CN114658371A

CN114658371A - Oil pipe and sleeve combined sealing thread structure and factory end assembling method

Info

Publication number: CN114658371A
Application number: CN202111508438.7A
Authority: CN
Inventors: 马晓峰; 张海兵
Original assignee: Xi'an Dexin Technology Co ltd
Current assignee: Xi'an Dexin Technology Co ltd
Priority date: 2021-10-20
Filing date: 2021-12-10
Publication date: 2022-06-24

Abstract

The invention provides a sealing thread structure of an oil pipe and sleeve combination and a factory end assembling method, comprising a pipe body, an assembling short section, a coupling, anti-loose locking thread grease, anti-loose oil sleeve thread grease and a sealing ring; the end part of the tube body is provided with external threads and a nose shoulder, and the end surface of the nose shoulder is processed with a sealing groove. The coupling is of a left-right axial symmetrical structure, and two ends of the coupling are provided with internal threads matched with the external threads of the pipe body; the assembly short section is an external thread joint with a positioning shoulder; during assembly, the assembly nipple is connected firstly, so that the end face of the coupling is contacted with the positioning shoulder of the assembly nipple; the external thread of the pipe body is screwed into the other side of the coupling, so that the end face of the pipe body is in contact with the end face of the assembling nipple and generates contact pressure; and then, the assembly short joint is disassembled, and a sealing ring is arranged on the end face of the pipe body. The invention accurately controls the screwing position and screwing torque of the factory end, and effectively ensures that stable contact pressure is formed between the nose shoulders of the pipe bodies on two sides in the coupling when the oil and the sleeve are used on site, thereby effectively ensuring the connection and sealing functions of the whole pipe string.

Description

Oil pipe and sleeve combined sealing thread structure and factory end assembling method

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of oil casings for exploration and development of energy sources such as petroleum, natural gas, coal bed gas and the like, in particular to a sealing thread structure of an oil pipe and casing combination and a factory end assembling method.

[ background ] A method for producing a semiconductor device

In the exploration and development process of energy sources such as petroleum, natural gas, coal bed gas and the like, oil and casing strings are needed to stabilize a well wall to form an oil-gas channel. In recent decades, the threaded connection mode of oil pipes and casings of various oil fields in China is to form an oil casing string by using single oil and casing. And the special petroleum thread for API is adopted for connection, and the API thread has the advantages of easy processing, convenient field matching short section, low processing cost, repeated screwing adaptation and the like. However, with the increase of the drilling depth of the oil well, the production of corrosive and high-pressure oil and gas wells and the injection of high-temperature and high-pressure steam into the heavy oil well, the application environment of the API thread is more severe and the application condition is more severe. The application environment when the oil well injects steam is as follows: pressure 15MPa, temperature 340 ℃. At the moment, the traditional API thread resists 150 ℃ and is broken through. The API thread is sealed under the cooperation of high-quality sealing grease, the sealing grease is firstly destroyed at the high temperature of 340 ℃, and then the working condition of the connection thread sealing is destroyed. In addition, the connection strength of the API thread is only 80% of the tensile strength of the pipe body, and one of the methods for improving the overall strength of the oil well downhole pipe column is to increase the thickness of the pipe body. The thicker the tubular body, the heavier the tubular string will increase the cost of steel used, and the greater the oil well tubular string load, which will create dual disadvantages for the user. Although various non-API special petroleum casing connecting threads exist in China at present, the common characteristics of the non-API special petroleum casing connecting threads are as follows: the metal-to-metal seal adopts conical surface seal and end surface seal. Because the relative displacement change range is large when the original API thread pin and box is screwed, the original API thread structure is usually sacrificed for ensuring the contact displacement of the pin and box, and non-API threads are adopted, so that a certain displacement value is reached. The non-API thread processing difficulty is large, the cost is high, and the large-area popularization and use are not facilitated. According to field data statistics, when the API thread is used for oil pumping of an oil well, the thread is leaked due to the problems that the counter torque of a factory end is loosened, the shoulder surface is not in place to jack or the torque of the on-site end is insufficient, the daily liquid production of each oil pumping well is reduced by 5-10%, and the economic loss caused by thread leakage is very huge.

Accordingly, there is a need for a sealed thread configuration and a factory end assembly method for a tubing and casing combination that overcomes one or more of the problems set forth above.

[ summary of the invention ]

In view of this, the invention provides a sealing thread structure of an oil pipe and casing combination and a factory end assembling method, which can overcome the problems that the counter torque of a factory end is loosened, the shoulder surface is not in place to jack or the torque of a field end is insufficient when the threaded connection is assembled in the prior art.

In one aspect, the present invention provides a sealing thread structure for a combination of an oil pipe and a casing, the sealing thread structure comprising: the anti-loosening oil casing pipe comprises a pipe body, a coupling, anti-loosening locking thread grease, anti-loosening oil casing pipe thread grease, an assembly nipple and a sealing ring, wherein external threads are machined at the end part of the pipe body, a nose shoulder is machined at the front end of each external thread, and a sealing groove is formed in the end face of the nose shoulder. The coupling is of a left-right axial symmetric structure, internal threads matched with external threads of the pipe body are respectively machined at two ends of the coupling, a hollow cylindrical section is machined in the middle of the coupling, the assembly nipple is an external threaded joint with a positioning shoulder, and when the pipe body end is in threaded connection and the coupling is assembled, anti-loosening locking thread grease and anti-loosening oil casing thread grease are required to be used simultaneously. The sealing ring is arranged in the sealing groove on the end face of the nose shoulder.

The above-described aspects and any possible implementations further provide an implementation in which the threads on both ends of the tubular body are API threads or non-API special threads.

The above aspect and any possible implementation further provides an implementation in which the nose shoulder on the end face of the tube body has a cross-sectional thickness of 2.5mm or more and an axial length of 4mm or less.

In accordance with the above aspect and any possible implementation manner, there is further provided an implementation manner, in which a seal groove is provided at the center of the wall thickness of the nose shoulder end surface of the pipe body, the width of the seal groove is less than or equal to 1/2 of the section thickness, and the axial depth is 3/4 of the width of the seal groove.

The above aspect and any possible implementation further provides an implementation that the internal connection hoop thread matches with the external pipe end face thread.

The above aspect and any possible implementation manner further provide an implementation manner, wherein the inner diameter of the hollow cylindrical section in the coupling is 0.2-0.6 mm larger than the outer diameter of the external thread nose shoulder, and the axial length is less than 2 times of the axial length of the external thread nose shoulder, which is 0.2-0.3 mm.

The above aspects and any possible implementation manner further provide an implementation manner that the assembled short section is processed with an external thread structure which is completely the same as the end face of the pipe body.

The above aspects and any possible implementation further provide an implementation, where the fitting nipple is machined with a positioning shoulder, and an outer diameter of the positioning shoulder is greater than or equal to an outer diameter of the coupling.

In accordance with the above-described aspects and any possible implementations, there is further provided an implementation in which the axial length of the fitting stub from the tube end to the locating shoulder is 1/2 of the axial length of the collar.

The above aspect and any possible implementation further provide an implementation, where the sealing ring is O-shaped, made of butadiene-acrylonitrile rubber, and has a diameter equal to a width of the sealing groove.

The above aspects and any possible implementation further provide a factory-end assembly method of a sealed threaded structure of a combination of an oil pipe and a casing, which is implemented based on the sealed threaded structure of the combination of the oil pipe and the casing, and the assembly method includes the following steps:

s1: before the pipe body is in threaded connection with the coupling, the coupling is in threaded connection with the assembly nipple, so that a positioning shoulder of the assembly nipple is in contact with the end face of the coupling;

s2: anti-thread sticking oil casing thread grease is uniformly smeared on the length of the nose shoulder side 1/2 of the external thread section of the pipe body, the oil casing thread grease is uniformly smeared and locked on the length of the side 1/2 of the thread section pipe body, and the external thread of the pipe body is screwed into the coupling;

s3: when the screwing-on torque value reaches a preset value and a nose shoulder touch signal appears on a torque curve, screwing-on operation of the external thread of the pipe body and the coupling is completed;

s4: and (4) disassembling the assembling short section, placing a sealing ring in the sealing groove of the end face of the nose shoulder of the pipe body, and connecting and assembling the factory end threads.

The aspect and any possible implementation manner described above further provide an implementation manner, a gap between the coupling end face and the positioning shoulder of the assembly nipple in S1 is less than or equal to 0.01mm, and the assembly nipple can be reused for many times.

Compared with the prior art, the invention can obtain the following technical effects:

1): the coupling structure is completely axisymmetric, and a nose shoulder is processed on the external thread of the pipe body;

2): the assembling short section is the same as the pipe body in material, has a thread structure completely the same as the external thread of the pipe body, and is provided with a positioning shoulder;

3): when the factory end assembly of threaded connection of oil and a sleeve is carried out, the assembly position of an assembly short section and a coupling is controlled through a positioning shoulder on the assembly short section, then anti-thread-sticking oil sleeve thread grease and locking oil sleeve thread grease are adopted in different thread sections of the oil and sleeve ends, and an upper buckling check criterion that a buckling torque value is in contact combination with the shoulder is adopted, so that the position and the torque of the threaded connection of the factory end oil sleeve are accurately controlled, and the accurate assembly and the fastening matching of the factory end of the threaded connection of the oil and the sleeve are realized;

4): the O-shaped rubber sealing structure is arranged on the end face of the nose shoulder of the external thread at the factory end, so that the sealing performance of the end face of the external thread of the pipe body at two sides of the coupling is more reliable.

5) The invention can effectively ensure that stable contact pressure is formed between the nose shoulders of the external threads of the pipe bodies on the two sides of the coupling when the oil and the casing are used on site, and ensure the connection and sealing functions of the whole pipe string.

[ description of the drawings ]

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic view of a sealed thread configuration of a tubing and casing combination as assembled according to one embodiment of the present invention.

Wherein, in the figure:

wherein: 1-a pipe body; 2, assembling short joints; 3-coupling; 4-anti-loose fastening oil casing thread grease; 5-anti-sticking thread grease for oil sleeves; 6-O type sealing ring; 1-1-external threads of the pipe; 1-2-external thread nose shoulder; 1-3-sealing the tank; 2-1-assembling the nipple external thread; 2-2-assembling a short section positioning shoulder; 3-1-collar internal threads; 3-2-coupling inner hollow cylinder section.

[ detailed description ] embodiments

In order to better understand the technical solution of the present invention, the following detailed description of the embodiments of the present invention is made with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any inventive step, are within the scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In one aspect, the present invention provides a sealing thread structure for a combination of an oil pipe and a casing, the sealing thread structure for a combination of an oil pipe and a casing comprising: the anti-loosening oil sleeve pipe comprises a pipe body, a coupling, anti-loosening locking thread grease, anti-loosening oil sleeve thread grease, an assembling short section and an O-shaped sealing ring, wherein external threads are machined at the end part of the pipe body, a nose shoulder is machined at the front end of each external thread, and a sealing groove is formed in the center of the wall thickness of the end face of the nose shoulder; the coupling is of a left-right axial symmetry structure, internal threads matched with external threads of the pipe body are respectively machined at two ends of the coupling, a hollow cylindrical section is machined in the middle of the coupling, the assembling nipple is an external thread joint with a positioning shoulder, and when the pipe body end is in threaded connection and the coupling is assembled, anti-loosening locking thread grease and anti-loosening oil casing thread grease are required to be used simultaneously. The O-shaped sealing ring is arranged in the sealing groove on the end face of the nose shoulder. The screw thread at both ends of the pipe body is API screw thread or non-API special screw thread. The cross-sectional thickness of body terminal surface nose shoulder more than or equal to 2.5mm, axial length less than or equal to 4mm, the width less than or equal to cross-sectional thickness's of nose shoulder terminal surface wall thickness center seal groove 1/2, axial depth are 3/4 of seal groove width, coupling internal thread and body terminal surface external screw thread phase-match. The inner diameter of the hollow cylindrical section in the coupling is 0.2-0.6 mm larger than the outer diameter of the external thread nose shoulder, and the axial length is less than 2 times of the axial length of the external thread nose shoulder, and is 0.2-0.3 mm. The assembled short section is processed with an external thread structure which is completely the same as the end face of the pipe body. And the assembly pup joint is processed with a positioning shoulder, and the outer diameter of the positioning shoulder is larger than or equal to that of the coupling. 1/2, wherein the axial length of the assembly nipple from the pipe end to the positioning shoulder is equal to the axial length of the coupling; the O-shaped sealing ring is made of butadiene-acrylonitrile rubber, and the diameter of the O-shaped sealing ring is equal to the width of the sealing groove.

The invention also provides a factory end assembling method of the oil pipe and casing combined sealing thread structure, which is realized based on the oil pipe and casing combined sealing thread structure, and comprises the following steps:

And the clearance between the end face of the coupling and the positioning shoulder of the assembly nipple in the S1 is less than or equal to 0.01mm, and the assembly nipple can be repeatedly used.

As shown in figure 1, the invention relates to a sealing thread structure of an oil pipe and casing combination, which comprises a pipe body 1, an assembly stub 2, a coupling 3, anti-loose locking thread grease 4, anti-thread-sticking oil casing thread grease 5 and an O-shaped sealing ring 6; the end part of the pipe body is processed with an external thread 1-1, the front end of the external thread is processed with a nose shoulder 1-2, and the center of the wall thickness of the end surface of the nose shoulder is provided with a sealing groove 1-3; the coupling 3 is of a left-right axial symmetrical structure, internal threads 3-1 matched with the external threads of the pipe body are respectively processed at two ends of the coupling, and a hollow cylindrical section 3-2 is processed in the middle of the coupling; the assembling short section 2 is an external thread joint with a positioning shoulder 2-2; when the pipe body end threaded connection 1-1 is assembled with the coupling 3, the anti-loosening locking thread grease 4 and the anti-sticking oil sleeve thread grease 5 are required to be used simultaneously. The O-shaped sealing ring 6 is made of butadiene-acrylonitrile rubber and has the diameter of 1.2 mm.

In one embodiment, the threads 1-1 on both ends of the tube body may be API threads or non-API special threads.

In one embodiment, the cross-sectional thickness of the nose shoulder 1-2 on the end face of the tube body is greater than or equal to 2.5mm, and the axial length is less than or equal to 4 mm.

In one embodiment, the tube body end face nose shoulder end face wall thickness center seal groove has a width of 1.2mm and an axial depth of 0.9 mm.

In one embodiment, the internal coupling threads 3-1 mate with the external pipe body end face threads 1-1.

In one embodiment, the inner diameter of the hollow cylindrical section 3-2 in the coupling is 0.2-0.6 mm larger than the outer diameter of the external thread nose shoulder 1-2, and the axial length is less than 2 times of the axial length of the external thread nose shoulder 1-2, and is 0.2-0.3 mm.

In one embodiment, the material of the assembly nipple 2 is the same as that of the pipe body 1, and the pipe end is provided with an external thread structure 2-1 which is completely the same as the end face of the pipe body.

In one embodiment, the assembly nipple 2 is machined with a positioning shoulder 2-2, and the outer diameter of the positioning shoulder 2-2 is larger than or equal to the outer diameter of the coupling 3.

In one particular embodiment, the axial length of fitting sub 2 from the pipe end to locating shoulder 2-2 is 1/2 of the axial length of collar 3.

In one embodiment, the O-ring 6 is made of butadiene rubber and has a diameter of 1.2 mm.

In one embodiment, a sealing thread structure of a combination of a tubing and a casing and a factory end assembling method are used for performing threaded connection of a coupling 3 and an assembling nipple 2 before a pipe body 1 and the coupling 3 are in threaded connection.

In a specific embodiment, the control standard of the threaded connection between the coupling 3 and the assembly nipple 2 is that the clearance between the coupling end face and a positioning shoulder 2-2 of the assembly nipple is less than or equal to 0.01 mm.

In one embodiment, a sealing thread structure of a combination of an oil pipe and a sleeve and a factory end assembly method are provided, when an external thread 1-1 of a pipe body 1 is screwed into a coupling 3, thread grease 5 of an anti-thread gluing oil sleeve is uniformly smeared on the length of a nose shoulder side 1/2 of a thread section, and thread grease 4 of an oil sleeve is uniformly smeared and locked on the length of a pipe body side 1/2 of the thread section.

In one embodiment, a sealing thread structure of a combination of a tubing and a casing and a factory end assembling method, the qualification criteria of the external thread 1-1 of the pipe body when the coupling 3 is screwed in are as follows: the upper buckling torque value reaches a preset value and a nose-shoulder touch signal appears on a torque curve.

In one embodiment, the sealing thread structure of the oil pipe and casing pipe combination and the factory end assembling method are characterized in that after a coupling 3 is screwed in through an external thread 1-1 of a pipe body, an assembling nipple 2 is detached, a sealing ring 6 is placed in a sealing groove 1-3 of the nose shoulder end face of the pipe body, and the factory end assembling is completed.

In one embodiment, the assembly nipple 2 can be reused for multiple times by adopting a sealing thread structure of an oil pipe and casing combination and a factory end assembly method.

The sealing thread structure and the factory end assembling method of the oil pipe and casing combination provided by the embodiment of the application are described in detail. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of additional like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely a relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B, may represent: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in this document generally indicates that the preceding and following associated objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the application, which should be limited only by the appended claims.

Claims

1. A seal thread construction of a tubing and casing combination, the seal thread construction of a tubing and casing combination comprising: the anti-loosening oil casing pipe comprises a pipe body, a coupling, anti-loosening locking thread grease, anti-loosening oil casing pipe thread grease, an assembling short section and a sealing ring; an external thread is processed at the end part of the pipe body, a nose shoulder is processed at the front end of the external thread, and a sealing groove is processed on the end surface of the nose shoulder; the coupling is of a left-right axial symmetric structure, internal threads matched with the external threads of the pipe body are respectively processed at two ends of the coupling, and a hollow cylindrical section is processed in the middle of the coupling; the assembly pup joint is an external thread joint with a positioning shoulder, and external threads are matched with internal threads of the coupling; when the threaded connection of the pipe body end is assembled with a coupling, anti-loosening locking thread grease and anti-thread-sticking oil casing thread grease are required to be used simultaneously.

2. The combined sealed thread construction of oil pipe and casing of claim 1, wherein the threads at both ends of the pipe body are API threads or non-API special threads.

3. The oil pipe and casing combined sealing thread structure of claim 1, wherein the cross-sectional thickness of the nose shoulder on the end face of the pipe body is greater than or equal to 2.5mm, and the axial length is less than or equal to 4 mm.

4. The oil pipe and casing combined sealing thread structure of claim 1, wherein the center of the wall thickness of the end face of the nose shoulder of the pipe body is provided with a sealing groove, the width of the sealing groove is less than or equal to 1/2 of the section thickness, and the axial depth is 3/4 of the width of the sealing groove.

5. The seal thread structure of the oil pipe and casing combination according to claim 1, wherein the inner diameter of the hollow cylindrical section in the coupling is 0.2 to 0.6mm larger than the outer diameter of the external thread nose shoulder, and the axial length is less than 2 times of the axial length of the external thread nose shoulder, which is 0.2 to 0.3 mm.

6. The combined sealed thread structure of oil pipe and casing according to claim 1, wherein the assembly nipple is machined with a positioning shoulder, and the outer diameter of the positioning shoulder is greater than or equal to the outer diameter of the coupling.

7. The tubular and casing combination sealed thread construction of claim 1 wherein the axial length of the assembly sub from the tubular end to the locating shoulder is 1/2 of the axial length of the collar.

8. The oil pipe and casing combined sealing thread structure of claim 1, wherein the sealing ring is O-shaped, made of butadiene acrylonitrile rubber, and has a diameter equal to the width of the sealing groove.

9. A factory-end assembly method of a sealed thread structure of an oil pipe and casing combination, which is implemented based on the sealed thread structure of the oil pipe and casing combination according to any one of claims 1 to 8, wherein the assembly method comprises the following steps:

s4: and (4) disassembling the assembling short section, loading the sealing ring, and finishing the threaded connection assembly of the factory end.

10. The assembly method according to claim 9, wherein the clearance between the coupling end face and the positioning shoulder of the assembly nipple in S1 is less than or equal to 0.01mm, and the assembly nipple can be reused for multiple times.