CN116137877A

CN116137877A - Metal felt and brush structure as sealing element in metal-metal mud motor

Info

Publication number: CN116137877A
Application number: CN202180060440.4A
Authority: CN
Inventors: 埃里克·巴特舍勒
Original assignee: Baker Hughes Oilfield Operations LLC
Current assignee: Baker Hughes Oilfield Operations LLC
Priority date: 2020-07-31
Filing date: 2021-07-28
Publication date: 2023-05-19
Also published as: WO2022026572A1; US20220034314A1; EP4189203A1

Abstract

The invention discloses a mud motor and a drill string with the mud motor. The mud motor includes a stator and a rotor. The liner between the stator and the rotor includes fibers forming a fiber pattern. The liner is a coating of at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor.

Description

Metal felt and brush structure as sealing element in metal-metal mud motor

Cross Reference to Related Applications

The present application claims the benefit of U.S. patent application 63/059,856 filed on 7/31 in 2020, which is incorporated herein by reference in its entirety.

Background

In the resource recovery industry, mud motors are used in downhole drill strings, for example, to power various tools of the drill string, such as drill bits, using a mud flow through the drill string. The mud motor includes a stator and a rotor that rotates within the stator and rubs against the stator as it rotates. Elastomeric motor liners are typically placed on the surface of the rotor or stator to reduce friction and increase motor efficiency. However, these elastomeric layers decompose at high temperatures, thereby degrading performance. Alternatively, the elastomer layer may be omitted, allowing the stator and rotor to meet at a metal-metal interface. However, the metal-to-metal interface makes the efficiency and operation of the mud motor susceptible to dimensional tolerances. Accordingly, there is a need to provide a mud motor liner that operates effectively at high temperatures for long periods of time.

Disclosure of Invention

In one aspect, a mud motor is disclosed. The mud motor includes a stator, a rotor, and a liner between the stator and the rotor, the liner including fibers forming a fiber pattern.

In another aspect, a drill string is disclosed. The drill string includes a mud motor having a stator and a rotor. The liner between the stator and the rotor includes fibers forming a fiber pattern.

Drawings

The following description should not be taken as limiting in any way. Referring to the drawings, like elements are numbered alike:

FIG. 1 shows a lower section of a drill string;

FIG. 2 shows a cross section of a mud motor in an embodiment; and

figures 3A-3D illustrate various fiber structures or fiber patterns suitable for forming liners for mud motors in various embodiments.

Detailed Description

The detailed description of one or more embodiments of the apparatus and methods disclosed herein is presented by way of example and not limitation with reference to the accompanying drawings.

Referring to fig. 1, a lower section of a drill string 100 is shown. The drill string 100 is configured to drill a borehole into the earth's subsurface. The lower section includes a top sub 102 and a mud motor 104 connected to the top sub 102. The mud motor 104 is connected at its lower end to a flexible shaft 106 and passes through a lower joint 108 located below the mud motor 104. The lower sub 108 may include an adjustable starting point 110 and a stabilizer 112, which may be used to orient the drill string 100. A drill bit 118 at the lower end of the lower sub 108 is used to cut the formation. In operation, drilling fluid or mud flows through the drill string 100 from a surface location to exit the drill string at the drill bit 118. As the mud passes through the mud motor 104, the mud rotates a rotor of the mud motor relative to a stator of the mud motor, thus causing rotation of the flexible shaft 106. Rotation of the flexible shaft 106 causes rotation of a drill bit 118 mechanically coupled to the flexible shaft 106.

Fig. 2 illustrates a cross section 200 of the mud motor 104 in one embodiment. The cross section shows the housing 202, the stator 204 and the rotor 206 within the housing 202. Fig. 2 shows the housing 202 and stator 204 separated. Alternatively, the housing 202 and stator 204 may be one integral piece. Stator 204 includes a lobed inner surface 208 and rotor 206 includes a lobed outer surface 210. The number of blades on the rotor 206 is less than the number of blades on the stator, resulting in eccentric rotation of the rotor. Either the inner leaf surface 208 or the outer leaf surface 210 or both may be lined. The lining material is preferably resilient to achieve efficient, easy assembly and reasonable tolerances. In one embodiment, an elastomer (e.g., rubber) is used as the material for the liner. However, a disadvantage of the elastomer is that it cannot withstand high temperatures, such as temperatures above 150 ℃, for example above 175 ℃ or even 200 ℃. In another embodiment, the fibrous structure is used as a material for a liner. The fibrous structure is made of fibers that form a fibrous pattern as discussed below with respect to fig. 3A-3D.

Figures 3A-3D illustrate various fiber structures or fiber patterns suitable for forming liners for mud motors in various embodiments. The disclosed fiber patterns form structures that function as sealing elements for their associated surfaces. For ease of explanation, the fiber pattern is discussed as being applied to the lobed inner surface 208 of the stator 204. However, it should be appreciated that the associated surface may also be the lobed outer surface 210 of the rotor 206. Fig. 3A shows a fiber pattern in which the fibers of the liner form a felt pattern on the lobed inner surface 208. The felt pattern includes a plurality of fibers 302 that have been entangled and pressed together. The entangling or pressing process produces fibers 302 of the mat structure that are randomly oriented or otherwise misaligned with one another. Fig. 3B illustrates an exemplary embodiment of fibers 302 forming a web pattern on the lobed inner surface 208. The web pattern is an ordered pattern of fibers 302, typically forming a two-dimensional pattern. As shown in fig. 3B, the fibers 302 form a glazing structure in which the fibers intersect each other at approximately right angles. However, the web pattern may include any other desired web pattern, including hexagonal web patterns, parallelogram web patterns, and the like. Fig. 3C shows a fiber 302 forming a mesh pattern. In the mesh pattern, the fibers 302 are aligned parallel to each other along a selected parallel direction and intersect above the lobed inner surface 208 of the stator. Fig. 3D shows fibers 302 aligned to form a brush pattern at the lobed inner surface 208. In the brush pattern, the fibers 302 are aligned perpendicular or substantially perpendicular to the lobed inner surface 208.

The fibers 302 may be made of any suitable metal to form a fiber pattern. Exemplary materials for the fibers include metals such as nickel, nickel alloys, stainless steel, low alloy steel, copper, or copper alloys. In other embodiments, the material of the fibers may be carbon fibers, glass fibers, or polymer fibers.

The liner may be adhered to the surface of the stator or rotor using any suitable adhering method, including sintering, welding, fusion welding, brazing, or applying an adhesive between the liner and its associated surface. In one embodiment, physical Vapor Deposition (PVD) or Chemical Vapor Deposition (CVD) may be used to chemically grow or deposit fibers onto the outer surface. The fibers may be coated with a suitable coating material to provide improved chemical, heat and corrosion resistance or better friction or mechanical properties.

As shown in fig. 3A-3D, the fiber pattern may include gaps 304 between the fibers 302. In various embodiments, gap 304 may remain open or idle. In other embodiments, the gap 304 may be filled or partially filled with a secondary material. The secondary material may be a polymer such as an elastomer, polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), or other composite material, or the like, or any combination thereof. In one embodiment, the gap 304 is at least partially filled with material, but without elastomer or rubber. Liners made from fiber patterns and free of elastomers are beneficial because the absence of an elastomer enables the liner to withstand higher temperatures, such as temperatures above 150 ℃, e.g., 175 ℃, or even 200 ℃. For example, mud motors that include liners made of fiber patterns (such as liners made of fiber patterns and free of elastomers) can operate under high temperature downhole conditions (e.g., at temperatures above 150 ℃, 175 ℃, or even 200 ℃) for significant amounts of time, such as for a period of time greater than 40, 120, or even 360 cycle hours (i.e., the amount of hours that drilling fluid is circulated through the motor). Such mud motors allow drilling operations to be performed in a downhole environment having an ambient temperature above 150C, 175C, or even 200C, where the drilling operations last 40, 120, or even 360 cycles hours without the need to pull the mud motor out of the borehole due to insufficient motor efficiency (e.g., insufficient motor torque, insufficient motor power, or insufficient rotational speed of the rotor relative to the motor stator).

The following illustrate some embodiments of the foregoing disclosure:

embodiment 1: a mud motor. The mud motor includes a stator, a rotor, and a liner between the stator and the rotor, the liner including fibers forming a fiber pattern.

Embodiment 2: the mud motor according to any preceding embodiment wherein the liner is a coating of at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor.

Embodiment 3: the mud motor according to any preceding embodiment wherein the liner is adhered by at least one of: (i) an adhesive; (ii) a sintering process; (iii) a welding process; (iv) a fusion welding process; and (v) a brazing method.

Embodiment 4: the mud motor according to any preceding embodiment wherein the pattern of fibers further comprises one of: (i) a felt pattern; (ii) a web pattern; (iii) a mesh pattern; and (iv) brushing the pattern.

Embodiment 5: the mud motor according to any of the previous embodiments, wherein the fibrous material comprises at least one of the following: (i) nickel; (ii) a nickel alloy; (iii) stainless steel; (iv) a low alloy steel; (v) copper; (vi) copper alloy; (vii) carbon fibers; (viii) glass fibers; and (ix) polymer fibers.

Embodiment 6: the mud motor according to any preceding embodiment wherein the pattern of fibers comprises interstices between the fibers.

Embodiment 7: the mud motor according to any of the previous embodiments, further comprising a secondary material in the gap, the secondary material being at least one of: (i) Polytetrafluoroethylene (PTFE); (ii) Polyetheretherketone (PEEK); (iii) a polymer; and (iv) an elastomer.

Embodiment 8: the mud motor according to any of the previous embodiments wherein the gap is unfilled.

Embodiment 9: the mud motor of any previous embodiment, wherein the mud motor is configured to operate at a temperature above 150C for more than 40 cycle hours.

Embodiment 10: a method of manufacturing a mud motor. A mud motor is formed that includes a stator and a rotor. The liner is disposed between the stator and the rotor, the liner including fibers forming a fiber pattern.

Embodiment 11: the method of any preceding embodiment, wherein the liner is a coating of at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor.

Embodiment 12: the method of any preceding embodiment, wherein the liner is adhered by at least one of: (i) an adhesive; (ii) a sintering process; (iii) a welding process; (iv) a fusion welding process; and (v) a brazing method.

Embodiment 13: the method of any preceding embodiment, wherein the pattern of fibers further comprises one of: (i) a felt pattern; (ii) a web pattern; (iii) a mesh pattern; and (iv) brushing the pattern.

Embodiment 14: the method of any preceding embodiment, wherein the material of the fibers comprises at least one of: (i) nickel; (ii) a nickel alloy; (iii) stainless steel; (iv) a low alloy steel; (v) copper; (vi) copper alloy; (vii) carbon fibers; (viii) glass fibers; and (ix) polymer fibers.

Embodiment 15: the method of any preceding embodiment, wherein the pattern of fibers comprises interstices between the fibers.

Embodiment 16: the method of any preceding embodiment, wherein the gap is filled with a secondary material, wherein the secondary material is at least one of: (i) PTFE (Polytetrafluoroethylene)

(polytetrafluoroethylene); (ii) PEEK (polyetheretherketone); (iii) a polymer; and (iv) an elastomer.

Embodiment 17: the method of any preceding embodiment, wherein the one or more gaps are unfilled.

Embodiment 18: the method of any preceding embodiment, wherein the mud motor is configured to operate at a temperature above 150C for more than 40 cycle hours.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Furthermore, it should be noted that the terms "first," "second," and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity).

The teachings of the present disclosure may be used in a variety of well operations. These operations may involve treating the formation, fluids residing in the formation, the wellbore, and/or equipment in the wellbore, such as producing tubing, with one or more treatment agents. The treatment agent may be in the form of a liquid, a gas, a solid, a semi-solid, and mixtures thereof. Exemplary treatments include, but are not limited to, fracturing fluids, acids, steam, water, brine, preservatives, cements, permeability modifiers, drilling muds, emulsifiers, demulsifiers, tracers, mobility improvers, and the like. Exemplary well operations include, but are not limited to, hydraulic fracturing, stimulation, tracer injection, cleaning, acidizing, steam injection, water injection, well cementing, and the like.

While the invention has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Furthermore, in the drawings and detailed description there have been disclosed exemplary embodiments of the invention and, although specific terms have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited.

Claims

1. A mud motor (104), comprising:

a stator (204);

a rotor (206); and

a liner between the stator (204) and the rotor (206), the liner comprising fibers (302) forming a fiber pattern.

2. The mud motor (104) of claim 1, wherein the liner is a coating of at least one of a lobed inner surface (208) of the stator (204) and a lobed outer surface (210) of the rotor (206).

3. The mud motor (104) of claim 2, wherein the liner is adhered by at least one of: (i) an adhesive; (ii) a sintering process; (iii) a welding process; (iv) a fusion welding process; and (v) a brazing method.

4. The mud motor (104) of claim 1, wherein the pattern of fibers further comprises one of: (i) a felt pattern; (ii) a web pattern; (iii) a mesh pattern; and (iv) brushing the pattern.

5. The mud motor (104) of claim 1, wherein the fibrous material comprises at least one of: (i) nickel; (ii) a nickel alloy; (iii) stainless steel; (iv) a low alloy steel; (v) copper; (vi) copper alloy; (vii) carbon fibers; (viii) glass fibers; and (ix) polymer fibers.

6. The mud motor (104) of claim 1, wherein the pattern of fibers includes gaps (304) between the fibers (302).

7. The mud motor (104) of claim 6, further comprising a secondary material in the gap (304), the secondary material being at least one of: (i) Polytetrafluoroethylene (PTFE); (ii) Polyetheretherketone (PEEK); (iii) a polymer; and (iv) an elastomer.

8. The mud motor (104) of claim 6, wherein the gap (304) is unfilled.

9. A method for manufacturing a mud motor (104), the method comprising:

forming a mud motor (104) comprising a stator (204) and a rotor (206); and

a liner is disposed between the stator (204) and the rotor (206), the liner including fibers (302) forming a fiber pattern.

10. The method of claim 8, wherein the liner is disposed between the stator (204) and the rotor (206) by coating at least one of a lobed inner surface (208) of the stator (204) and a lobed outer surface (210) of the rotor (206) with the liner.

11. The method of claim 10, further comprising adhering the liner by at least one of: (i) an adhesive; (ii) a sintering process; (iii) a welding process; (iv) a fusion welding process;

and (v) a brazing method.

12. The method of claim 9, wherein the fiber pattern further comprises one of: (i) a felt pattern; (ii) a web pattern; (iii) a mesh pattern; and (iv) brushing the pattern.

13. The method of claim 9, wherein the material of the fibers (302) comprises at least one of: (i) nickel; (ii) a nickel alloy; (iii) stainless steel; (iv) a low alloy steel; (v) copper; (vi) copper alloy; (vii) carbon fibers; (viii) glass fibers; and (ix) polymer fibers.

14. The method of claim 9, wherein the pattern of fibers includes one or more gaps (304) between the fibers.

15. The method of claim 14, wherein the gap is filled with a secondary material, wherein the secondary material is at least one of: (i) PTFE (polytetrafluoroethylene); (ii) PEEK (polyetheretherketone); (iii) a polymer; and (iv) an elastomer.