hole in the Pre-Khuff section. This may necessitate drilling with high mud weight to stabilize the hole.
• Possible abnormally pressured zones in the Qusaiba, as it was seen in HRUR-2.
• Slow drilling & coring ROP due to hard / abrasive / well cemented sands.
Well Name
Distance DESCRIPTION
HRUR-2
2005 47.4 km NW Drilled 5-7/8” hole section w/ 83 pcf mud to 20,267’. While circulating prior to POH for core, observed well flowing. Circulated bottoms up, observed influx was water w/ some gas. (predominantly CO2 ). Made several check trips to shoe w/ extended flow checks while gradually increasing MW. The well was finally stabilized w/ 119 pcf mud. Conditioned mud, took open hole logs and temporarily suspended well to continue drilling at a later stage using 15K BOPs. The well was deepened by ADC-23 to 20,760 using 119 pcf mud. The new interval was logged and the section was plugged and abandoned.
KHRS-82 1996 44.9 km SE Started w/ 93 pcf mud. Reached TD @ 15,700’ ( 1,334’ below the pre Unayzah unconformity) w/ 95 pcf mud. Cut two cores (120’) across the Unayzah formation, ran open hole logs, performed a BFDST to Unayzah formation, setting packer @ 13,917’ and lifted well with N2 to 12,000’, had no signs of formation influx, the well was dead. P & A hole section and temporarily suspended the well.
KHRS-4 1958 38.4 km SE Successfully drilled across the Khuff and Pre-Khuff in one section. Started 6” hole section w/ 104 pcf mud and reached TD @ 13,565’ w/ 100 pcf mud. Cut 21 cores ( total 1,014’ ) w/o problems. Abandoned open hole section by placing cement plug f/ 11,530’ to 11,130’. Perforated interval 10,836’ to 10,848’, well flowed salt water. Set cement retainer packer @ 10,810’ and placed cement plug above it. Cut 7” casing @ 10,006’ and recovered same. Perforated well f/ 4,765’ to 4,947’ and completed as Arab D oil producer. Released rig.
DRILLING FLUID
Start drilling this hole section with 86 pcf inhibitive KCl Polymer mud. If possible use mud from the previous hole section. The expected bottom hole temperature at section TD is ± 286 °F. Use Drispac to provide filtration control.
Based on prognosed reservoir pressures, a Mud Wt of 86 - 90 pcf is adequate to provide over-balance across the Unayzah, and Qusaiba reservoirs. However, hole stability requirements may necessitate going to higher mud weight. Offset wells drilled the section with 92 – 119 pcf mud. Apply good drilling practices to minimize the risk of differential sticking while drilling and while coring.
It is recommended to run centrifuges (two) while drilling this hole section to improve drilling performance.
Refer to the Drilling Fluid Attachment for recommended mud properties and formulation.
CORING PROGRAM
If hydrocarbon shows are encountered in the Unayzah A Reservoir, cut a 120’ core conventionally. Coring should continue until the base of the reservoir or hydrocarbon zone is penetrated. Note that a geologist should be on site to pick the coring point(s).
TESTING PROGRAM
An open hole test may be requested to evaluate the Basal Khuff clastics / Unayzah A Reservoir. However, the decision for open hole testing will be based on the anticipated formation pressure and safety of the well.
DIRECTIONAL SURVEYS
1. Drop Totco on each bit trip, if hole conditions permits.
2. Run Gyro Multi-Shot survey from liner point to 9 5/8” casing shoe and tie in to the previous survey runs. Wellbore temperature (above 280 deg F) may necessitate running the tool with a heat shield
LOGGING PROGRAM (Schlumberger)
Run the following borehole logs to 100 feet above the 9 5/8-inch casing shoe:
Run 1: AIT -Sonic
Run 2: LDS-TLD-MCFL-CNL-HNGS
Run 3: FMI
Run 4: ECS-CMR
Run 5: MDT on standby
Run 6 : MSCT on standby
NOTES:
• Report the maximum - BHT for each run with the elapsed time (ΔT) after circulation, from the open-hole logs.
CASING AND CEMENT DETAILS
LINER TYPE SHOE DEPTH LENGTH TOP OF LINER
7" 35# VM-110HCSS, VAM TOP HC
(SAP# 1000-777-544) ± 16,891’
(±200 into Qusaiba Formation) ± 1,294’
± 15,597’
(± 500' above 9-5/8" shoe)
LINER RUNNING PROCEDURE:
1. After running open hole logs, RIH with 8-3/8” bit to TD, circulate and condition mud. Reduce gels and PV to minimum to suspend solids. Circulate minimum of (2) full circulations. Ensure hole is clean pumping 30 bbls Hi-Vis pill and check clean shakers before POH.
2. Before pulling out of hole to run the liner, rotate and record the torque readings, just off bottom, and with the bit just inside the previous casing shoe (cased hole torque) at 5, 10 and 20 RPM. This can be useful if the liner needs to be rotated in open hole or if the running tool needs to be mechanically released.
3. Strap DP while pulling out of to run 7”carbon steel liner.
4. Run 7” liner as follows:
QTY Length Description
1 ea. 2’ 7" 35#, Float Shoe, Baker, Vam Top HC
2 jts. 80' 7" 35#, VM-110HCSS, Vam Top HC
1 ea. 2’ 7" 35#, Float Collar, Baker, Vam Top HC
2 jts. 80' 7" 35#, VM-110HCSS, Vam Top HC
1 ea. 2’ 7" 35#, Landing Collar, Baker, Vam Top HC
27 jts. jts. 1,093' 7" 35#, VM-110HCSS, Vam Top HC
1 35' 7” X 9-5/8” 35# Baker Flexloc Hydraulic Hanger w/ TBR and ZXP liner top packer, Vam Top HC.
* Use all bare casing
Notes:
• Cementing best practice scorecard is attached (ATTACHMENT # 8).
• Top of 7” Liner @ 15,597’, 500’ above 9-5/8” casing shoe.
• Set the Maximum Allowable Circulating Pressure (MACP). This is the maximum standpipe pressure allowable during running the liner and circulating before the liner set.
• Ensure cross-over from 7” VAM TOP HC to DP is on location prior to running liner.
• Place 1 x 10' marker joint at least one jt. above the Unayzah A Formation.
• 1 centralizer per joint the first 5 joints.
• 1 centralizer per joint for the first 7 joints of the liner below the 9-5/8” casing shoe.
• Examine the caliper log & place 1 centralizer per joint above and below any washouts.
• 1 centralizer every 2 joints elsewhere. Total ± 19 Centralizers.
• Use 7” Spiral Glider Centralizer (Material ID: 10-000-227-19).
• Stop Collar (Material ID: 10-000-228-50) for Spiral Glider Centralizer. Need two stop-collars per centralizer. Total ± 38 Stop Collars.
• Liner Hanger Manufacturer representative shall check liner hanger to ensure that 'higher strength' shear pins are installed. Determine the pressures required to set the hydraulic liner hanger, release the running tool and blow the ball seat. The pressure to set the liner hanger is stamped or written on the liner hanger. Ensure the rig pump pop valves are set high enough to allow the ball seat to be sheared.
• Inspect the liner pipe as per standard Aramco policies, (visual inspection at the wellsite of body and threads, sonic/ electromagnetic inspection at the pipe yard, API drift test at the wellsite).
• Caliper the ball (Brass Ball) to ensure it is the correct size for the ball seat in the landing collar and will pass through the drill pipe tool joints. Check that the ball seats in the landing collar correctly.
• Confirm whether the liner can be rotated if necessary while RIH (and with what limitations: maximum torque, running tool released if left hand torque is encountered).
• Load the liner wiper plug into the drill string cementing head.
• Make-up Torque: VAM TOP HC; Optimum: 22,800 ft-lb, Minimum: 20,600 ft-lb & Maximum: 25,000 ft-lb.
1. Make up a joint of drill pipe above the setting tool and rig up cementing head. Break circulation. Circulate one liner volume of mud at the planned cement pumping/ displacement rate to ensure floats are clear (do not exceed the MACP). Note the standpipe pressure and liner weight and drag (pumps off).
2. Prepare polymer or casing dope to be poured into the TBR when rigging up liner hanger (in order to minimize the occurrence of hydraulic lock.)
3. Run liner on 4″ X 5-1/2” DP filling every 10 stands. Rabbit each stand while RIH. With the liner shoe at the previous casing shoe, circulate a minimum of one annular volume to ensure floats are clear and that the mud is as programmed. Circulate at the planned cement pumping/ displacement rate if possible. Do not exceed MACP. Measure the torque at different rotary speeds (5, 10, 20 and 30 rpm). Do not exceed 75 % of the make up torque used in the string (usually the liner pipe connections). Record the string weight and drag (up and down) (pumps off, no rotation).
4. Prepare the cementing head, line from the cementing head to the rig floor manifold (single line is adequate), circulating line and cementing line before running the liner into open hole. This will minimize the time that the liner is not moved or circulated at TD or if difficulties are encountered. The cement head should be made up to a single and kept in the mouse hole or laid out on the cat walk for immediate use. Allow enough line from the floor manifold to the cementing head to reciprocate the liner 20 ft and to sting out of the liner hanger after cementing.
5. Continue RIH in open hole with the 7” liner controlling the running speed. Fill the drill pipe on every stand so the smooth running of the liner is not interrupted. If excess drag is encountered circulate the liner (monitor standpipe pressure continuously to stay below MACP) and wash to bottom. Liner rotation may be an option, consult with the liner hanger representative.
6. Stop and break circulation at least once, half way through the open hole, or as required. Prior to breaking circulation, reciprocate pipe to break the gel strength. Circulate slowly with low pump pressures. (Note the shear pin setting for the hydraulic hanger; DO NOT exceed the MACP. Observe the same precaution if washing to bottom is required. Baker representative should be on the rig floor while running liner in the open hole.
7. With the liner within 30 ft of TD, install the single joint cementing head and lines. Break circulation slowly while reciprocating the pipe. Increase circulation rate slowly. Tag bottom. Circulate at reduced rate until bottoms-up is past the liner hanger. Monitor standpipe pressure for increase (packing off) and reduce pump rate if necessary. Do not exceed MACP. Reciprocate the string 10 to 20 ft. Calculate the annular velocity in the drill pipe by casing annulus and ensure it is adequate to lift cuttings from the hole (compare it to the annular velocity used while drilling).
8. Increase the circulation rate to at least the rate planned for pumping and displacing cement. A higher circulation rate may be useful if the cement slurry is expected to U-tube significantly. Circulate bottoms up. Monitor shakers for an increase in cuttings and final clean up. Reciprocate pipe continuously (10 to 20 ft stroke) and monitor standpipe pressure. Ensure that liner shoe is within 2 ft of TD at the bottom of the stroke (to ensure the hole is cleaned to bottom).
9. Install cementing head. Pump a weighted (equal to the cement slurry density) high viscosity sweep to confirm annulus cleanliness. Monitor shakers when the sweep returns to surface for any increase in cuttings volume. Repeat the sweep if any doubt about annulus cleanliness exists. Pump rate can be increased for additional cleaning (do not exceed MACP). Record weight of liner and setting string while circulating and reciprocating.
10. During the final circulation time stop pumping and pump enough water from the cementing unit to fill the surface lines and pressure test the lines. Resume circulation using the rig pumps.
11. When satisfied that the hole is clean, then pump the ball down. Pressure up and set the hanger. Slack off until the liner is resting on hanger. Pressurize further to release the setting tool. Pick up 2'-3' and note the loss of the liner weight. Set down 15,000 lb of string weight on hanger or as suggested by liner hanger service representative and maintain throughout the cement job. Pressure up again to shear the ball seat in the landing collar.
12. Break circulation slowly and increase rate to the planned cementing rate. Monitor standpipe pressure. A steady pressure (at constant pump rate) is a good indication that packing off is not occurring. Circulate at least one annular volume to ensure no packing off is taking place in the annulus and the circulation pressures are comparable with the values obtained before setting the liner hanger.
13. Cement 7" liner as follows:
CEMENTING PROCEDURE:
Pump 60 bbls. of Halliburton weighted Spacer, ahead of cement slurry. Spacer weight will be decided afterwards depending upon the actual MW used.
Option- I
In case a Barefoot DST is run, pump
390 Sx Class G + 35% SSA-1 + 5% MB-HT + 0.04 gps D-Air-3000L + 0.30 gps Stabilizer 434B + 1.5 gps Latex 2000 + 0.50% CFR-3 + 0.15% Halad-344 + 1.25% HR-12
Slurry Weight 125 pcf
Yield 1.41 ft3/sx
Mix Water / Mix Fluid 3.32 / 5.16 gps
Thickening Time 8:00 Hrs:Min
BHST (Est.) / BHCT (Est.) 283/232 °F
Add BIOCIDE to the mixing water prior to mixing additives.
Option-II
In case there is no Barefoot DST in this section, pump
410 Sx Class “G” + 35% SSA-1 + 1% MB-HT + 0.015 gps D-Air-3000L + 0.45% CFR-3 + 0.55% Halad-413 + 0.25% Halad-344 + 1.20% HR-12
Slurry Weight 125 Pcf
Slurry Yield 1.36 Ft3/sk
Mix Water 5.05 gps
Thickening Time 6:00 Hrs:Min
BHST ( Est ) / BHCT ( Est ) 283 / 232 0F
Notes:
a. Calculations include 10” open hole, 25% excess in OH, 10% excess in cased hole, 165’ casing shoe track and 500' rise above liner top around 5" DP + 5 bbl of cement behind the plug.
b. Actual cement volumes will be adjusted based on OH caliper log volume.
c. Cement additives will be revised, as required, following lab testing.
d. The actual thickening time will be decided prior to any pilot test in agreement with the foreman and drilling engineer.
e. Batch mix slurry.
f. Pump 5 bbl cement behind DP wiper plug. Displace cement with mud.
g. Reduce the displacement rate to 2 - 3 BPM before DP wiper plug engages the liner wiper plug and before bumping the plug. The pump rate should be returned to the planned displacement rate between these two events.
h. Place 30 bbls. of Halliburton weighted Spacer across the 7” TOL to avoid direct mud to cement interface when stinging out from the liner hanger.
i. After bumping the plug, pull back and set the ZXP packer as per BOT technician; Open a line from the floor manifold to the annulus or trip tank before attempting to unsting so pressures are equalized as the running tool is picked up. Be prepared for U-tubing mud to come from the open line when the running tool packoff comes out of the TBR. Take any U-tube volume into the trip tank and note the volume returned. Lay down the cement head with one single to the cat walk or mouse hole. Do not break up the floor manifold and lines at this time.
j. Pull a minimum of 10 stands above the liner. Reverse out to clear DP. Reciprocate the pipe during reverse circulation (do not pull/push tool joints through the annular, keep the annular rubber lubricated and adjust annular closing pressure to the minimum needed to prevent flow past the rubber).
k. POOH with setting tool completely laying down 5” drill pipe.
l. WOC time will be provided at a later date. This will be based upon how successful the actual job went and compressive strength tests at BHST simulating the top of liner. Do not start liner clean out until cement compressive strength testing shows at least 500 psi of strength (measured from plug bump time). Similarly liner pressure testing should not be attempted until cement compressive strength has reached 1500 psi.
BOP REQUIREMENTS:
Re- configure and test BOPE as per Aramco requirements.
CASING TEST AND CLEAN OUT:
1. RIH cautiously with 8-3/8" bit, circulate every 2000' or as required. Keep the pipe moving at all times when circulating and monitoring bottoms up for indications of contaminated cement. Be alert for possibility of contaminated cement at shallow depths while RIH. Tag top of cement and clean out to the 7" liner top. Circulate hole clean. If cement is found soft, clean out to 100’ above TOL carefully. Allow sufficient time for cement to harden. Then clean out cement to TOL. POOH.
2. RIH with 5-7/8” bit and clean inside the 7” liner. Continue clean out float equipment to 20’ above 7” liner shoe, test liner to 130 pcf EMW. Drill shoe and 5’ of new formation and perform the FIT with 130 pcf EMW or leak-off whichever comes earlier.
Note: Negative testing of 7” TOL will be decided later on, depending upon the quality of cement job and the actual mud weight used.
5-7/8” HOLE SECTION
Drill the 5-7/8” hole to the core point and conventionally core 60’ in the Sarah reservoir as instructed by the Wellsite geologist. If there is any hydrocarbon show, a barefoot test may be requested. Continue drilling and/or coring ahead to the well TD at ±18,150’ (±900’ below top of Sarah Formation). Run and cement 4-1/2” liner at TD if required.
POTENTIAL HOLE PROBLEMS
• Possible tight / tectonically stressed hole in this section. This may necessitate drilling with high mud weight to stabilize the hole.
• Slow drilling & coring ROP due to hard / abrasive / well cemented sands.
HRUR-2 is the only offset well that penetrated below the Unayzah formation; however, both the Qusaiba and Sarah were not found since the remainder of the paleozic is missing. The Rudanian was penetrated at 20,267’, depth at which a salt water flow had to be controlled with 119 pcf mud. The well was temporarily suspended until 2008, when it was re-entered with 15K surface control equipment and 7” tieback to surface. The well was drilled from 20,267’ to the top of the basement which was encountered a few feet above the well’s TD @ 20,764’.
Well Name Distance DESCRIPTION
HRUR-2
2005 47.4 km NW Drilled 5-7/8” hole section w/ 83 pcf mud to 20,267’. While circulating prior to POH for core, observed well flowing. Circulated bottoms up, observed influx was water w/ some gas. (predominantly CO2 ). Made several check trips to shoe with extended flow checks while gradually increasing MW. The well was finally stabilized with 119 pcf mud. Conditioned mud, took open hole logs and temporarily suspended well to continue drilling at a later stage using 15K BOPs. The well was deepened by ADC-23 to 20,760 using 119 pcf mud. The new interval was logged and the section was plugged and abandoned.
DRILLING FLUID
Utilize the mud used in the previous section. Reduce the mud density to 86 pcf and maintain the mud properties as prescribed. Increase mud weight, as required.
Notes: Refer to the Drilling Fluid Attachment for recommended mud properties and formulation.
CORING PROGRAM
Cut 60’ core starting above the Sarah in order to catch some of the Base Qusaiba Hot shale. The coring should continue until the base of the reservoir or hydrocarbon zone is penetrated. Note that a geologist should be on site to pick the coring point(s).
TESTING PROGRAM
An open hole test may be requested to evaluate the Sarah; however, the decision for open hole testing will be based on the anticipated formation pressure and safety of the well.
DIRECTIONAL SURVEYS:
- Drop Totco survey prior to POH for bit trips.
- At 4-1/2” liner point, drop Gyro Multi-Shot and survey at 100' stations while POH from TD to the 9-5/8” casing shoe. Tie it with the previous survey run.
LOGGING PROGRAM (Schlumberger):
At total depth ±18,150’, run the following borehole logs to 100 feet above the 7” liner shoe:
Run 1: AIT-Sonic
Run 2: LDS-MSFL-CNL-HNGS
Run 3: Slim FMS
Run 4: ECS (5”OD)
Run 5: CMR (5.2”OD)
Run 6: MDT on standby
Run 7 : MSCT on standby
Run 8 : VSP with zero offset from TD to surface.
Note:
Prior to POH for logging operations, carry out wiper trip and properly circulate hole clean and condition the mud as per recommendations on the drilling fluids attachment. At the end of the logging operations condition the mud again as recommended. Ensure hole is in very good condition before POH to run the liner.
CASING AND CEMENT DETAILS:
A supplement will be issued, if required for liner running, cementing and cleanout procedure.
CASED HOLE TESTING/SUSPENSION/COMPLETION:
A detailed testing / suspension / completion program will be issued after evaluation of OH logs, cores, samples and any hydrocarbon shows.
APPROVED:
______________________________________________
_____________________________________
Jamal Al-Watban, Manager (A) W. H. Turki, General Manager (A)
Gas Exploration & Development Drilling Department Drilling & Workover Operations
________________________________________________
_____________________________________
Muhammad M. Al-Saggaf, Chief Petroleum Engineer (A) Ali Y. Al-Hauwaj, Manager
Petroleum Engineering Area Exploration Department
Regular Distribution
JPM/jpm
Attachments:
1. Geologic Horizons and Reservoir Pressure Data Regular distribution
2. Drilling Well Cost Estimate Regular distribution
3. Drilling Fluid Program Regular distribution
4. Bit Program Regular distribution
5. Wellhead Schematic Rig only
6. Casing Head Support Unit Sketch Rig only
7. Location and offset Wells Map Regular distribution
8. Cementing Best Practices Scorecard Rig only
9. Inner String Cementing Procedure Rig only
10. Drilling Spreadsheet Regular Distribution
ATTACHEMENT-1 – Geologic Horizons and Reservoir Pressure Data
ATTACHEMENT-2 – Drilling Well Cost Estimate
ATTACHEMENT-3 Drilling Fluid Program
34" hole section, 30" casing @ 115'( ±109’ into UER)
28" hole section, 24" casing @ 2,130’ (±400’ into WASIA)
SPUD MUD
A Spud Mud composed of pre-hydrated bentonite flocculated with caustic should be sufficient to drill the above intervals. Small amount of XC Polymer can be used to develop additional viscosity as needed. Use high viscosity sweeping pills as necessary and spot a similar pill on bottom prior to running the casing. Add 5–10 ppb sized CaCO3 medium and coarse along with 5–10 ppb mica prior to penetrating potential loss circulation zones (UER, Aruma) to try to maintain circulation. Use all the solids removal equipment to discard drill solids and maintain low mud density with additions of diesel oil if required. In case of lost circulation, drill with water and use high viscosity sweeping pills identical to the Spud Mud composition as follows:
Formulation and Material Concentration for one barrel
Material Unit Quantity(per bbl) Property Unit Value
Make-up Water bbl 0.96 Density lb/ft3 63- 64
*Soda Ash lb 0.5 – 1.0 Funnel Viscosity sec/qt 60 – 80
Bentonite lb 20 – 25 pH 9.5 – 10
Caustic lb 0.25 – 0.75
XC Polymer lb 0.5 – 1.0 Total hardness 600 ppm
Starch lb 2-3 ** if required to reduce the filtrate
Barite lb as needed to increase density
Oil bbl 2–5 % if needed to reduce density.
In case of lost circulation, drill with water and use high viscosity sweeping pills (gel slip) identical to the Spud Mud composition and add while drilling 30–80 ppb LCM.
NOTE:
• Good solids control equipment performance is essential in order to minimize dumping and diluting to control mud weight and viscosity. Utilize the finest mesh shaker screens compatible with the circulation rate. Water additions should be made at the shaker pit to accelerate the settling of fine solids in the sand trap.
• Circulate a high viscosity pill to clean hole before running casing. Dump sand traps as needed and after cementing the casing.
• **If required, starch (PolySal) should be added to reduce the API filtrate to 10-12 cc and decrease wall cake thickness to avoid getting stuck in the Aruma Shale.
• Pump high vis pills to insure cuttings removal prior to making connection. Spot a special treatment of the required volume of weighted-spud mud (e.g. 70-75pcf or as required) prior to POOH for casing as below (CasingGo Treatment).
• L/D stabilizers & reamers if tight hole or hole caving is encountered.
• In case circulation is maintained, add 2-3 ppb starch to reduce fluid loss across Lower Aruma Shale.
CasingGo Treatment before running 24” casing:
While on bottom circulate maximum two times and condition the spud mud by adding: combination of 3-4 ppb marble fine & 2-3 ppb marble medium at the suction while circulating and conditioning the mud for effective bridging / filtration improvement. Add 1–2 sx Soltex and 1 drum BlackNite over one circulation.
After the above treatment (before POOH), spot/displace the open hole with weighted
lubricating pill (75 pcf or more as required) by isolating a clean volume of the drilling fluid
and/or spud mud from the active system in the pill tank and add the following:
1) Lubricant: TorqTrim II or equivalent: 0.3-0.5 gpb.
2) BlackNite (Gilsonite): 0.3-0.5 gpb.
3) Soltex 1-2 ppb
4) XC Polymer for YP=23-30 0.25-.75 ppb
5) Starch for API filtrate 4-6 cc.
6) Spot the required volume of the treated mud to cover the open-hole from TD to the last lost zone (if applicable).
The above modifications will help stabilize the hole by plastering the well bore wall with a good resilient wall cake prior to running casing.
22" hole section, 18-5/8 " casing @ 5,203' BHST=143o F (±100’ into Hith)
Dilute the mud left from the previous section (if applicable) and maintain low mud density if needed or mix new mud as below. Add 5-10 ppb sized CaCO3 medium & coarse along with 5-10 ppb mica medium prior to penetrating potential loss circulation zones to try to maintain circulation. Use all the solids removal equipment to discard drill solids and maintain low mud density with diesel oil if required. In case of complete sudden loss circulation, increase mud viscosity to 100 sec/qt, add CaCO3 course and mica medium (30-50 ppb each) and drill with mud to generate cuttings. This will help in sealing off the loss circulation zones.
Loss of circulation and water flow may be encountered while drilling this section. Drilling may continue by applying the following:
• Sweep the hole prior to making connections with 50 bbl high viscosity PHB mud.
• When water is used for drilling, it should be treated with lime (1 ppb) in order to reduce corrosion.
• Do not drill Biyadh with water and gel slip; drill it with mud with controlled filtration (API <= 10 cc /30min).
The table below shows formulations for low density fluid to drill the 22" hole section:
Formulation & Order of Addition (one barrel) Average Fluid Properties
Density, lb/ft3 58 59 60 61 58 59 60 61
Water bbl 0.55 0.65 0.69 0.79
Bentonite lb : 10 - 12 Plastic Vis. Cp: 14-18 (*ALAP)
XC Polymer lb : 0.25 - 0.5 Yield Point lb/100ft2 24-26
Starch lb : 2 – 4 10 sec. gel lb/100ft2 10-15
Diesel bbl : 0.45 0.35 0.30 0.20 10 min. gel lb/100ft2 15-20
Tanamul gal : 0.05 – 0.07 API Filtrate cc/30min 10-14
Caustic as required lb : 0.5 - 1.0 pH 9.5-10.0
CaCO3 fine lb : 2 – 4 6 RPM Reading 14 - 18
CaCO3 medium 1b 2 - 4
*ALAP = As low as possible
The table below shows formulation to prepare additional mud with 64-68 pcf as a backup if 100% losses occur:
Formulation and order of addition: ( one barrel ) Average Fluid Properties:
Mud (previous section) : 0.92 Density lb/ft3 : 64 -68
Bentonite, : 5.00 Plastic viscosity cp : 12 – 18
Starch lb : 2.00 Yield point lb/100ft2 : 24 - 26
Caustic lb : 0.50 10 sec. gel lb/100ft2 : 10 – 15
Diesel bbl : 0.04 (if required) 10 min. gel lb/100ft2 : 15 - 20
Barite lb: as & if needed Filtrate, API ml/30min : 10-14
Soltex lb: 1-2 if needed & circulation regained for wall cake improvement.
NOTES:
• Increase the mud density as hole conditions dictates with barite or CaCO3 fine (10 microns).
• The order of addition should be followed as prescribed above.
• Reduce the filtrate and filter cake thickness with starch.
• Utilize the finest mesh shaker screens compatible with the circulation rate. Use 170/230 mesh shale shaker screens and mud cleaner with 250 mesh to discard drilled solids.
• Use XC polymer (0.25–0.5 ppb) for additional suspension. Maintain bentonite content in the active system to 10-12 ppb. (MBT: 10 – 15).
• Good hole cleaning is critical and should not be compromised. Sweep the hole prior to making connections using 30–50 bbl high viscosity mud.
• Spot required volume of special treated mud (CasingGo Treatment) prior to POH for casing as specified below.
• Circulate high viscosity sweeps to clean the hole as needed and before running casing. Dump sand traps as needed.
• Starch (PolySal) should be added to reduce wall cake thickness and filtrate to avoid getting stuck in shale formations.
• BlackNite, Soltex, and TorqTrim (if required) should be added while mud is being circulated. Do not add these chemicals in the initial mix and don’t pre-mix them.
• Be prepared to mix enough mud as loss of circulation is expected. Mud can also be obtained from Shedgum mud plant.
Recommendations to drill safely across the Wasia, Shuaiba, and Biyadh formations:
• If LC (loss circulation) occurs in the Wasia, attempt to cure losses with LCM or cement plugs before drilling ahead. If LC can not be cured, drill ahead with mud, 65-70 pcf (controlled filtration) and required mud (75 pcf or as required) weight of mud cap: DO NOT ALLOW WATER TO COME IN CONTACT WITH WASIA to minimize chances of shale sloughing. If significant tight hole is encountered, POOH to casing shoe and commence reaming the entire hole section. POOH slowly through the Wasia to minimize chances of swabbing-in the well.
• At the top of Shu’aiba, stop drilling and circulate hole clean with hi-vis sweep. Pre-treat the active mud system with LCM (10-20 ppb marble medium, 20-40 ppb marble coarse, and 5-10 ppb mica coarse,) to at least minimize chances of encountering LC. Add +/- 10 ppb Mica coarse to the ‘active mud system’ while drilling the Shu’aiba. At all times efficient hole cleaning is required by maintaining appropriate mud properties and circulation rates. DO NOT BY-PASS THE SHAKER.
• If LC occurs while drilling the Shu’aiba despite taking the above measures, stop drilling and attempt to regain circulation by pumping LCM. In the event that circulation is not regained and if tight hole or hole caving is encountered while drilling, switch to mud, 65-70pcf (API Filtrate = 6-8 cc) with mud-cap, 75pcf or as required, (40 BPH) and drill ahead.
• If drilling with LC, at 50 ft above top Biyadh, switch back to mud and continue drilling with mud-cap to CP. DO NOT drill Biyadh with water. At CP, circulate hole clean with Hi-Vis, raise MW if required to control sloughing shale. Perform wiper trip if required (back-ream if necessary).
CasingGo Treatment before running 18-5/8” casing:
If required reaming before running the casing, circulate hole clean and treat the spud mud with the following:
a) Add of 3-4 ppb marble fine & 3-4 ppb marble medium at the suction for effective bridging and filtration improvement. Add one super sack of marble fine & medium per circulation.
b) Measure the YP/Gels. Add bentonite/XC-Polymer for additional gels / YP (minimum 22-25).
c) Add starch as needed to control the filtration as required/recommended.
If reaming is not required, while on bottom circulate maximum two bottoms up and condition the spud mud by: add combination of marble fine (3-4 ppb) & medium (2-3 ppb) at the suction while circulating for effective bridging and filtration improvement. If deemed necessary, add a one time treatment/one circulation of 1-2 ppb Soltex and 0.1 gal/bbl BlackNite.
After the above treatment (before POOH), at the TD, spot/displace the open hole to
weighted lubricating pill (75pcf or higher as required) by isolating a clean volume of the drilling
fluid and/or spud mud from the active system in the pill tank and add the following:
below:
1) TorqTrim II lubricant: 0.2-0.5 gpb.
2) BlackNite (Gilsonite): 0.1-0.2 gpb.
3) Reduce the API filtrate with starch to 4 cc.
4) If required add XC-Polymer (0.25-1.0 ppb) to obtain required/enough gel before running the casing (YP= 25-30)
5) It is recommended to spot the required volume of the treated mud to cover the open hole from bottom to the last lost zone (if applicable).
6) Soltex 1-2 1b/bbl.
The above modifications should help stabilize the hole by with effective plastering of the wellbore wall giving a good resilient wall cake in preparation for running the casing.
16" hole section, 13-3/8" casing 12,276' BHST=228 o F
(±30’ below of Jilh dolomite)
Continue drilling with the same mud used in the previous section. Increase the mud density as hole conditions dictate. Utilize the barite-mud available at Shedgum plant. If tight hole problems encountered while drilling Marrat & Minjur formations, the active volume should be treated with KCl (3.0 - 5.0 %) to prevent clay swelling. Stable hole must be secured with effective plastering of the wellbore wall with good resilient wall cake. Add Soltex, if needed, while drilling before entering Marrat and Minjur Shale formations. Reduce the filtrate rate and cake thickness with additions of starch and Soltex.
Formulation and Material Concentration for one barrel Average Fluid Properties
Material Unit Quantity
(per bbl) Property Unit Value
68 74
Previous Mud (63 pcf) bbl 0.96 0.93 Density lb./ ft3 68 74
XC-polymer lb 0.25 – 0.5 PV Cp 16 22
Starch lb 2.0 - 3.0 YP lb/100 ft2 22 25
KCl lb 7.00 7.00 Gels, 10 sec/ 10 min lb/100 ft2 8/12 12/15
KOH lb 0.5 1.0 API Filtrate ml/30 min 6 -8 6 – 8
Lime (if required) lb 0.25 0.50 pH 9.5-10 9.5-10
Barite lb 16.0 88.0 6 RPM Reading 12-15 12-15
Mix new volume as needed and maintain the mud characteristics as prescribed below:
NOTE:
• Add one super sack each of marble fine & medium while drilling/per circulation or as required (by leaking into the system or on suction pit as applicable) for effective bridging and filtration control improvement. Keep/maintain the require mud weight as programmed.
• The order of addition mentioned above should be followed.
• Switch form starch to PAC-UL to control fluid loss once BHT exceed 240F.
• Good hole cleaning is critical and should not be compromised. Sweep the hole prior to making connections using 30 – 50 bbl high viscosity mud.
• Trip slowly to prevent undue swab pressures.
• In case of sudden loss of circulation, increase the mud viscosity to 100 sec/qt, use CaCO3 coarse and mica (30 – 50 ppb each) and drill with mud to generate cuttings. This will help sealing off the loss zones and reaching the casing point quicker.
• Increase the mud density as hole conditions dictates with barite.
• Use 180-200 mesh shale shaker screens and mud cleaner with 260 mesh screen to discard drilled solids.
• Use XC Polymer (0.25 – 0.75 ppb) for suspension in order to reduce the bentonite content in the active mud system to 6 – 8 ppb. (MBT: 6 – 8).
• TorqTrim II (if required) should be added while the mud is being circulated. Do not add in the initial mix and don’t pre-mix them.
• Do not dump mud; send it to the Shedgum plant.
• Sulfide ion test must be run regularly to determine the need for adding H2S scavenger (zinc oxide: 1-2 ppb). Report on the morning report the concentration of sulfide ions, twice per shift, in the mud in parts per million (ppm S=).
• Monitor torque and drag and add mud lubricant as needed.
• Condition the hole to the required mud properties before POOH to run casing and spot the special below pill. Do not back ream unless absolutely necessary.
Below is the special mud treatment and guidelines (CasingGo) before running the 13-3/8”
Casing:
Spot/displace the open hole with weighted lubricating pill (the weight of the pill is as required) by isolating a clean volume of the drilling fluid from the active system in the pill tank and apply treatment as below:
1) Reduce the API filtrate to 4 cc/30 min. This is very crucial property BEFORE RUNNING THE CASING.
2) Add lubricant, TorqTrim II or equivalent, 0.3-0.5 gpb.
3) BlackNite (Gilsonite) 0.25-0.5 gpb
4) Add required XC-Polymer (0.25-.75 ppb) to obtain required/enough gel before running the liner (YP= 25-30)
5) It is recommended to spot the required volume of the treated mud to cover the open hole.
6) Add Soltex 1-2 ppb.
12" hole section, 9-5/8” Casing @ 16,097’ BHST=274 o F (450’ into Khuff-D Anhydrite)
LSND KCl mud System:
Start drilling the 12” hole section with low solids non-dispersed 100 pcf mud. Use the formulation and the order of addition below to mix the required volume.
Formulation and order of addition: (one barrel) Average Fluid Properties:
Density lb/ft3 100
Water bbl 0.779 PV cp 25-35
XC-Polymer lb 0.5-1.00 YP lb/100ft2 25-30
Drispac/ PAC -L 1b 0.5 – 1.0 10 sec gel lb/100ft2 6-8
KCl
KOH 1b
1b 50
0.3-0.5 10 min gel lb/100ft2 10-12
Lime lb 0.25-0.5 Filtrate, HTHP @296oF/500psi ml/30min 18-20
Barite lb 230 pH 9.5-10
Sodium sulfite
1b
0.25-0.30
MBT active clay lb/bbl 4-6
In case abnormally high pressure is encountered while drilling the Base Jilh Dolomite, increase the mud density as required to control the subsurface pressure. The mud density should be increased as hole conditions dictates. Up to 150 pcf may be needed while drilling the Jilh / Sudair. The high density drilling mud can be prepared as follows:
High density, low-clay content deflocculated drilling mud system.
Formulation and Material Concentration for one barrel Average Fluid Properties
Material Unit Quantity
(per bbl) Property Unit Value
105 120
Fresh Water bbl 0.87 0.77 Density lb./ ft3 105 120
Soda Ash lb 0.25 – 0.30 PV cp 28 38
XC polymer lb 0.5 1.0 YP lb/100 ft2 30 35
High Temp Starch Hostadril lb 1-2 1-2 Gels, 10 sec/ 10 min lb/100 ft2 10/20 12/24
Drispac/PAC L lb 0.25 0.5 HPHT Filtrate ml/30 min 12-18 12-18
KCL lb 37 38 pH 9.5-10 9.5-10
Lime lb 0.25 0.25 MBT, active clay lb/bbl <7.0 <8.0
Barite lb 210 309.0 Cl- Mg/l x 1000 59 60
Sodium Sulfite lb 0.25 – 0.30
ThermaThin lb 1.0 – 3.0
KOH lb 0.25 0.5
NOTE:
• Small additions of sodium sulfite will remove the oxygen and stabilize the polymers to a bottom hole temperature up to 325°F.
• Increase the mud density as needed with barite
• Add water at the rate of 10–15 bbl/hour while drilling to avoid dehydration and excessive thickening.
• Utilize the finest mesh shaker screens compatible with the circulation rate used (180-200 mesh is recommended for this hole section). Maintaining low clay concentration in the system will prevent excessive viscosity and gel strength. Mud cleaner with +230 mesh screen can be run with this system.
• Active mud volume should be as small as practical to reduce mud treatment cost.
• If needed, a deflocculant such as ThermaThin (1-3 ppb) along with freshwater additions will be needed to maintain the desired rheology of the high-density mud
• Maintain pH (9.5 - 10) with & KOH only.
• Add combination of marble fine & medium at the suction while drilling for effective bridging, filtration improvement. Add one super sack of each (marble fine and medium) per circulation or as required while drilling. Maintain the same required mud weight.
• Prior to casing run, condition the required volume of mud and add the following: LC Lube F = 1.0 ppb, Soltex = 1.0-2.0 ppb, BlackNite = 0.25-.3 gpb, and ensure that HTHP filtrate & Cake is per program
• Trip slowly to prevent undue swab pressures.
• Use the finest mesh shaker screens possible. Monitor shakers and notify driller if any problems.
• Good hole cleaning is the key issue and must not be compromised. Sweep the hole prior to making connections with 25 - 50 bbl high viscosity mud.
• TorqTrim (when needed) should be added while drilling/conditioning the mud. Do not add in the initial mix or pre-mixed them.
• It is recommended to produce low HTHP fluid loss. So, we need close monitoring of measuring this property at least twice a day and to be reported to the foreman. Moreover, to have effective implementation of strengthening the wellbore is to prevent pressure transfer into the troublesome zone (sticking risk zone) by delivering very low fluid loss.
• When the static bottom hole temperature reaches 250°F, stop using Starch and rely on Drispac for filtration control. Small additions of sodium sulfite will remove the oxygen and stabilize the polymers to a bottom hole temperature up to 325°F. Maintain pH (9.5 - 10) with KOH.
• If the Driller notices a tendency for the hole to be grabbing the pipe on connections, immediately report the problem to see if LC Lube can be added to the system.
8-3/8" Hole Section - 7” Liner @ 16,891’ MD (200’ into Qusaiba) BHST=283 o F
Utilize mud used in the previous section. Reduce mud density to 86 pcf and maintain the mud properties as prescribed below.
Use the formulation and the order of addition below to mix the required volume. Mud HTHP filtration rates, filtrate chlorides, yield point, and gel strength should be closely monitored and precisely measured and reported minimum two times a day.
Formulation and order of addition: (one barrel) Average Fluid Properties:
Density lb/ft3 86-106
Water bbl 0.8 - 0.745 PV cp 18 - 24
XC-Polymer lb 0.75 - 1.0 YP lb/100ft2 22 - 26
Drispac UL 1b 0.25 - 0.50
10 sec gel lb/100ft2 4 - 6
NaCl
KCL
KOH 1b
lb
1b 50.0 - 55.0
22
0.30 - 0.5 10 min gel
lb/100ft2 10 - 14
Lime lb 0.25 - 0.25 HTHP FL @325oF/500psi
HTHP Cake ml/30min
32nd in 12 - 18
1 - 2
Barite
CaCO3 “fine”
CaCO3 medium
1b
1b
1b 185 - 275
10.0
10.0 pH 9.5 - 10
Sodium sulfite**
1b
0.25 - 0.30
6 RPM Reading 8 - 12
Baranex lb 2 - 4
NOTE:
• Small additions of sodium sulfite and biocide-B54 (0.20 ppb) will remove the oxygen and stabilize the polymers at the anticipated high bottom hole temperatures.
• When the static bottom hole temperature reaches 250°F, rely on Drispac UL or Hostadril for filtration control. Small additions of sodium sulfite will remove the oxygen and stabilize the polymers to a bottom hole temperature up to 325°F.
• The order of addition should be followed to avoid foaming problems.
• Increase the mud density as needed with barite. A combination of CaCO3 fine & medium is used in the formulation as bridging material. Add CaCO3 medium very slowly through the mixing hopper at the suction pit to compensate for losses over shale shaker. While drilling, add one super sack of CaCO3 medium per circulation. Maintain the required mud weight as programmed.
• Maintain pH (9.5-10) with KOH.
• Maintaining low clay concentration in the system (MBT=2-4 lb / bbl) will prevent excessive viscosity and gel strength.
• Use 80 mesh shale shaker screens for the first couple circulations or until the mud has sheared properly. Then utilize the finest mesh shaker screens compatible with the circulation rate used (180-200 mesh is recommended for this hole section). Mud cleaner with +230 mesh screen can be run with this system.
• It is recommended to utilize the high speed centrifuge (two) on the active system (3000-3400 rpm) to remove the ultra-fine solids and maintain the PV as low as possible.
• Active mud volume should be as small as practical to reduce mud treatment cost.
• For assistant, please contact Adel Ansari on 872-3284 or Nimer on 872-3295. Dhahran D&FCU Lab/Building # 2291/Room#117/124.,Fax # 872-3927.
5-7/8" Hole Section – TD @ 18,150’ MD (900’ into Sarah) BHST=297 o F
Use the same mud from the previous section and drill this section with 86 pcf mud. Maintain the mud properties as prescribed above. Increase mud weight as required.
ATTACHEMENT-4 – BIT FORECAST
RIG: PA-866 WELL: ADHN-1 TYPE Vertical K2 – Wildcat
Bit Size IADC AMS # Bit Type Quantity Remarks
34" 1-3-5 VAREL LA-3 2
28" 1-3-1 SEC XN3 2
4-4-5 HTC GTX-C3-12 1
22" 4-3-5 SMITH MGS12C 1
4-3-5 HTC GTX-T3-C3-11H 1
4-3-5 SEC EBXT12S 1
16" 1-3-1 SEC XN-1/XN-3 1 CLEAN OUT
PDC HTC HC507ZX 1
M4-2-1 REED DSX70 1
PDC VAREL MKS70R 1
5-1-5 SMITH GS20BDC 3
12" 1-3-7 SEC XL3N 1
PDC SEC FM3863Z 1
PDC HTC HC410Z 1
PDC SMITH M746PX 1
M-4-3-2 DIAM MDM829 1
8-3/8" 1-3-7 SEC X3S 1 CLEAN OUT
PDC HTC HC409Z 1 Vertical Application
PDC SEC FMH3941Z 1
6-3-7 SMITH GF50YBD 2
6-4-7 HTC MX-S68DX3 2
5-7/8" 6-2-7 SMITH XR40YODPD 6
PDC HCC HC409Z 1 Vertical Application
6-3-7 HTC MXS-66DX3 6
Note:
1) The order in which the bits are placed is not necessarily the order in which they will be run.
2) Bits different to those specified above may be used in case a better performance is observed.
Best bit runs in offset or similar wells
Hole Size Well No. Bit Description Hydraulic ROP/
Footage Formation
34” HRUR-2 Varel, 135
L3A, TFA 1.72
WOB 8
RPM 30 Q 524
P 160
MW 64 5 / 67 UER
28” HRUR-2 Security, 131
XN-3, TFA 0.8958
WOB 50, RPM 90 Q 850
P 1250
MW 64 22.5 / 1800 UER- Aruma
HWYH-984 Hughes, 435
GTX311, TFA 0.92
WOB 65, RPM 120 Q 1200
P 180
MW 63 36.9/ 1495 UER- Aruma
22” HRDH-998 Smith , 435
MGS12SC, TFA 0.92
WOB 70, RPM 110 Q 1270
P 2720
MW 62 40.8 / 2450 Ahmadi – Mid Thamama
UTMN-1833 Hughes, 435
GTX11H, TFA 0.92
WOB 70, RPM 120 Q 1200
P 2650
MW 63 44.8 / 2036 Ahmadi - Biyadh
16” UTMN-1859 Hughes, PDC
HC507ZX, TFA 1.353
WOB 40 , RPM 201 Q 1070
P 2450
MW 63 34.8 / 3779 Hith - Minjur
HRDH-1000 Reed, PDC
DSX70, TFA 1.767
WOB 45 , RPM 170 Q 1100
P 2400
MW 72 34.8/ 4482 MTL-Minjur
12” HRDH-669 Security, PDC
FM3863, TFA 1.203
WOB 40, RPM 142 Q 890
P 4050
MW 102 33.5/ 1612 BJD-Khuff B
HRDH-1009 Smith, PDC
M716, TFA 1.503, WOB 35
RPM 190 Q 900
P 3900
MW 100 37.2 / 1545 BJD-Khuff A
8-3/8” KSAB-2 Smith, PDC
MS816, TFA 0.884
WOB 35, RPM 100 Q 575
P 2463
MW 80 7.23 / 365 Unayzah A – Unayzah B
KSAB-2 Hughes , 637
MXS-68 TFA 0.45
WOB 40, RPM 60 Q 590
P 3480
MW 86 8.5 / 195 Jubah
5-7/8” HRUR-2 Hughes, PDC
HC407Z, TFA 0.724
WOB 17, RPM 85 Q 300
P 3167
MW 84 18.2 / 501 Pre Unayzah Unconformity - Robutain
MRDF-1 Smith, 437
XR40YPD, TFA 0.3359
WOB 24, RPM 65
Q 334
P 3300
MW 83 7.5 / 263 Mid Qusaiba Sandstone
ATTACHEMENT-5 - HDBA-1 Wellhead/Tree Schematic
ATTACHMENT-6
CASING HEAD SUPPORT UNIT
BASE PLATES
BOTTOM BASE PLATE
ATTACHMENT-7: Location and offset Wells Map
ATTACHMENT-8: CEMENTING BEST PRACTICES SCORE CARD
9 5/8” Casing
Item #
*Parameter
*Measurement
Available Score
Planned Score
Actual Score
Actual Measure
1 Drilling Mud PV/YP Ratio 1.50 – 2.00 3
1 Drilling Mud PV/YP Ratio 1.25 – 1.49 2 2
1 Drilling Mud PV/YP Ratio 1.00 – 1.24 1
1 Drilling Mud PV/YP Ratio < 1.00 -2
2 Drilling Mud Gel Strengths 10 minute < 2 x 10 second 3 3
2 Drilling Mud Gel Strengths 10 minute > 12 lb/100 ft2 -2
3 API FL & Cake where BHST < 3000 F API FL < 8 and Filter Cake < 2 2 2
3 HTHP FL & Cake where BHST > 3000 F HPHT FL < 20 and Filter Cake < 4 2
4 2-Arm Caliper Average Hole Size 1.5” - 2” > Casing OD 3
4 2-Arm Caliper Average Hole Size 2.01” – 3” > Casing OD 2
4 2-Arm Caliper Average Hole Size 3.01” - 4” > Casing OD 1 1
4 2-Arm Caliper Average Hole Size > 4.5” > Casing OD -2
5 2-Arm Caliper Hole Size Across First 280’ of OH Drilled Below the Shoe + Centralize 1 per jnt on entire 280’ / 7 jnts Hole Size is no larger than Casing Tube OD + 3.5” 3
6 Cement Displacement Rate > 200 ft/min Annular Velocity for 50-75% of Displacement 2 2
6 Cement Displacement Rate > 200 ft/min Annular Velocity for 75% of Displacement 3
7 Centralization > 70% Standoff 2
7 Centralization 60-69% Standoff 1 1
7 “ Strategic “Centralization Directly Above & Below Washouts per Caliper Log 1
8 Pipe Reciprocation During Mud Circulation+ Yes 2
8 Pipe Rotation During Cement Job 81-100% of Displacement 3
8 Pipe Rotation During Cement Job 60-80% of Displacement 2 2
9 Circulation > 2.0 x Bottoms-Up 2 2
10 Static Time < 3 minutes 1 1
10 Static Time > 15 minutes -1
11 Top & Bottom Plug Yes 1 0
12 Weighted Spacer Annular Length > 1000 feet 1 1
12 Turbulent Spacer Contact Time > 10 minutes 2
7” Liner
Item
# *Parameter *Measurement Available Score Planned Score Actual Score Actual Measure
1 Drilling Mud PV/YP Ratio 1.50 – 2.00 +3
1 Drilling Mud PV/YP Ratio 1.25 – 1.49 +2 2
1 Drilling Mud PV/YP Ratio 1.00 – 1.24 +1
1 Drilling Mud PV/YP Ratio < 1.00 -2
2 Drilling Mud Gel Strengths 10 minute < 2 x 10 second +3 3
2 Drilling Mud Gel Strengths 10 minute > 12 lb/100 ft2 -2
3 API FL & Cake where BHST < 3000 F API FL < 8 AND Filter Cake < 2 +2 2
3 HPHT FL & Cake where BHST > 3000 F HPHT FL< 20 & Filter Cake < 4 +2
4 2-Arm Caliper Average Hole Size 1.5” - 2” > Casing OD +3 3
4 2-Arm Caliper Average Hole Size 2.01” – 3” > Casing OD +2
4 2-Arm Caliper Average Hole Size 3.01” - 4” > Casing OD +1
4 2-Arm Caliper Average Hole Size > 4.5” > Casing OD -2
5 2-Arm Caliper Hole Size Across First 280’ of OH Drilled Below the Shoe + Centralize 1 per jnt on entire 280’ / 7 jnts Hole Size is no larger than Casing Tube OD + 3.5” +3 3
6 Cement Displacement Rate > 200 ft/min Annular Velocity for 50-75% of Displacement +2
6 Cement Displacement Rate > 200 ft/min Annular Velocity for > 75% of Displacement +3 3
7 Centralization > 70% Standoff +2 2
7 Centralization 60-69% Standoff +1
7 “Strategic” Centralization Directly Above & Below Washouts Per Caliper Log +1
7 Centralization 1 Centralizer / Joint in Liner-Lap +2
8 Pipe Reciprocation During Mud Circulation+ Yes +2
8 Pipe Rotation During Cement Job > 75% f/ Spacer @ shoe to Bump +3
8 Pipe Rotation During Cement Job 50-75% f/ Spacer @ shoe to Bump +2 2
9 Circulation > 2.0 x Bottoms-Up +2 2
Document Actual Average Circulation Rate, Pressure & AV ____ BPM @ ____ PSI @ ____ ft/min AV
10 Static Time < 3 minutes +1 1
10 Static Time > 15 minutes -1
11 Top & Bottom Plug Yes +1
12 Weighted Spacer Annular Length > 1000 feet +1 1
12 Tuned-Spacer (or equivalent) > 1000 feet +2
13 Batch-Mix Cement? Entire Slurry +2 2
13 Batch-Mix Cement? Tail Slurry across Production Zones +1
14 Use Pressurized Cement Balance? Yes +1 1
14 No -1
15
15 Rig Pump Planned as “Rapid Standby” in Case of Leak in Cementing Lines? Yes
No 1
-1 1
16 Stirred Fluid Loss (Final Test) < 55 cc / 30 min @ 1000 psi 1 1
16 Stirred Fluid Loss (Final Test) > 55 cc / 30 min @ 1000 psi -1
17 Free Fluid @ 450 (Final Test) = 0 +1 1
17 Free Fluid @ 450 (Final Test) > 1 cc -1
4-1/2” Liner
Item
# *Parameter *Measurement Available Score Planned Score Actual Score Actual Measure
1 Drilling Mud PV/YP Ratio 1.50 – 2.00 +3
1 Drilling Mud PV/YP Ratio 1.25 – 1.49 +2 2
1 Drilling Mud PV/YP Ratio 1.00 – 1.24 +1
1 Drilling Mud PV/YP Ratio < 1.00 -2
2 Drilling Mud Gel Strengths 10 minute < 2 x 10 second +3 3
2 Drilling Mud Gel Strengths 10 minute > 12 lb/100 ft2 -2
3 API FL & Cake where BHST < 3000 F API FL < 8 AND Filter Cake < 2 +2 2
3 HPHT FL & Cake where BHST > 3000 F HPHT FL< 20 & Filter Cake < 4 +2
4 2-Arm Caliper Average Hole Size 1.5” - 2” > Casing OD +3 3
4 2-Arm Caliper Average Hole Size 2.01” – 3” > Casing OD +2
4 2-Arm Caliper Average Hole Size 3.01” - 4” > Casing OD +1
4 2-Arm Caliper Average Hole Size > 4.5” > Casing OD -2
5 2-Arm Caliper Hole Size Across First 280’ of OH Drilled Below the Shoe + Centralize 1 per jnt on entire 280’ / 7 jnts Hole Size is no larger than Casing Tube OD + 3.5” +3 3
6 Cement Displacement Rate > 200 ft/min Annular Velocity for 50-75% of Displacement +2
6 Cement Displacement Rate > 200 ft/min Annular Velocity for > 75% of Displacement +3 3
7 Centralization > 70% Standoff +2 2
7 Centralization 60-69% Standoff +1
7 “Strategic” Centralization Directly Above & Below Washouts Per Caliper Log +1
7 Centralization 1 Centralizer / Joint in Liner-Lap +2
8 Pipe Reciprocation During Mud Circulation+ Yes +2
8 Pipe Rotation During Cement Job > 75% f/ Spacer @ shoe to Bump +3
8 Pipe Rotation During Cement Job 50-75% f/ Spacer @ shoe to Bump +2 2
9 Circulation > 2.0 x Bottoms-Up +2 2
Document Actual Average Circulation Rate, Pressure & AV ____ BPM @ ____ PSI @ ____ ft/min AV
10 Static Time < 3 minutes +1 1
10 Static Time > 15 minutes -1
11 Top & Bottom Plug Yes +1
12 Weighted Spacer Annular Length > 1000 feet +1 1
12 Tuned-Spacer (or equivalent) > 1000 feet +2
13 Batch-Mix Cement? Entire Slurry +2 2
13 Batch-Mix Cement? Tail Slurry across Production Zones +1
14 Use Pressurized Cement Balance? Yes +1 1
14 No -1
15
15 Rig Pump Planned as “Rapid Standby” in Case of Leak in Cementing Lines? Yes
No 1
-1 1
16 Stirred Fluid Loss (Final Test) < 55 cc / 30 min @ 1000 psi 1 1
16 Stirred Fluid Loss (Final Test) > 55 cc / 30 min @ 1000 psi -1
17 Free Fluid @ 450 (Final Test) = 0 +1 1
17 Free Fluid @ 450 (Final Test) > 1 cc -1
ATTACHMENT-9
ISC Stinger running procedures
• Check the ISC Stinger - ensure all the o-rings are in place and do not have any nicks or cuts. Replacement o-rings are available through the Tool House. Before installing new o-rings, clean cement or mud out of the o-ring grooves. Check that the bottom of the Stinger is not "egg" shaped or distorted.
• Rabbit the pipe the ISC Stinger is to be made up on
• Make up the ISC Stinger and the DP.
• A centralizer for the size of casing should be used above the ISC Stinger
• Run In Hole with the ISC Stinger - Rabbit the pipe on the way in to ensure there are no obstructions.
• Gently Stab into the latch-in float shoe/collar
• Fill the annulus between the outside of the drill pipe and the inside of the casing with water (to minimize potential for collapse of the casing while pumping cement)
• If there is not sufficient weight of drill pipe, the drill pipe may need to be chained down to prevent the ISC Stinger from being pumped out during cementing.
• Install the circulating head
• Mix and pump the required volume of cement. STOP
• Remove the circulating head and put the ISC dart into the drill pipe. Ensure that the top dart fin is far enough down the drill pipe so that the fin does not get pinched when the circulating head is re-installed
• Install the circulating head.
• Pump 3 - 5 barrels of cement on top of the ISC dart. (There may be enough cement left in the lines from the cement unit to the rig floor). This cement allows overdisplacement of the dart to ensure the dart seats. It also allows cement to be placed on top of the dart after the ISC Stinger is pulled out of the float shoe/collar.
• Pump the required displacement to bump the dart into the float shoe/collar. Bump the dart at 1 barrels per minute to ensure the dart has momentum to pass through the stinger and latch into the float shoe/collar.
NOTE: Displace with cement unit. Do not use rig pumps.
• Apply 1000 psi above final circulation pressure to the drill pipe.
• Bleed off pressure to check that float equipment is holding
• Pressure up on the drill pipe to between 750 - 800 psi
• Slowly pull the ISC Stinger out of the float shoe/collar while maintaining this pressure on the drill pipe. (This is to ensure that the ISC dart stays in place as the Stinger is removed)
• Pull out of hole with the ISC Stinger
• Wash the Stinger down - inspect for damage - store the stinger and centralizers properly for the next ISC job.
ATTACHMENT-10
Drilling Spreadsheet
