Downhole motor with steering capability

Abstract

A downhole motor having: a body having an outer surface and a longitudinal extent; a first flow passage defined within the body and disposed along the longitudinal extent of the body; and a second flow passage extending from the first flow passage to a channel at the outer surface, wherein Bernoulli suction is generated at the channel. A method for drilling a wellbore includes directing a fluid through a first flow passage defined within a body of a drill bit and disposed along a longitudinal extent of the body; directing a portion of the fluid from the first flow passage through a second flow passage to a channel at the outer surface to create a Bernoulli suction at the channel; and drilling a curved section of the wellbore by using the Bernoulli suction at the passage.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of an earlier filing date of U.S. Patent Application Serial No. 63 / 425,809, filed on November 16, 2022, the entire disclosure of which is incorporated herein by reference. Background Art

[0003] It is well known that downhole motors are used to drive drill bits in downhole environments. These downhole motors typically rotate the drill bit via a rotor, while the stator of the motor is substantially stationary relative to the ground. In cases where the drilled path needs to deviate, steering devices are used in conjunction with these motors. Such devices include bent sub - assemblies that bias a tool connected to the motor towards a desired direction and / or extension members that push against the borehole wall in a direction opposite to the desired forward direction of the drill bit. While known methods work acceptably, alternatives and improvements are always welcome in the art. Summary of the Invention

[0004] An embodiment of a downhole motor includes: a stator; a rotor configured to rotate relative to the stator; a body connected to the stator, the body having an outer surface and a longitudinal extent; a drive device connected to the rotor and disposed within the body and configured to connect to a downhole device to be driven; a first flow passage defined within the body and disposed along the longitudinal extent of the body; and a second flow passage extending from the first flow passage to a channel at the outer surface, where Bernoulli suction is generated at the channel.

[0005] An embodiment of a method for drilling a borehole in a subterranean formation includes: conveying a downhole motor into the borehole, the downhole motor including a stator, a rotor configured to rotate relative to the stator, and a body connected to the stator having an outer surface and a longitudinal extent; guiding fluid through a first flow passage defined within the body and disposed along the longitudinal extent of the body to rotate the rotor relative to the stator, thereby driving a downhole device connected to the rotor; guiding a portion of the fluid from the first flow passage through a second flow passage to a channel at the outer surface to generate Bernoulli suction at the channel; and drilling a curved section of the borehole by using the Bernoulli suction at the channel.

[0006] An embodiment of a borehole system includes a borehole in a subterranean formation and a downhole motor disposed within the borehole. Brief Description of the Drawings

[0007] The following description should not be regarded as limiting in any way. Referring to the drawings, like numerals designate like elements:

[0008] Figure 1 Perspective view of a downhole motor with steering capabilities;

[0009] Figure 2 and Figure 3 View illustrating the drive assembly of the downhole motor with steering capabilities;

[0010] Figure 3A Cross-sectional view of the downhole motor with steering capabilities, illustrating the directional flow within the downhole motor.

[0011] Figure 4 Schematic view of a lift valve;

[0012] Figure 5 Schematic view of a sleeve valve;

[0013] Figure 6 A wellbore system including a downhole motor with steering capabilities as disclosed herein; and

[0014] Figure 7 Illustrates a method of drilling a curved section and a tangential section of a wellbore using a wellbore system as disclosed herein. Detailed Description

[0015] A detailed description of one or more embodiments of the devices and methods disclosed herein is presented by way of example and not limitation with reference to the accompanying drawings.

[0016] Referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 3A , a motor 10 with steering capabilities is illustrated, such as a downhole motor or a mud motor. The motor 10 includes a body 12 having an inner surface 14 and an outer surface 16 and a longitudinal extent.

[0017] The body 12 also houses a drive assembly 19 (see Figure 2 and Figure 3 ), which drive assembly includes a drive shaft 34 and a drive transmission shaft 48. The drive shaft 34 is configured to be connected to the rotor 39 of the motor 10 at the upper side and to a downhole device or tool to be driven (such as a drill bit 35) at the lower side.

[0018] A first flow passage 18 is defined within the body 12 by the inner surface 14 and is disposed along the longitudinal extent of the body 12. The first flow passage 18 is configured to allow fluid 57 to flow from a surface location 74 ( Figure 6)Flow through the first flow path to the drill bit 35. The second flow path 20 is defined in the body 12 and extends from the first flow path 18 to the outer surface 16 of the body 12. One or more channels 22 are formed at the outer surface 16 of the body 12 and are in fluid communication with the second flow path 20 via a flow outlet 23, at which the second flow path 20 terminates, and fluid 57 enters the annular space between the inner surface 28 of the wellbore 30 and the motor 10. The channels 22 can be part of a stabilizer 84 known in the art and can be formed as a recess in the body 12 or by material buildup on the outer surface 16 of the body 12 (e.g., sleeve, clamped stabilizer) or both. If material is built up on the outer surface 16, it can be adhered to the body 12 by fusion welding, brazing, adhesives, fasteners, etc. and can be aligned or angled in embodiments with other channels distributed along the drill string 56( Figure 6 )). The channels 22 provide a flow path where the flow velocity is higher due to additional flow through the second flow path 20. The higher flow velocity in the channels including the second flow path 20 results in a reduced pressure relative to the pressure in the channels without the second flow path 20. The reduced pressure in the channels having the second flow path 20 results in a force (referred to as Bernoulli suction) perpendicular to the longitudinal axis of the motor 10, which will cause the motor 10 to bend, thereby resulting in a steering force available to steer the drill bit 35 and the motor 10 in a desired direction. In some embodiments, one or more stabilizers 33 can be provided on the drill string 56. One or more stabilizers can be positioned between the body 12 and the drill bit 35 or above the body 12. In embodiments, the Bernoulli suction and the steering force can be in the same direction or can be in opposite directions.

[0019] In any case, one or more channels 22 will have a barrier 24 at one or more sides of the channel 22. For example, if the channel 22 is part of a stabilizer (such as stabilizer 84), the vanes 41 of that stabilizer can also act as the barrier 24 on one or either side of the channel 22. In some cases, the barrier 24 will include an expansion element 26 that extends radially from the barrier 24 to reduce the distance between the barrier 24 and the inner surface 28 of the wellbore 30 when the motor 10 is in use. Reducing the distance between the barrier 24 and the inner surface 28 of the wellbore 30 reduces flow leakage from the channel 22 and thus improves the development of higher velocity fluid flow in the channel 22 that is intended to have such higher fluid velocity flow. This naturally also results in a greater pressure reduction in the channel 22 and thus a greater steering input (e.g., greater steering force) on the motor 10 in the azimuthal direction of the channel 22 relative to the longitudinal axis 17 of the motor 10. The expansion element 26 can include a wiper blade of flexible or soft material, an element including an expandable or shape memory material, a spring-loaded element, etc. The flexible or soft material can include a material having a relatively low stiffness (e.g., lower than the stiffness of steel), which can be elastic in an embodiment. For example, the expansion element 26 can include a foam material or a rubber material that has a lower stiffness than steel and is elastic in nature. Although the barrier 24 discussed above is essentially structural, it is also contemplated to use additional fluid flow introduced other than the fluid flow through the channel 22 to create a barrier. The additional fluid flow can be directed and configured to reduce or prevent fluid exchange between two or more channels 22 and thus act in the barrier capacity to cause the fluid 57 flowing in the channel 22 to tend to remain flowing in the channel 22.

[0020] Still referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 3A ,although Figure 1An example of a passage 22 is illustrated, which passage includes a flow outlet 23 at which a second flow passage 20 terminates, and fluid 57 enters an annular space between an inner surface 28 of a wellbore 30 and a motor 10. However, it is possible that more than one passage 22 can be provided with corresponding second flow passages 20 and flow outlets 23 to fluidly connect a first flow passage 18 with more than one passage 22 and be configured for a particular motor 10. More passages 22 generating Bernoulli suction will increase the generated steering force but will also spread the Bernoulli suction over a larger area around the motor 10. The directional granularity is enhanced with the smaller azimuthal area involved, but this is typically accompanied by a reduced Bernoulli effect. In some cases, the passages 22 are narrow such that more than one passage 22 will still generate a lower pressure fluid flow in a more closely azimuthal direction, and thus may already have balance and can enhance the balance. For example, in an embodiment, the width of the passage 22 is less than 60°, such as less than 45° or even less than 30°. Additionally, in an embodiment, a passage 22 having a flow outlet 23 with a corresponding second flow passage 20 can be narrower than other passages 22 included in the body 12 that do not include a flow outlet 23 connected to the second flow passage 20 and the first flow passage 18.

[0021] Regardless of whether one or more passages 22 are configured with corresponding second flow passages 20 and flow outlets 23 to fluidly connect a first flow passage 18 with more than one passage 22, the result is that the motor 10 will be pulled in the direction of the lower pressure fluid in the passage 22 that is configured with the corresponding second flow passage 20 and flow outlet 23, and a steering force is applied to the motor 10, the drive device 19, and / or a drill bit 35 attached to the motor 10. It should be understood that Figure 1The upward drilling end of the motor 10 is oriented to the right side of the figure such that the downhole flow arrow 31 illustrates the direction of downhole fluid flow and the return flow arrow 32 illustrates the direction of return fluid flow between the motor 10 and the inner surface 28 and the wall of the wellbore 30. Additionally, it is contemplated that the second flow passage 20 may be angled relative to the orthogonal plane of the longitudinal axis 17 of the motor 10 such that the fluid 57 (e.g., drilling fluid, drilling mud, or simply mud) exiting the second flow passage 20 at the flow outlet 23 also has a directional component in the direction of the upward drilling or in the direction of the return fluid flow (indicated by the return flow arrow 32) in use. The fluid 57 diverted from the first flow passage 18 into the second flow passage 20 will cause the return fluid flow at the exit of the second flow passage 20 in the passage 22 to flow at a greater velocity than the return fluid flowing naturally at the region of the return passage 22 of the motor 10 that is not configured to include the second flow passage 20 between the inner surface 28 of the wellbore 30 and the motor 10. The Bernoulli effect generated in the passage 22 causes the steering force and the attached tool (e.g., the motor 10, the drive device 19, and / or the drill bit 35) to tend towards the direction of the second flow passage 20, which allows the wellbore 30 to be steered. The remaining fluid will exit the drill string 56( Figure 6 ) through the nozzles 83 in the drill bit 35 and reach the smaller section through the bearing section bypass (i.e., through the radial bearing 65 and / or the axial bearing 73).

[0022] The motor 10 may include a rotor 39 disposed within a stator 37. The rotor 39 is fixedly connected to a drive assembly 19 that includes a drive shaft 48 and a drive axle 34 that is in turn fixedly connected to a drill bit 35. The stator 37 is fixedly connected to a body 12 that includes a passage 22. When in operation, downhole flowing fluid 57 (indicated by downhole flow arrow 31) will cause the rotor 39 to rotate relative to the stator 37, thereby causing the drill bit 35 to rotate via the drive assembly 19. Bearings (e.g., radial bearing 65 and / or axial bearing 73) may support the rotation of the rotor 39 relative to the stator 37. The stator 37 may rotate relative to the wellbore 30 (e.g., via a downhole orientation tool 55 or surface equipment, not shown), or may be stationary (non-rotating) relative to the wellbore 30. When the stator 37 and the body 12 including the passage 22 are stationary relative to the wellbore 30 (i.e., earth stationary, which means not rotating relative to the wellbore 30), the passage 22 including the flow outlet 23 is at a fixed azimuth angle about the longitudinal axis 17 of the motor 10. In this case, the Bernoulli suction generated by the fluid 57 exiting the flow outlet 23 occurs only at a fixed azimuthal interval (e.g., the azimuthal interval defined by the width of the passage 22), while the drill bit 35 continues to rotate via the drive shaft 48 and the drive axle 34 and drilling continues. Thus, the Bernoulli suction acts as a steering force on the passage 22 and the body 12 and is directed azimuthally about the longitudinal axis 17 of the motor 10 at which the passage 22 remains stationary. Since the stator 37 may be earth stationary or rotating based on surface input and stopped at any time, the azimuthal orientation of the passage 22 relative to the wellbore 30 or a reference attached to the wellbore 30 (e.g., magnetic north or the gravity “up” direction) may be selected such that steering occurs in that direction. Alternatively, if the stator 37 is allowed to rotate and thus the body 12 including the passage 22 is allowed to rotate, the steering force caused by the fluid 57 exiting the flow outlet 23 will also rotate about the longitudinal axis 17 of the motor 10 and will thus cancel out over one or more rotations of the body 12, or become distributed over approximately 360 degrees of the motor 10 and cancel out, thereby not providing a steering effect to the motor 10 and / or the drill bit 35.

[0023] In an embodiment, the second flow passage 20 may be closed by a valve 38. The valve 38 is configured to fully open, fully close, or block the flow from the first flow passage 18 through the second flow passage 20 to the flow outlet 23, thereby allowing, preventing, or regulating the fluid flow through the second flow passage 20 to the passage 22, and thus controlling the Bernoulli suction generated by the fluid 57 exiting the second flow passage 20 at the flow outlet 23 and flowing along the passage 22. The instructions for the valve 38 may come from a controller 87, such as a local controller or a remote controller, including a surface controller. The controller may be an electrical controller, a mechanical controller, etc., and may act based on human input.

[0024] Now turning to Figure 3B , the flow barrier 24 can include, for example, a tip seal 210 in a groove 240 (such as an elongate groove) along or between the channels 22 (see Figure 2 ). The flow barrier 24 including the tip seal 210 can be arranged substantially parallel to the longitudinal axis 17 of the motor 10 or can be arranged at an angle relative to the longitudinal axis 17 of the motor 10. Such a tip seal 210 can be powered by a biasing member 230 which can include an active element (such as an actuator) and / or can include a passive element (such as a (weak) spring) in an embodiment (e.g., a spring with a relatively low stiffness which is configured to extend with a relatively low force and engage the inner surface 28 of the borehole 30 to keep friction and frictional forces at a relatively low level while still inhibiting fluid flow therethrough. In some cases, the shape of the outer radial surface of the drill bit 35 may not exactly match the shape of the inner surface 28 of the borehole 30 or the borehole wall 220. In these cases, there may be a fluid-filled space or one or more cavities, such as a first cavity 250 and / or a second cavity 260, between the drill bit 35 / motor 10 and the borehole wall 220. The flow barrier 24 or the tip seal 210 has the effect of restricting or reducing the fluid connection between adjacent first and second cavities and thus restricting or reducing the fluid flow between the first and second cavities, and thereby increasing the sealing effect between the channels 22. Reducing the fluid connection between adjacent first and second cavities further confines the region of relatively high flow rate to a separate azimuthal range defined by the first or second cavity. If Bernoulli suction creates a desired lateral offset towards the borehole wall 220 in the direction of the low-pressure region, the tip seal 210 can thus squeeze the spring to retract. The spring is sized to hold the tip seal 210 in its extended position.

[0025] The valve 38 can be a lift type (see Figure 4 ), a rotary type or can be a sleeve type (see Figure 5 ), etc. In Figure 4In [the figure], valve 38 is shown as a reciprocating valve (e.g., a poppet valve or a mushroom valve), where actuator 25 causes a reciprocating motion of a blocking member (e.g., a plug) 29 to press it onto an opening (e.g., a base) 27 or release it from the opening to regulate the flow of fluid 57 through second flow passage 20. Alternatively, actuator 25 can also rotate a rotating member (not shown) operably connected to blocking member 29 and cause a reciprocating motion of blocking member 29 (e.g., when the rotating member is a camshaft rotated by actuator 25 and operably connected to blocking member 29, where rotation of the camshaft causes a reciprocating motion of blocking member 29). As another example, valve 38 can be a rotary valve, where rotation of a passage (e.g., a passage included in a lateral plug) connects or disconnects first flow passage 18 from second flow passage 20 to regulate the flow of fluid 57 through flow outlet 23 and corresponding passage 22. For a rotary valve, blocking member 29 can rotate relative to opening 27. In yet another example, valve 38 can be of the sleeve type. Sleeve 36 is disposed within body 12 and is rotatable therein. Sleeve 36 includes a port 40 that can be selectively aligned or misaligned with second flow passage 20 to allow or not allow fluid to flow into second flow passage 20. It is also contemplated that sleeve port 40 can be positioned such that it overlaps but is not fully aligned with second flow passage 20, which will allow fluid flow in second flow passage 20 but will block the flow. Valve 38 can be configured to close second flow passage 20 during rotation of body 12 to which motor 10 is attached, and open second flow passage 20 when the rotation stops or remains stationary. In one embodiment, valve 38 can be configured to automatically close second flow passage 20 during rotation of body 12 to which motor 10 is attached, and automatically open second flow passage 20 when the rotation stops or remains stationary. For example, a directional sensor 89 (e.g., a magnetometer, a gravimeter, or a gyroscope) can send data related to the azimuthal position of body 12 about longitudinal axis 17 to controller 87, and controller 87 can identify based on this data whether body 12 is rotating or remaining stationary, and based on this information, can send instructions to open or close valve 38. Sleeve 36 can respond to another action that keeps motor 10 stationary. Springs can be used to achieve this function. Alternatively, sleeve 36 can be configured to respond to reverse rotation of the drill string to open or close port 40. Alternatively, springs and / or dampers can be employed to open and close sleeve 36. In another alternative embodiment, sleeve 36 can be configured with elements that contact inner surface 28 of wellbore 30, and those elements are configured to open or close sleeve 36.

[0026] As disclosed, motor 10 and its use in a downhole environment result in reduced stress and wear on motor components, reduced friction during operation in wellbore 30 due to steering input occurring without wellbore wall contact, smoother drilling, reduced flange formation in the wellbore wall, etc.

[0027] Reference Figure 6 , the wellbore system 50 includes a wellbore 30 in a subterranean formation 54. The wellbore includes a curved section 93 and a tangential or straight section 99. A drill string 56 is disposed in the wellbore 30. In an embodiment, the drill string may be a rotary steerable drill string or a coiled tubing drill string. A downhole motor 10 having steering capabilities is provided as part of the drill string 56.

[0028] Now refer to Figure 7, which illustrates a method for drilling a borehole 30 that includes a curved section 93 and a tangential section 99. To drill the curved section 93, step 710 includes rotating or orienting the body 12 of the motor 10 such that the passage 22 that includes the flow outlet 23 points in a desired direction. An orientation sensor 89 (e.g., a magnetometer, a gravimeter, or a gyroscope) can measure and transmit data related to the azimuthal position of the body 12 about the longitudinal axis 17. The orientation sensor 89 can be positioned downhole (e.g., within the stator 37), or can be positioned in an uphole at the surface location 74. To rotate or orient the body 12 to the desired azimuth, the body 12 can be rotated by equipment at the surface location 74, or can be oriented by downhole equipment such as a downhole orientation tool 55. When the data sensed by the orientation sensor 89 indicates that the passage 22 points in the desired direction, in step 720, the rotation / orientation of the body 12 is stopped and fluid flow is circulated through the motor 10 and the body 12. The fluid flow will cause the rotor 39 of the motor 10 to rotate relative to the stator 37, which in turn will drive the drill bit 35 to rotate and penetrate into the formation 54 via the drive means 19. A portion of this fluid flow will also flow through the second flow passage 20 and the flow outlet 23 to create a higher flow velocity in the passage 22 relative to other azimuthal positions around the circumference of the body 12. The higher flow velocity in the passage 22 will create a Bernoulli suction force at the passage 22 towards the desired azimuth, which causes the drill string 56 to bend and thus results in a steering force that causes the drill bit 35 to deviate from a linear advancement, which ultimately results in the curved section 93 of the borehole 30. When it is desired to travel tangentially (such as the tangential section 99) at a particular depth of the borehole 30, in step 730, the stator 37 and the body 12 of the motor 10 will be rotated, for example, by corresponding equipment (such as a rotary table) at the surface location 74 while still maintaining the flow of the fluid 57. By rotating the body 12, the Bernoulli suction force generated by the additional fluid passing through the second flow passage 20 and the flow outlet 23 will also rotate about the longitudinal axis 17 of the motor 10 and thus will cancel out or become distributed over approximately 360 degrees of the motor 10 over one or more rotations of the body 12 to drill the borehole 30 without any deviation and create the tangential section 99 of the borehole 30. Alternatively, when the body 12 is rotating (e.g., when the orientation sensor 89 transmits data indicating that the body 12 is rotating), the actuator 25 can operate the valve 38 in the second flow passage 20 to close the second flow passage 20.

[0029] Some embodiments of the foregoing disclosure are shown below:

[0030] Embodiment 1: A downhole motor, comprising: a stator; a rotor configured to rotate relative to the stator; a body connected to the stator, the body having an outer surface and a longitudinal extent; a drive device, the drive device being connected to the rotor and disposed in the body and configured to be connected to a downhole device to be driven; a first flow path, the first flow path being defined within the body and disposed along the longitudinal extent of the body; and a second flow path, the second flow path extending from the first flow path to a channel at the outer surface, wherein Bernoulli suction is generated at the channel.

[0031] Embodiment 2: A downhole motor according to any of the preceding embodiments, wherein at least a portion of the second flow path is angled relative to an orthogonal plane to the longitudinal axis of the body and terminates at a flow outlet in the channel, the flow outlet allowing fluid to leave the second flow path in a direction toward the upward borehole.

[0032] Embodiment 3: A downhole motor according to any preceding embodiment, wherein the downhole device is a drill bit connected to the drive device.

[0033] Embodiment 4: A downhole motor according to any preceding embodiment, wherein the channel is defined by one or more flow barriers.

[0034] Embodiment 5: A downhole motor according to any preceding embodiment, wherein the flow barrier comprises a soft material.

[0035] Embodiment 6: A downhole motor according to any preceding embodiment, wherein the flow barrier is spring loaded.

[0036] Embodiment 7: A downhole motor according to any preceding embodiment, wherein the flow barrier comprises one or more sealing extensions.

[0037] Embodiment 8: According to any of the preceding embodiments, the downhole motor further comprises a downhole orientation tool, wherein the downhole orientation tool is configured to orient the channel to a direction of a preselected azimuth or azimuth interval.

[0038] Embodiment 9: The downhole motor according to any of the preceding embodiments, further comprising a valve in the body, the valve selectively allowing, preventing or blocking flow through the second passage.

[0039] Embodiment 10: A downhole motor according to any preceding embodiment, further comprising an orientation sensor, wherein the valve is operated based on measurements of the orientation sensor.

[0040] Embodiment 11: A method for drilling a wellbore in an underground formation, the method comprising: delivering a downhole motor into the wellbore, the downhole motor comprising a stator, a rotor configured to rotate relative to the stator, and a body connected to the stator having an outer surface and a longitudinal extent; guiding a fluid through a first flow path defined within the body and arranged along the longitudinal extent of the body to rotate the rotor relative to the stator, thereby driving a downhole device connected to the rotor; guiding a portion of the fluid from the first flow path through a second flow path to a channel at the outer surface to generate Bernoulli suction at the channel; and drilling a curved section of the wellbore by using the Bernoulli suction at the channel.

[0041] Embodiment 12: The method of any preceding embodiment, wherein directing the portion of the fluid from the first flow path through the second flow path to the channel further comprises causing the portion of the fluid to exit from the second flow path in a direction toward an upward borehole.

[0042] Embodiment 13: The method according to any of the preceding embodiments, wherein the downhole device is a drill bit connected to the driving device.

[0043] Embodiment 14: The method according to any preceding embodiment, wherein the channel is defined by one or more flow barriers.

[0044] Embodiment 15: The method according to any preceding embodiment, wherein the flow barrier comprises a soft material or one or more sealing extensions.

[0045] Embodiment 16: The method according to any preceding embodiment, wherein the flow barrier is spring loaded.

[0046] Embodiment 17: The method according to any preceding embodiment, further comprising drilling a linear section of the wellbore with the downhole motor.

[0047] Embodiment 18: The method according to any of the preceding embodiments, further comprising orienting the channel in a direction of a preselected azimuth angle or azimuth angle interval.

[0048] Embodiment 19: The method of any preceding embodiment, further comprising actuating a valve to allow, prevent, or block fluid flow through the second fluid passage.

[0049] Embodiment 20: The method according to any preceding embodiment, further comprising sensing information related to the azimuth angle of the passage with an orientation sensor, and operating the valve based on the measurement of the orientation sensor.

[0050] Embodiment 21: A wellbore system comprising a wellbore in a subterranean formation and a downhole motor disposed in the wellbore as described in any of the preceding embodiments.

[0051] In the context of describing the present invention (particularly in the context of the appended claims), the use of the terms "a", "an", and "the" and similar referents should be construed to cover both the singular and the plural unless otherwise indicated herein or clearly contradicted by the context. Further, it should be noted that the terms "first", "second", etc. herein do not denote any order, quantity, or importance, but are used to distinguish one element from another. The terms "about", "substantially", and "approximately" are intended to include the degree of error associated with a particular quantity of measurement based on the equipment available at the time of filing the application. For example, "about" and / or "substantially" and / or "approximately" includes a range of ±8% of a given value.

[0052] The teachings of the present disclosure can be used in a variety of well operations. These operations can involve using one or more treatment agents to treat the formation, fluids resident in the formation, the wellbore, and / or equipment in the wellbore, such as production tubing. The treatment agents can be in the form of liquids, gases, solids, semi-solids, and mixtures thereof. Exemplary treatment agents include, but are not limited to, fracturing fluids, acids, steam, water, brine, preservatives, cements, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, mobility improvers, etc. Exemplary well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water injection, cementing, etc.

[0053] Although the present invention has been described with reference to one or more exemplary embodiments, those skilled in the art will understand that various changes can be made and equivalents can be substituted for its elements without departing from the scope of the present invention. Additionally, many modifications can be made to adapt a particular situation or material to the teachings of the present invention without departing from its basic scope. Accordingly, it is intended that the present invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out the present invention, but that the present invention will include all embodiments falling within the scope of the claims. Additionally, in the drawings and the detailed description, exemplary embodiments of the present invention have been disclosed, and although specific terms have been employed, they have been used only in a general and descriptive sense and not for purposes of limitation, and thus the scope of the present invention is not so limited.

Claims

1. A downhole motor (10), characterized in that: stator (37); a rotor (39) configured to rotate relative to the stator (37); a body (12) connected to the stator (37), the body having an outer surface (16) and a longitudinal extent (17); a driving device (19) connected to the rotor (39), disposed in the body (12), and configured to be connected to a downhole device (35) to be driven; a first flow passage (18) defined within the body (12) and disposed along the longitudinal extent of the body (12); and A second flow passage (20) extends from the first flow passage (18) to a channel (22) at the outer surface (16), wherein a Bernoulli suction force is generated at the channel (22).

2. A downhole motor (10) according to claim 1, wherein at least a portion of the second flow passage (20) is angled relative to an orthogonal plane to the longitudinal axis (17) of the body (12) and terminates at a flow outlet (23) in the channel (22), the flow outlet allowing fluid to leave the second flow passage (20) in a direction toward the upper borehole.

3. The downhole motor (10) according to claim 1, wherein the downhole device (35) is a drill bit connected to the drive device (19).

4. The downhole motor (10) of claim 1, wherein the passage (22) is defined by one or more flow barriers (24).

5. The downhole motor (10) of claim 4, wherein the flow barrier (24) comprises a soft material.

6. The downhole motor (10) of claim 4, wherein the flow barrier (24) is spring loaded.

7. The downhole motor (10) of claim 4, wherein the flow barrier (24) comprises one or more sealing extensions.

8. The downhole motor (10) of claim 1, further characterized by a downhole orientation tool (55) configured to orient the channel (22) in a direction of a preselected azimuth or azimuth interval.

9. The downhole motor (10) of claim 1, further comprising a valve (38) in the body (12) that selectively allows, prevents, or blocks flow through the second passage (20).

10. The downhole motor (10) of claim 9, further characterized by an orientation sensor (89), wherein the valve (38) is operated based on measurements of the orientation sensor (89).

11. A method for drilling a wellbore (30) in an underground formation (54), the method comprising: A downhole motor (10) is delivered into the wellbore (30), wherein the downhole motor (10) is characterized by: stator (37); a rotor (39) configured to rotate relative to the stator (37); a body (12) connected to the stator (37), the body having an outer surface (16) and a longitudinal extent (17); directing a fluid (57) through a first flow passage (18) defined within the body (12) and disposed along the longitudinal extent (17) of the body (12) to rotate the rotor (39) relative to the stator (37) to drive a downhole device (35) connected to the rotor (39); directing a portion of the fluid (57) from the first flow passage (18) through the second flow passage (20) to the channel (22) at the outer surface (20) to generate Bernoulli suction at the channel (22); and A curved section (93) of the wellbore (30) is drilled by using Bernoulli suction forces at the passage (22).

12. The method of claim 11, wherein directing the portion of the fluid (57) from the first flow path (18) through the second flow path (20) to the channel (22) is further characterized by causing the portion of the fluid (57) to exit from the second flow path (20) in a direction toward an upward borehole.

13. The method according to claim 11, wherein the downhole device (35) is a drill bit (35) connected to the driving device (19).

14. The method of claim 11, wherein the channel (22) is defined by one or more flow barriers (24).

15. The method of claim 14, wherein the flow barrier (24) comprises a soft material or one or more sealing extensions.

16. The method of claim 14, wherein the flow barrier (24) is spring loaded.

17. The method of claim 11, further characterized by drilling a straight section (99) of the wellbore (30) with the downhole motor (10).

18. The method of claim 11, further characterized by orienting the channel (22) in a direction of a preselected azimuth or azimuth interval.

19. The method of claim 11, further characterized by actuating a valve (38) to allow, prevent, or block fluid flow through the second fluid passage (20).

20. The method of claim 19, further characterized by sensing information related to the azimuth of the passage (22) with an orientation sensor (89), and operating the valve (38) based on the measurement of the orientation sensor (89).

21. A wellbore system (50), characterized in that: a wellbore (30) in a subterranean formation (54); and The downhole motor (10) of claim 1, wherein the downhole motor is disposed in the wellbore (40).

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