Complete details of Draw Works equipment in oil rigs

7/21/2019 Complete details of Draw Works equipment in oil rigs

http://slidepdf.com/reader/full/complete-details-of-draw-works-equipment-in-oil-rigs 1/23

1 INTRODUCTIONThe ADS-10SD (Automatic Drawworks System) is a combination of a gear drivenmechanicaldrawworks equipped with two AC variable speed motors and a multi-discfriction brake with anadvanced control system. The ADS-10SD is driven by two ACmotors powering one 1800horsepower capacity gearbox. The system is used forhoisting and lowering the travelingequipment of a drilling rig to remove and insertdrilling tubulars into a well bore.

The ADS-10SD is modular in design and consists of a single unitized frame tosupport the drumshaft assembly and AC motors and to provide torque reactionpoints for the modular gearbox andthe brake assembly. The frame is designed toreact the load from the drill line, interface with thecustomers support structure andallow for 4-point lift of the entire machine for installationpurposes. The drum shaftassembly consists of the wire rope drum, the drum shaft and twobearing carriers forinterfacing with the frame assembly. The drum is designed to carry therequired drillline and uses patented Lebus grooving to assure proper spooling of the drill line.The

bearing carriers are designed to interface with the frame assembly to provideanchorage andallow removal of the drum shaft assembly from the front of themachine. The gearbox isassembled to the drum shaft for transferring power from the AC motors. The gearbox utilizeshelical gearing resulting in smooth and quietoperation.The ADS-10SD is designed to use AC motors and associated electricaldynamic braking systemas the primary braking mechanism. Control of the NOVfriction brake provides parking andemergency functions. The multi-disc brakeassembly is air cooled and mounted to the side of thedrum shaft support upright. Thetorque from the drum shaft is transferred to the rotating elementsof the brake throughsplined drive gear sleeves. The body of the brake is bolted directly to thedrum shaft support upright and transfers the brake torque from the drum shaft to the

drawworksskid through the support upright. The braking system is a spring appliedair cooled design thatapplies the brake if there is a loss of air pressure (fail safe).The ADS-10SD integrates the control of hoisting and braking into an intelligent, faulttolerant,operator friendly system. The primary control of the system is via a single joystick that allows theoperator to command proportional hoisting and loweringspeeds with a single input. The controlsystem controls the Variable FrequencyDrives (VFD) / motors and mechanical brake to maintainthe ADS operatingparameters and control block velocity throughout the entire range of travel ofthe block.

0The VFDs must be configured in a master/slave configuration. The drivesmust be changeablebetween the master and slave configuration to allow for

continued operations in the event of adrive or motor failure / reassignment.The main advantage of an AC powered gear driven drawworks is the ability tooperate in hoist,lower and stop modes without setting a parking brake or engagingand disengaging a drum clutcheach time a change is made from one mode toanother. Additionally, taking advantage of the highspeed and torque of AC motors, afull range of hoisting speeds and loads can be accomplishedwith a single speedgearbox.By using 100% dynamic braking resistors for all operations within theirpower capacity, setting ofthe brake can be kept to a minimum thereby increasing theefficiency of tripping and simplifyingthe tasks performed by the driller. Themechanical brakes are only used for emergency stops,parking, and for emergencymanual load-lowering in case of a power outage.



Description

FeaturesThe ADS-10SD is a gear-driven drawworks with VFD-controlled AC motors and a multi-plate, aircooled, parking/E-Stop friction brake. The drawworks components are mounted on a unitized skid.The driller, at an operator control station, uses a dedicated joystick and switches to remotely

operate the ADS through an Amphion Control System. (Refer to the Amphion User’s Manual formore details.)The ADS-10SD provides a full-capability hoisting system consisting of AC-powered hoist motors(2), a single speed gearbox, a wireline drum, a plate disc brake and an ADS control system.

Wire Rope DrumThe wire rope drum is supported by two bearing carriers mounted to a structural steel skid. Thedrum is fitted with Lebus grooving for customer-specified wire. A crown saver toggle valve islocated above the drum. The valve is located where it can be activated by the wire rope, just shortof the point at which a crown collision would occur. When the valve is activated it sends a signal toa crown saver pressure switch which alerts the control system to stop the drum.

Gearbox (Wet Sump)Power is transmitted from the hoisting motor through a single-speed double reduction, helical gear

assembly. The gears are splash-lubricated from the oil in the gearbox sump and the bearings arelubricated via a pressurized lubrication system.The gearbox has its own oil lubrication circuit. This circuit contains a positive displacement pump(with 105 psi internal bypass), a 20 micron oil filter (with a 55 psi differential dirt alarm and a 60 psidifferential mechanical bypass), a thermostatic valve, a heat exchanger, and various mechanicalgauges and pressure transmitters. When the oil is below 120° F, about 1/4 of the flow is sent to thegearbox bearings and 3/4 of the flow is diverted directly back to the gearbox sump. When the oilexceeds 120° F, about 1/4 of the flow is sent to the bearings and 3/4 of the flow is diverted to theheat exchanger. From there, the flow is directed immediately back to the gearbox sump.The heat exchanger is air-cooled. (See "Oil Lube System" on page 2-5.)

AC MotorsThe ADS uses the motors to drive the wire rope drum through the gearbox. The motors arecoupled to the gearbox with double spherical gear drive couplings. The wide range of motor speed

allows the ADS to achieve a broad range of hoisting speeds. Using multiple motors increaseshoisting capability.

Motor BlowersThe motor blowers provide open-loop, forced air cooling to the AC motors.

Friction Brake (Air Cooled)The brake is a spring set, fail safe, 36” diameter, air cooled, multi-plate disc brake. Air pressuremust be applied to compress the springs and release the brake. When air pressure is removed, thesprings expand and the brake is engaged. The brake applies braking torque to the drum assemblyduring both emergency stop and parking operations. The brake assembly is mounted to one endof the drumshaft and is secured in a brake support carriage.

Rotary EncodersRotary encoders provide speed and block position information. Encoders are direct-coupled toeach motor and are also coupled to the gearbox intermediate shaft.

Sensing and Feedback DevicesSensing devices are used to monitor equipment functions. Sensor device outputs are sent to thecontrol system where they are processed to provide feedback for closed-loop control and todisplay status information to the driller. Several types of sensing devices are used. The varioussensing and feedback devices and their locations are illustrated in Chapter 5 of this manual.

ADS Control SystemThe ADS control system is based on a National Oilwell Varco tool controller and includes allnecessary software to control the drawworks and provide operator control and status functions.The tool controller system is based on Profibus DP serial communications for tool field equipmentwhere the remote I/O technology minimizes rig and tool cabling and provides the flexibility to utilizesmart type sensors/devices. This link connects with VFDs and plate disk brake controllers tocontrol hoisting and lowering speeds. The tool controller peer-to-peer communications and



interface to a higher level network is accomplished via Ethernet communications and forms thebackbone of the Amphion system. The ADS tool controller is located in one of the two NationalOilwell Varco multi-tool control cabinets (MTC) that is housed in the drill floor LER. UPS supply isrequired for the MTC housing the ADS controller.

Sensor ModuleThe ADS is equipped with the necessary skid-mounted sensors that are required to achieve the

performance stated in the functional design specification. These will typically be differentialpressure switches, absolute encoders, air pressure switches, servo valves, pressure transmitters,RTDs, solenoid valves, flow transmitters and proximity sensors. Sensors mounted off skid are tobe provided as part of the drilling instrumentation package.

General Arrangement



2 SAFETY FUNCTIONSThe Driller’s experience and skill provides primary safety functions. The ADS controlsystemprovides secondary functions of which the most important are:

2.1 Drill Line ProtectionThe purpose of this protection is to give maximum life to the drill line; however theDriller isprimarily responsible for accelerating and decelerating in a manner that doesnot foul or damagethe drill line. Drum acceleration when lowering is automaticallylimited, based on hook load andthe number of lines strung, to a value that will keeptension on the drill line. Deceleration is alsolimited when hoisting to keep a similartension on the line.2.2 Drill String Maximum Pull Limit ProtectionThe purpose of this protection is to avoid submitting the drill string to excessivetension.Maximum pull protection is provided by allowing the Driller to enter amaximum hook load that hecan pull. This value is used to calculate a velocity limitduring hoisting. Because of the need touse a filtered hook load signal to reduce theeffects of acceleration loading, the actual measuredhook load during the operationmay be slightly higher or lower than the value entered. Thisvelocity limit does notoverride the deceleration rates of the system, so if the limit is reached andthe systemis moving fast the system will decelerate per the calculated deceleration rate.Thiscould cause a large overshoot of the entered hook load value. The Driller shoulduse cautionwhen running in tight formation. This protection cannot prevent againstover-pull in everysituation, but the control system will be able to detect and respondto an over-pull condition fasterthan the driller would be able to respond.



2.3 Collision Protection

The purpose of this protection is to avoid collisions with the crown and drill floor. Thedriller,however, is primarily responsible for operating the ADS in a manner such thatcollisions do notoccur. Deceleration limits when lowering are calculated based on the

hook load, number ofmotors, and number of lines strung. Deceleration limits whenhoisting are based on accelerationrequired to keep the drill line in tension. Fromthese deceleration limits stopping distances arecalculated. Driller-entered limitsdefine the allowable zones of travel for the traveling assembly.The combination ofthe deceleration limits, calculated stopping distances and Driller-enteredlimitscombine to define the velocity profile (or safe operating envelope). The ADScontrol system usesthis information to control the movement of the traveling assembly and allowoperating the systemat the highest acceptable speeds while keeping the systemwithin the operating limits of theassociated equipment. Additional informationregarding parameters that govern the operatingprofile will follow in later sections.

2.4 Equipment Protection

Various parameters are monitored to ensure that the equipment is operating properlyand will notbe damaged by loss of utilities. Major parameters being monitoredinclude Lube Oil Pressure,Brake Supply Air Pressures, Rig Supply Control AirPressure, VFD and motor parameters. Lossof these services or components, oroperation outside the recommended limits of thesecomponents may cause the ADScontrol system to enter a fault mode and slow or stop the ADSuntil the problem iscorrected. For some fault modes, a Driller-initiated override is available thatwill allowthe block to move at maximum speed if the Driller determines that the overall safetyofthe rig is best served by sacrificing the ADS or associated equipment.

2.5 Zone Management Protection

The ADS controller is capable of working in a drilling rig equipped with a ZoneManagementSystem (ZMS). The ZMS avoids collisions between the travelingequipment and other tools thatunder normal operations may enter the travelingrange of the traveling equipment. The ADScontroller continuously provides the ZMSsystem with a safe stopping height value. Based ontools positions the ZMScontinuously provides the ADS with a ZMS entry height. If the ZMS entryheight is

higher than the lower travel limit, the ADS controller uses the ZMS entry height asthelower limit. The ZMS always checks the safe stopping height signal before theZMS changes theZMS entry height. If the traveling equipment cannot be stoppedbefore the ZMS entry height, theZMS does not allow another tool to enter the zone.

2.6 Critical Sensor Redundancy

2.6.1 Hook Load Measurement Validation

The hook load measurement system is comprised of three sensors. An automatictwo out of threevoting logic assures that the system operates with a validated hook

load measurement. TheDriller is given the option to manually select the source forhook load measurement but this isintended as a temporary condition to overcome



the failure of two of the measuring sensors duringa well emergency. The Driller isgiven a clear warning that an erroneous hook load measurementcan cause thesystem to drastically overshoot its stopping target or decelerate in anexcessivemanner. The Driller is also given a warning that an erroneous hook loadreading can lead tocollisions or birdnesting of the drill line and that by manually

selecting the hook load source themeasurement validation is disabled. An alarm isalways present in the system if the hook loadmeasurement is not in Auto.

2.6.2 Block Position Verification

Block position is calculated by the ADS control system based on multiple drum shaftencoderinputs. Encoders mounted on the intermediate shaft of the gearboxes feedcounts during drumrevolution into the ADS control system. A set of screens guidethe Driller through a calibrationprocedure which also allows entry of the currentnumber of lines. The calibration process takesinto consideration drum diameter,wraps per layer, wire rope diameter and layer change locationsand allows the ADS

control system to relate drum rotation to block travel.Block position calibration pointsinclude the drill floor and a layer change which is visuallyestablished by the Driller.Ifone of the encoders fails, an alarm is generated on the Amphion screen. Operationis allowedto continue as normal and the active sensor switches to the valid encoder. If asecond encoderfails, the system is faulted and must be operated in single encodermode if block movement isrequired.

2.7 Velocity Control Implementation

The general control theory of the ADS control system is best represented by thefollowing graph ofthe desired velocity profile for the traveling assembly:



The ADS control system allows the maximum acceleration, maximum velocity andmaximumdeceleration of the traveling assembly in both the hoisting and lowering

directions while maintaining safe and reliable operation. By following the velocityprofile, the ADS control systemallows the driller to maximize the speed of tripsbetween positions in the derrick (between thetravel limits) while maintaining safeoperation. The driller is able to scale back the block speedfrom these maximumlimits at any time by adjusting the control joy stick position to less than100%.

Definitions:

Lower Deceleration Point – When lowering, the lower deceleration point is thelowest position atwhich braking can be utilized to safely stop the block withoutpassing the lower travel stop. Thelower deceleration point is calculated by adding the

calculated stopping distance for downwardtravel to the lower travel stop position.Stopping distance is calculated based on available brakingtorque and system inertia(which, in addition to constant system parameters, includes variablessuch as linesstrung, hook load and block position).

Lower Travel Stop – The lower travel stop is the first Driller defined position of lowertravel (ineffect when the Autodriller is not engaged). The Control System will notallow the lower travelstop position to be set below the lower travel limit. It is theresponsibility of the Driller to properlyset the lower travel stop position to prevent thetraveling assembly from impacting the floor orother equipment. After the controlsystem stops the elevators at the lower travel stop, the joystickmust be placed intothe center position before further lowering is possible. After centering thejoystick, the joystick can be used to lower the block to the lower travel limit.



Lower Travel Limit – The lower travel limit is the Driller defined position of lowermost travel.The Control System will not allow the lower travel limit position to be setbelow the known positionof the floor. It is the responsibility of the Driller to properlyset the lower travel limit position toprevent equipment hanging below the blocks or

top drive from impacting the floor or otherequipment. The ADS Control System, aspart of the ZMS, will automatically adjust the lowertravel limit based on informationregarding the position of other equipment that must enter thezone in which the blocktravels.

Drill Stop Point - The drill stop point is the Driller defined position of lower mosttravel whendrilling. The Driller must enter a value that corresponds to the blockposition that can beaccomplished when the links are fully tilted to the drill position.Since the zero elevator position isadjusted with the links in the float position the DrillStop Point will typically be a negative value.

Hoisting Deceleration Point – When hoisting, the hoisting deceleration point is theuppermostposition at which the block will begin deceleration to safely stop the blockswithout passing thehigh travel stop and keep tension in the drill line. The hoistingdeceleration point is calculated bysubtracting the stopping distance from the hightravel stop. Stopping distance is calculated basedon available braking torque andsystem inertia (which, in addition to constant system parameters,includes variablessuch as lines strung, hook load and block position).



High Travel Stop – The high travel stop point is the Driller-defined position of uppertravel. TheControl System will not allow the high travel stop position to be set abovethe high travel limit.The control system stops the top of the blocks at the high travelstop, the joystick must be placedinto the center position before further hoisting ispossible. After centering the joystick, the joystickcan then be used to hoist the block

to the high travel limit.

High Travel Limit – The high travel limit is the Driller-defined position of uppermosttravel. Justas the ADS control system will assist the operator in preventing floorcollisions, it will also assist inpreventing crown collisions by not allowing a high travellimit to be set above what is known by thecontrol system to be the maximum heightbefore impacting the crown block.

Dynamic Braking – Dynamic braking is defined as the use of the ADS motors ingenerator modeto provide braking. When dynamic braking is in use, the powergenerated is returned to the DCbus. If this results in the voltage on the bus

increasing, because there is insufficient load on thebus to absorb the power, choppercircuits will feed power from the DC bus to a resistor bank. Incase of a chopper orresistor failure, the ADS Control System will stop the system using thefriction brakes(defined as a Category 2 Brake Only Stop) The ADS Control System will thenreducethe available braking power figure accordingly and will use the reduced power tocalculatemaximum velocity and stopping distance.

Velocity Control – The VFD system works as a velocity control system.The positionof the ADS control joystick is a velocity command sent to thecontroller which thencommands the VFD and/or brake controller to go tothe desired block speed (aslimited by the velocity profile). The centralposition of the joystick represents zerovelocity (stationary drum). Thedifference between the desired velocity and the actualvelocity is an errorsignal. The magnitude of this error signal determines the force tobeapplied to the load.



3 PARK BRAKE MODEThe Park Brake Mode is intended to be used by the Driller to support the loadutilizing the NOVfriction brakes for long periods of time or when the Driller is notpresent at the Driller’s console.The ADS Control System will enter the Park BrakeMode when the Driller activates the parkingbrake switch. Alternatively, the ADSControl System will enter Park Brake Mode automaticallydue to a certain period ofinactivity (10 minutes) at zero speed command (joystick at centerposition).If theDriller activates the parking brake switch while the block is moving, the block willbedecelerated at the maximum rate according to the velocity profile. When the drumis stopped, theNOV friction brakes will be set as described in the Torque Transfersequence.If the parking brake was applied due to inactivity time-out or by the ParkBrake switch, the Drillermust toggle the Park Brake switch to the off position torelease the Park Brake Mode. When theDriller disengages from the Park BrakeMode the load is transferred from the NOV friction brakesto the motors as describedin the Torque Transfer sequence.

4 TORQUE TRANSFER SEQUENCEThe torque transfer sequence is a method of smoothly transitioning the load from theNOV frictionbrakes to the ADS motors or from the ADS motors to the NOV frictionbrakes.

4.1 Transferring From Brakes to Motors:The spring applied brake must have sufficient air supply pressure before allowing thetorquetransfer sequence from brake to motors to be initiated. Transferring the loadfrom the NOV frictionbrake to the ADS motors is accomplished by sending a smallhoisting speed command (roughly 5motor RPM) and a torque limit to the VFD

system. The torque limit is based on hook load, gearratio, number of lines andnumber of motors and is of a magnitude large enough to support theload (excessivetorque could cause damage to the system and related tools). Once thefeedbacktorque equals the calculated torque limit the brake is ramped to zero torqueover a short period oftime. As soon as the system detects movement in the hoistdirection the speed command isramped to zero and the torque limit is ramped tomaximum. Ramping of the brake torque andmotor torque limit in this fashion (asopposed to instantaneous changes) prevents transients,which could causeunnecessary and undesirable gearbox vibration. If the drum rotation indicatestheblocks are moving downward the brake is set and an alarm is generated indicatingtorquetransfer fail. If the feedback torque does not reach the torque limit the systemwaits until torque isreached or driller parks the system. If the drum does not move inhoist direction and torque isreached after 10 seconds an alarm is generated and thesystem returns to park. The driller mustrepeat the torque transfer sequence.

4.2 Transferring From Motors to Brakes:Transferring the load from the drawworks motors to the friction brake isaccomplished in a similarmanner. Once the load is stopped and is being held by themotors, the torque limit is set to valuelarge enough to support the load (based on thetorque feedback from the drive plus 10%). Thebrake is then ramped to full torqueover a short period of time. As soon as the load is beingsupported by the friction

brake (as determined by the brake pressure feedback), the motor torqueis ramped tozero over a short period of time. Ramping of the brake torque and motor torque



limitin this fashion (as opposed to instantaneous changes) and limiting the motortorque preventstransients, which could cause unnecessary and undesirable gearboxvibration. In the event ofbrake failure when transferring the load from motor to brake,if the movement in the loweringdirection is measured (by a defined amount) themotor torque limit is ramped back to maximum(with a zero motor speed command),

the motor/ VFD is not turned off and a warning is generatedindicating that the loadshould be set in slips as the brake cannot hold load.

5 LOWERING THE BLOCK5.1 Accelerating:Under normal operating conditions,when the operatorcommandsdownward travel of the block from astoppedcondition, (where the motorsare supporting the load) theADS control

system will accelerate the blockfollowing thevelocity profile. To achievethe fastest acceleration possible,theControl System has the ability to drivethe motors toassist in driving thesystem down. The ControlSystemcalculates the maximum safedownward acceleration (topreventfouling or birdnesting the drill line).Based on thecalculated acceleration,the Control System provides

theappropriate speed and torque limitcommands to the VFDsystem. Thevelocity command is ramped ascalculated bythe ADS Control Systemuntil either the velocity indicated bythecontrol joystick position or a maximumvelocity isachieved (as limited byequipment constraints such aspowerdissipation capacity of thebraking resistors, and motorpowerlimitations).

5.2 Maintaining Maximum Velocity:The maximum velocity is determined from the positionand inertia of the load, theavailable braking resistorcapacity, and the motor power limitations. Once theblockhas been accelerated to the maximum loweringvelocity, the velocity is maintained(and over speed isprevented) by utilizing the velocity control of the VFDsystem.

5.3 Decelerating and Stopping: As the Driller continues to command lowering, the block will continue to travel downat thecommanded velocity until reaching the lower travel stop. The Driller can stop

the block beforereaching the lower travel stop by returning the control joystick to the



center position therebycommanding zero velocity. The block will decelerate to zerovelocity per the velocity profile andsufficient motor torque is applied to hold the load. 5.4 Lowering with Manual ControlIn the event the control system is not functional to lower the block, the manual brakepressurecontrol valve located on the drawworks skid can be used to release the

brakes and lower the load.There must be sufficient air pressure to release thebrakes. If there is no air pressure the brakeswill remain engaged.

6 HOISTING THE BLOCK6.1 Accelerating:Under normal operating conditions, when the operator commands upward travel ofthe block froma stopped condition (where the motors are supporting the load) the ADS Control System willcommand the VFDs to accelerate the block upward. Thevelocity command to the VFD is rampedas calculated by the ADS Control Systemuntil either the velocity indicated by the control joystickposition or a maximum

velocity (limited by equipment constraints such as motor power limitations)isachieved.

6.2 Maintaining Maximum Velocity:The maximum velocity is determined from the position and inertia of the load, andthe availablecapacity of the motors. Once the block has been accelerated to thecommanded hoisting velocity,the velocity is maintained by utilizing the VFD system.

6.3 Decelerating and Stopping:When the blocks reach the hoisting deceleration point, the motors are used todecelerate the loadsafely to the high travel stop (as calculated to prevent fouling or

birdnesting the drill line). Whenthe velocity drops to zero, sufficient motor torque isapplied to hold the load.

7 BRAKE TESTING7.1 Brake Capacity Testing



The Driller can test the drawworks brake toensure the brake has the holding capacity toholdrated load. The test should be performedbefore any heavy lift. The system will perform atorque transfer from brake to the motors and then

record the torquerequired to hold the travelingassembly load. Once the per motor holdingtorque value is knownthe system then sets thebrake. Once the brake is engaged (checking tomake sure the pressureis less than 5 psi) themotor torque is ramped to the torque limitrequired to test that brake sectionby giving a verysmall block hoisting speed command (2 ft/min)and a torque limit (equal to thetorque limitrequired to test the brake) to the drive. Thesystem looks for movement of the drumby

monitoring the drum encoders. If movement is less than 7,000 counts after 15seconds thesystem passes and the pass indicator is illuminated for the brake andwill stay on until the test isperformed again. If the system slips by 7,000 encodercounts or 16.61 degrees of drummovement the brake fails and the fail indicator isilluminated for the brake and will stay on until thetest is performed again. (If thebrake slips at a speed of 2 ft/min for the 15 seconds of the testthere would beapproximately 75,000 counts).Note: Due to the input shaft torque limit the drawworkssystem cannot apply torque up to therating of the brake.Once the brake has beentested the system zeros the speed command and returns to park. A brake capacitypercentage is calculated. A Reduced Hook Load Capacity is calculated bytaking theCapacity (decimal format) from the brake (T motor_total ) times the rated hook load forthesystem.

7.2 Brake Slip Test (Brake insufficient to hold load)Every time the system is parked the control system checks to ensure that the load issupported bythe brake before turning off the drive. If movement is detected (9.5º ofdrum movement) the motortorque limit is ramped back to maximum (with a zeromotor speed command), the motor/ VFD isnot turned off and the following warningmessage is displayed.



8 APPLICATION OF BRAKES, EMERGENCY STOPBased on hardware faults and/or process conditions or variables the ADS controllermay initiatestop sequences. The ADS control system can perform four types ofstops.

8.1 Category 0 Stop A Category 0 Stop is defined as stopping byimmediateremoval of power to the hoistingmachine actuators (i.e.an uncontrolled stop).

When a Category 0 Stop isgenerated thesystem will simultaneously: Dump all airfromspring applied brakes and set all drives tocoast. Anemergency stop is considered aCategory 0 Stop.Conditions Leading to aCategory 0 Stop:

Driller’s Emergency Stop pushbutton

Local Control (Slip and Cut Station) EStop

ADS controller failure

Crown-O-Matic switch activation

Loss of Communications with remote

I/O block controlling brake bypass solenoidvalves and Park brake solenoid valves.

Block lowering when commandinghoist.Refer to the Alarm & Fault ResponseSpecification for a complete listing ofconditions that result in a Category 0Stop.

8.2 Category 2 Stop A controlled stop with power left available tothe hoistingmachine actuators. A Category 2stop is the normaloperational condition that



occurs when the driller placesthe Drawworks in the "parked" state.ConditionsLeading to a Category 2 Stop:

Both velocity inputs failed

Loss of communication with remote I/O(except brake valve I/O)

Low Air Pressure to Brake system Two out of three drawworks encodersfailed (and all encoders are enabled)

Two out of three hook load sensorsfailed (and all hook load sensors areenabled)

Failed torque transfer sequence (motor /brake)

E-Stop from push button other than Active Driller’s chair

Refer to the Alarm & Fault Response Specification for acomplete listing of conditionsthat result in a Category 2 Stop.

8.3 Category 2 Brake Only Stop A Category 2 Brake Only stop is acontrolled stop usingthe NOVfriction brakes. Torque is zeroed tothe hoistingmachine actuators. ACategory 2 Brake Only

Stopdecelerates with the sameprofile as a Category 2Stop.Conditions Leading to aCategory 2 Brake Only Stop:

Velocity not following command

Block movement whilecommanded tobe stopped

Loss of communication with aVFD

VFD, Chopper or Resistor failureRefer to the Alarm & FaultResponse Specification for acomplete listing of conditions thatresult in a Category 2Brake Only Stop.

8.4 Soft Trip



The Soft Trip is an operational condition that occurs when the ADS system detects anon-criticalfailure. When a Soft Trip occurs an alarm is immediately issued to theHMI. With an active SoftTrip the system prevents the block from traveling at morethan 25% of the currently enteredmaximum speeds (for hoisting and lowering).If theblock is traveling at more than 25% of speed when a Soft Trip occurs the alarm is

given butthe system continues to operate at the normal speed until the speed isreduced below 25%manually by the driller or automatically by the system whenapproaching the travel limit. Oncebelow 25% of full speed the system clamps anyfurther commands from the driller.At any time the driller can enable traveling speedsover 25% by holding the joystick past 25% ofcommanded speed and pressing andreleasing the override button. The limitation will re-engageas soon as speed isreduced again.If the system is parked while a Soft Trip is active the driller can onlyRelease Park brakes again bypressing and holding the override button while issuingthe “release park brakes” command. Oncepark brakes are released and the load istransferred to the motors the system will continue to bein Soft Trip mode.Conditionsleading to a Soft Trip:

Gearbox Lubrication Pressure Low Trip Brake Air Supply Pressure Low TripRefer to the Alarm & Fault Response Specification for a complete listing ofconditions that result ina Soft Trip.

9 ASSIGNING THE ADSThe assignment of the ADS is made via the Amphion HMI screen.

10 BLOCK POSITION CALIBRATIONThe Driller enters into the position calibration mode via HMI screen selection. While

in the BlockPosition Calibration Mode, ALL position based limits and safeties aredisabled and the Driller isnotified via HMI of this condition. The lower travel limits andupper travel limits are disabled untilthe block position calibration is completed.

11 POSITION/TRAVEL LIMITSThe ADS control system provides travel limits based on the position of the blocks inthe derrick.Two travel limits are set near the top of allowable travel, and two are setat the bottom. All travellimits are configurable by the operator. The upper limits arelimited to be below the bottom of thecrown and the lower travel limit is limited by thedrill floor at zero. All travel limits are overriddenwhen in the Block Position Calibration

and Slip & Cut modes. When in Autodrilling the lowertravel limit is the drill stop pointsetting which is only active when the Autodriller is enabled. Thedrill stop point can beset below the level of the floor to maximize drilling with links tilted out.The ADS alsoutilizes a crown saver pneumatic toggle valve which, when contacted by the wireropeas the block approaches the crown, triggers an immediate Category 0 stop. Thepneumaticcircuit is vented and the E-Stop circuit reset by pressing the override pushbutton while the togglevalve is manually returned to its normal position. When thecrown saver toggle valve is activatedor whenever a Category 0 stop occurs whilehoisting the block, a large warning window appearson all HMIs of the chair withDrawworks ownership. The warning indicates that the drill line mayhave birdnestedas the result of a Category 0 Stop while hoisting and that a visual inspection ofthe

drum must be performed before continuing operations.



12 SYSTEM OVERRIDEThe Driller has the ability to override the ADS Control System by pushing andholding an overridepushbutton located on the Driller’s chair console. When the

system is operating in override mode,the travel limits are inactive and the system isallowed to operate at maximum speed.

13 SYSTEM OPERATING MODES13.1 NormalNormal mode is used for most operations. When the Control System is in the normalmode thejoystick control is scaled to the Driller defined maximum speeds. Allposition based travel limitsare active.

13.2 Slow Mode

Slow mode is used for fine position control. During slow mode the joystick controlsare scaled tothe driller entered maximum up to 20 ft/min. All position based limitsand safeties are active.

13.3 Slip & Cut ModeDuring Slip & Cut Mode, the drum speed is limited to the driller entered value(maximum drumspool speed) and all position based limits and safeties are disabled. A notification/ warning is sentto the Driller’s Amphion screen indicating the system isin Slip & Cut Mode. All brake functionsare as normal.

13.4 Brake Only Mode

The Brake Only mode allows the Driller to lower the block to secure the drillstring inthe event of afailure of the VFD system or motors. Brake Only mode is the defaultmode of operation achievedby the system automatically when there is a Category 2trip that involves a failure in the VFDs ormotors. Using a Brake Only mode category2 stop the system decelerates the load in a controlledmanner following the velocityprofile. Brake Only mode can also be manually selected from thescreen. When inbrake only mode the Driller can select to turn "ON" the drawworks and thesystem willstart the lube pump. Velocity is limited to keep the lowering power to 100 HP.

14 MAXIMUM PULL LIMIT

A maximum pull limit can be entered by selecting the max pull limit button on theTripping screen.While hoisting the block, the system will slow and ultimately stop theblock as the hook loadapproaches the entered pull limit. The torque is not limited inany way as a result of the maximumpull limit and the system is allowed to lower.

15 MINIMUM HOOK LOAD A minimum hook load can be entered by selecting the Load Limits button on theTripping Screenand then selecting Minimum button on the pop-up screen. Thesystem will perform a Category 0stop if the measured hook load decreases to theentered value.



16 BRIDGE PROTECTIONBridge protection is provided by allowing the Driller to enter a drag limit that is usedin conjunctionwith hook load feedback to calculate a velocity limit during lowering. Asthe hook load approachesthe Drag Limit Setpoint the block is slowed. If the limit isreached while block is moving, thespeed setpoint is zeroed. The system will performa Category 0 stop if the measured drag is 1.5times the setpoint drag limit and theblock is still moving. The system auto-disables bridgeprotection when 5 foot fromlower limit (for setting slips when tripping) and re-enables when blockis raised 5 footabove lower limit. The system will automatically zero the Drag when thesystembegins to lower after it has been hoisted to a height 5 feet below the upperstop point. If the lockhas not been hoisted to within 5 feet of the upper stop point thesystem will not auto zero Drag.

17 ELECTRONIC DRILLER MODEThe Electronic Driller is one of the Operating Modes of the ADS Control System.

Auto-drillingselection is made through any of the Driller’s HMI screens. TheElectronic Driller is designed toprovide a constant drilling state at the bit. Thisconstant state is achieved through closed-loopcontrol of a selected primary drillingparameter (usually WOB or delta-P) and the ability to regulatethe AC motors for acontinuous feed of the drill line. Further drilling control is provided bycontinuouslyrunning secondary control parameters of ROP and torque. These parametersprovidethe necessary control for a steady state during unexpected events, such as adrillingbreak or stick-slip situation. This closed loop control is utilized to regulate the AC motors. Themain benefit of the Electronic Driller is to provide a system capableof significantly improving theefficiency of drilling operations (as measured by time todepth and number of bits used) overconventional control of the drilling rig

equipment.The Electronic Driller has four modes of control, which can be activatedindividually orincombination to form the optimum drilling control for the Driller. TheRate of Penetration or ROPcontroller is always active during auto drilling and servesas a limit to the maximum drilling rateallowed. The four individual modes of controlare:

17.1 ROP ModeThe ADS Control System will control the rate of drum rotation (descent of thetraveling equipment)to maintain a preset rate of penetration. This control mode isuseful when setting the bit on thebottom or when drilling soft formations wherecontrolling the penetration rate is important in drillinga consistent hole.

17.2 WOB ModeThe ADS Control System will control the rate of drum rotation (descent of thetraveling equipment)to maintain a preset constant weight on bit.

17.3 Delta P ModeThe ADS Control System will control the rate of drum rotation (descent of thetraveling equipment)to maintain a preset pressure in the standpipe. This controlmode is useful when utilizing downholemotors. The delta standpipe pressure is anindication of the drilling bit’s reaction to Roque intothe formation.



17.4 Torque ModeThe ADS Control System will control the rate of drum rotation (descent of thetraveling equipment)to maintain a preset top drive torque. This control mode mightbe used to increase the life of PDCbits and can also be used to reduce the possibilityand effects of slip stick.The WOB, Delta P and Torque controllers can be turned on

individually, but will probably becombined to form ideal drilling combinations. Forexample, WOB and ROP will be used mostoften to smoothly control the movementof the drill string and maintain constant WOB. Delta P and ROP will be used whendrilling with down hole motors and desiring to limit rate of penetration.With either ofthe above, torque could be added to reduce the possibility of stick-slip occurring.Thesystem will use regenerative braking as required to control the rate of drum rotation.

18 AUTO REAMING MODE

Auto Reaming selection is made from the Drilling Screen. The following Setup menuis displayed.

The driller enters a pull limit, hoisting speed, lowering speed and reaming distance.When theauto ream feature is enabled, once the elevator height has reached the drillstop point the systemwill automatically hoist at the entered hoisting reaming speed

until the block has traveled thereaming distance at which time the block will belowered at the lowering reaming speed until theelevators reach the drill low stop



point. The system will continue to ream until the driller turns autoreaming off or untilhe takes control of the system with the joystick. While lowering the blockduring autoreaming, the WOB, Torque and Delta P functions work as they do when AutoDrilling.The ROP is controlled to the lowering reaming speed as entered by thedriller. While hoisting theblock, the system will slow and ultimately stop the block as

the hook load approaches the pulllimit.

19 ADS CONTROL SYSTEM AND ELECTRICAL SPECIFICATION The ADS electrical design takes into account the hazardous area classification of aparticulardrilling rig installation. Electrical and control system designs have beenchosen to satisfactorilymeet or exceed the requirements of their respectively classedareas.The ADS utilizes (IEC / CENELEC) Ex electrical components and isconstructed according to IECstandards for marine applications. All hardware is ratedfor IP 56 min apart from the NOV drillingmotors which are rated IP 45 (drilling motor junction boxes are rated IP56).

Notes:

All externally mounted systems are suitable for a Zone 1 application exceptthe brakeservo valve control assembly which is Zone 2.

Auxiliary motors are 380-420 VAC, 50 HZ.

Standard NOV world class cable will be used on the skidThe ADS Amphion Controller is located in one of the two NOV Multi Tool Controlcabinets (MTC)housed in the Drill Floor LER, these MTC’s form an integral part ofthe Drilling Control & DrillingAcquisition System (DCDA). The Amphion controller isbased on a NOV Single Board Computer.The controller with its associated softwareprovides the safe operation of the ADS. The Amphioncontroller is designed tocommunicate to field devices via Profibus DP utilizing Remote I/O. TheProfibusRemote I/O technology minimizes cabling and provides the flexibility to utilize smarttypesensors / devices. Communications between the MTC cabinets and the ADSSkid is done on adual redundant Profibus Fiber Optic ring which also provides noiseimmunity. The ADS controlsystem communicates with the driller’s workstation acrossa higher lever Ethernet network, thisEthernet network also facilitates peer to peercommunications for Zone Management.

20 DESIGN DATA20.1 Size & Weight:

Maximum Width 119.0” (302.3 cm)

Maximum Length 248.0” (629.9 cm)

Maximum Height 107.4” (272.8 cm)

Maximum Weight (dry) 68,500 lbs (31,071 kg)



20.2 Prime Mover

AC Motor GEB 22

Manufacturer General Electric

Intermittent (Zone 2) Power Rating(each)

1,400 HP (1,044.0 kW) @45 °C

Continuous (Zone 2) Power Rating(each)

1,150 HP (857.5 kW)

Maximum Motor Speed 3,000 RPM

Motor Cooling (Local Blower EachMotor):

3,000 SCFM Air (84.95 m3/min)

20.3 Gearbox Data

Type: Single Speed, Double Reduction,Parallel Shaft

Power Rating: 1,800 HP (1,342.3 kW)

Ratios: -

Overall Ratio: 10.69:1

1st Stage (Input) 2.77:1

2nd Stage 3.86:1

Torque Rating 14,000 ft-lbs (18,981 Nm) Input shaft(Both ides

combined)11,000 ft-lbs (14,814 Nm) per side ofinput shaft (If only one side powering)

20.4 Drum Data

Wire Rope Diameter 1 3/8 in (3.49 cm)

Drum Tread Diameter 30 in (76.2 cm)

Drum Length (between wear plates) 54.25 in (137.8 cm)

Grooving Lebus for 1 3/8 in (3.49 cm) Dia. Rope

20.5 Brake Data

20.5.1 Dynamic Braking SystemDynamic Braking System: Regenerative braking using dynamic braking choppersand resistors to the fullpower capacity of the drilling drives and motors.



20.5.2 Emergency and Parking BrakeSpring Applied, Air Cooled, Pneumatically Released, Multi-Disc Brake.

Nominal Spring Balance Pressure(0 ftlbs nominal torque but residualdragpossible)

105 psi (723.9 kPA)

Full Release Pressure 120 psi (827.4 kPA) 1/4 inch Brake Clearance -

Static Capacity 287,500 ftlbs (389,798 Nm)

Dynamic Capacity 244,500 ftlbs (331,498 Nm)

3/8 inch Brake Clearance -

Static Capacity 266,200 ftlbs (360,919 Nm)

Dynamic Capacity 226,200 ftlbs (306,668 Nm)

Maximum Brake Pressure 150 psi (1,034.2 kPA)

Maximum Disc Temperature 280.4 °F (138 °C) continuous (as measured from OD of Rotors) 348.8 °F (176 °C) intermittent

Air Quality: Per ISO 4406 code 16/13

Dew point: 10° C below min. ambient temp, not toexceed 2° C

20.6 Hoisting Performance 1,800 HP (1,342 kW)



Specifications

Motor HP, total 1,800 HP 1,342 kW

Peak Motor Torque, total 14,000 ftlbs 18,981 Nm

Wire Line Diameter 1.375 in 3.49 cm

Drum Diameter 30 in 76.2 cmDrum Length 54.25 in 137.8 cm

Max Fast Line Pull, 1st Layer 111,096 lbs 50,392 kg

Max Fast Line Pull, 2n Layer 103,258 lbs 46,837 kg

Max Fast Line Pull, 3r Layer 96,453 lbs 43,750 kg

Hook Load Capacity (lbs) - 8 Lines, 3rd Layer 680,495 lbs 308,677 kg

Hook Load Capacity (lbs) - 10 Lines, 3r Layer 827,802 lbs 375,484 kg

Hook Load Capacity (lbs) - 12 Lines, 3rd Layer 966,974 lbs 438,612 kg

Complete details of Draw Works equipment in oil rigs

Documents

Transcript of Complete details of Draw Works equipment in oil rigs