E DRILLER

Maximizing the drilling perfor- mance of today's complex drilling programs requires greater control of the drawworks. Varco's Electronic Driller provides that control by helping drillers carefully monitor multiple parameters and make instant control adjustments. Field data on the Electronic Driller indicates a signifi- cant reduction in average rotating hours when com- pared to offset wells drilled with pneumatic auto drillers or by hand. Electronic Driller is the only auto drilling system that maintains a constant drilling state through continuous pay out of the drill line. This constancy ensures opti- mum bit contact with the formation, thereby reducing bit bounce and increasing productivity. Equally impres- sive is the greater repeatability of drilling performance in wells drilled with the Electronic Driller. Varco's drilling system also provides safer rig opera- tions during tripping. Connection times improve because the Electronic Driller can reposition the eleva- tor for the floormen and derrickman, which reduces driller stress by helping him with critical control func- tions. Disc Brakes To achieve the full benefits of the Electronic Drillers' control capabilities, the Drawworks auxiliary brake is replaced by a plate disc brake assembly. Unlike elec- tromagnetic or traditional band brakes, Electronic Driller is able to use the plate disc brake to maintain a constant drilling state under varying load conditions. For rigs with existing disc brakes, the Electronic Driller can easily be integrated for proper control. For rigs without disc brakes, the Varco system offers a disc brake module, suitable for rig upgrades or new draw- works installations. And since our disc brake remains virtually silent during operation (in contrast to band brakes), the rig crew enjoys a safer working environ- ment. Actual brake specification and configuration will depend on a rig survey. Electronic Driller Features Maintains steady drilling condition through im- proved control of the Drawworks' disc brake Maintains a constant control parameter, i.e. WOB, delta-P (used with downhole motor) or surface torque Ability to monitor and switch between control pa- rameters (WOB, delta-P, torque and ROP) Secondary parameters can be used to respond to abnormal drilling conditions Varco's control logic allows for smooth, continuous pay out of drill line Safer rig operations through block control and the elimination of band brake’s quealing Crown and floor savers prevent traveling assembly collisions Traveling block speed limits protect against swab and surge effects Weight deviation (pipe drag) monitoring detects overpull and slack-off weight situations during POOH and RIH Fully integrates with Rigsense and V-ICIS systems




The ADS family of hoisting systems represents the next step in Varco's strategy to continuously advance the efficiency, productivity and safety of the drilling process. Varco applied the same advanced technology they used to design their AC top drives and automated pipe handling system to the hoisting process. The result is a feature-rich hoisting system that dramati- cally reduces time-to-depth and provides drillers with enhanced hoisting control capabilities. The Varco ADS: AC-powered motors that provide significantly more performance and have made possible a ma- chine that requires approximately half the space and weight with lower maintenance than tradition- al drawworks. A sophisticated braking system that offers precise proportional control, to improve drilling and trip- ping efficiency while increasing safety. Automation of repetitive hoisting and drilling oper- ations through user-friendly, touchscreen Elec- tronic Driller interface or V-ICIS eD. Unique AC-power control characteristics, such as regenerative braking and load holding without us- ing the friction brakes. ADS Performance Model ADS Modularity 500,000 1,000,000 2,000,000 1,500,000 2,500,000 ADS-10S ADS-30Q ADS-30T ADS-10


Drawworks Disc Brakes 21 The hydraulic accumulators are used to improve response time and provide a short term back up pressure supply in the event the elec- tric and air pumps fail. UNIQUE CALIPERS. THE MAIN SERVICE CALIPER ASSEMBLY. Depending on the size of the drawworks, there are four to six service brake calipers. Each caliper consists of a stainless steel piston that operates in a hardened stainless steel bushing contained in a stainless steel cylinder, two lever arms, and two brake pad assemblies. Changing pads or replacing calipers requires only a few minutes. The cylinders are designed to operate at maximum system pres- sure however, the normal operating pressure is much less. SPRING-SET PARKING/EMERGENCY CALIPER. In addition to the hydraulically-actuated calipers, each disc brake system includes two spring-set, hydraulically-released calipers. These calipers use a hydraulic piston to compress a stack of Belleville disc springs. During normal operation, hydraulic pressure keeps the springs compressed and the parking brake released. However, in the event of complete loss of hydraulic pressure, elec- trical failure, or by operation of a manual valve, the springs extend and set the brake. Not only do they act when pressure is lost unexpectedly, but they may also serve as a parking brake when the rig is idle for extended periods or while undergoing maintenance. A crown protection device can be installed in the system, which when tripped, activates the calipers. Main (Service) Caliper Emergency Caliper Main (Service) Caliper


Drawworks Disc Brakes 20 IMPROVED BRAKING RELIABILITY FOR DRILLING RIGS. As drilling depths increase and hookloads get heavier, conventional band brakes are often taxed to their limits. The National Oilwell Universal Disc Brake offers these advantages over conventional band brakes. GREATER HOLDING POWER. The disc brake has significantly greater resistance to fade than a band brake, and requires less mechanical input force by the driller to control the heaviest loads. LESS DOWNTIME. Change out of brake pads is easy and fast. Unlike most band brakes, there is no need to worry about kinking or other damage during removal and installation. Also, access for main- tenance is on the front side of the drum shaft. RELIABLE OPERATION. Conservative power ratings, redun- dancy, and auxiliary back-up systems all assure reliable operation. ACCURATE CONTROL. The brake control system, coupled with the hydraulics, provide a high degree of control. NO BRAKE HANDLE "KICK-BACK". Dragging brake bands of conventional brakes can cause severe and dangerous brake handle kickback. This cannot happen with disc brakes. EASE OF REMOTE CONTROL. The brake can be controlled from positions remote from the traditional driller's position without complicated mechanical systems. LESS NOISE. Significant noise reduction for drilling in noise sensitive environments. PROVEN. This braking system is being used successfully on a number or rigs. ADAPTABLE. The disc brake system replaces band brakes, upgrading your present drawworks. EASY TO RETROFIT. The system is simple to install on existing National Oilwell drawworks. The Universal Disc Brake System consists of three major components: the discs, the hydraulic system, and the caliper assemblies. THE DISCS. The system uses two hardfaced discs machined from alloy steel with an internal water jacket. Disc thickness is three inches. Disc diameter is normally four to five inches greater than the band brake rim. Both braking surfaces on each disc are hardfaced with a weld over- lay. The hardfacing increases disc life and minimizes surface grooving. THE HYDRAULICS. The hydraulic power unit consists of: • A stainless steel hydraulic reservoir. • An electrically-driven, variable-displacement, internally pressure- compensated hydraulic pump. • A pressure relief valve. • Two pressure reducing/relieving valves. • Four piston type accumulators. • An emergency air-driven pump and two air-piloted hydraulic valves. • Nickel plated steel block manifold. In a typical installation, the variable displacement pump is set to maintain maximum system pressure, while the relief valve will open at approximately 200 psi above the maximum pressure. This protects the system in the event of a pump malfunction. The two primary accumulators, isolated from each other by check valves, supply pressure to the two main valves at the driller's brake handle


Drawworks Disc Brakes 22 DUAL BRAKES FOR GREATER SAFETY. This is actually a dual braking system. The hydraulic circuits for the driller's side and the off-driller's side service caliper assemblies are completely independent. ADDITIONAL BACK-UP. The air-operated back-up hydraulic pump supplies hydraulic fluid at approximately the maximum system pressure to operate the brake in the unlikely event of a primary pump failure. ACCURATE CONTROL. The driller can control the main service brakes to a fine degree. Sensitive operations are accomplished with ease. ELECTRONIC REMOTE CONTROL PACKAGE. With the growing trend to remove the operation of the drilling func- tion to enclosed areas and driller’s cabins, National Oilwell can now offer the ability to electronically control the drawworks functions. Whether use of an existing band brake or with a disk brake system, the interface of the drawworks controls can be safely operated through the electronic control package. ELECTRONIC JOYSTICK CONTROLS. Safely remove the driller from harsh environments and offer precise control of all of the drawworks functions. TOUCH SCREEN, MENU DRIVEN. With the provision of electronic driller’s control screen, every func- tion and operation of the drawworks is displayed for ease of opera- tion and can also provide warning signals to prevent dangerous conditions and limits. SYSTEM COMPATIBLE. The National Oilwell electronic remote control package can inter- face with other rig floor systems to provide a reliable, safe and inte- grated system. With the installation of the National Oilwell electronic drawworks controls, the driller can be assured the operation of the drawworks is performing to the safe design limits and capabilities of the equipment. TOTAL PACKAGE. With the addition of the Energy Monitor and Autodriller System a complete package which provides not only operator interface, but additional safety features to maintain safe and reliable operation in harsh environments. CREW SAFETY AND OPERATION LIMITS. When the Energy Monitor System is in operation, the preset limits of safe operation are continuously monitored. If ever these limits are approached, the Energy Monitor System warns the operator of approaching limits. The system automatically applies braking func- tions when these limits are exceeded to bring the equipment safely under control. AN IMPORTANT OPTION. To take full advantage of the benefits afforded by the Universal Disc Brake System, National Oilwell offers an integrated PLC based Energy Monitor and Autodriller System. This system ensures that the maximum kinetic energy of the traveling equipment is not exceeded, while monitoring the position of the traveling equipment within preset limits of travel. It also provides precise control of bit weight when drilling


8 Drawworks National Oilwell’s E-3000 family of drawworks is specifically designed for deep offshore and exploratory drilling. They are rated for 3000 horsepower (2238Kw) and a nominal depth range up to 30,000 ft. (9144m). Clutch shifting is air controlled from the driller’s console. When coupled to the National Oilwell disc brake system, this makes an ideal arrangement for remote mounted driller’s controls. Standard high and low clutches are Twin Disc PO342. Motor arrangement can be fitted with 2 or 3 drilling motors driven off the rear section of the drawworks to the input shaft. The National Oilwell Universal Disc Brake System is used on the E- 3000-UDB and M-3000-UDB. This system replaces the standard band brake system with a hydraulically controlled disc brake system. It provides improved performance over conventional band brakes. E-3000 & E-3000-UDB ELECTRIC / M-3000 & M-3000-UDB MECHANICAL 206 305 257 178 380 264 231 148 342 220 High 418 606 875 1224 12 lines 521 362 756 525 1091 755 1527 1074 16 lines 10 lines 468 310 679 438 981 630 1373 880 14 lines 8 lines Low High 2nd Low 2nd Transmission High Low Drum Clutch Total load in 1000 lbs. SPECIFICATIONS NATIONAL Type A-1 air catheads or other upon request. Airflex 24VC650 air clutch for rotary drive. Twin Disc PO342 for high drum drive. Airflex 24C3500 air clutch for coring reel drive. 66 in. OD x 12 in. wide water cooled brake rims, or 72 in. dia, discs. 16000 to 30000 ft. depth rating. 123/4 in. dia. x 703/4 in. long coring reel drum. Equalizer type drum brakes. 36 in. dia. x 62 in. long main drum. Twin Disc PO342 for low drum drive. 3000 input horsepower rating. Dimensions, weights, and other specifications for all drawworks are on pages 12 and 13. E-3000 with standard PO-342 clutch-hoisting capacities* Rated for 3000 combined input horsepower. M-3000 with standard PO-342 clutch-hoisting capacities* Rated for 3000 combined input horsepower. High Low Drum Clutch 255 450 610 1224 12 lines 318 220 561 390 761 530 1527 1074 16 lines 10 lines 286 180 504 325 684 440 1373 880 14 lines 8 lines High Low High Low Transmission Total load in 1000 lbs. *These loads are the heaviest that should be handled within the designed capaci- ty of the drawworks, regardless of power available.