The present disclosure relates generally to the field of well drilling operations. More specifically, embodiments of the present disclosure relate to a controlled slip-able connection (controlled slip connection) for use with down-hole components in a down-hole environment.
In conventional oil and gas operations, a well is typically drilled to a desired depth with a drill string, which includes drill pipe and a drilling bottom hole assembly (BHA). In certain applications, directional drilling techniques may be used for drilling wells with non-vertical (e.g., horizontal, curved, or angled) sections. Traditionally, when creating or drilling a non-vertical portion of a directional drill hole using a mud motor style setup, a bent axis motor-bit assembly is held stationary using the torsional resistance of the drill string from the top of the hole. As the drilling length increases, the drill pipe becomes more and more flexible making it more difficult to hold the rotational orientation of the drill bit and mud motor. It is now recognized that, once in the non-vertical (e.g., horizontal) section of a well hole, it becomes difficult to keep weight on the bit as the stationary pipe tends to stick and bind in the hole. This is not as prevalent during straight line or vertical motion as the drill pipe is rotated along with the drill bit so the static friction is broken and the more slippery dynamic friction takes over, which allows the pipe to slide more freely and keep the weight on the bit more constant.
In a first embodiment, a device includes controlled slip connection system configured to be coupled between a drill pipe and a directional drilling assembly, wherein the slip connection system is configured to enable continual rotation of the drill pipe while providing a rotationally stationary surface for a mud motor of the directional drilling assembly to react against.
In a second embodiment, a controlled slip connection system includes a pump section configured to couple to a drill pipe, a hydraulic section coupled to the pump section, and a controller section coupled to the hydraulic section, wherein the controller section is configured to couple to a mud motor of a directional drilling assembly, and wherein the controlled slip connection system is configured to slip at a rotational rate of the drill pipe.
In a third embodiment, a method of positioning a drill string within a wellbore includes detecting an orientation of a controlled slip connection system coupled between a drill pipe and a mud motor of the drill string with at least one sensor, adjusting a flow rate of hydraulic fluid in a hydraulic fluid circuit in fluid communication with a hydraulic pump coupled to the drill pipe with a controller, rotating the drill pipe, and pumping a drilling mud flow through the drill pipe and the controlled slip connection system to the mud motor.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
The present disclosure relates generally to a device and method that provides a controlled slip-able connection (or controlled slip connection) between an upper portion of a drill string and a directional drilling assembly (e.g., a mud motor and drill bit). The controlled slip-able connection is configured to allow the upper portion of the drill string (e.g., drill pipe), which is normally rotationally stationary during directional maneuvers, to continually rotate, which provides the desirable dynamic friction realm that is available during straight or vertical drilling runs. As discussed in detail below, the controlled slip connection also provides a rotationally stationary surface for a mud motor to react against regardless of the drill string's (e.g., the upper portion of the drill string or drill pipe) speed of rotation or position. The controlled slip connection may include an electrical generator with a controlled variable resistive load, a mechanical clutch with control over a breaking torque or other energy reducing rotary connection, a vane motor with control or metering valve that throttles a hydraulic fluid to control slip or rotation of the controlled slip connection, a constant or variable displacement hydraulic pump, or other component configured to enable and control absorption of torque and/or torque transfer from the upper portion of the drill string. As a result, the drill string may be rotated during a directional drilling operation, while the directional drilling assembly (e.g., mud motor and drill bit) remains stationary, which may reduce static friction between the drill string and the wellbore and help modify (e.g., reduce) the weight (e.g., force) of the drill string acting on the mud motor and drill bit.
Turning now to the drawings,
The casing 16 may be lowered into the wellbore 24 with a running tool. As shown, once each level of casing 16 is lowered into the wellbore 24 of the well, the casing 16 is secured or cemented in place with cement 26. For example, the cement 26 may be pumped into the wellbore 24 after each level of casing 16 is landed in place within the wellbore 24. Furthermore, the well 10 may include a liner 28 disposed within the wellbore 24 and the casing 16 (e.g., the intermediate casing 22) and held in place by cement 26. Specifically, the liner 28 may be hung from the casing 16 (e.g., the intermediate casing 22) within the wellbore 24. With the levels of casing 16 and the liner 28 in place, a drill pipe 30 (e.g., upper portion of a drill string) and a drilling BHA 32 may extend into the wellbore 24 for operation. For example, the drill pipe 30 and the drilling BHA 32 may complete a drilling process within the wellbore 24. In certain embodiments, the drilling BHA 32 may include a variety of tools that are used to complete the drilling process. In the illustrated embodiment, the BHA 32 includes components configured to enable a directional drilling process (e.g., a drilling process configured to create a lateral section 34 of the wellbore 24). In particular, the BHA 32 includes a mud motor 36 (e.g., a bent axis mud motor), which is configured to use drilling fluid (e.g., mud) as a motive fluid to drive rotation of a drill bit 38 (e.g., a bent axis bit). The mud motor 36 may include a bend, which enables orientation of the drill bit 38 in a direction that is offset of a central axis of the wellbore 24.
The BHA 32 further includes a controlled slip connection system 40 that is coupled between the mud motor 36 and the drill pipe 30. As discussed in further detail below, the controlled slip connection system 40 includes various components configured to enable rotation of the drill pipe 30 while drilling with the mud motor 36 in a directional drilling process. In particular, the controlled slip connection system 40 enables the mud motor 36 to stay rotationally stationary or essentially rotationally stationary relative to the Earth (e.g., within 0 to 10, 1 to 8, 2 to 6, or 3 to 4 percent rotation about a circumference of the mud motor 36) of the while the drill pipe 30 is rotated by absorbing torque from the drill pipe 30 and/or converting torque from the drill pipe 30 to waste energy (e.g., heat) or hydraulic fluid flow. The controlled slip connection system 40 may also include other components configured to enable adjustment of the position (e.g., angular or rotational position) of the mud motor 36 during the directional drilling process (e.g., adjust a drilling direction of the bent axis of the mud motor 36 and the drill bit 38). As will be appreciated, the ability to rotate the drill pipe 30 while using the mud motor 36 in a directional drilling process may reduce static friction between the drill pipe 30 and the wellbore 24 and help modify the weight (e.g., force) of the drill pipe 30 acting on the drill bit 38.
In the illustrated embodiment, the pump section 50 includes a hydraulic pump or motor 56 (e.g., a vane motor) that is fluidly coupled to a hydraulic fluid circuit 58 extending from the hydraulic pump 56 and through the hydraulic section 52. The hydraulic pump 56 has a stator portion 60 that is concentric with, and extends about, a rotor portion 62, which is coupled to the drill pipe 30. Bearings 64 and seals 66 are also disposed between the stator portion 60 and the rotor portion 62. As will be appreciated, the bearings 64 facilitate and improve rotation of the rotor portion 62 relative to the stator portion 60, and the seals 66 reduce leakage of hydraulic fluid from a compression chamber 68 between the stator portion 60 and the rotor portion 62.
As the drill pipe 30 rotates, the rotor portion 62 of the hydraulic pump 56 also rotates within the stator portion 60 of the hydraulic pump 56. As will be appreciated, rotation of the rotor portion 62 causes hydraulic fluid within the compression chamber 68 of the hydraulic pump 56 to be compressed and pressurized within in the hydraulic pump 56. The compressed and pressurized hydraulic fluid may then flow through the hydraulic fluid circuit 58, as indicated by arrows 70.
The flow of the hydraulic fluid through the hydraulic fluid circuit 58 is regulated by a control valve 72 (e.g., a servo valve or an electronically controlled proportional metering valve) disposed along the hydraulic fluid circuit 58 within the hydraulic section 52. When the control valve 72 is in an opened position, the hydraulic fluid may flow freely through the hydraulic fluid circuit 58, thereby allowing unrestricted operation of the hydraulic pump 56 (e.g., allowing the rotor portion 62 and the stator portion 60 to freely rotate relative to one another). For example, as discussed below, when the control valve 72 is in a fully opened position, a resistance torque acting on the drill bit 38 and the mud motor 38 (e.g., caused by torque of the rotating drill bit 38) may cause the controller section 54, the hydraulic section 52, and the stator portion 60 of the hydraulic pump 56 to rotate in a direction opposite the direction of the drill pipe 30 and the rotor portion 62 of the hydraulic pump 56. Conversely, when the control valve 72 is in a closed position, flow of the hydraulic fluid through the hydraulic fluid circuit 58, thereby restricting and/or blocking free operation of the hydraulic pump 56 (e.g., blocking relative rotation of the rotor portion 62 and the stator portion 60). For example, when the control valve 72 is in a fully closed position, the stator portion 60 and the rotor portion 62 may “lock up” and rotate together (e.g., in the same direction and at the same speed). As a result, the controller section 54, the hydraulic section 52, and the mud motor 36 may also rotate in the same direction and at the same speed as the drill pipe 30. As discussed below, the operation of the control valve 72 may be regulated to enable adjustment of the orientation and/or position of the mud motor 36. Additionally, the operation (e.g., position) of the control valve 72 may be regulated such that the torque transferred from the drill pipe 30 to the hydraulic fluid is equal to or approximately equal to the resistance torque of the mud motor 36, which enables stationary positioning of the mud motor 36 during rotation of the drill pipe 30. As used herein and above, the term “stationary positioning” refers to the mud motor 36 being essentially non-rotating relative to the Earth. As a result, the drill pipe 30 may be rotated during a directional drilling operation, which may reduce static friction between the drill pipe 30 and the wellbore 24 and help modify the weight (e.g., force) of the drill pipe 30 acting on the drill bit 38.
Furthermore, while the controlled slip connection system 40 is useful for maintaining and/or adjusting a direction of a bent axis drill bit 38 while rotating the drill pipe 30 during a directional drilling operation, the controlled slip connection system 40 may also be used during a traditional vertical drilling operation. For example, during a vertical drilling operation, the control valve 72 may be closed, thereby blocking flow of the hydraulic fluid through the hydraulic pump 56 and hydraulic fluid circuit 58, thereby “locking up” the stator portion 60 and rotor portion 62 of the hydraulic pump 56. As a result, the torque of the drill pipe 30 may be transferred to the mud motor 36, thereby enabling the drill pipe 30 and mud motor 36 to rotate together to reduce friction between the BHA 32 and the wellbore 24.
Additional components are also disposed along the hydraulic fluid circuit 58. For example, the hydraulic fluid circuit 58 includes a reservoir 74, which is a compartment that enables additional hydraulic fluid to be stored and flow through the hydraulic fluid circuit 58. In certain embodiments, the reservoir 74 may be accessible from an exterior of the hydraulic section 52 to enable flushing and replacement of the hydraulic fluid within the hydraulic fluid circuit 58. The hydraulic fluid circuit 58 also includes a heat exchanger 76. In particular, the heat exchanger 76 is positioned along the hydraulic fluid circuit 58 within a central mud flow passage 78 of the controlled slip connection system 40. During a drilling process, drilling mud is pumped through the drill pipe 30 and through the central mud flow passage 78 of the controlled slip connection system 40 to the mud motor 36, as indicated by arrows 80. As the drilling mud passes across the heat exchanger 76, heat may be exchanged between the hydraulic fluid flowing through the hydraulic fluid circuit 58 and the mud flowing through the central mud flow passage 78. More specifically, heat may be transferred from the hydraulic fluid, which increases in temperature as it is compressed and pressurized by operation of the hydraulic pump 56, to the mud flowing through the central mud flow passage 78. In this manner, at least a portion of the torque of the drill pipe 30 transferred to the hydraulic fluid may be discharged as waste heat.
The controller section 54 of the controlled slip connection system 40 includes a variety of components configured to enable monitoring and adjustment of the position of the controlled slip connection system 40 and the mud motor 36. For example, the controller section 54 includes a controller 82 configured to regulate operation of the control valve 72 disposed along the hydraulic fluid circuit 58. In other words, the controller 82 is configured to regulate a position of the control valve 72 to adjust the flow of hydraulic fluid through the hydraulic fluid circuit 58. In the illustrated embodiment, the controller 82 includes a processor (e.g., a microprocessor) 84 and a memory 86. The memory 86 is a non-transitory (not merely a signal), computer-readable media, which may include executable instructions that may be executed by the processor 84. For example, the executable instructions stored on the memory 86 may include instructions for control signals to be applied by the controller 82 based on feedback received from one or more sensors 88 of the controller section 54. As mentioned above, the controller 82 may be configured to control operation of the control valve 72 based on a detected or measured position or orientation (e.g., angular, circular, or rotational position) of the controlled slip connection system 40. As such, the sensors 88 may include a magnetometer, an accelerometer, gyroscope, gravitational sensor, azimuth sensor, another type of position sensor, or any combination thereof. Based on the measured position or orientation (e.g., circular position and/or angular orientation) of the controlled slip connection system 40, the controller 82 may adjust the position of the control valve 72 to increase the flow of hydraulic fluid in the hydraulic fluid circuit 58, thereby allowing free operation of the hydraulic pump 56 and enabling counter-rotation of the controlled slip connection system 40 and the mud motor 36 relative to the drill pipe 30, or decrease the flow of hydraulic fluid, thereby restricting operation of the hydraulic pump 56 and enabling co-rotation of the drill pipe 30, the controlled slip connection system 40 and the mud motor 36. In certain embodiments, the controller 82 may also be configured to communicate operating parameters of the controlled slip connection system 40, such as parameters measured by the sensors 88, to a system (e.g., a user interface) at a surface of the well 10.
The BHA 32 (e.g., the controlled slip connection system 40 and the mud motor 36) may also include other components. For example, in the illustrated embodiment, the controller section 54 includes a battery 90, which may provide power to the controller 82 and the sensors 88. In other embodiments, the mud motor 36 may include a generator 92 in addition to or instead of the battery 90. The generator 92 may use a flow of drilling mud from the drill pipe 30 to drive a turbine or other device configured to generate electrical power for powering the various components of the controller section 54 (e.g., the controller 82 and the sensors 88). In certain embodiments, the power produced by the generator 92 may be used to recharge the battery 90. The controller section 54 also includes a motor 94, which may be used to drive other components of the controlled slip connection system 40 or BHA 32.
As mentioned above, the controlled slip connection system 40 may include other components to control torque transfer between the drill pipe 30 and the mud motor 36 in place of the hydraulic pump 56 and hydraulic fluid circuit 58. For example, the controlled slip connection 40 may include a mechanical clutch system, an electromagnetic system, and electrical generator system, another type of variable or constant displacement pump, or other system configured to variably absorb and/or transfer torque from the drill pipe 30. Additionally, in such embodiments, the controlled slip connection system 40 may include other components (e.g., sensors, controllers, etc.) to control operation of the torque transfer systems to enable monitoring and adjustment of the position of the mud motor 36.
As indicated by arrow 100, during a directional drilling operation, the drill pipe 30 is rotated to help reduce friction between the drill pipe 30 and the wellbore 24. Similarly, the drill bit 38 is driven into rotation, as indicated by arrow 102, by the mud motor 36 during a directional drilling operation. The controlled slip connection system 40 (e.g., a processor of the controlled slip connection system 40) uses sensors 88 (e.g., gravitational sensors) to detect a gravitational force, indicated by arrow 104, acting on the controlled slip connection 40, and the controlled slip connection system 40 (e.g., a processor of the controlled slip connection system 40) uses the detected gravitational force as a reference point for determining and adjusting a direction of the bent axis of the drill bit 38. In other words, the sensors 88 of the controlled slip connection system 40 measure the angular (e.g., rotational) position or orientation of the controller section 54 and the mud motor 36 relative to the Earth. Based on changes in the measured position or orientation of the controller section 54 of the mud motor 36, the controller 82 may then adjust the position of the control valve 72 to adjust the torque transferred to the mud motor 36 by the controlled slip connection system 40 in the manner described above, thereby adjusting the position or orientation of the mud motor 36 to adjust the direction of directional drilling.
If the stationary portion of the controlled slip connection system 40 (e.g., the stator portion 60 of the pump section 50, the hydraulic section 52, and the controller section 54), which is fixed to the mud motor 36, rotates clockwise or counterclockwise beyond a threshold or set point, the controller 82 may adjust the position of the control valve 72 to adjust the torque transferred from the drill pipe 30 to the controlled slip connection system 40 and the mud motor 36 to adjust the position or orientation of the mud motor 36. For example, in
Furthermore, as discussed above, when the control valve 72 is in a position such that the controlled slip connection system 40 slips at the rate of the drill pipe 30 and the mud motor 36 is kept stationary, at least a portion of the torque of the rotating drill pipe 30 is transferred to the hydraulic fluid as waste heat. The heat of the hydraulic fluid may then be transferred to the drilling mud flowing through the central mud flow passage 78 by the heat exchanger 76 shown in
As discussed in detail above, the present disclosure relates generally to the controlled slip connection system 40 coupled between an upper portion of the drill pipe 30 and the mud motor 36 and drill bit 38. The controlled slip connection system 40 is configured to allow the upper portion of the drill pipe 30 to continually rotate, which provides the desirable dynamic friction realm that is available during straight or vertical drilling runs, during a directional drilling operation. The controlled slip connection system 40 also provides a rotationally stationary surface for the mud motor 36 to react against regardless of the drill pipe 30 speed of rotation or position. In certain embodiments, the controlled slip connection system 40 includes the pump section 50 with hydraulic pump 56, the hydraulic section 52 with the hydraulic circuit 58, and the controller section 54, which is configured to regulate a flow of hydraulic fluid through the hydraulic fluid circuit 58 and the hydraulic pump 56 to control an amount of torque transferred from the drill pipe 30 to the mud motor 36. However, other embodiments of the controlled slip connection system 40 may include an electrical generator with a controlled variable resistive load, a mechanical clutch with control over a breaking torque or other energy reducing rotary connection, or other component configured to enable and control absorption of torque and/or torque transfer from the upper portion of the drill pipe 30 to the mud motor 36. As a result, the drill pipe 30 may be rotated during a directional drilling operation, which may reduce static friction between the drill pipe 30 and the wellbore 24 and help modify (e.g., reduce) the weight (e.g., force) of the drill pipe 30 acting on the mud motor 36 and drill bit 38.
While only certain features of present embodiments have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.
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