RU2605475C2 - Device and method of controlling or limiting rotor orbit in screw engines or pumps - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: group of inventions is related to drilling, i.e. to rotary drilling hydraulic drives installed in borehole. Assembly of hydraulic downhole motor comprises screw motor having near end and far end and comprising stator and rotor. Stator comprises metal case, first elastomer material arranged in metal case, and first rigid material, arranged radially and directed inward from and at least partially covering first elastomer material. Rotor contains metal core, second elastomer material, located around metal core, and second rigid material arranged around second elastomer material. Stator first rigid material contacts rotor second rigid material.

EFFECT: enabling limiting of rotor geometric center displacement trajectory.

12 cl, 21 dwg

Description

FIELD OF TECHNOLOGY

[1] The embodiments disclosed herein relate to apparatus and methods for controlling or limiting the position of the rotor relative to the stator in a screw motor or pump. In another aspect, embodiments disclosed herein relate to apparatus and methods for adjusting or limiting the position of a rotor relative to a stator in a downhole hydraulic motor.

BACKGROUND OF THE INVENTION

[2] Screw motors or pumps, also called positive displacement motors or pumps, as well as positive displacement motors or pumps, work to trap fluid in a cavity. Cavities are formed in the spaces between the rotor and the stator, and the relative rotation between these components is a mechanism that determines the progress of the cavity and its passage along the axis along the length of the device from the inlet end to the outlet end. If the rotor is rotated, the fluid is forced along it in the cavities, and the device operates like a pump. If the fluid is pumped to the inlet end of the cavity at a higher pressure than the pressure at the outlet end, the forces generated on the rotor cause it to rotate, and the device works like an engine.

[3] In order to rotate the rotor in the stator and generate cavities that must move axially, the profiles of both components must have specific shapes. Typically, the rotor (2) should be a helical shaft with a cross-sectional shape similar to that shown in FIG. 1. The number of calls on the rotor (2) can vary from one to any number. The stator (4) has a profile that matches the shape of the rotor (2), with the number of strokes varying between two and any number, examples of which are shown in FIG. 2. In the corresponding rotor-stator pair, the number of entries on the stator (4) should be one greater than the number of entries on the rotor (2). A cross section of a typical combination of rotor (2) and stator (4) is shown in FIG. 3, the rotor (2) has three strokes, and the stator (4) has four strokes, the rotor (2) is placed in the stator (4).

[4] One of the surfaces, often the surface of the stator (4), is elastically deformed so that the seals (6) can be maintained between the contact points of the rotor (2) and the stator (4). Seals (6) form many cavities (8) between the rotor (2) and the stator (4) and provide relative rotation between the rotor (2) and the stator (4). The cross sections of the rotor (2) and stator (4) generally remain unchanged along the length of the motor or pump (10), but rotate along the axis along the helical profile. A longitudinal section of a part of the engine or pump (10) is shown in FIG. four.

[5] The rotor (2) does not have to have a fixed length. The selected length is often determined by steps, where one step has the length of the full revolution of the stator approach (4). Cavities (8) are formed between the stator (4) and the rotor (2).

[6] From the sections in FIG. 3 and FIG. 4 it is understood that the geometric center of the rotor (2) does not remain stationary relative to the stator (4) during rotation of the rotor (2). In general, if the rotor (2) has two or more approaches, the trajectory of the central point essentially runs along a circle with variations due to the exact characteristics of the surface profiles and the deformation of the elastic materials used to maintain the seals (6) between the cavities. As in the version of the engine where the rotor (2) generates driving torque, the same as in the version of the pump where the rotor (2) is driven, the drive shaft (12) is required to convert planetary rotation to rotation around a fixed axis. This arrangement (12) of the drive shaft has a movable joint (14) for the operation of this mechanism. In the engine embodiment, the outer end of the drive shaft (13) is connected to the driven component, for example, a drill bit in the embodiment of the hydraulic downhole motor. For the pump, the outer end of the drive shaft (13) is connected by a rotating drive unit, for example, an engine.

[7] The torque generated in the rotor (2) in the embodiment where the device is a motor, or required for the rotor (2) in the embodiment where the device is a pump, is a complex combination of pressure forces acting in the cavities (8) and reactive forces between the contact points between the stator (4) and the rotor (2). Its action is the rotation of the rotor (2) in the engine variant or the resistance to rotation in the pump variant. In both cases, there is also a resultant transverse force pushing the rotor (2) into the stator (4). The direction of this force is rotated with the rotation of the rotor (2). There is also a centrifugal force generated by the planetary motion of the rotor. And in a variant of the engine, for example in a downhole hydraulic motor, there may be a transverse component of the axial pressure that the transmission carries.

SUMMARY OF THE INVENTION

[8] It was found that the result of the action on the rotor of the forces pushing the rotor into the stator can be the deformation of the elastic surface of the stator and the creation of a gap on one side of the device. If this happens, then the fluid may pass along the device between the cavities with the fluid. The result is a decrease in productivity and maximum pump pressure and a decrease in rotation speed, as well as a limitation of the developed torque in the engine version.

[9] The embodiments disclosed herein can be used to overcome some of the limitations of known slurry pumps and other screw motors or pumps, or at least to provide an alternative to known slurry pumps and other screw motors or pumps.

[10] According to a first aspect of the embodiments disclosed herein, a screw motor or pump is provided, comprising: a rotor, a stator and a device for controlling or restricting the movement of the rotor relative to the stator.

[11] As discussed, the surface of the rotor or stator can be made of non-rigid material to provide a seal between the contacting surfaces of the rotor and stator, and in one or more embodiments, the movement of the rotor relative to the stator is controlled or limited to minimize deformation of the non-rigid material and sequential opening the gaps between the contacting surfaces of the rotor and stator.

[12] In one or more embodiments, the movement of the rotor is limited to follow when the desired path is rotated.

[13] In one or more embodiments, the movement of the rotor is limited by a precession device designed so that it can make the rotation of the rotor dependent on the position of the rotor.

[14] In one or more embodiments, the precession device consists of a gear wheel connected to a rotor shaft that follows a gear path connected to the stator.

[15] In one or more embodiments, the ratio of the number of entries on the wheel to the number of entries on the track is the same as the ratio of the number of entries on the rotor to the number of entries on the stator.

[16] In one or more embodiments, the toothed wheel has a deformable layer on an outer surface cooperating with the track. Alternatively, or in addition, the gear track has a deformable layer on a surface that interacts with the gear wheel.

[17] In one or more embodiments, the radial movement of the rotor relative to the stator is controlled or limited.

[18] In one or more embodiments, the movement of the geometric center of the rotor is limited to a predetermined path when using an engine or pump.

[19] In one or more embodiments, a wheel assembly is created at one or more locations to control or limit the movement of the rotor in the stator or around the circumference of the stator.

[20] In one or more embodiments, the wheel assembly comprises a wheel mounted on a rotor shaft, wherein the wheel is configured to circle around the inner surface of the stator.

[21] In one or more embodiments, the outer diameter of the wheel is equal to the diameter of the inner surface of the stator minus twice the predetermined maximum displacement of the rotor from its geometric center line.

[22] Alternatively, the wheel assembly may comprise a wheel mounted on the stator shaft, wherein the wheel is configured to rotor the circumference of the outer surface of the stator. One skilled in the art will recognize that in such an embodiment, the internal component is fixedly mounted (while becoming a stator or stationary element), while the external component of the motor or pump rotates (rotor or rotating element).

[23] In one or more embodiments, the outer diameter of the wheel is equal to the diameter of the inner surface of the rotor minus twice the predetermined maximum displacement of the rotor from its geometric center line.

[24] In one or more embodiments, the wheel assembly is mounted in place in an engine or pump, where the profile of the rotor and stator is substantially circular.

[25] In one or more embodiments, the wheel assembly further comprises a bearing for providing relative rotation between the wheel and the rotor. The bearing may preferably be a needle bearing.

[26] In one or more embodiments, the wheel has openings for allowing fluid to pass through them.

[27] In one or more embodiments, the interacting surfaces of the rotor and stator are substantially rigid in the region of the wheel assembly.

[28] In one or more embodiments, a stationary insert is created at one or more locations to control or limit the movement of the rotor in or around the stator.

[29] In one or more embodiments, the fixed insert is installed in the outer element of the rotor and stator pair and has a central hole through which the shaft of the inner element of the rotor and stator pair can pass, the diameter of the central hole being selected to limit the radial movement of the rotor relative to the stator.

[30] In one or more embodiments, the fixed insert has an additional plurality of openings to allow for fluid to pass through them.

[31] In one or more embodiments, the fixed insert is mounted in place in an engine or pump where the profiles of the rotor and / or stator are substantially circular.

[32] In one or more embodiments, the central bore is substantially circular, such that the rotor shaft may circle the central bore, or the rotor and the fixed insert may circle the stator.

[33] In one or more embodiments, the drive shaft is configured at one or more locations to control or limit the movement of the rotor in or around the stator.

[34] In one or more embodiments, the drive shaft arrangement comprises: a drive shaft and a driven shaft, wherein rotation can be transmitted when two shafts are not parallel; and a mechanism for limiting the angle between the drive shaft and the driven shaft, which restricts the movement of the rotor relative to the stator.

[35] In one or more embodiments, the mechanism for limiting the angle between the drive shaft and the driven shaft is a buffer ring.

[36] In one or more embodiments, a rotating insert is created at one or more locations to control or limit the movement of the rotor into the stator.

[37] In one or more embodiments, the rotary insert is installed in the stator and has an opening through which the rotor shaft can pass, the opening being offset from the center of the rotating insert so that the movement of the rotor is limited by a predetermined path.

[38] In one or more embodiments, the rotatable insert rotates freely in the stator.

[39] In one or more embodiments, the rotor rotates freely in a rotating insert.

[40] In one or more embodiments, a bearing is equipped to allow rotation of the rotating insert and / or rotor.

[41] In one or more embodiments, the rotatable insert further comprises a plurality of openings for allowing through passage of fluid therethrough.

[42] In one or more embodiments, a piston assembly is created at one or more locations to control or limit the movement of the rotor in or around the stator.

[43] In one or more embodiments, the piston assembly comprises a plurality of inwardly facing pistons spaced around the circumference of the outer member of the rotor and stator pair to control rotor movement relative to the stator. The pistons can preferably be spaced at equal intervals around the circumference of the outer element of the rotor and stator pair.

[44] In one or more embodiments, the pistons are mounted in an insert that is itself mounted on the outer member of the rotor and stator pair.

[45] In one or more embodiments, the outer member of the rotor and stator pair locally thickens in the piston mounting areas.

[46] In one or more embodiments, the insert is provided with a plurality of openings to allow for fluid to pass through them.

[47] According to a second aspect of the embodiments disclosed herein, a method for improving the performance of a screw motor or pump is provided, comprising the step of controlling or restricting the movement of the rotor relative to the stator to minimize opening of gaps between the rotor and the stator.

[48] In one or more embodiments, adjusting or restricting the movement of the rotor relative to the stator is in addition to any restriction due to contact with the stator or connection made at the ends of the rotor.

[49] In one or more embodiments, the radial movement of the rotor is controlled or limited relative to the stator.

[50] In one or more embodiments, the rotor is controlled to follow a predetermined combination of trajectory and rotation using a precession device.

[51] In one or more embodiments, the movement of the geometric center of the rotor is limited to a predetermined path.

[52] In one or more embodiments, a wheel is provided between the rotor and the stator to limit movement between them.

[53] In one or more embodiments, a stationary insert between the rotor and the stator is equipped to limit movement between them.

[54] In one or more embodiments, the drive shaft is coupled to the rotor to limit relative movement between the rotor and the stator.

[55] In one or more embodiments, the rotating insert is equipped between the rotor and the stator, the insert having an opening offset from its center through which the rotor shaft extends to limit relative movement between the rotor and the stator.

[56] In one or more embodiments, a piston device is provided between the rotor and the stator to limit movement between them.

[57] In another aspect, embodiments disclosed herein relate to a method for drilling a wellbore through an underground formation. The method may include: passing the drilling fluid through the layout of the hydraulic downhole motor, the layout of the hydraulic downhole motor comprising a screw motor having a proximal end and a distal end, the motor comprising: a stator and a rotor, the stator surface being made of non-rigid material to provide a seal between the contacting surfaces of the rotor and stator; at least one device mounted near at least one of the proximal end and the distal end, and at least one device limits the radial and / or tangential movement of the rotor relative to the stator; and drilling the formation using a drill bit directly or indirectly connected to the rotor.

[58] In another aspect, embodiments disclosed herein relate to a downhole hydraulic motor assembly comprising a screw motor having an inlet end and an outlet end. The motor may include: a stator and a rotor, wherein the stator surface is made of non-rigid material to provide a seal between the contacting surfaces of the rotor and stator; at least one device mounted near at least one inlet end and outlet end, and at least one device limits the radial and / or tangential movement of the rotor relative to the stator.

[59] In another aspect, embodiments disclosed herein relate to a drilling assembly. The drill assembly may include: a hydraulic downhole motor assembly comprising a screw motor having a proximal end and a distal end including: a stator and a rotor, wherein the stator surface is made of a non-rigid material to provide a seal between the contacting surfaces of the rotor and stator; at least one device mounted near at least one of the proximal end and the distal end, and at least one device limits the radial and / or tangential movement of the rotor relative to the stator; and an output shaft of the engine directly or indirectly connected to the distal end of the rotor; and a drill bit directly or indirectly connected to the distal end of the motor output shaft.

[60] In another aspect, embodiments disclosed herein relate to a screw motor or pump arrangement having an inlet end and an outlet end. The motor or pump may include: an internal element mounted in the external element, one representing the stator, and the other a rotor, wherein the surface of the rotor or stator is made of non-rigid material to provide a seal between the contacting surfaces of the rotor and stator; at least one device mounted near at least one of the inlet end and the outlet end, and at least one device restricts radial and / or tangential movement of the rotor relative to the stator.

[61] In another aspect, embodiments disclosed herein relate to a method of manufacturing a screw motor or pump having an inlet end and an outlet end, the method comprising: installing an internal element in an external element, one representing a stator and the other rotor; moreover, the inner element has a section with a shaped screw outer surface; moreover, the outer element contains a first section with a shaped helical inner surface and at least one second section with a circular inner surface, and at least one second section is located near at least one of the inlet end and the outlet end and is coaxial with the first section; the functional connection of at least one device for restraining the radial and / or tangential movement of the rotor relative to the stator with at least one of the inner element and the outer element on a length segment of the corresponding at least one second section.

[62] In another aspect, embodiments disclosed herein relate to a method of manufacturing an external element of a screw motor or pump, for example, a stator for a hydraulic downhole motor, the method comprising: combining the tubular external element with an injection molding device, machining, and / or coating spraying, wherein the axial line of the tubular outer element and the axial line of the device may be combined or not aligned; injection molding, machining and / or spraying the coating of the first inner portion of the outer element to create a shaped screw inner surface and at least one second inner portion with an inner surface of approximately constant inner diameter and coaxial with the first inner portion, the second inner portion is configured to accommodate a device for limiting radial and / or tangential displacement of an internal element installed therein.

[63] In another aspect, embodiments disclosed herein relate to a downhole hydraulic motor assembly including a screw motor having a proximal end and a distal end, the motor having: a stator and a rotor; and at least one device mounted near at least one of the proximal end and the distal end, and at least one device restricts radial and / or tangential movement of the rotor relative to the stator; wherein the stator contains a contact surface made of rigid material.

[64] In another aspect, embodiments disclosed herein relate to a directionally guided drill head, an adjustable deflecting sub, a bottom drill string assembly, or a stabilizer comprising a hydraulic downhole motor assembly described above including a screw motor having a proximal the end and the far end, and the engine has: a stator and a rotor; and at least one device mounted near at least one of the proximal end and the distal end, and at least one device restricts radial and / or tangential movement of the rotor relative to the stator; wherein the stator contains a contact surface made of rigid material.

[65] In another aspect, embodiments disclosed herein relate to a method of drilling a borehole through an underground formation, the method including: passing the drilling fluid through a hydraulic downhole motor assembly described above and including a screw motor having a proximal the end and the far end, and the engine has: a stator and a rotor; and at least one device mounted near at least one of the proximal end and the distal end, and at least one device restricts radial and / or tangential movement of the rotor relative to the stator; wherein the stator contains a contact surface made of rigid material. In other aspects, embodiments disclosed herein relate to a method of drilling a borehole through a subterranean formation, the method comprising: passing the drilling fluid through a directionally controlled drill head, an adjustable deflection sub, a bottom hole assembly, or a stabilizer, including such a layout of a downhole hydraulic motor. The formation is then drilled using a drill bit directly or indirectly connected to the rotor.

[66] In another aspect, embodiments disclosed herein relate to a drilling assembly including a hydraulic downhole motor assembly described above and including a screw motor having a proximal end and a distal end, the motor having: a stator and a rotor ; and at least one device mounted near at least one of the proximal end and the distal end, and at least one device restricts radial and / or tangential movement of the rotor relative to the stator; wherein the stator contains a contact surface made of rigid material. In other aspects, embodiments disclosed herein relate to a drilling assembly including a directionally guided drill head, an adjustable deflection sub, a drill string assembly, or a stabilizer incorporating such a hydraulic downhole motor assembly.

[67] In another aspect, embodiments disclosed herein relate to a downhole hydraulic motor arrangement comprising a screw motor, the motor including: a stator and a rotor; wherein the stator and rotor comprise a contact surface made of rigid material.

BRIEF DESCRIPTION OF THE DRAWINGS

[68] The motors and pumps disclosed herein are described by way of example only with reference to the accompanying drawings, in which the following is shown.

In FIG. 1 shows a cross section of several known rotors.

In FIG. 2 shows a cross section of several known stators.

In FIG. 3 shows a cross section of a known screw motor or pump.

In FIG. 4 shows a longitudinal section of a known screw motor or pump.

In FIG. 5 shows a cross section of a first embodiment of an engine or pump with a device for controlling or limiting radial movement of the rotor relative to the stator.

In FIG. 6 shows a longitudinal section of a screw motor or pump equipped with the device of FIG. 5.

In FIG. 7 shows a cross section of a second embodiment of an engine or pump with a device for controlling or limiting the radial movement of the rotor relative to the stator.

In FIG. 8 shows a cross section of a third embodiment of an engine or pump with a device for controlling or limiting the radial movement of the rotor relative to the stator.

In FIG. 9 shows a cross section of a fourth embodiment of an engine or pump with a device for controlling or limiting the radial movement of the rotor relative to the stator.

In FIG. 10 shows a cross section of a fifth embodiment of an engine or pump with a device for controlling or limiting radial movement of the rotor relative to the stator.

In FIG. 11A-11C show transverse and longitudinal sections of a liner configured to coaxialize a device for restricting the movement of the rotor relative to the stator according to the embodiments disclosed herein.

In FIG. 12A shows a cross section of a first embodiment of a motor or pump with a device for tracking the path and rotation of the rotor relative to the stator.

In FIG. 12B is a longitudinal sectional view of part of a screw motor or pump equipped with the device of FIG. 12A.

In FIG. 13-15 show various downhole hydraulic motor / drilling arrangements with one or more trajectory and rotor tracking devices relative to the stator.

In FIG. 16-18 illustrate rotors and stators applicable in downhole hydraulic motors according to the embodiments disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION

[69] In the embodiments of the motors or pumps disclosed herein, the rotor is held to perform a predetermined movement, in other words, the path of the geometric center of the rotor is limited, and in some cases, rotation is limited by this path. Although various embodiments are shown, it is understood that other systems for controlling or restricting the radial and / or tangential movement of the rotor relative to the stator can also be designed within the scope of the present invention. The movement of the rotor relative to the stator is generally limited only by the characteristic elastic deformation of the materials used to manufacture the rotor and stator (for example, deflection / compression of the rubber coating of the stator, etc.). When used herein, restraint of rotor movement relative to the stator refers to preventing or restricting movement greater than that leading to characteristic elastic deformation or acceptable for materials used to make the rotor and stator during operation of the latter.

[70] It is understood that the embodiments shown have a rotor as a component that rotates in the stator, and most pumps and motors are designed in this way, but embodiments also work if the internal component is stationary and the external component rotates.

[71] In FIG. 5 and 6 show a first embodiment of a device (20) for regulating or limiting the radial movement of the rotor (22) relative to the stator (24). The device comprises a wheel assembly (20) for use in one or more places on the rotor (22). A section of the wheel assembly (20) is shown in FIG. 5.

[72] The support wheel (26) is supported on the rotor shaft (22) by a needle bearing (28), although other suitable bearings can also be used, for example, roller bearings or plain bearings. In some embodiments, bearings (28) are plain bearings containing silicon carbide, tungsten carbide, silicon nitride, or other similar wear resistant materials. The support wheel can be made of steel or other materials suitable for the design environment. The outer surface of the support wheel (26) is slidable or rolling on the inner surface of the stator housing (24) in a place where the profile is approximately circular. The difference between the radii of the supporting wheel (26) and the inner surface of the stator housing (24) determines the maximum displacement of the rotor axis from the stator axis. The support wheel (26) has channels (27) built into it, to increase the area of fluid passage along the device, the channels can be of any number or shape, provided that they are large enough to allow the passage of solid particles that may be in the working fluid or pumped fluid. The stator housing (24) has a circular profile at the point of contact with the wheel (26) with the bearing, so that the axial line of the rotor shaft (22) should be kept approximately in a circle of a fixed radius, which helps to prevent the opening of gaps between the surfaces of the rotor (22) and the stator ( 24). In FIG. 6 shows a longitudinal section of an engine or pump equipped with a wheel assembly (20) of FIG. 5 only at one end, although additional wheel assemblies can be installed in additional locations.

[73] In some embodiments, the support wheel (26) may slide or roll in contact with the inner surface of the stator cylinder itself. In other embodiments, the support wheel (26) may slide or roll in contact with a coating applied to the inner surface of the stator cylinder. During the manufacture of some stators, the inner surface of the cylinder, such as the surface of the pipe, is coated, for example, by applying or spraying the coating material on the inner surface of the cylinder. However, due to the complexity of the stator manufacturing process, the alignment of the obtained stator with the stator cylinder cannot be guaranteed. Thus, the stator inner coating (90) obtained during manufacture can be offset from the center line (92) of the stator cylinder (94), as shown in FIG. 11A, where the obtained liner has an axial line (96) offset from the axial line (92) of the stator cylinder (94). As noted above, the outer surface of the support wheel (26) is adapted to slide or roll along the inner surface of the stator housing (24), where the profile is approximately circular. In this case, the supporting wheel (26) must slide or roll along the inner surface of the coating material so that the supporting wheel (26) slides or rolls with an axial line coinciding with the axial line of the stator liner (i.e., it is aligned with the stator liner and rotor, but not with the stator cylinder). The manufacture of a stator for use with a wheel (26) with a bearing may thus include a coating device, injection molding, or machining of a portion (98) of a constant diameter (e.g., rubber from a thickness of 1.6 mm (1/16 inch) up to 12.8 mm (1/2 inch) at one or both ends of the stator, as shown in Fig. 11B and 11C, to ensure that the wheels (26) with the bearing along the path of the rotor are held in the correct range and obtain the desired advantage.

[74] As noted above, the difference between the radii of the supporting wheel (26) and the inner surface of the stator housing (24) determines the maximum displacement of the rotor axis from the stator axis. In addition, for proper functioning, the support wheel (26) must maintain a relationship for sliding and / or rolling with the inner surface of the stator to constantly restrain the rotor during its rotation, i.e. maintaining contact when rotating all 360 °. Due to the eccentric rotation of the rotor, the ratio of the diameter of the supporting wheel (26) to the diameter of the inner surface of the stator (90) is an important variable, where an incorrect ratio can lead to unsteady contact of the supporting wheel with the inner surface of the stator, i.e. interconnections without rolling or without sliding.

[75] In addition to the diameter, the length of the support wheel (26) should also be sufficient for operation under lateral loads applied due to runout of the rotor. The support wheel (26) must be of sufficient length to meet the design requirements. The length of the support wheel (26) may depend on the number of starts, the torque of the engine / pump and other variables known to the person skilled in the art, and may also be limited by the available space between the rotor and the drive shaft.

[76] The support wheel (26) limits the amount of runout created by the eccentric rotation of the rotor. This, in turn, can limit the formation of gaps in the flow passage along the length of the motor / pump, limiting compression or deflection in the inner coating of the stator, for example, from rubber or other elastic material. In some embodiments, the support wheel may limit the deflection of the inner stator coating to less than 0.64 mm (0.025 inches), less than 0.5 mm (0.02 inches) in other embodiments, and less than 0.38 mm (0.015 inches) in other embodiments. Similar deflection limits can also be obtained using other embodiments disclosed herein.

[77] The support wheel (26), as described above, creates a radial restriction of the movement of the rotor by holding the rotor in contact with the stator (ie, creating a contact force when displaced that does not interfere with the generation of torque). The resulting reduced normal force at the contact point between the rotor and stator can reduce braking forces, improving compression at the contact points with minimizing leakage paths. By limiting the formation of flow passage gaps (leak paths) along the length of the rotor, pressure losses can be reduced by increasing the output power of the engine. In addition, restricting the movement of the rotor can reduce stator wear, especially near the top of approaches, where the tangential speeds are the highest.

[78] In FIG. 7 shows a second embodiment of a device (30) for controlling or restricting the movement of the rotor (32) relative to the stator (34), in which a fixed insert (36) is installed inside the stator (34). The fixed insert (36) can be equipped at one or more places in the stator (34). The fixed insert (36) has a central opening (38) or a similar narrowing of the inner diameter of the stator (34) to limit the radial movement of the rotor (32) relative to the stator (34). The fixed insert (36) may also comprise a plurality of holes (37) to allow fluid to flow along the motor or pump. The fixed insert (36) ensures that the rotor shaft (32) is held back so that the center line should remain approximately in a circle of a fixed radius, which helps to prevent the opening of gaps between the surfaces of the rotor (32) and the stator (34).

[79] Similar to the embodiments of FIG. 5, 6 and 11, the stationary insert (36), as shown in FIG. 7 can be placed in the molded stator profile so that the fixed insert (36) is aligned with the stator liner (32). In some embodiments, the fixed insert (36) may be a raised portion of the cast stator profile. In some embodiments, the ratio of the diameter of the fixed insert (36) to the diameter of the rotor (32) may be such that a diameter of a regular or clean rolling is obtained. Bearings can also be used to provide sliding between the stationary insert (36) and the rotor (32), where the ratio of the diameter of the correct rolling is not used. Similar problems to the above with regard to flow paths, torque requirements and insert lengths should be solved by holding the rotor in accordance with the embodiment of FIG. 7. With regard to torque requirements, in some embodiments, an increased rotor section near the stationary insert (36) may be required instead of narrowing the rotor section to create a sliding or rolling relationship.

[80] A third embodiment of a device (40) for controlling or restricting the movement of the rotor (42) relative to the stator (44) is shown in FIG. 8. A modified drive shaft (43) is equipped at one end of the rotor (42) to limit the radial movement of the rotor (42). A similar articulated shaft can also be equipped at the other end to limit the radial movement of the rotor (42). The swivel angle at one end of the drive shaft (43) can be limited, for example, by a buffer ring (46) attached to the output shaft in the engine version (45) or the input shaft in the pump version (45) so that when entering the contact, a restriction is established on the radial movement of the rotor. An equivalent embodiment may have a buffer ring (46) attached to the rotor (42), which should similarly limit the radial movement of the rotor (42). The drive shaft (43) limits the movement of the axial line of the rotor shaft to hold approximately in a circle of a fixed radius, which helps to prevent the opening of gaps between the surfaces of the rotor and the stator.

[81] A fourth embodiment of a device (50) for controlling or restricting the movement of the rotor (52) relative to the stator (54) is shown in FIG. 9. The device (50) consists of a rotating circular insert (56) mounted inside the stator housing (54), which can rotate around the longitudinal axis relative to the stator (54). The rotating insert (56) can be equipped at one or more places in the stator (54). The rotation of the insert (56) relative to the stator (54) provides a bearing between the stator and the insert (not shown). The hole (58) is made in the insert (56), the center of the hole (58) is offset from the center of the insert (56) by a distance equal to the maximum allowable displacement of the rotor axis from the axis of the stator. The diameter of the hole (58) is sufficient for the passage of the rotor (52) through it and free rotation in it. An additional bearing (not shown) is provided between the insert (56) and the rotor (52) to allow rotation of the rotor (52) relative to the insert (56). Openings (57) pass through the round insert (56), creating a fluid path along the motor or pump. The insert (56) provides such a retention of the rotor shaft (52), in which the center line remains approximately in a circle of a fixed radius, which helps to prevent the opening of gaps between the surfaces of the rotor (52) and the stator (54).

[82] A fifth embodiment of a device (60) for controlling or restricting the movement of the rotor (62) relative to the stator (64) is shown in FIG. 10. Many pistons (65), the reaction of which creates a bound material (66), which can be solid, liquid or gaseous, are used to limit the radial movement of the rotor (62). The piston assembly (65) can be equipped at one or more places in the stator (64). In FIG. 10 shows an example where eight such pistons (65) are used, although a different number of pistons can also be used. Cylindrical housings (63) for pistons (65) are machined in a round insert (67) installed inside the stator housing (64) and are of sufficient thickness to prevent structural damage under the influence of arising loads. The round insert (67) is provided with a plurality of openings (68) for allowing fluid to pass along the motor or pump. When the rotor (62) comes into contact with the piston (65), the bonded material (66) is compressed and prevents the free movement of the piston (65), thereby restricting the movement of the rotor (62). The device (60) provides such a retention of the rotor shaft (62), in which the center line remains approximately in a circle of a fixed radius, which helps to prevent the opening of gaps between the surfaces of the rotor (62) and the stator (64).

[83] The embodiments described above and shown in FIG. 5-11, provide a limitation or restraint of the radial movement of the rotor (i.e., set the limits of the planetary trajectory of the rotor during rotation). The embodiments disclosed herein can effectively limit radial movement from the centerline, for example, by the stop shown in FIG. 5, and may also limit radial movement to the center line, for example, with the stop shown in FIG. 9.

[84] In addition to the substantially circular radial restraint means shown in FIG. 5-11, it is also possible to restrain the movement of the rotor by applying a non-circular stop, for example, shown in FIG. 12A (cross section) and 12B (longitudinal section). In this embodiment, the precession device (70) comprising a gear wheel (72) with a profile similar to but not identical to the profile of the rotor (74) is functionally connected to the rotor shaft (75). Similarly, a gear wheel (72) should interact with a track (76) having a profile similar to, but not identical to, the stator profile (78). The track (76) may be made of a material similar to the material of the stator (78) or of a material that shrinks less than the stator (78), for example, harder rubber, hard plastic, ceramic, polycrystalline synthetic diamonds or steel. The precession device (70) can be used in one or more places on the length of the rotor (74). In addition to solving the problems of forces arising at the inlet end or outlet end of the engine, using the appropriate location and / or construction materials, the track profile (76) can be made similar to the stator profile (78), and the corresponding sections (76, 78) can be shifted by phase so that the planetary trajectory of the rotor in the stator (78) is limited. In other words, the sections can be shifted in phase so that during operation the forces leading the rotor away from the ideal orbit become balanced and effectively limit the planetary trajectory of the rotor.

[85] The precession device (70) controls the rotor (74) so that the rotor moves along a predetermined path and with a given rotation relative to the stator (78). Containment of this type can effectively limit its rotation to the orbital position when the rotor rotates. The gear wheel (72) interacts with the gear track (76), so that the profiles of the gear wheel (72) and track (76) limit the path when the rotor (74) rotates to predetermined limits.

[86] The gear wheel (72) is connected to the rotor shaft (75) substantially motionless. The ratio of the number of entries on the wheel (72) and the number of entries on the track (76) is the same as the ratio of the number of entries on the rotor (74) and the number of entries on the stator (78). The entry profiles on the wheel (72) and on the track (76) should determine the value of deformation by the rotor (74) of the stator sealing surface (78), at which the opening of gaps between them is limited.

[87] In order to provide some consistency of rotation, the surface of the gear wheel (72) or track (76) may have an elastic coating, for example of rubber. A gear wheel (72) and a track (76) may have parallel sides or extend at helical angles to provide some slight axial movement and conform to manufacturing tolerances.

[88] The profile and composition (construction material, compressibility, etc.) of the gear wheels (72) can be designed such that the deformation of the rubber in the stator (78) is limited. In other embodiments, the profile and composition of the gear wheel (72) can be designed such that the deformation of the rubber in the stator (78) is maintained at a fixed level. The interaction between the rotor (74) and the rubber in the stator (78) is used to maintain the seal, where the torque is generated mainly on the gear wheel (72). This not only ensures that the load is limited from pressure to the point where the seal stops working (very high pressure), but also ensures that the contact forces in the rubber are kept essentially independent of the pressure value. This reduces wear and fatigue failure in rubber, and also improves the efficiency of the engine / pump.

[89] Motors according to the embodiments disclosed herein can be used, for example, as a downhole hydraulic motor in a drilling assembly. As shown in FIG. 13, during operation, the drilling fluid is pumped to the inlet end (102) of the hydraulic downhole motor (100) at a pressure higher than the pressure at the outlet end (104), generating forces on the rotor (105) and causing the rotation of the rotor (105). The rotor (105) is operatively connected to the drive shaft (106) to convert the planetary rotation of the rotor (105) into rotation around a fixed axis (108). The far end of the drive shaft (not shown) is directly or indirectly connected to a drill bit (not shown), the rotation of which can be used to drill an underground formation.

[90] The forces acting on the rotor (105) during operation include forces arising from the pressure drop across the engine (100) from the inlet (near) end (102) to the outlet (far) end (104). The pressure drop can result in a tilt moment. There is also a downward force exerted on the drill string, commonly referred to as the "axial load on the bit", this force is necessarily transmitted through the rotor - drive shaft - drill bit connections. As a result of planetary and axial interconnections of drive shaft connections, angular and / or radial forces can be applied to the rotor (105). As a result of the rotation of the rotor (105), tangential forces also arise.

[91] Each of these forces can affect the nature of the interaction of the rotor (105) with the stator (114) (for example, compression forces generating seals along the edges of the resulting cavities, sliding, braking or friction forces between the rotor (105) and the stator (114) during rotation of the rotor, etc.) and can cause a gap along the length of the engine (100), reducing the efficiency of the engine. In addition, the effect of these forces may differ near the inlet end (102) and the outlet end (104). The various rotor containment devices disclosed hereinabove can be used to control or limit the movement of the rotor (105) near the inlet end 102, the outlet end 104, or both.

[92] Other examples of various displacement motors (100) using motion limited rotors disclosed herein, for example for drilling applications, are shown in FIG. 14-15, where the same positions represent the same parts. As shown in FIG. 13 and discussed below, embodiments of the engine (100) may include a stop (118) near the outlet (far) end (104) to restrain the movement of the rotor (105). As shown in FIG. 14, embodiments of the motor (100) may include a stop (120) near the inlet (proximal) end (102) to limit the movement of the rotor (105). As shown in FIG. 15, embodiments of the motor (100) may include stops (118), (120) near the inlet end (102) and the outlet end (104), respectively, to limit the movement of the rotor (105).

[93] When two or more restrictors are used, as in FIG. 15, the stops (118), (120) may be the same or different. For example, as described above, the forces transmitted to the rotor (105) may differ at the inlet end from the forces at the outlet end, resulting in different orbit radii for the center of the rotor at the inlet and outlet ends. Thus, it is preferable to have a rotor radial stop (105) close to the inlet end (102), for example, the stop shown in FIG. 5, which can operate effectively in combination with a stop for radial movement of the rotor to the axis, for example, with a stop shown in FIG. 9 or FIG. 12A, 12B. In this case, the limiters can effectively limit the size of the gap formed between the rotor and the stator, improving the efficiency of the engine.

[94] Although in FIG. 15 shows one stop at each, inlet end and outlet, end, each or both, inlet and outlet ends, may have several movement restricting devices. For example, the inlet end and / or the outlet end may include a radial stop, for example, shown in FIG. 5 and a toothed limiter, for example, shown in FIG. 12 mounted in series.

[95] Several restrictors (one or more at each end or both ends) should be selected and / or designed to complement each other to obtain the desired seal improvement (elimination of flow passage gaps) without negatively affecting the operation or wear of the rotor. For example, restrictors at the inlet and outlet ends can both act in the same direction or in the same phases, eliminating the application of opposite loads on the rotor and preventing the rotor from blocking due to opposing forces. In this case, the operation of the engine can be improved by eliminating the risk of jamming.

[96] The devices disclosed herein can be used to restrain radial and / or tangential displacements of the rotor relative to the stator, to reduce, minimize, or eliminate gaps in the passage of flow along the length of the motor, which improves motor efficiency. The devices disclosed herein may also reduce stator wear.

[97] Improving engine efficiency, for example, improving compaction and higher output per unit length, as noted above, can be used in some embodiments to reduce the overall length of the engine while maintaining the required output. A shortened power section can have numerous advantages and applications, discussed below.

[98] The limited total length of the power section can provide trouble-free passage of a stream of solid particles, for example, a washing solution including a solid phase, through the motor, even if the rotor and stator have contact surfaces made of rigid materials. A limited overall length may also provide flexibility in the selection of materials of construction that might otherwise have unacceptable prices.

[99] In some embodiments, the rotor and / or stator may be made of metal, composite, ceramic, polycrystalline diamonds, hard plastic, or hard rubber as a structural material. For example, both, the rotor and the stator, can be made of metal, with the creation of metal-to-metal contact along the length of the power section.

[100] In other embodiments, the rotor and / or stator may be formed with an elastic layer (for example, nitrile butadiene rubber) and a hard layer, for example, of hard rubber or plastic, ceramic, composite, or with a metal coating arranged as a contact surface on top of the elastic inner layer. For example, the rotor may be metallic, similar to the rotors currently manufactured, and the stator may consist of rubber with a metal coating, where the metal layer contacts the rotor during engine operation. Similarly, a layer of hard rubber or reinforced rubber can be created as the layer closest to the center line coming into contact with the rotor. Typical “multilayer” stators of the prior art have a hard or reinforced inner elastomeric layer, contrary to the present embodiments, to provide the required compression and sealing properties of the outer layer. However, due to the reduced length of the power sections, it is possible to use a hard contact layer that improves the wear resistance of the motor (rotor, stator, or both) with the required output power. An example of a multilayer stator is given, but multilayer rotors can also be used, for example, a rotor with a metal core that provides torque, and an elastomeric material located on the core and a metal shell. These embodiments are shown in FIG. 16 and 17 for the rotor and stator, respectively, where the stator (FIG. 16) may include a metal housing 1602, an elastomeric layer 1604 and a hard layer 1606 creating a contact surface 1608, and the rotor (FIG. 17) may include a metal a core 1702, an elastomeric layer 1704, and a hard layer or sheath 1706 creating a contact surface 1708.

[101] In embodiments where the respective contact areas of the rotor and stator (stators) are both, for example, metal, made of hard plastic, composite or ceramic, it may be necessary to limit friction, wear and other undesirable aspects of the interaction between the rotor and the stator, which may cause premature failure or jamming of the rotating component. The contact surfaces of the insert and / or rotor can be coated or machined to reduce at least one of friction and wear. Processing may include chromium plating, high-speed powder coating using HVOF or HVAF technology, and diffusion during sintering, among others. Power sections with metal-to-metal contact can also provide both a sufficient tolerance to withstand waste and a sufficient contact density to limit the rotor's movement close to ideal, gaining the above advantages without the use of restraining devices.

[102] Similarly, the relatively small contact length between the restraining devices and the rotor or stator can provide flexibility in material requirements and similarly to combinations of hard or hard coated materials that can be used for restraining devices.

[103] Alternatively, an elastic elastomer can be used for the contact surface on both, the rotor and the stator. Reducing the usually high frictional loads obtained by restrictive devices can provide the use of elastomeric stators and rotors in combination, providing the required performance of the pump (power output, wear resistance, etc.).

[104] The benefits of using motion restricting devices may also provide alternative stator designs. For example, as shown in FIG. 18, the stator can be made using a profile of hybrid or with desired material properties. As shown in FIG. 18, the ridges and recesses of the stator 1805 can be made of different materials, where the recesses 1807 are made of elastic elastomeric material 1810, and the ridges 1812 are made of hard material 1815, for example, hard plastic, hard rubber, metal, ceramic or composite material. The forces that occur during nutation of the rotor differ for ridges and grooves, the grooves collide with compressive forces, and the ridges withstand shear forces. The hybrid design may result in the contact of the rotor, which may be metallic, with the rigid material of the stator flanges, which may also be metallic, but allow passage without problems of the flow of solid particles, for example, a washing solution including a solid phase, through the motor.

[105] One potential advantage of limiting the movement of the motor may be the reduction of vibrations associated with the hydraulic downhole motor. Limited shear forces can result in reduced runout or a planetary trajectory in a narrower range compared to an engine without a limiter. As a result of vibration reduction, drilling can be improved, for example, with one or more of the following: improved barrel quality, evenly calibrated barrel and improved control of the direction of drilling.

[106] Reducing the length of the engine also allows modification of the drill string components to be included in the engine. For example, a variable deflection housing typically includes a transmission shaft for transmitting the torque generated in the power section of the drilling motor to the support section of the drilling motor. Due to a possible reduction in the size of the engine, due to the movement-limiting devices disclosed in this document, it becomes possible to turn the engine into a curved casing together with the transmission shaft. Similarly, the engines of the embodiments disclosed herein can preferably be included in a directional stabilizer drill head or other various parts of the bottom hole assembly (BHA).

[107] The reduced length may also allow the installation of a wire passing through the engine and create space for additional downhole instrumentation, for example, engine monitoring devices and / or components below the engine. Instrumentation can preferably monitor engine speed, pressure drop, and other factors, possibly preventing shutdowns and ensuring that the engine operates at high efficiency or peak efficiency, each of which can result in improved drilling efficiency (increased penetration rate, reduced downtime due to engine shutdown, etc.).

[108] Although the restraint device installed near the rotor in the propulsion unit, for example, shown in FIG. 13, one of ordinary skill in the art will understand that a transmission shaft extending from the rotor to a lower component of the drill string and including or operating with restraining devices can also be used to improve rotor sealing and engine efficiency. For example, a radial stop may be mounted on or operated with a transmission shaft at the upper end of an adjustable deflecting housing that connects to the motor unit / motor sub. In this case, it is possible to effectively move the restraining device into a stiffer housing and remove it from the stator tube, which can create various advantages, for example, extended equipment life, among other advantages.

[109] The embodiments herein are given by way of example only, and it is understood that other systems for controlling or restricting the movement of the rotor relative to the stator can also be designed within the scope of the concepts disclosed herein.

[110] It is also understood that although in the shown embodiments there is a rotor as a component rotating in the stator, and most pumps and motors are made exactly like this, the embodiments disclosed herein should work similarly if the internal component is fixedly mounted and the external component rotates.

Claims (12)

1. An arrangement of a downhole hydraulic motor comprising a screw motor having a proximal end and a distal end, comprising:
a stator containing:
metal case;
a first elastomeric material located in a metal body; and
a first rigid material located radially and directed inward from and at least partially covering the first elastomeric material; and
rotor containing:
metal core;
a second elastomeric material located around the metal core; and
a second rigid material located around the second elastomeric material, wherein the first stator rigid material is in contact with the second rigid rotor material. 2. The layout of the hydraulic downhole motor according to claim 1, in which the first rigid material of the stator contains at least one of the following: metal, composite, ceramic, hard plastic or polycrystalline diamond. 3. The layout of the hydraulic downhole motor according to claim 1, in which the second hard material is different from the first hard material. 4. The layout of the hydraulic downhole motor according to claim 1, in which the second rigid material of the rotor contains at least one of the following: metal, composite, ceramic, hard plastic or polycrystalline diamond. 5. The layout of the downhole hydraulic motor according to claim 1, wherein at least one of the first and second hard materials is coated or processed to reduce at least one of friction and wear. 6. A method of drilling a wellbore through an underground formation, in which:
passing the drilling fluid through the layout of the hydraulic downhole motor according to claim 1; and
carry out drilling of the reservoir. 7. An arrangement of a downhole hydraulic motor comprising a screw motor, comprising:
stator and rotor;
wherein the stator has a profile including portions of the ridges and portions of the recesses, while the portions of the ridges contain rigid material, and the portions of the recesses contain elastic material, and alternating portions of the rigid material and elastic material form the inner cavity of the stator; and wherein
the stator and rotor each comprises a contact surface made at least partially of rigid material. 8. The layout of the hydraulic downhole motor according to claim 7, in which the rigid material contains at least one of the following: metal, composite, ceramic, hard plastic or polycrystalline diamond. 9. The hydraulic downhole motor assembly of claim 7, wherein the contact surface of at least one of the stator and rotor is coated or machined to reduce at least one of friction and wear. 10. The layout of the downhole hydraulic motor according to claim 7, which also includes at least one device restricting radial and / or tangential movement of the rotor relative to the stator, which is installed in an adjustable deflecting sub, functionally connected to the end of the motor layout. 11. The layout of the hydraulic downhole motor according to claim 1, in which the second rigid material is the same as the first rigid material. 12. The layout of the downhole hydraulic motor according to claim 7, in which the contact surfaces of the stator and rotor are made of the same material.

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