Patent Grant
10337251
Not applicable.
In drilling a borehole into an earthen formation, such as for the recovery of hydrocarbons or minerals from a subsurface formation, it is typical practice to connect a drill bit onto the lower end of a drillstring formed from a plurality of pipe joints connected together end-to-end, and then rotate the drillstring so that the drill bit progresses downward into the earth to create a borehole along a predetermined trajectory. In addition to pipe joints, the drillstring typically includes heavier tubular members known as drill collars positioned between the pipe joints and the drill bit. The drill collars increase the weight applied to the drill bit to enhance its operational effectiveness. Other accessories commonly incorporated into drillstrings include stabilizers to assist in maintaining the desired direction of the drilled borehole, and reamers to ensure that the drilled borehole is maintained at a desired gauge (i.e., diameter). In vertical drilling operations, the drillstring and drill bit are typically rotated from the surface with a top dive or rotary table. Drilling fluid or “mud” is typically pumped under pressure down the drillstring, out the face of the drill bit into the borehole, and then up the annulus between the drillstring and the borehole sidewall to the surface. The drilling fluid, which may be water-based or oil-based, is typically viscous to enhance its ability to carry borehole cuttings to the surface. The drilling fluid can perform various other valuable functions, including enhancement of drill bit performance (e.g., by ejection of fluid under pressure through ports in the drill bit, creating mud jets that blast into and weaken the underlying formation in advance of the drill bit), drill bit cooling, and formation of a protective cake on the borehole wall (to stabilize and seal the borehole wall).
In some applications, horizontal and other non-vertical or deviated boreholes are drilled (i.e., “directional drilling”) to facilitate greater exposure to and production from larger regions of subsurface hydrocarbon-bearing formations than would be possible using only vertical boreholes. In directional drilling, specialized drillstring components and “bottomhole assemblies” (BHAs) may be used to induce, monitor, and control deviations in the path of the drill bit, so as to produce a borehole of the desired deviated configuration. Directional drilling may be carried out using a downhole or mud motor provided in the BHA at the lower end of the drillstring immediately above the drill bit. Downhole mud motors may include several components, such as, for example (in order, starting from the top of the motor): (1) a power section including a stator and a rotor rotatably disposed in the stator; (2) a driveshaft assembly including a driveshaft disposed within a housing, with the upper end of the driveshaft being coupled to the lower end of the rotor; and (3) a bearing assembly positioned between the driveshaft assembly and the drill bit for supporting radial and thrust loads. For directional drilling, the motor may include a bent housing to provide an angle of deflection between the drill bit and the BHA. The axial distance between the lower end of the drill bit and bend in the motor is commonly referred to as the “bit-to-bend” distance.
An embodiment of a bend adjustment assembly for a downhole mud motor comprises a driveshaft housing, a driveshaft rotatably disposed in the driveshaft housing, a bearing mandrel coupled to the driveshaft, wherein the bend adjustment assembly includes a first position that provides a first deflection angle between a longitudinal axis of the driveshaft housing and a longitudinal axis of the bearing mandrel, wherein the bend adjustment assembly includes a second position that provides a second deflection angle between the longitudinal axis of the driveshaft housing and the longitudinal axis of the bearing mandrel that is different from the first deflection angle, and an actuator assembly configured to shift the bend adjustment assembly between the first position and the second position in response to a change in at least one of flowrate of a drilling fluid supplied to the downhole mud motor, pressure of the drilling fluid supplied to the downhole mud motor, and relative rotation between the driveshaft housing and the bearing mandrel. In some embodiments, the actuator assembly comprises an actuator housing through which the bearing mandrel extends, an actuator piston coupled to the actuator housing, wherein the actuator piston comprises a first plurality of teeth, and a teeth ring coupled to the bearing mandrel and comprising a second plurality of teeth, wherein the actuator piston is configured to matingly engage the first plurality of teeth with the second plurality of teeth of the teeth ring to transfer torque between the actuator housing and the bearing mandrel in response to the change in at least one of flowrate and pressure of the drilling fluid supplied to the downhole mud motor. In some embodiments, the actuator assembly further comprises a biasing member configured to bias the first plurality of teeth of the actuator piston into mating engagement with the second plurality of teeth of the teeth ring. In certain embodiments, the actuator assembly comprises a biasing member configured to apply a mechanical force against the actuator piston to bias the actuator piston in a first axial direction and to apply a hydraulic force against the actuator piston to bias the actuator piston in a second axial direction opposite the first axial direction. In certain embodiments, the bend adjustment assembly further comprises an offset housing comprising a first longitudinal axis and a first offset engagement surface concentric to a second longitudinal axis that is offset from the first longitudinal axis, an adjustment mandrel comprising a third longitudinal axis and a second offset engagement surface concentric to a fourth longitudinal axis that is offset from the third longitudinal axis, wherein the second offset engagement surface is in mating engagement with the first offset engagement surface, and a locking piston disposed in the offset housing, wherein the locking piston comprises a locked position restricting relative rotation between the offset housing and the adjustment mandrel, and an unlocked position, axially spaced from the locked position, permitting relative rotation between the offset housing and the adjustment mandrel, wherein the locking piston is configured to shift between the locked position and the unlocked position in response to a change in at least one of flowrate and pressure of the drilling fluid supplied to the downhole mud motor. In some embodiments, the bend adjustment assembly is locked in at least one of the first and second positions when the locking piston is disposed in the locked position. In some embodiments, the bend adjustment assembly further comprises a first annular seal disposed on an outer surface of the locking piston, a second annular seal disposed on an outer surface of a compensating piston of the bend adjustment assembly, a sealed chamber extending axially between the first annular seal and the second annular seal, and a biasing member in engagement with the compensating piston, wherein the biasing member biases the locking piston towards the unlocked position. In certain embodiments, the bend adjustment assembly further comprises an offset housing comprising a first longitudinal axis and a first offset engagement surface concentric to a second longitudinal axis that is offset from the first longitudinal axis, an adjustment mandrel comprising a third longitudinal axis and a second offset engagement surface concentric to a fourth longitudinal axis that is offset from the third longitudinal axis, wherein the second offset engagement surface is in mating engagement with the first offset engagement surface, and a locking piston disposed in the offset housing about the driveshaft, and wherein the locking piston is configured to alter a restriction to fluid flow of the drilling fluid supplied to the downhole mud motor in response to shifting the locking piston between a first axial position and a second axial position. In some embodiments, the bend adjustment assembly further comprises a thrust bearing assembly including a vibration race having a nonplanar engagement surface. In some embodiments, the bend adjustment assembly further comprises an offset housing comprising a first longitudinal axis and a first offset engagement surface concentric to a second longitudinal axis that is offset from the first longitudinal axis, and an adjustment mandrel comprising a third longitudinal axis and a second offset engagement surface concentric to a fourth longitudinal axis that is offset from the third longitudinal axis, wherein the second offset engagement surface is in mating engagement with the first offset engagement surface, the offset housing comprises an arcuate extension concentric to the second longitudinal axis and defined by a first pair of circumferentially spaced shoulders, the adjustment mandrel comprises a first arcuate groove concentric to the fourth longitudinal axis and defined by a second pair of circumferentially spaced shoulders, a first shoulder of the first pair of shoulders contacts a first shoulder of the second pair of shoulders when the bend adjustment assembly is in the first position, and a second shoulder of the first pair of shoulders contacts a second shoulder of the second pair of shoulders when the bend adjustment assembly is in the second position.
An embodiment of a bend adjustment assembly for a downhole mud motor comprises an offset housing comprising a first longitudinal axis, a first offset engagement surface concentric to a second longitudinal axis offset from the first longitudinal axis, and an arcuate extension concentric to the second longitudinal axis and defined by a first pair of circumferentially spaced shoulders, and an adjustment mandrel comprising a third longitudinal axis, a second offset engagement surface concentric to a fourth longitudinal axis offset from the third longitudinal axis, and a first arcuate groove concentric to the fourth longitudinal axis and defined by a second pair of circumferentially spaced shoulders, wherein the first offset engagement surface matingly engages the second offset engagement surface and the arcuate extension of the offset housing is disposed in the first arcuate groove of the adjustment mandrel, wherein the bend adjustment assembly includes a first position with a first shoulder of the first pair of shoulders contacting a first shoulder of the second pair of shoulders, and wherein the first position provides a first deflection angle between the first longitudinal axis of the offset housing and the third longitudinal axis of the adjustment mandrel, wherein the bend adjustment assembly includes a second position angularly spaced from the first position with a second shoulder of the first pair of shoulders contacting a second shoulder of the second pair of shoulders, and wherein the second position provides a second deflection angle between the first longitudinal axis of the offset housing and the third longitudinal axis of the adjustment mandrel that is different from the first deflection angle. In some embodiments, the offset housing comprises a locked position locking the bend adjustment assembly in at least one of the first and second positions and an unlocked position permitting the bend adjustment assembly to shift between the first and second positions, and an angular distance between the second pair of shoulders defines a magnitude of the difference between the first deflection angle and the second deflection angle. In some embodiments, the bend adjustment assembly is configured to shift from the first position to the second position in response to at least one of flowrate and pressure of a drilling fluid supplied to the downhole mud motor, and shift from the second position to the first position in response to a change in relative rotation between the offset housing and the adjustment mandrel, the bend adjustment assembly is configured to shift from the first position to the second position in response to rotation of the offset housing in a first direction relative to the adjustment mandrel, and shift from the second position to the first position in response to rotation of the offset housing in a second direction relative to the adjustment mandrel that is opposite the first direction. In certain embodiments, the adjustment mandrel further comprises a second arcuate groove concentric to the fourth longitudinal axis and defined by a third pair of circumferentially spaced shoulders, and the bend adjustment assembly includes a third position angularly spaced from the first and second positions with a second shoulder of the first pair of shoulders contacting a second shoulder of the third pair of shoulders, and wherein the third position provides a third deflection angle between the first longitudinal axis of the offset housing and the third longitudinal axis of the adjustment mandrel that is different from the first and second deflection angles. In certain embodiments, the bend adjustment assembly further comprises a locking piston disposed in the offset housing, wherein the locking piston comprises a locked position restricting relative rotation between the offset housing and the adjustment mandrel, and an unlocked position, axially spaced from the locked position, permitting relative rotation between the offset housing and the adjustment mandrel, wherein the locking piston is configured to shift between the locked position and the unlocked position in response to a change in at least one of flowrate and pressure of the drilling fluid supplied to the downhole mud motor. In certain embodiments, the locking piston comprises a key, the adjustment mandrel comprises a first slot and a second slot each extending into an end of the adjustment mandrel, wherein a length of the second slot is different from a length of the first slot, and relative rotation between the adjustment mandrel and the offset housing is restricted when the key of the locking piston is received in either the first slot or the second slot of the adjustment mandrel. In some embodiments, the bend adjustment assembly is locked in the first position when the key of the locking piston is received in the first slot of the adjustment mandrel, and the bend adjustment assembly is locked in the second position when the key of the locking piston is received in the second slot of the adjustment mandrel. In some embodiments, the locking piston is configured to induce a pressure signal providing a surface indication of the deflection angle of the bend adjustment assembly. In certain embodiments, the bend adjustment assembly further comprises a locking piston disposed in the offset housing, and a radial port formed in the offset housing, wherein the locking piston comprises first and second locked positions each restricting relative rotation between the offset housing and the adjustment mandrel, and an unlocked position, axially spaced from the first and second locked positions, permitting relative rotation between the offset housing and the adjustment mandrel, wherein the locking piston is configured to lock the bend adjustment assembly in the first position when the locking piston is in the first locked position, and lock the bend adjustment assembly in the second position when the locking piston is in the second position, wherein the locking piston axially covers the radial port when the locking piston is in at least one of the first locked position, second locked position, and unlocked position to restrict fluid flow through the radial port into the offset housing. In certain embodiments, the bend adjustment assembly further comprises an actuator assembly configured to shift the bend adjustment assembly between the first position and the second position in response to a change in at least one of flowrate of a drilling fluid supplied to the downhole mud motor, pressure of the drilling fluid supplied to the downhole mud motor, and relative rotation between the driveshaft housing and the bearing mandrel. In some embodiments, the actuator assembly is in fluid communication with a sealed volume of oil in which a bearing of the downhole motor is disposed. In some embodiments, the actuator assembly comprises: an actuator housing through which the bearing mandrel extends, an actuator piston coupled to the actuator housing, wherein the actuator piston comprises a first plurality of teeth, and a teeth ring coupled to the bearing mandrel and comprising a second plurality of teeth, wherein the actuator piston is configured to matingly engage the first plurality of teeth with the second plurality of teeth of the teeth ring to transfer torque between the actuator housing and the bearing mandrel in response to the change in flowrate of the drilling fluid supplied to the downhole mud motor. In some embodiments, the actuator assembly comprises an actuator housing through which the bearing mandrel extends, an actuator piston disposed in the actuator housing, and a teeth ring coupled to the bearing mandrel, wherein the actuator piston is configured to permit relative rotation between the actuator housing and the bearing mandrel in response to the application of a torque to the actuator piston from the teeth ring which exceeds a threshold torque.
An embodiment of a method for forming a deviated borehole comprises (a) providing a bend adjustment assembly of a downhole mud motor in a first position that provides a first deflection angle between a longitudinal axis of a driveshaft housing of the downhole mud motor and a longitudinal axis of a bearing mandrel of the downhole mud motor, and (b) with the downhole mud motor positioned in the borehole, actuating the bend adjustment assembly from the first position to a second position that provides a second deflection angle between the longitudinal axis of the driveshaft housing and the longitudinal axis of the bearing mandrel, the second deflection angle being different from the first deflection angle. In some embodiments, (b) comprises (b1) pumping drilling fluid into the borehole from the surface pump at a first flowrate that is less than the drilling flowrate for a first time period, (b2) following the first time period, pumping drilling fluid in the borehole from the surface pump at a second flowrate that is different than the first flowrate for a second time period. In some embodiments, (b) comprises (b1) ceasing the pumping of drilling fluid into the borehole from the surface pump for a first time period, (b2) rotating a drillstring coupled to the bend adjustment assembly from a surface of the borehole for a second time period, and (b3) following the second time period, pumping drilling fluid into the borehole from the surface pump at a flowrate greater than zero for a third time period. In certain embodiments, (b) comprises (b1) pumping drilling fluid into the borehole from the surface pump at a first flowrate that is less than the drilling flowrate for a first time period, (b2) rotating a drillstring coupled to the bend adjustment assembly from a surface of the borehole for a second time period, and (b3) applying weight on bit (WOB) to the downhole mud motor while rotating the drillstring and pumping drilling fluid into the borehole from the surface pump at a second flowrate that is greater than the first flowrate for a third time period. In some embodiments, the method further comprises (c) oscillating the bearing mandrel axially in a bearing housing of the downhole mud motor in response to pumping drilling fluid into the borehole from the surface pump. In some embodiments, the method further comprises (c) with the downhole mud motor positioned in the borehole, actuating the bend adjustment assembly from the second position to a third position that provides a third deflection angle between the longitudinal axis of the driveshaft housing and the longitudinal axis of the bearing mandrel, the third deflection angle being different from the first deflection angle and the second deflection angle. In certain embodiments, (b) comprises (b1) pumping drilling fluid into the borehole from the surface pump at a first flowrate that is less than the drilling flowrate for a first time period, and (b2) following the first time period, pumping drilling fluid in the borehole from the surface pump at a second flowrate that is different than the first flowrate, and (c) comprises (c1) pumping drilling fluid into the borehole from the surface pump at the first flowrate for a third time period, and (c2) following the third time period, pumping drilling fluid in the borehole from the surface pump at a third flowrate. In certain embodiments, (b) comprises (b1) shifting a locking piston of the downhole mud motor from a locked position to an unlocked position axially spaced from the locked position to permit the bend adjustment assembly to actuate between the first position and the second position, (b2) rotating an offset housing of an actuator assembly of the bend adjustment assembly relative to an adjustment mandrel of the bend adjustment assembly to actuate the bend adjustment assembly from the first position to the second position, and (b3) shifting the locking piston from the unlocked position to the locked position to lock the bend adjustment assembly in the second position.
For a detailed description of disclosed embodiments, reference will now be made to the accompanying drawings in which:
The following discussion is directed to various embodiments. However, one skilled in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection as accomplished via other devices, components, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. Any reference to up or down in the description and the claims is made for purposes of clarity, with “up”, “upper”, “upwardly”, “uphole”, or “upstream” meaning toward the surface of the borehole and with “down”, “lower”, “downwardly”, “downhole”, or “downstream” meaning toward the terminal end of the borehole, regardless of the borehole orientation.
Referring to
Power section 40 of BHA 30 converts the fluid pressure of the drilling fluid pumped downward through drillstring 21 into rotational torque for driving the rotation of drill bit 90. Driveshaft assembly 100 and bearing assembly 200 transfer the torque generated in power section 40 to bit 90. With force or weight applied to the drill bit 90, also referred to as weight-on-bit (“WOB”), the rotating drill bit 90 engages the earthen formation and proceeds to form borehole 16 along a predetermined path toward a target zone. The drilling fluid or mud pumped down the drillstring 21 and through BHA 30 passes out of the face of drill bit 90 and back up the annulus 18 formed between drillstring 21 and the wall 19 of borehole 16. The drilling fluid cools the bit 90, and flushes the cuttings away from the face of bit 90 and carries the cuttings to the surface.
Referring to
During operation of the hydraulic drive section 40, fluid is pumped under pressure into one end of the hydraulic drive section 40 where it fills a first set of open cavities 70. A pressure differential across the adjacent cavities 70 forces the rotor 50 to rotate relative to the stator 60. As the rotor 50 rotates inside the stator 60, adjacent cavities 70 are opened and filled with fluid. As this rotation and filling process repeats in a continuous manner, the fluid flows progressively down the length of hydraulic drive section 40 and continues to drive the rotation of the rotor 50. Driveshaft assembly 100 shown in
In the embodiment of
In general, driveshaft assembly 100 functions to transfer torque from the eccentrically-rotating rotor 50 of power section 40 to a concentrically-rotating bearing mandrel 220 of bearing assembly 200 and drill bit 90. As best shown in
Referring to
As best shown in
Driveshaft 120 of driveshaft assembly 100 has a linear central or longitudinal axis, a first or upper end 120A, and a second or lower end 120B opposite end 120A. Upper end 120A is pivotally coupled to the lower end of rotor 50 with a driveshaft adapter 130 and a first or upper universal joint 140A, and lower end 120B is pivotally coupled to an upper end 220A of bearing mandrel 220 with a second or lower universal joint 140B. In the embodiment of
In the embodiment of
Universal joints 140A and 140B allow ends 120A and 120B of driveshaft 120 to pivot relative to adapter 130 and bearing mandrel 220, respectively, while transmitting rotational torque between rotor 50 and bearing mandrel 220. Driveshaft adapter 130 is coaxially aligned with rotor 50. Since rotor axis 58 is radially offset and/or oriented at an acute angle relative to the central axis of bearing mandrel 220, the central axis of driveshaft 120 is skewed or oriented at an acute angle relative to axis 115 of housing 110, axis 58 of rotor 50, and a central or longitudinal axis 225 of bearing mandrel 220. However, universal joints 140A and 140B accommodate for the angularly skewed driveshaft 120, while simultaneously permitting rotation of the driveshaft 120 within driveshaft housing 110.
In general, each universal joint (e.g., each universal joint 140A and 140B) may comprise any joint or coupling that allows two parts that are coupled together and not coaxially aligned with each other (e.g., driveshaft 120 and adapter 130 oriented at an acute angle relative to each other) limited freedom of movement in any direction while transmitting rotary motion and torque including, without limitation, universal joints (Cardan joints, Hardy-Spicer joints, Hooke joints, etc.), constant velocity joints, or any other custom designed joint. In other embodiments, driveshaft assembly 100 may include a flexible shaft comprising a flexible material (e.g., Titanium, etc.) that is directly coupled (e.g., threadably coupled) to rotor 50 of power section 40 in lieu of driveshaft 120, where physical deflection of the flexible shaft (the flexible shaft may have a greater length relative driveshaft 120) accommodates axial misalignment between driveshaft assembly 100 and bearing assembly 200 while allowing for the transfer of torque therebetween.
As previously described, adapter 130 couples driveshaft 120 to the lower end of rotor 50. During drilling operations, high pressure drilling fluid or mud is pumped under pressure down drillstring 21 and through cavities 70 between rotor 50 and stator 60, causing rotor 50 to rotate relative to stator 60. Rotation of rotor 50 drives the rotation of driveshaft adapter 130, driveshaft 120, bearing assembly mandrel 220, and drill bit 90. The drilling fluid flowing down drillstring 21 through power section 40 also flows through driveshaft assembly 100 and bearing assembly 200 to drill bit 90, where the drilling fluid flows through nozzles in the face of bit 90 into annulus 18. Within driveshaft assembly 100 and the upper portion of bearing assembly 200, the drilling fluid flows through an annulus 116 formed between driveshaft housing 110 and driveshaft 120.
Still referring to
In the embodiment of
In the embodiment of
In the embodiment of
In the embodiment of
Annular thrust bearing assembly 232 is disposed about mandrel 220 and permits rotation of mandrel 220 relative to housing 210 while simultaneously supporting axial loads in both directions (e.g., off-bottom and on-bottom axial loads). In this embodiment, thrust bearing assembly 232 generally comprises a pair of caged roller bearings and corresponding races, with the central race threadedly engaged to bearing mandrel 220. In other embodiments, one or more other types of thrust bearings may be included in bearing assembly 200, including ball bearings, planar bearings, etc. In still other embodiments, the thrust bearing assemblies of bearing assembly 200 may be disposed in the same or different thrust bearing chambers (e.g., two-shoulder or four-shoulder thrust bearing chambers). In the embodiment of
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In the embodiment of
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In the embodiment of
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In the embodiment of
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In this embodiment, the combination of sealing engagement between seal 382 of locking piston 380 and the inner surface 322 of lower housing 320, and seal 320S of housing 320 and the outer surface of locking piston 380, defines a lower axial end of locking chamber 395. Locking chamber 395 extends longitudinally from the lower axial end thereof to an upper axial end defined by the combination of sealing engagement between the outer seal 358A of compensating piston 356 and the inner seal 358B of piston 356. Particularly, lower adjustment mandrel 370 and upper adjustment mandrel 360 each include axially extending ports similar in configuration to the ports 330 of lower housing 320 such that fluid communication is provided between the annular space directly adjacent shoulder 386 of locking piston 380 and the annular space directly adjacent a lower end of compensating piston 356. Locking chamber 395 is sealed from annulus 116 such that drilling fluid flowing into annulus 116 is not permitted to communicate with fluid disposed in locking chamber 395, where locking chamber 395 is filled with lubricant.
Referring to
In the embodiment of
As shown particularly in
In some embodiments, locker assembly 400 permits rotation in mud motor 35 to rotate rotor 50 and bearing mandrel 220 until bend adjustment assembly 300 has fully actuated, and then, subsequently, ratchet or slip while transferring relatively large amounts of torque to bearing housing 210. This reaction torque may be adjusted by increasing the hydraulic force or hydraulic pressure acting on actuator piston 402, which may be accomplished by increasing flowrate through mud motor 35. When additional torque is needed a lower flowrate or fluid pressure can be applied to locker assembly 400 to modulate the torque and thereby rotate bend adjustment assembly 300. The fluid pressure is transferred to actuator piston 402 by compensating piston 226. In some embodiments, the pressure drop across drill bit 90 may be used to increase the pressure acting on actuator piston 402 as flowrate through mud motor 35 is increased. Additionally, ratcheting of locker assembly 400 once bend adjustment assembly 300 reaches a fully bent position may provide a relatively high torque when teeth 424 are engaged and riding up the ramp and a very low torque when locker assembly 400 ratchets to the next tooth when the slipping torque value has been reached (locker assembly 400 catching again after it slips one tooth of teeth 424). This behavior of locker assembly 400 may provide a relatively good pressure signal indicator that bend adjustment assembly 300 has fully actuated and is ready to be locked.
Having described the structure of the embodiment of driveshaft assembly 100, bearing assembly 200, and bend adjustment assembly 300 shown in
In the embodiment of
As described above, in the embodiment of
Also as described above, locker assembly 400 is configured to control the actuation of bend adjustment assembly 300, and thereby, control the degree of bend 301. In the embodiment of
Directly following the first time period, surface pump 23 resumes pumping drilling mud into drillstring 21 at a first flowrate that is reduced by a predetermined percentage from a maximum mud flowrate of well system 10, where the maximum mud flowrate of well system 10 is dependent on the application, including the size of drillstring 21 and BHA 30. For instance, the maximum mud flowrate of well system 10 may comprise the maximum mud flowrate that may be pumped through drillstring 21 and BHA 30 before components of drillstring 21 and/or BHA 30 are eroded or otherwise damaged by the mud flowing therethrough. In some embodiments, the first flowrate of drilling mud from surface pump 23 comprises approximately 1%-30% of the maximum mud flowrate of well system 10; however, in other embodiments, the first flowrate may vary. For instance, in some embodiments, the first flowrate may comprise zero or substantially zero fluid flow. In this embodiment, surface pump 23 continues to pump drilling mud into drillstring 21 at the first flowrate for a predetermined second time period while rotary system 24 remains inactive. In some embodiments, the second time period comprises approximately 15-120 seconds; however, in other embodiments, the second time period may vary.
During the second time period with drilling mud flowing through BHA 30 from drillstring 21 at the first flowrate, rotational torque is transmitted to bearing mandrel 220 via rotor 50 of power section 40 and driveshaft 120. Additionally, biasing member 412 applies a biasing force against shoulder 404 of actuator piston 402 to urge actuator piston 402 into contact with teeth ring 420, with teeth 410 of piston 402 in meshing engagement with the teeth 424 of teeth ring 420. In this arrangement, torque applied to bearing mandrel 220 is transmitted to actuator housing 340 via the meshing engagement between teeth 424 of teeth ring 420 (rotationally fixed to bearing mandrel 220) and teeth 410 of actuator piston 402 (rotationally fixed to actuator housing 340). Rotational torque applied to actuator housing 340 via locker assembly 400 is transmitted to offset housings 310, 320, which rotate (along with bearing housing 210) in a first rotational direction relative adjustment mandrels 360, 370. Particularly, extension 328 of lower housing 320 rotates through arcuate recess 374 of lower adjustment mandrel 370 until a shoulder 328S engages a corresponding shoulder 375 of recess 374, restricting further relative rotation between offset housings 310, 320, and adjustment mandrels 360, 370. Following the rotation of lower housing 320, bend adjustment assembly 300 forms second deflection angle θ2, and thus, provides bend 301 (shown in
Directly following the second time period, with bend adjustment assembly 300 now forming second deflection angle θ2, the flowrate of drilling mud from surface pump 23 is increased from the first flowrate to a second flowrate that is greater than the first flowrate. In some embodiments, the second flowrate of drilling mud from surface pump 23 comprises approximately 50%-100% of the maximum mud flowrate of well system 10; however, in other embodiments, the second flowrate may vary. Following the second time period with drilling mud flowing through BHA 30 from drillstring 21 at the second flowrate, the fluid pressure applied to the lower end 380B of locking piston 380 is sufficiently increased to overcome the biasing force applied against the upper end 380A of piston 380 via biasing member 354, actuating or displacing locking piston 380 from the unlocked position to the locked position with keys 384 received in short slots 376 (shown in
Additionally, with drilling mud flowing through BHA 30 from drillstring 21 at the second flowrate, fluid pressure applied against the lower end 402B of actuator piston 402 from the drilling fluid (such as through leakage of the drilling fluid in the space disposed radially between the inner surface of actuator piston 402 and the outer surface of bearing mandrel 220) is increased, overcoming the biasing force applied against shoulder 404 by biasing member 412 and thereby disengaging actuator piston 402 from teeth ring 420 (shown in
On occasion, it may be desirable to actuate bend adjustment assembly 300 from the second or bent (in this embodiment) position 305 (shown in
Following the third and fourth time periods (the fourth time period ending either at the same time as the third time period or after the third time period has ended), with bend adjustment assembly 300 disposed in the straight position 303 shown in
Following the fifth period of time, the flowrate of drilling mud from surface pump 23 is increased from the third flowrate to a flowrate near or at the maximum mud flowrate of well system 10 to thereby disengage locker assembly 400 and dispose locking piston 380 in the locked position. Once surface pump 23 is pumping drilling mud at the drilling or maximum mud flowrate of well system 10, rotation of drillstring 21 via rotary system 24 may be ceased or continued at the actuation rotational speed. With drilling mud being pumped into drillstring 21 at the third flowrate and the drillstring 21 being rotated at the actuation rotational speed, locker assembly 400 is disengaged and locking piston 380 is disposed in the locked position with keys 384 received in long slots 378 (shown in
In other embodiments, instead of surface pump 23 at the third flowrate for a period of time following the third and fourth time periods, surface pump 23 may be operated immediately at 100% of the maximum mud flowrate of well system 10 to disengage locker assembly 400 and dispose locking piston 380 in the locked position. Once surface pump 23 is pumping drilling mud at the drilling or maximum mud flowrate of well system 10, rotation of drillstring 21 via rotary system 24 may be ceased or continued at the actuation rotational speed.
In an alternative embodiment, the procedures for shifting bend adjustment assembly 300 between the first position 303 and the second position 305 may be reversed by reconfiguring lower adjustment mandrel 370 of bend adjustment assembly 300. Particularly, in this alternative embodiment, the position of arcuate recess 374 is shifted 180° about the circumference of lower adjustment mandrel 370. By shifting the angular position of arcuate recess 374 180° about the circumference of lower adjustment mandrel 370, the alternative embodiment of bend adjustment assembly 300 may be shifted from the first position 303 to the second position 305 by ceasing the pumping of drilling fluid from surface pump 23 for the third period of time to shift locking piston 380 into the unlocked position. Then, either concurrent with third time period or following the start of the third time period, activating rotary system 24 to rotate drillstring 21 at the actuation rotational speed for the fourth period of time to apply reactive torque to bearing housing 210 and rotate offset housing 320 relative to adjustment mandrel 370 in the second rotational direction, thereby shifting the alternative embodiment of bend adjustment assembly 300 into the second position 305. Surface pump 23 may then be operated at the third flowrate for the fifth period of time or immediately operated at the maximum mud flowrate of well system 10 to shift locking piston into the locked position, thereby locking the alternative embodiment of bend adjustment assembly 300 into the second position 305.
Additionally, the alternative embodiment of bend adjustment assembly 300 may be shifted from the second position 305 to the first position 303 by ceasing rotation of drillstring 21 from rotary system 24 and ceasing the pumping of drilling mud from surface pump 23 for the first time period to thereby shift locking piston 380 into the unlocked position. Following the first time period, surface pump 23 resumes pumping drilling mud into drillstring 21 at the first flowrate for the second period of time while rotary system 24 remains inactive, thereby rotating lower adjustment mandrel 370 in the first rotational direction to shift the alternative embodiment of bend adjustment assembly 300 into the first position 301. Following the second time period, with the alternative embodiment of bend adjustment assembly 300 now disposed in first position 303, the flowrate of drilling mud from surface pump 23 is increased from the first flowrate to the second flowrate to shift locking piston 380 into the locked position, thereby locking the alternative embodiment of bend adjustment assembly 300 in the first position 303.
Referring to
Referring to
Additionally, in the embodiment of
In this embodiment, the upper and lower housings 310, 320 of bend adjustment assembly 300 may use different angles to permit bend adjustment assembly 300 to enter into multiple distinct “bent” positions to provide a “bent to bent” configuration. Particularly, by making upper housing 310 have a higher angle with a higher offset from the central axis of upper housing 310 and then providing a very low angle in the lower housing 320, smaller changes to the deflection angle (e.g., magnitude of bend 301) are possible. For example, lower housing 320 may be rotated 180 degrees and thus the high side of the deflection angle is dictated by the upper offset angle, which does not change position rotationally. Thus, the scribe for a MWD tool of drillstring 21 does not change either when the bend is adjusted with the lower offset at 0 or 180 degrees from this high side location of upper housing 310. Additionally, in some embodiments, upper housing 310 and lower housing 320 are additive in one position and subtract in the other—meaning that the resultant bend of this embodiment of bend adjustment assembly 300 may be, for example, approximately 1.5+0.5 or 2.0 degree if the upper offset angle is 1.5 degrees and the lower offsets angle is 0.5 degrees. The bend of this embodiment of bend adjustment assembly 300 with the lower housing 320 rotated 180 degrees may be, for example, 1 degree or 1.5-0.5 degrees. In this manner, a bent to bent configuration may be achieved with bend adjustment assembly 300 that utilizes similar methods and mechanisms as described above, including the permanent pressure signal and locking mechanisms described herein.
Referring to
Upper housing extension 820 of bend adjustment assembly 800 is generally tubular and has a first or upper end 820A, a second or lower end 820B, a central bore or passage defined by a generally cylindrical inner surface 822 extending between ends 820A and 820B, and a generally cylindrical outer surface 824 extending between ends 820A and 820B. In this embodiment, the inner surface 822 of upper housing extension 820 includes an engagement surface 826 extending from upper end 820A that matingly engages the offset engagement surface 365 of upper adjustment mandrel 360′. Additionally, in this embodiment, the outer surface 824 of upper housing extension 820 includes a threaded connector coupled with the upper threaded connector 806 of upper housing 802 and an annular shoulder 828 facing lower adjustment mandrel 840.
Lower adjustment mandrel 840 of bend adjustment assembly 800 is generally tubular and has a first or upper end 840A, a second or lower end 840B, a central bore or passage extending therebetween that is defined by a generally cylindrical inner surface extending between ends 840A, 840B, and a generally cylindrical outer surface 842 extending between ends 840A, 840B. In this embodiment, outer surface 842 of lower adjustment mandrel 840 includes an offset engagement surface 844, an annular seal 846 in sealing engagement with the inner surface of lower housing 320′, a first or lower arcuately extending recess 848, and a second or upper arcuately extending recess 850 axially spaced from lower arcuate recess 848. Offset engagement surface 844 has a central or longitudinal axis that is offset or disposed at an angle relative to a central or longitudinal axis of the upper end 840A of upper adjustment mandrel 840 and the lower end 320B of lower housing 320′, where offset engagement surface 844 is disposed directly adjacent or overlaps the offset engagement surface 323 of lower housing 320′. In this embodiment, a plurality of circumferentially spaced cylindrical splines or keys 845 are positioned radially between lower adjustment mandrel 840 and upper adjustment mandrel 360′ to restrict relative rotation between lower adjustment mandrel 840 and upper adjustment mandrel 360′ while allowing for relative axial movement therebetween. Additionally, upper adjustment mandrel 360′ includes an annular seal 805 that sealingly engages the inner surface of lower adjustment mandrel 840.
Lower arcuate recess 848 of lower adjustment mandrel 840 is defined by an inner terminal end 848E, a first shoulder 849A, and a second shoulder 849B circumferentially spaced from first shoulder 849A. Similarly, upper arcuate recess 850 of lower adjustment mandrel 840 is defined by an inner terminal end 850E, a first shoulder 851A, and a second shoulder 851B circumferentially spaced from first shoulder 851A. The inner end 848E of lower arcuate recess 848 is positioned nearer to the lower end 840B of mandrel 840 than the inner end 850E of upper arcuate recess 850. Additionally, while first shoulder 849A of lower arcuate recess 848 is generally circumferentially aligned with first shoulder 851A of upper arcuate recess 850, second shoulder 849B of lower arcuate recess 848 is circumferentially spaced from second shoulder 851B of upper arcuate recess 850. In this arrangement, the circumferential length extending between shoulders 849A, 849B of lower arcuate recess 848, is greater than the circumferential length extending between shoulders 851A, 851B of upper arcuate recess 850. Particularly, in this embodiment, lower arcuate recess 848 extends approximately 160° about the circumference of lower adjustment mandrel 840 while upper arcuate recess 850 extends approximately 60° about the circumference of lower adjustment mandrel 840; however, in other embodiments, the circumferential length of both lower arcuate recess 848 and upper arcuate recess 850 about lower adjustment mandrel 840 may vary. As will be discussed further herein,
In this embodiment, lower adjustment mandrel 840 also includes a pair of circumferentially spaced first or short slots 852, a pair of circumferentially spaced second or long slots 854A, and a second pair of circumferentially spaced long slots 854B, where both short slots 852 and long slots 854A, 854B extend axially into lower adjustment mandrel 840 from lower end 840B. In this embodiment: each short slot 852 is circumferentially spaced approximately 180° apart, each long slot 854A is circumferentially spaced approximately 180° apart, and each long slot 854B is circumferentially spaced approximately 180° apart. Each pair of circumferentially spaced slots 852, 854A, and 854B is configured to matingly receive and engage the keys 384 of locking piston 380 to restrict relative rotation between lower adjustment mandrel 840 and lower housing 320′.
Unlike the lower adjustment mandrel 370 of bend adjustment assembly 300, lower adjustment mandrel 840 of bend adjustment assembly 800 is permitted to move axially relative to lower housing 320′. Particularly, lower adjustment mandrel 840 is permitted to travel between a first axial position in upper housing 806 (shown in
As described above, bend adjustment assembly 800 is adjustable between more than two positions while disposed in borehole 16. Particularly, in this embodiment, bend adjustment assembly 800 is adjustable between a first position that is unbent, a first bent position providing a first deflection angle between the longitudinal axis 95 of drill bit 90 and the longitudinal axis 25 of drillstring 21, and a second bend position providing a second deflection angle between the longitudinal axis 95 of drill bit 90 and the longitudinal axis 25 of drillstring 21 that is greater than the first deflection angle. In other embodiments, bend adjustment assembly 800 may incorporate a fixed bend, similar to the fixed bend provided by bent housing 602 of the driveshaft assembly 600 shown in
In this embodiment, bend adjustment assembly 800 is initially deployed in borehole 16 in the first position where there is no deflection angle between the longitudinal axis 95 of drill bit 90 and the longitudinal axis 25 of drillstring 21. In the first position of bend adjustment assembly 800, lower adjustment mandrel 840 is retained in the lower position by shear pin 858. Additionally, in the first position, extension 328 of lower housing 320′ is received in upper arcuate recess 850 of lower adjustment mandrel 840 with a first of the axially extending shoulders 328S of extension 328 contacting or disposed directly adjacent first shoulder 851A of upper arcuate recess 850 and the second of the axially extending shoulders 328S of extension 328 circumferentially spaced from second shoulder 851B of upper arcuate recess 850.
As borehole 16 is drilled by the drill bit 90 of BHA 30 with bend adjustment assembly 800 disposed in the first position, drillstring 21 is rotated by rotary system 24 and drilling mud is pumped through drillstring 21 from surface pump 23 at a drilling flowrate. In some embodiments, the drilling flowrate comprises approximately 50%-80% of the maximum mud flowrate of well system 10. While drillstring 21 is rotated by rotary system 24 and mud is pumped through drillstring 21 at the drilling flowrate, locking piston 380 is disposed in the locked position with keys 384 of locking piston 380 are received in the first pair of long slots 854B, thereby restricting relative rotation between lower adjustment mandrel 840 and lower housing 320′ (locking piston 380 being rotationally locked with lower housing 320′).
When it is desired to actuate bend adjustment assembly 800 from the first position to the second position and thereby provide the first deflection angle between drill bit 90 and drillstring 21, rotation of drillstring 21 from rotary system 24 is ceased and the pumping of drilling mud from surface pump 23 is ceased for a predetermined first time period. In some embodiments, the first time period over which pumping is ceased from surface pump 23 comprises approximately 15-60 seconds; however, in other embodiments, the first time period may vary. With the flow of drilling fluid to power section 40 ceased, biasing member 354 displaces locking piston 380 from the locked position with keys 384 received in the first pair of long slots 854A of lower adjustment mandrel 840, to the unlocked position with keys 384 free from long slots 854A, thereby unlocking lower housing 320′ from lower adjustment mandrel 840.
Following the first time period, surface pump 23 resumes pumping drilling mud into drillstring 21 at a first flowrate that is reduced by a predetermined percentage from the maximum mud flowrate of well system 10. In some embodiments, the first flowrate of drilling mud from surface pump 23 comprises approximately 1%-30% of the maximum mud flowrate of well system 10; however, in other embodiments, the first flowrate may vary. For instance, in some embodiments, the first flowrate may comprise zero or substantially zero fluid flow. In this embodiment, surface pump 23 continues to pump drilling mud into drillstring 21 at the first flowrate for a predetermined second time period while rotary system 24 remains inactive. In some embodiments, the second time period comprises approximately 15-120 seconds; however, in other embodiments, the second time period may vary.
During the second time period rotational torque is transmitted to bearing mandrel 220 via rotor 50 of power section 40 and driveshaft 120. Additionally, torque applied to bearing mandrel 220 is transmitted to actuator housing 340 via the meshing engagement between teeth 424 of teeth ring 420 and teeth 410 of actuator piston 402. Rotational torque applied to actuator housing 340 via locker assembly 400 is transmitted to housings 310, 320′, which rotate in the first rotational direction relative lower adjustment mandrel 840. Particularly, lower housing 320′ rotates until one of the shoulders 328S of lower housing 320′ contacts second shoulder 851B of the upper arcuate recess 850 of lower adjustment mandrel 840, restricting further rotation of lower housing 320′ in the first rotational direction. Following the rotation of lower housing 320′, bend adjustment assembly 800 is disposed in the second position, thereby forming the first deflection angle of assembly 800 between drill bit 90 and drillstring 21.
Following the second time period, with bend adjustment assembly 800 now disposed in the second position, the flowrate of drilling mud from surface pump 23 is increased from the first flowrate to a second flowrate that is greater than the first flowrate to displace locking piston 380 back into the locked position with keys 384 now received in the second pair of long slots 854B of lower adjustment mandrel 800. In some embodiments, the second flowrate of drilling mud from surface pump 23 comprises the drilling flowrate (e.g., approximately 50%-100% of 50%-80% of the maximum mud flowrate of well system 10); however, in other embodiments, the second flowrate may vary. Additionally, with drilling mud flowing through BHA 30 from drillstring 21 at the second flowrate, actuator piston 402 is disengaged from teeth ring 420, preventing torque from being transmitted from bearing mandrel 220 to actuator housing 340. With locking piston 380 now disposed in the locked position and actuator piston 402 being disengaged from teeth ring 420, BHA 30 may resume drilling borehole 16.
When it is desired to actuate bend adjustment assembly 800 from the second position to the third position and thereby provide the second deflection angle of assembly 800 between drill bit 90 and drillstring 21, rotation of drillstring 21 by rotary system 24 is ceased and the mud flowrate of surface pump 23 is increased to a third flowrate that is greater than the drilling flowrate. In some embodiments, the third flowrate of drilling mud from surface pump 23 comprises approximately 80%-100% of the maximum mud flowrate of well system 10; however, in other embodiments, the first flowrate may vary. The increased flowrate provided by the third flowrate increases the hydraulic pressure acting against the lower end 380B of locking piston 380, with locking piston 380 transmitting the hydraulic pressure force applied against lower end 380B to lower adjustment mandrel 840 via contact between keys 384 of locking piston 380 and the lower end 840B of lower adjustment mandrel 840. In this embodiment, the force applied to lower adjustment mandrel 840 from locking piston 380 is sufficient to shear the shear pin 858, thereby allowing both locking piston 380 and lower adjustment mandrel 840 to shift or move axially upwards through lower housing 320′ and upper housing 802 until lower adjustment mandrel 840 is disposed in the second axial position with the upper end 840A of lower adjustment mandrel 840 contacting shoulder 828 of upper housing extension 820. Following the displacement of lower adjustment mandrel 840 into the second axial position, extension 328 of lower housing 320′ is received in lower arcuate recess 848 (and is spaced from the inner end 850E of upper arcuate recess 850) of lower adjustment mandrel 840, with axially extending shoulders 328S of extension 328 circumferentially spaced from both the first and second shoulders 849A, 849B of upper arcuate recess 848.
Once lower adjustment mandrel 840 is located in the second axial position, the pumping of drilling mud from surface pump 23 is ceased for a predetermined third time period. In some embodiments, the third time period over which pumping is ceased from surface pump 23 comprises approximately 15-60 seconds; however, in other embodiments, the third time period may vary. With the flow of drilling fluid to power section 40 ceased, biasing member 354 displaces locking piston 380 from the locked position with keys 384 received in the second pair of long slots 854B of lower adjustment mandrel 840, to the unlocked position with keys 384 free from long slots 854B, thereby unlocking lower housing 320′ from lower adjustment mandrel 840.
Following the third time period, surface pump 23 resumes pumping drilling mud into drillstring 21 at the first flowrate for a predetermined fourth time period while rotary system 24 remains inactive. In some embodiments, the fourth time period comprises approximately 15-120 seconds; however, in other embodiments, the fourth time period may vary. During the fourth time period rotational torque is transmitted to actuator housing 340 via the meshing engagement between teeth 424 of teeth ring 420 and teeth 410 of actuator piston 402. Rotational torque applied to actuator housing 340 via locker assembly 400 is transmitted to housings 310, 320′, which rotate in the first rotational direction relative lower adjustment mandrel 840. Particularly, lower housing 320′ rotates until one of the shoulders 328S of lower housing 320′ contacts second shoulder 49B of the lower arcuate recess 848 of lower adjustment mandrel 840, restricting further rotation of lower housing 320′ in the first rotational direction. Following the rotation of lower housing 320′, bend adjustment assembly 800 is disposed in the third position, thereby forming the second deflection angle of assembly 800 between drill bit 90 and drillstring 21. With bend adjustment assembly 800 now disposed in the third position, the flowrate of drilling mud from surface pump 23 is increased from the first flowrate to the second flowrate to displace locking piston 380 back into the locked position with keys 384 now received in short slots 852 of lower adjustment mandrel 800. Additionally, with drilling mud flowing through BHA 30 from drillstring 21 at the second flowrate, actuator piston 402 is disengaged from teeth ring 420, preventing torque from being transmitted from bearing mandrel 220 to actuator housing 340. With locking piston 380 now disposed in the locked position and actuator piston 402 being disengaged from teeth ring 420, BHA 30 may resume drilling borehole 16.
In this embodiment, the transition of locking piston 380 into the locked position with keys 384 received in short slots 852 of lower adjustment mandrel 840 is indicated or registered at the surface by an increase in pressure at the outlet of surface pump 23 in response to the formation of a flow restriction in bend adjustment assembly 800. Particularly, as shown particularly in
Conversely, when keys 384 are received in short slots 852 of lower adjustment mandrel 840 (shown in
On occasion, it may be desirable to shift bend adjustment assembly 800 from the third position (corresponding with the second deflection angle of assembly 800) to the first position (corresponding to the unbent position of assembly 800). In this embodiment, bend adjustment assembly 800 is actuated from the third position to the first position by ceasing the pumping of drilling fluid from surface pump 23 for a predetermined fifth period of time. Either concurrent with the fifth time period or following the start of the fifth time period, rotary system 24 is activated to rotate drillstring 21 at the actuation rotational speed for a predetermined sixth period of time. In some embodiments, both the fifth time period and the sixth time period each comprise approximately 15-120 seconds; however, in other embodiments, the fifth and sixth time periods may vary. During the sixth time period, with drillstring 21 rotating at the actuation rotational speed, reactive torque is applied to bearing housing 210 via physical engagement between stabilizers 211 and the wall 19 of borehole 16, thereby rotating lower housing 320′ relative to lower adjustment mandrel 840 in the second rotational direction. Rotation of lower housing 320′ causes extension 328 to rotate through lower arcuate recess 848 of lower adjustment mandrel 840 until a shoulder 328S of extension 328 contacts the first shoulder 849A of lower arcuate recess 848, restricting further rotation of lower housing 320′ in the second rotational direction. Following the fifth and sixth time periods (the sixth time period ending either at the same time as the fifth time period or after the fifth time period has ended), drilling mud is pumped through drillstring 21 from surface pump 23 at the drilling flowrate to permit BHA 30 to continue drilling borehole 16 with bend adjustment assembly 800 disposed in the first position such that no deflection angle is provided between the longitudinal axis 95 of drill bit 90 and the longitudinal axis 25 of drillstring 21.
Referring to
Additionally, the design of the bend adjustment assembly (e.g., bend adjustment assemblies 300, 800) where lock piston 380 is activated using biasing member 354 and a fluid column positioned upwards from lock piston 380 allows relatively large biasing forces to be applied to locking piston 380 while avoiding a relatively long bit-to-bend distance (e.g., bit-to-bend distance D shown in
In some embodiments, the choke or lock piston 380 must pass the majority of the drilling fluid flow to drill bit 90, and thus, must be able to pass large debris through lock piston 380. In some embodiments, components of mud motor 35 (e.g., lock piston 380, driveshaft 120) may comprise erosion resistant materials to handle high fluid velocities. In some embodiments, the portion of driveshaft 120 disposed within lock piston 380 may be covered by an annular member coated with erosion resistant material to reduce costs. In certain embodiments, an outer surface of driveshaft 120 may be provided with axial slots to allow large debris to pass through lock piston 380 while allowing the flow to be choked tighter than what would normally be allowed without the inclusion of the axial slots or grooves on the outer surface of driveshaft 120. When the choke is made as a separate, non-integral component of driveshaft 120 (e.g., an annular member placed over a portion of the outer surface of driveshaft 120), the debris resistant features such as slots and grooves can be cheaply formed on the separate, non-integral component. The inclusion of these features allows the choke to have a high pressure drop with the potential added benefit of allowing drilling cuttings, LCM, debris, and rocks to pass the choke without plugging off during operation in the tightly choked position.
In some embodiments, lock piston 380 may be used with cam ramp angles added to the sides of the slots 376, 378 of lower adjustment mandrel 370 to allow the bend adjustment assembly 300 to be actuated in response to displacing lock piston 380 uphole. Particularly, keys 384 of lock piston 380 engage an angled cam ramp adjacent to the slots 376 or 378 of lower adjustment mandrel 370 to provide a torque to lower housing 320 via splines of lower housing 320 that interact with lock piston 380 when lock piston 380 is displaced in the uphole direction. The torque provided in response to axially moving lock piston 380 can be relatively large and is only dependent on the resultant hydraulic force acting on lock piston 380. In certain embodiments, by increasing the flowrate through downhole mud motor 35 large hydraulic pressures and thus rotational forces may be transferred by lock piston 380 and slots 376, 378 of lower adjustment mandrel 370 via the cam ramp angles interaction. Lock piston 380 and lower adjustment mandrel 370 may be configured to rotate clockwise or counterclockwise when axial force is applied to lock piston 380 by switching the side of the slot 376, 378 of lower adjustment mandrel 370 the cam ramp is positioned. In certain embodiments, the rotation of lower housing 320 is only performed when lock piston 380 moves in a single direction (uphole in this embodiment), there being no rotational force transferred when lock piston 380 is displaced in the opposite direction.
Referring to
The vibration race 920 of thrust bearing assembly 912 is configured to provide additional movement (e.g., axial movement, hammering, vibration, etc.) to the bearing mandrel 220 of bearing assembly 900. In this embodiment, vibration race 920 includes a nonplanar (e.g., wavy, etc.) engagement surface 922 (shown in
Additionally, the layout of bearing assembly 900 is altered from bearing assemblies 200, 500 to allow the addition of thrust bearing assembly 912 (including vibration race 920) while incorporating a high torque bearing design. The layout of bearing assembly 900 allows the addition of the vibration race 920 of thrust bearing assembly 912. In some embodiments, thrust bearing assembly 912 provides a high frequency low amplitude oscillation to bearing mandrel 220, which thereby increases and decreases the WOB applied to the drill bit 90 of BHA 30 and helps to increase rate of penetration (ROP) in harder earthen formations. The high frequency low amplitude oscillation induced by vibration race 920 may also extend the life of drill bit 90 and decrease stick-slip that often occurs in applications including relatively hard earthen formations.
Further, the layout of bearing assembly 900 allow the small amplitude oscillation induced by vibration race 920 to occur with little to no detriment to the functionality of the bend adjustment assembly (e.g., bend adjustment assemblies 300, 800, etc.) of BHA 30. In this embodiment, the engagement surface 922 of vibration race includes a plurality of ramps formed therein, where the number of ramps equals the number of bearing rollers received in cage 916. In the off-bottom position the oscillating action is disengaged, providing the ability to perform adjustments to the bend adjustment assembly of BHA 30 off-bottom without the presence of oscillations and then, subsequently, oscillate downhole once WOB is applied to drill bit 90. Moreover, the functionality of the bend adjustment assembly of BHA 30 is not affected by the inclusion of the vibration race 920 of thrust bearing assembly 912.
Referring to
At block 944 of method 940, the pumping of drilling fluid into the borehole is ceased for a first time period. In some embodiments, block 944 comprises reducing the rate of pumping of drilling fluid (without ceasing pumping into the borehole) such that a reduced flowrate is provided through the downhole mud motor (e.g., below 10% of the drilling flowrate). In some embodiments, the first time period of block 944 comprises approximately 15-120 seconds. In certain embodiments, block 944 comprises pumping drilling fluid into drillstring 21 (shown in
At block 946 of method 940, drilling fluid is pumped into the borehole at a first flowrate to provide the downhole mud motor (disposed in the borehole) with a second deflection angle that is different from the first deflection angle. In some embodiments, block 946 comprises pumping drilling fluid into drillstring 21 from surface pump 23 at 0%-30% of either the desired drilling flowrate or the maximum drilling fluid flowrate of drillstring 21 and/or BHA 30. In some embodiments, block 946 comprises pumping drilling fluid at the first flowrate to provide the downhole mud motor with a second deflection angle that is greater than the first deflection angle (e.g., creates or provides a greater bend along the downhole mud motor). In some embodiments, block 946 comprises pumping drilling fluid into the borehole at the first flowrate while drillstring 21 is not rotated (e.g., held stationary) by rotary system 24 (shown in
At block 948 of method 940, drilling fluid is pumped into the borehole at a second flowrate that is different from the first flowrate to lock the downhole mud motor (disposed in the borehole) in the second deflection angle. In some embodiments, block 948 comprises pumping drilling fluid into drillstring 21 from surface pump 23 at 50%-100% of either the desired drilling flowrate or maximum drilling fluid flowrate of drillstring 21 and/or BHA 30. In some embodiments, block 948 comprises pumping drilling fluid into the borehole at the second flowrate while drillstring 21 is not rotated (e.g., held stationary) by rotary system 24. In certain embodiments, block 948 comprises pumping drilling fluid into borehole 16 at the second flowrate to actuate locking piston 380 (shown in
Referring to
At block 964 of method 960, the pumping of drilling fluid into the borehole is ceased for a first time period. In some embodiments, the first time period of block 964 comprises approximately 15-120 seconds. In certain embodiments, block 964 comprises pumping drilling fluid into drillstring 21 (shown in
At block 966 of method 960, the downhole mud motor (disposed in the borehole) is rotated from a surface of the borehole for a second time period to provide the downhole mud motor with a second deflection angle that is different from the first deflection angle. In some embodiments, the second time period of block 966 comprises approximately 15-120 seconds. In some embodiments, block 966 comprises rotating the downhole mud motor from the surface of the borehole for the second time period to provide the downhole mud motor with a second deflection angle that is less than the first deflection angle (e.g., reduces or eliminates a bend along the downhole mud motor). In certain embodiments, block 966 comprises rotating drillstring 21 via rotary system 24 at approximately 1-30 RPM.
In some embodiments, block 966 comprises rotating drillstring 21 via rotary system 24 to rotate bearing housing 210 (shown in
At block 968 of method 960, drilling fluid is pumped into the borehole to lock the downhole mud motor (disposed in the borehole) in the second deflection angle. In some embodiments, block 968 comprises pumping drilling fluid into drillstring 21 from surface pump 23 at 50%-100% of either the desired drilling flowrate or maximum drilling fluid flowrate of drillstring 21 and/or BHA 30. In some embodiments, block 968 comprises pumping drilling fluid into drillstring 21 from surface pump 23 at 75%-100% of either the desired drilling flowrate or maximum drilling fluid flowrate of drillstring 21 and/or BHA 30. In certain embodiments, block 968 comprises pumping drilling fluid into borehole 16 at the second flowrate to actuate locking piston 380 (shown in
Referring to
At block 984 of method 980, drilling fluid is pumped into the borehole at a first flowrate for a first time period. In some embodiments, block 984 comprises reducing the flowrate below 10% of the drilling flowrate (the first flowrate being below 10% of the drilling flowrate). In some embodiments, the first time period of block 984 comprises approximately 15-120 seconds. In certain embodiments, block 984 comprises pumping drilling fluid into drillstring 21 (shown in
At block 986 of method 980, the downhole mud motor (disposed in the borehole) is rotated from a surface of the borehole (e.g., borehole 16) for a second time period to provide the downhole mud motor (e.g., downhole mud motor 35) with a second deflection angle that is different from the first deflection angle. In some embodiments, the second time period of block 986 comprises approximately 15-120 seconds. In some embodiments, block 986 comprises rotating the downhole mud motor from the surface of the borehole for the second time period to provide the downhole mud motor with a second deflection angle that is less than the first deflection angle (e.g., reduces or eliminates a bend along the downhole mud motor). In certain embodiments, block 986 comprises rotating drillstring 21 via rotary system 24 at approximately 1-30 RPM.
In some embodiments, block 986 comprises rotating drillstring 21 via rotary system 24 to rotate bearing housing 210 (shown in
At block 990 of method 980, while rotation and WOB are applied to the downhole mud motor, drilling fluid is pumped into the borehole at a third flowrate that is different from the first and second flowrates to lock the downhole mud motor (disposed in the borehole) in the second deflection angle. In some embodiments, block 990 comprises pumping drilling fluid into drillstring 21 from surface pump 23 at 50%-100% of either the desired drilling flowrate or maximum drilling fluid flowrate of drillstring 21 and/or BHA 30. In some embodiments, block 990 comprises pumping drilling fluid into drillstring 21 from surface pump 23 at 75%-100% of either the desired drilling flowrate or maximum drilling fluid flowrate of drillstring 21 and/or BHA 30. In certain embodiments, block 990 comprises pumping drilling fluid into borehole 16 at the third flowrate to actuate locking piston 380 (shown in
While disclosed embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.
This application is a continuation of international application No. PCT/US2018/034721 filed May 25, 2018, and entitled “Downhole Adjustable Bend Assemblies,” which claims benefit of U.S. provisional patent application No. 62/511,148 filed May 25, 2017, entitled “Downhole Adjustable Bend Assembly,” U.S. provisional patent application No. 62/582,672 filed Nov. 7, 2017, entitled “Downhole Adjustable Bend Assembly,” and U.S. provisional patent application No. 62/663,723 filed Apr. 27, 2018, entitled “Downhole Adjustable Bend Assemblies,” each of which are hereby incorporated herein by reference in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5117927 | Askew | Jun 1992 | A |
| 6394193 | Askew | May 2002 | B1 |
| 9605481 | Bleeker | Mar 2017 | B1 |
| 20160290049 | Kedare et al. | Oct 2016 | A1 |
| 20170089142 | Schaaf | Mar 2017 | A1 |
| Entry |
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| International Search Report and Written Opinion dated Oct. 10, 2018, for International Application No. PCT/US2018/034721. |
| Number | Date | Country | |
|---|---|---|---|
| 20180363380 A1 | Dec 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62663723 | Apr 2018 | US | |
| 62582672 | Nov 2017 | US | |
| 62511148 | May 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2018/034721 | May 2018 | US |
| Child | 16007545 | US |
