1. Field of the Invention
The present invention generally relates to a riser auxiliary line jumper system for a rotating control device.
2. Description of the Related Art
In wellbore construction and completion operations, a wellbore is formed to access hydrocarbon-bearing formations (e.g., crude oil and/or natural gas) by the use of drilling. Drilling is accomplished by utilizing a drill bit that is mounted on the end of a drill string. To drill within the wellbore to a predetermined depth, the drill string is often rotated by a top drive or rotary table on a surface platform or rig, and/or by a downhole motor mounted towards the lower end of the drill string. After drilling to a predetermined depth, the drill string and drill bit are removed and a section of casing is lowered into the wellbore. An annulus is thus formed between the string of casing and the formation. The casing string is temporarily hung from the surface of the well. A cementing operation is then conducted in order to fill the annulus with cement. The casing string is cemented into the wellbore by circulating cement into the annulus defined between the outer wall of the casing and the borehole. The combination of cement and casing strengthens the wellbore and facilitates the isolation of certain areas of the formation behind the casing for the production of hydrocarbons.
Deep water offshore drilling operations are typically carried out by a mobile offshore drilling unit (MODU), such as a drill ship or a semi-submersible, having the drilling rig aboard and often make use of a marine riser extending between the wellhead of the well that is being drilled in a subsea formation and the MODU. The marine riser is a tubular string made up of a plurality of tubular sections that are connected in end-to-end relationship. The riser allows return of the drilling mud with drill cuttings from the hole that is being drilled. Also, the marine riser is adapted for being used as a guide means for lowering equipment (such as a drill string carrying a drill bit) into the hole.
The present invention generally relates to a riser auxiliary line jumper system for a rotating control device. In one embodiment, a method for deploying a marine riser includes: assembling a rotating control device (RCD) spool with the marine riser; lowering the RCD spool through a rotary table of a drilling rig and into a moonpool of an offshore drilling unit; connecting a hose to an upper and lower adapter of the RCD spool in the moonpool; and lowering the RCD spool and the connected hose through the moonpool.
In another embodiment, a jumper system for assembling a marine riser includes a rotating control device (RCD) spool having: an RCD housing; an upper adapter connected to the RCD housing and having a hose nipple; and a lower adapter connected to the RCD housing and having a hose nipple. The system further includes a jumper spool having: a hose; an upper latch connected to the hose and operable to engage the upper adapter nipple; and a lower latch connected to the hose and operable to engage the lower adapter nipple.
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
The drilling system 1 may include a mobile offshore drilling unit (MODU) 1m, such as a semi-submersible, a drilling rig 1r, a fluid handling system 1h (only partially shown, see
Alternatively, the MODU 1m may be a drill ship. Alternatively, a fixed offshore drilling unit or a non-mobile floating offshore drilling unit may be used instead of the MODU 1m.
The drilling rig 1r may include a derrick 3 having a rig floor 4 at its lower end having an opening corresponding to the moonpool. The rig 1r may further include a traveling block 6 be supported by wire rope 7 connected at its upper end to a crown block 8. The wire rope 7 may be woven through sheaves of the blocks 6, 8 and extend to drawworks 9 for reeling thereof, thereby raising or lowering the traveling block 6 relative to the derrick 3. A running tool 38 may be connected to the traveling block 6, such as by a rig compensator 31. Alternatively, the rig compensator may be disposed between the crown block 8 and the derrick 3.
The fluid transport system 1t may include an upper marine riser package (UMRP) 20 (only partially shown, see
A conductor string 51 may be driven into the seafloor 2f. The conductor string 51 may include a housing and joints of conductor pipe connected together, such as by threaded connections. Once the conductor string 51 has been set, a subsea wellbore 55 may be drilled into the seafloor 2f and a casing string 52 may be deployed into the wellbore. The casing string 52 may include a wellhead housing and joints of casing connected together, such as by threaded connections. The wellhead housing may land in the conductor housing during deployment of the casing string 52. The casing string 52 may be cemented 53 into the wellbore 55. The casing string 52 may extend to a depth adjacent a bottom of an upper formation 54u. The upper formation 54u may be non-productive and a lower formation 54b may be a hydrocarbon-bearing reservoir. Alternatively, the lower formation 54b may be environmentally sensitive, such as an aquifer, or unstable. Although shown as vertical, the wellbore 55 may include a vertical portion and a deviated, such as horizontal, portion.
The PCA 1p may include a wellhead adapter 40b, one or more flow crosses 41u,m,b, one or more blow out preventers (BOPS) 42a,u,b, a lower marine riser package (LMRP), one or more accumulators 44, and a receiver 46. The LMRP may include a control pod 48, a flex joint 43, and a connector 40u. The wellhead adapter 40b, flow crosses 41u,m,b, BOPS 42a,u,b, receiver 46, connector 40u, and flex joint 43, may each include a housing having a longitudinal bore therethrough and may each be connected, such as by flanges, such that a continuous bore is maintained therethrough. The bore may have drift diameter, corresponding to a drift diameter of the wellhead 50.
Each of the connector 40u and wellhead adapter 40b may include one or more fasteners, such as dogs, for fastening the LMRP to the BOPS 42a,u,b and the PCA 1p to an external profile of the wellhead housing, respectively. Each of the connector 40u and wellhead adapter 40b may further include a seal sleeve for engaging an internal profile of the respective receiver 46 and wellhead housing. Each of the connector 40u and wellhead adapter 40b may be in electric or hydraulic communication with the control pod 48 and/or further include an electric or hydraulic actuator and an interface, such as a hot stab, so that a remotely operated subsea vehicle (ROV) (not shown) may operate the actuator for engaging the dogs with the external profile.
The LMRP may receive a lower end of the riser 25 and connect the riser to the PCA 1p. The control pod 48 may be in electric, hydraulic, and/or optical communication with a rig controller (not shown) onboard the MODU 1m via an umbilical 49. The control pod 48 may include one or more control valves (not shown) in communication with the BOPS 42a,u,b for operation thereof. Each control valve may include an electric or hydraulic actuator in communication with the umbilical 49. The umbilical 49 may include one or more hydraulic or electric control conduit/cables for the actuators. The accumulators 44 may store pressurized hydraulic fluid for operating the BOPS 42a,u,b. Additionally, the accumulators 44 may be used for operating one or more of the other components of the PCA 1p. The umbilical 49 may further include hydraulic, electric, and/or optic control conduit/cables for operating various functions of the PCA 1p. The rig controller may operate the PCA 1p via the umbilical 49 and the control pod 48.
A lower end of the booster line 27 may be connected to a branch of the flow cross 41u by a shutoff valve 45a. A booster manifold may also connect to the booster line lower end and have a prong connected to a respective branch of each flow cross 41m,b. Shutoff valves 45b,c may be disposed in respective prongs of the booster manifold. Alternatively, the kill line may be connected to the branches of the flow crosses 41m,b instead of the booster manifold. An upper end of the booster line 27 may be connected to an outlet of a booster pump (not shown) and an upper end of the choke line may be connected to a rig choke (not shown). A lower end of the choke line 28 may have prongs connected to respective second branches of the flow crosses 41m,b. Shutoff valves 45d,e may be disposed in respective prongs of the choke line lower end.
A pressure sensor 47a may be connected to a second branch of the upper flow cross 41u. Pressure sensors 47b,c may be connected to the choke line prongs between respective shutoff valves 45d,e and respective flow cross second branches. Each pressure sensor 47a-c may be in data communication with the control pod 48. The lines 27, 28 and may extend between the MODU 1m and the PCA 1p by being fastened to flanged connections 25f between joints of the riser 25. The umbilical 49 may also extend between the MODU 1m and the PCA 1p. Each shutoff valve 45a-e may be automated and have a hydraulic actuator (not shown) operable by the control pod 48 via fluid communication with a respective umbilical conduit or the LMRP accumulators 44. Alternatively, the valve actuators may be electrical or pneumatic.
Once deployed, the riser 25 may extend from the PCA 1p to the MODU 1m and may connect to the MODU via the UMRP 20. The UMRP 20 may include a diverter 21 (only housing shown), a flex joint 22, a slip (aka telescopic) joint 23, a tensioner 24, and a rotating control device (RCD) spool 60. A lower end of the RCD spool 60 may be connected to an upper end of the riser 25, such as by a flanged connection. The slip joint 23 may include an outer barrel connected to an upper end of the RCD spool 60, such as by a flanged connection, and an inner barrel connected to the flex joint 22, such as by a flanged connection. The outer barrel may also be connected to the tensioner 24, such as by a tensioner ring, and may further include a termination ring for connecting upper ends of the lines 27, 28 to respective hoses 27h, 28h leading to the MODU 1m.
The flex joint 22 may also connect to a mandrel of the diverter 21, such as by a flanged connection. The diverter mandrel may be hung from the diverter housing during deployment of the riser 25. The diverter housing may also be connected to the rig floor 4, such as by a bracket. The slip joint 23 may be operable to extend and retract in response to heave of the MODU 1m relative to the riser 25 while the tensioner 24 may reel wire rope in response to the heave, thereby supporting the riser 25 from the MODU 1m while accommodating the heave. The flex joints 23, 43 may accommodate respective horizontal and/or rotational (aka pitch and roll) movement of the MODU 1m relative to the riser 25 and the riser relative to the PCA 1p. The riser 25 may have one or more buoyancy modules (not shown) disposed therealong to reduce load on the tensioner 24.
In operation, a lower portion of the riser 25 may be assembled using the running tool 38 and a riser spider (not shown). The riser 25 may be lowered through a rotary table 37 located on the rig floor 4. A lower end of the riser 25 may then be connected to the PCA 1p in the moonpool. The PCA 1p may be lowered through the moonpool by assembling joints of the riser 25 using the flanges 25f. Once the PCA 1p nears the wellhead 50, the RCD spool 60 may be connected to an upper end of the riser 25 using the running tool 38 and spider. The RCD spool 60 may then be lowered through the rotary table 37 into the moonpool. A jumper spool 100 may then be installed on the RCD spool 60 in the moonpool. The spools 60, 100 may then be lowered through the moonpool by assembling the other UMRP components (slip joint locked). The diverter mandrel may be landed into the diverter housing and the tensioner 24 connected to the tensioner ring. The tensioner 24 and slip joint 23 may then be operated to land the PCA 1p onto the wellhead 50 and the PCA latched to the wellhead.
The pod 48 and umbilical 49 may be deployed with the PCA 1p as shown. Alternatively, the pod 48 may be deployed in a separate step after the riser deployment operation. In this alternative, the pod 48 may be lowered to the PCA 1p using the umbilical 49 and then latched to a receptacle (not shown) of the LMRP.
The RCD 63 may be convertible between an idle mode (
Each stripper may include a gland or retainer and a seal. Each stripper seal may be directional and oriented to seal against drill pipe 10p in response to higher pressure in the riser 25 than the UMRP 20. Each stripper seal may have a conical shape for fluid pressure to act against a respective tapered surface thereof, thereby generating sealing pressure against the drill pipe 10p. Each stripper seal may have an inner diameter slightly less than a pipe diameter of the drill pipe 10p to form an interference fit therebetween. Each stripper seal may be flexible enough to accommodate and seal against threaded couplings of the drill pipe 10p having a larger tool joint diameter. The drill pipe 10p may be received through a bore of the bearing assembly so that the stripper seals may engage the drill pipe. The stripper seals may provide a desired barrier in the riser 25 either when the drill pipe 10p is stationary or rotating. Once deployed, the RCD 63 may be submerged adjacent the waterline 2s. The RCD interface may be in fluid communication with a hydraulic power unit (HPU) 32h (
Alternatively, an active seal RCD may be used. Alternatively, the RCD 63 may be located above the waterline 2s and/or along the UMRP 20 at any other location besides a lower end thereof. Alternatively, the RCD 63 may be assembled as part of the riser 25 at any location therealong or as part of the PCA 1p.
The lower adapter 62 may be tubular and include an upper flange 64, a lower flange 66, and a body 65 connecting the flanges. The upper flange 64 may mate with a lower flange of the RCD 63, thereby connecting the two components. The lower flange 66 may mate with an upper flange 25u of the riser 25, thereby connecting the two components. Each flange 64, 66 may have a respective neck portion 64n, 66n and rim portion 64r, 66r. The upper flange rim portion 64r may have holes formed therethrough and spaced therearound for receiving fasteners, such as bolts or studs and nuts. The upper flange rim portion 64r may further have a seal face formed in an upper surface thereof for receiving a gasket.
The lower flange rim portion 66r may have sockets and holes (not shown) formed therethrough and spaced therearound in an alternating fashion. The lower flange holes may receive fasteners, such as bolts or studs and nuts. Each lower flange socket may receive a collar 67c of a respective hose nipple 67. The lower flange rim portion 66r may have a socket for each auxiliary line 27, 28. Each collar 67c may have a shoulder formed in a lower end thereof and each socket be oversized and have a shoulder formed at an upper end thereof, thereby trapping the collar 67c while allowing longitudinal play of the collar. Each collar 67c may carry one or more seals on an inner surface thereof for receiving a coupling of the respective auxiliary line 27, 28. The interface between the lower flange 66 and the upper riser flange 25u may be sealed by a seal sleeve 68 carrying one or more seals for each flange along an outer surface thereof. The lower flange neck 66n may have a recess formed in a lower end thereof and a neck of the upper riser flange may have a corresponding recess for receiving the seal sleeve 68 and trapping the sleeve between shoulders of the recesses.
Each hose nipple 67 may further have a catch 67h formed at an upper portion thereof and a body 67b connecting the catch and the collar 67c. The catch 67h may have a latch profile 67p formed in an outer surface thereof and a recessed seal bore 67r formed in an inner surface thereof. The upper adapter 61 may be similar to the lower adapter 62 except for being inverted and scaled to mate with an upper flange of the RCD 63 and with a lower flange 23f of the slip joint 23.
The jumper spool 100 may include upper 101 and lower 102 latches for each auxiliary line 27, 28, a frame 103, a linear actuator 104-106, a hose 127, 128 for each auxiliary line 27, 28, a microcontroller 107, a junction 108, and a lifting lug 111. The linear actuator 104-106 may include a slider 104, a lead screw 105, and a submersible electric motor 106. The linear actuator 104-106, lower latches 102, microcontroller 107, a junction 108, a lifting lug 111 may each be connected to the frame 103, such as by fastening (not shown). The frame 103 may be annular and have a passage (not shown) formed therein and sized to receive the RCD spool 60 such that the jumper spool 100 may be radially inserted around the RCD spool.
The slider 104 may be transversely connected to the frame 103 with freedom to move longitudinally relative thereto. The upper latch 101 may be connected to the slider 104, such as by fastening (not shown). An upper end of each hose 127, 128 may be connected to the respective upper latch 101, such as by a flanged connection, and a lower end of each hose 127, 128 may be connected to the respective lower latch 102, such as by a flanged connection. Each hose 127, 128 may be made from a flexible polymer material, such as a thermoplastic or elastomer, or may be a metal or alloy bellows. Each hose 127, 128 may or may not be reinforced, such as by metal or alloy cords. The microcontroller 107 may be in electrical communication with the motor 106, the junction 108, the upper latch 101, and the lower latch 102 via respective submersible cables 110a-d.
Each lower latch 102 may include a housing 115, a mandrel 116, a fastener, such as collet 119b,f, and a linear actuator 117, 118, 120. The linear actuator 117, 118, 120 may include a lock 117, a spring 118 and a solenoid 120. The housing 115 may have a skirt 115s, a flange 115f, and a head 115h connecting the skirt and the flange. The mandrel 116 may have a stinger 116s, a body 116b, a shoulder 116h connecting the stinger and the body, and a flange 116f formed at an upper end thereof extending from the body. The mandrel 116 may be disposed in the skirt 115s and have sockets formed in the flange 116f for receiving fasteners extending through holes formed through the head 115h, thereby connecting the mandrel and the housing 115. The housing 115 may have a bore formed through the flange 115f and the head 115h and the mandrel 116 may have a bore formed therethrough corresponding to the housing bore, thereby forming a flow bore through the lower latch 102. The stinger 116s may carry a seal on an outer surface thereof.
The collet 119b,f may be disposed around the mandrel 116 and connected to the mandrel shoulder 116h, such as by a shearable connection including one or more shear screws. The collet 119b,f may include a base 119b and a plurality of split fingers 119f extending from the base. The fingers 225f may have lugs formed at an end distal from the base and be naturally biased toward a retracted position (shown).
The lock 117 may have a shoulder 117h formed at an upper end thereof and a sleeve 117s extending from the shoulder. The lock 117 may be longitudinally movable relative to the housing 115 and mandrel 116 between a locked position (
Additionally, a target (not shown) may be embedded (i.e., bonded or press fit) in an upper surface of the nipple catch 67h and a proximity sensor (not shown) may be disposed in a lower surface of the mandrel shoulder 116h. The target may be a ring made from a magnetic material or permanent magnet. The nipple 67 may be made from the diamagnetic or paramagnetic material. The proximity sensor may or may not include a biasing magnet depending on whether the target is a permanent magnet. The proximity sensor may include a semiconductor and may be in electrical communication with the microcontroller for receiving a regulated current. The proximity sensor and/or target may be oriented so that the magnetic field generated by the biasing magnet/permanent magnet target is perpendicular to the current. The proximity sensor may further include an amplifier for amplifying the Hall voltage output by the semiconductor when the target is in proximity to the sensor. Alternatively, the proximity sensors may be inductive, capacitive, or utilize radio frequency identification tags (RFID).
The upper latches 101 may be similar to the lower latches 102 except for being inverted.
In operation, once the RCD spool 60 has been inserted into the moonpool through the rotary table 37, a lift line 112 located in the moonpool may be connected to the lifting lug 111 and a power line 113 located in the moonpool may be connected to the junction 107. The power line 113 may also accommodate data communication between a service technician and the microcontroller. The technician may instruct the microcontroller 107 to prepare for installation of the jumper spool 100. The microcontroller 107 may respond by unlocking the upper 101 and lower 102 latches. A winch connected to the lift line 112 may be operated to hoist the jumper spool 100. The technician may guide the jumper spool 100 onto the RCD spool 60 and orient the jumper spool 100 so that the latches 101, 102 are aligned with the respective nipple pairs. The winch may then be operated to lower the lower latches 102 onto the lower adapter 62.
As the lower latches 102 engage the respective lower nipples 67, the stinger 116s may engage the seal bore 67r and a first chamfered surface of the finger lugs may engage a chamfered surface of the respective latch profiles 67p, thereby pushing the fingers 119f radially outward. Lowering may continue until the finger lugs are aligned with a groove of the profile 67p, thereby allowing stiffness of the fingers 119f to return the fingers to their natural position. Lowering may continue until the landing seat of each mandrel 116 engages the landing seat of the respective nipple catch 67h. The microcontroller 107 may then lock the lower latches 102 and supply electricity to the motor 106 at a first polarity. A shaft of the lead screw 105 may be torsionally connected to a rotor of the motor 106. The motor 106 may rotate the rotor and the shaft, thereby driving the slider 104 upward and pushing the upper latches 101 into engagement with the upper adapter 61 until the mandrels have seated against the respective upper nipples. The microcontroller 107 may then lock the upper latches 101 and shut down the motor 106. The motor 106 may be reversible to disconnect the upper latches 101 from the upper adapter 61. The technician may then disconnect the power line 113 and lifting line 112 from the jumper spool 100.
Deployment of the riser 25 may then continue. Once the termination joint reaches the moonpool, hoses 27h, 28h may be connected to respective auxiliary line ports of the termination joint, thereby connecting the auxiliary lines 27, 28 to the respective booster pump and rig choke.
Alternatively, the jumper spool 100 may be deployed using a pipe handler arm (not shown) to eliminate manual handling of the jumper spool. Alternatively, the lifting line 112 and power line 113 may be combined into a wireline. Alternatively, the lifting line 112 may carry a battery pack for wired or wireless engagement with the junction 108 instead of using the power line 113. Alternatively, the upper latches 101 and upper adapter nipples may each be gooseneck-shaped to eliminate the linear actuator 104-106. Alternatively, the linear actuator 104-106 may be replaced by a hydraulically powered piston and cylinder assembly and the power line 113 replaced by one or more hydraulic hoses and/or each lock 117 may be a piston and a hydraulic hose may replace each of the cables 110c,d, thereby obviating the need for the solenoid 120.
The drilling rig 1r may further include a rail (not shown) extending from the rig floor 4 toward the crown block 8. The top drive 5 may include an extender (not shown), motor, an inlet, a gear box, a swivel, a quill, a trolley (not shown), a pipe hoist (not shown), and a backup wrench (not shown). The top drive motor may be electric or hydraulic and have a rotor and stator. The motor may be operable to rotate the rotor relative to the stator which may also torsionally drive the quill via one or more gears (not shown) of the gear box. The quill may have a coupling (not shown), such as splines, formed at an upper end thereof and torsionally connecting the quill to a mating coupling of one of the gears. Housings of the motor, swivel, gear box, and backup wrench may be connected to one another, such as by fastening, so as to form a non-rotating frame. The top drive 5 may further include an interface (not shown) for receiving power and/or control lines.
The trolley may ride along the rail, thereby torsionally restraining the frame while allowing vertical movement of the top drive 5 with the travelling block. The traveling block may be connected to the frame via the rig compensator to suspend the top drive from the derrick 3. The swivel may include one or more bearings for longitudinally and rotationally supporting rotation of the quill relative to the frame. The inlet may have a coupling for connection to a Kelly hose 17h and provide fluid communication between the Kelly hose and a bore of the quill. The quill may have a coupling, such as a threaded pin, formed at a lower end thereof for connection to a mating coupling, such as a threaded box, at a top of the drill string 10.
The drill string 10 may include a bottomhole assembly (BHA) 10b and joints of drill pipe 10p connected together, such as by threaded couplings. The BHA 10b may be connected to the drill pipe 10p, such as by a threaded connection, and include a drill bit 12 and one or more drill collars 11 connected thereto, such as by a threaded connection. The drill bit 12 may be rotated 13 by the top drive 5 via the drill pipe 10p and/or the BHA 10b may further include a drilling motor (not shown) for rotating the drill bit. The BHA 10b may further include an instrumentation sub (not shown), such as a measurement while drilling (MWD) and/or a logging while drilling (LWD) sub.
The fluid handling system 1h may include a fluid tank 15, a supply line 17p,h, one or more shutoff valves 18a-f, an RCD return line 26, a diverter return line 29, a mud pump 30, a hydraulic power unit (HPU) 32h, a hydraulic manifold 32m, a cuttings separator, such as shale shaker 33, a pressure gauge 34, the programmable logic controller (PLC) 35, a return bypass spool 36r, a supply bypass spool 36s. A first end of the return line 29 may be connected to an outlet of the diverter 21 and a second end of the return line may be connected to the inlet of the shaker 33. A lower end of the RCD return line 19 may be connected to an outlet of the RCD 63 and an upper end of the return line may have shutoff valve 18c and be blind flanged. An upper end of the return bypass spool 36r may be connected to the shaker inlet and a lower end of the return bypass spool may have shutoff valve 18b and be blind flanged. A transfer line 16 may connect an outlet of the fluid tank 15 to the inlet of the mud pump 30. A lower end of the supply line 17p,h may be connected to the outlet of the mud pump 30 and an upper end of the supply line may be connected to the top drive inlet. The pressure gauge 34 and supply shutoff valve 18f may be assembled as part of the supply line 17p,h. A first end of the supply bypass spool 36s may be connected to the outlet of the mud pump 30d and a second end of the bypass spool may be connected to the standpipe 17p and may each be blind flanged. The shutoff valves 18d,e may be assembled as part of the supply bypass spool 36s.
In the overbalanced drilling mode, the mud pump 30 may pump the drilling fluid 14d from the transfer line 16, through the pump outlet, standpipe 17p and Kelly hose 17h to the top drive 5. The drilling fluid 14d may flow from the Kelly hose 17h and into the drill string 10 via the top drive inlet. The drilling fluid 14d may flow down through the drill string 10 and exit the drill bit 12, where the fluid may circulate the cuttings away from the bit and carry the cuttings up the annulus 56 formed between an inner surface of the casing 52 or wellbore 55 and the outer surface of the drill string 10. The returns 14r may flow through the annulus 56 to the wellhead 50. The returns 14r may continue from the wellhead 50 and into the riser 25 via the PCA 1p. The returns 14r may flow up the riser 25 to the diverter 21. The returns 14r may flow into the diverter return line 29 via the diverter outlet. The returns 14r may continue through the diverter return line 29 to the shale shaker 33 and be processed thereby to remove the cuttings, thereby completing a cycle. As the drilling fluid 14d and returns 14r circulate, the drill string 10 may be rotated 13 by the top drive 5 and lowered by the traveling block, thereby extending the wellbore 55 into the lower formation.
The drilling fluid 14d may include a base liquid. The base liquid may be base oil, water, brine, or a water/oil emulsion. The base oil may be diesel, kerosene, naphtha, mineral oil, or synthetic oil. The drilling fluid 14d may further include solids dissolved or suspended in the base liquid, such as organophilic clay, lignite, and/or asphalt, thereby forming a mud.
To shift the drilling system 1, a managed pressure return spool (not shown) may be connected to the RCD return line 26 and the bypass return spool 36r. The managed pressure return spool may include a returns pressure sensor, a returns choke, a returns flow meter, and a gas detector. A managed pressure supply spool (not shown) may be connected to the supply bypass spool 36s. The managed pressure supply spool may include a supply pressure sensor and a supply flow meter. Each pressure sensor may be in data communication with the PLC 35. The returns pressure sensor may be operable to measure backpressure exerted by the returns choke. The supply pressure sensor may be operable to measure standpipe pressure.
The returns flow meter may be a mass flow meter, such as a Coriolis flow meter, and may be in data communication with the PLC 35. The returns flow meter may be connected in the spool downstream of the returns choke and may be operable to measure a flow rate of the returns 14r. The supply flow meter may be a volumetric flow meter, such as a Venturi flow meter. The supply flow meter may be operable to measure a flow rate of drilling fluid 14d supplied by the mud pump 30 to the drill string 10 via the top drive 5. The PLC 35 may receive a density measurement of the drilling fluid 14d from a mud blender (not shown) to determine a mass flow rate of the drilling fluid. The gas detector may include a probe having a membrane for sampling gas from the returns 14r, a gas chromatograph, and a carrier system for delivering the gas sample to the chromatograph. Alternatively, the supply flow meter may be a mass flow meter.
Additionally, a degassing spool (not shown) may be connected to a second return bypass spool (not shown). The degassing spool may include automated shutoff valves at each end and a mud-gas separator (MGS). A first end of the degassing spool may be connected to the return spool between the gas detector and the shaker 33 and a second end of the degasser spool may be connected to an inlet of the shaker. The MGS may include an inlet and a liquid outlet assembled as part of the degassing spool and a gas outlet connected to a flare or a gas storage vessel. The PLC 35 may utilize the flow meters to perform a mass balance between the drilling fluid and returns flow rates and activate the degassing spool in response to detecting a kick of formation fluid.
The RCD 63 may be shifted from idle mode to active mode by retrieving the protector sleeve and replacing the protector sleeve with the bearing assembly. Once the spools have been installed and the RCD has been shifted, drilling may recommence in the managed pressure mode. The RCD 63 may divert the returns 14r into the RCD return line 26 and through the managed pressure return spool to the shaker 33. During drilling, the PLC 35 may perform the mass balance and adjust the returns choke accordingly, such as tightening the choke in response to a kick and loosening the choke in response to loss of the returns. As part of the shift to managed pressure mode, a density of the drilling fluid 14d may be reduced to correspond to a pore pressure gradient of the lower formation 54b.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Number | Date | Country | |
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61740839 | Dec 2012 | US |