Soluble pressure test device and method for tubing string in shaft

Abstract

The invention belongs to the technical field of tubing string detection, and discloses a soluble pressure test device and method for a tubing string in a shaft. Comprising a soluble ball, a soluble ball seat and a ball seat body, a first through hole is formed in the center of the ball seat body, the top of the ball seat body is fixedly connected with the top of the soluble ball seat, a second through hole is formed in the center of the soluble ball seat, the top of the soluble ball seat and the soluble ball form a sealing structure, a plurality of salt storage grooves are formed in the top face of the soluble ball seat, and a neck bush is arranged in each salt storage groove; the soluble ball seat and the soluble ball are both made of magnesium-aluminum alloy materials. According to the invention, the soluble ball and the soluble ball seat which are made of the magnesium-aluminum alloy are used for carrying out a pressure-bearing test, the salt storage groove is formed in the soluble ball seat for storing NaCl particles, Cl <-> reacts with the magnesium-aluminum alloy to remove the soluble ball, the tubing string does not need to be repeatedly transported and disassembled, and the sealing property and the stability of the tubing string are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of oil pipe string detection, and in particular relates to a soluble pressure testing device and method for an oil pipe string in a wellbore. Background Art

[0002] In the daily production process of oil wells, due to production process adjustments, lifting equipment failures in the wellbore, wax deposition in the oil well, and well repair operations, the purpose of which is to ensure that the oil well can produce normally. In the process of oil well operation, after the well repair operation is completed, the well completion oil pipe string is lowered to form an injection and production channel. The thread and structural integrity of the well pipe will be checked on the ground. After the inspection is completed, it will be connected to the well one by one. When the pipe string reaches the designed depth, the sealing performance of the pipe string needs to be tested. The existing test method is to form a matching sealing structure between the steel ball and the ball seat that has been put into the well, and the sealing performance of the oil pipe string can be tested under a certain design pressure. However, in the existing test method, after the test is completed, the pipe string needs to be pulled out again and the pressure test ball is removed. After the removal is completed, the oil pipe pressure test is no longer performed when entering the well again. This kind of oil pipe string cannot verify the reliability of the connection between the last oil pipes, and cannot guarantee the sealing performance of the last well string. As a result, the oil pipe string is unable to withstand pressure from time to time. As the production progresses, the pressure bearing performance of the oil pipe string will be further reduced, leading to accidents such as re-workover operations. Summary of the invention

[0003] The purpose of the present invention is to provide a soluble pressure testing device and method for an oil tubing string in a wellbore, so as to solve the technical problem that the existing oil tubing string pressure test needs to be first lowered into the well for testing, then taken out of the well for disassembly after the test, and finally lowered into the well again. The repeated disassembly of the oil tubing string leads to unreliable sealing and pressure bearing properties, which is easy to cause well repair accidents.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] In a first aspect, a soluble pressure testing device for an oil pipe string in a wellbore comprises a soluble ball, a soluble ball seat and a ball seat body, wherein a first through hole is provided at the center of the ball seat body, the top of the ball seat body is fixedly connected to the top of the soluble ball seat, a second through hole is provided at the center of the soluble ball seat, the top of the soluble ball seat and the soluble ball form a sealing structure, a plurality of salt storage tanks are provided on the top surface of the soluble ball seat, each of the salt storage tanks is provided with an inner sleeve, and the soluble ball seat and the soluble ball are both made of magnesium-aluminum alloy material.

[0006] A further improvement of the present invention is that a transition slope section is provided above the second through hole, the diameter of the transition slope section gradually decreases from top to bottom, and the minimum diameter of the transition slope section is equal to the diameter of the second through hole.

[0007] A further improvement of the present invention is that a first threaded hole is formed at the bottom of each salt storage tank, and a plurality of second threaded holes are formed on the top surface of the ball seat body, and each of the second threaded holes corresponds to a first threaded hole.

[0008] A further improvement of the present invention is that: an annular groove is provided on the bottom surface of the soluble ball seat, and a sealing ring is provided in the annular groove.

[0009] A further improvement of the present invention is that the inner sleeve is made of anti-corrosion material.

[0010] A further improvement of the present invention is that both the upper part and the lower part of the ball seat body are provided with external threads.

[0011] A further improvement of the present invention is that the diameters of the first through hole and the second through hole are the same.

[0012] A further improvement of the present invention is that a fixing screw is provided in each of the first threaded holes.

[0013] A further improvement of the present invention is that the sealing ring is made of cyanide nitrile rubber.

[0014] In a second aspect, a soluble pressure testing method for an oil pipe string in a wellbore comprises the following steps:

[0015] The soluble ball seat is fixedly connected to the ball seat body, and the ball seat body is fixedly connected to the oil pipe string. An inner sleeve is set in each salt storage tank, and NaCl particles are filled in the inner sleeve. The oil pipe string and the ball seat body are lowered into the well, and the soluble ball is put into the oil pipe string so that the soluble ball seals the second through hole of the soluble ball seat. The pressure test of the pipe string is carried out. After the test, the NaCl particles in the inner sleeve are dissolved to produce Cl - , Cl - The soluble ball and the soluble ball seat are dissolved, and the passage in the oil pipe string is opened.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] 1. The present invention uses a soluble ball and a soluble ball seat made of magnesium-aluminum alloy to carry out a pressure test, and opens a salt storage tank on the soluble ball seat to store NaCl particles. - Reaction with magnesium-aluminum alloy to remove soluble balls eliminates the need for repeated transportation and disassembly of the tubing string, ensuring the tightness and stability of the tubing string;

[0018] 2. The present invention improves the sealing performance by providing a sealing ring to ensure the accuracy of the pressure test results;

[0019] 3. The present invention provides external threads on the upper and lower parts of the ball seat body, so as to facilitate fixed connection with the oil pipe string. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] In the attached picture:

[0022] Figure 1 This is a schematic diagram of the overall structure of a soluble pressure test device for an oil pipe string in a wellbore according to the present invention:

[0023] Figure 2 It is a front view of a soluble ball seat in a soluble pressure testing device for an oil pipe string in a wellbore according to the present invention;

[0024] Figure 3 The present invention is a top view of a soluble ball seat in a soluble pressure testing device for an oil pipe string in a wellbore.

[0025] In the figure: 1: soluble ball; 2: soluble ball seat; 3: inner sleeve; 4: fixing screw; 5: sealing ring; 6: ball seat body. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0027] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0028] Example 1

[0029] A soluble pressure testing device for an oil pipe string in a wellbore, such as Figures 1 to 3 As shown, it includes a soluble ball 1, a soluble ball seat 2, an inner sleeve, a fixing screw 4, a sealing ring 5 and a ball seat body 6. The ball seat body 6 is a cylinder with a first through hole 7 opened in the center;

[0030] The soluble ball seat 2 is a cylinder, with a second through hole 8 in the center, a transition slope section 9 is provided above the second through hole, and the outer diameter of the soluble ball seat 2 is the same as the outer diameter of the ball seat body 6, the aperture of the first through hole 7 is the same as the aperture of the second through hole 8, the diameter of the transition slope section 9 gradually decreases from top to bottom, and the minimum diameter of the transition slope section 9 is the diameter of the second through hole 8;

[0031] The soluble ball 1 is arranged on the top of the soluble ball seat 2, and the transition slope section 9 is closely matched with the soluble ball 1, so that the soluble ball 1 and the soluble ball seat 2 form a pressure-bearing "locking bottom valve" in the oil pipe string;

[0032] The bottom of the soluble ball seat 2 is fixedly connected to the top of the ball seat body 6. The bottom of the soluble ball seat 2 is evenly provided with a plurality of first threaded holes along the circumferential direction. The top surface of the ball seat body 6 is provided with a plurality of second threaded holes. The first threaded holes and the second threaded holes correspond to each other one by one. A fixing screw 4 is provided in each first threaded hole. The ball seat body 6 and the soluble ball seat 2 are fixedly connected by the fixing screw and the threaded hole. A salt storage tank is provided above each first threaded hole. An inner sleeve 3 is provided in each salt storage tank. The inner sleeve 3 is a cylinder with a sealed bottom. The inner sleeve 3 is used to store NaCl.

[0033] Specifically, the inner liner 3 is made of corrosion-resistant material;

[0034] Specifically, the upper and lower parts of the ball seat body 6 are provided with external threads, and the external threads are used to connect the oil pipe string, and the external threads are set according to API Spec 5B standard;

[0035] Specifically, the ball seat body is processed into external thread structures at both ends, generally 2-7 / 8NU thread or 2-7 / 8EU thread, according to the specifications and steel grade of the oil pipe in the oil pipe string.

[0036] Specifically, an annular groove is provided on the adjacent surface of the soluble ball seat 2 and the ball seat body 6, and a sealing ring 5 is provided in the annular groove, and the sealing ring 5 ensures the sealing between the soluble ball seat 2 and the ball seat body 6;

[0037] Specifically, the soluble ball 1 and the soluble ball seat 2 are both made of magnesium-aluminum alloy.

[0038] Example 2

[0039] An actual use example of a soluble pressure test device for an oil pipe string in a wellbore, comprising a soluble ball 1 of φ40 mm, the soluble ball 1 being made of a magnesium-aluminum alloy material and processed into a sphere;

[0040] The soluble ball seat 2 is also made of magnesium-aluminum alloy material, and the slope of the transition slope section 9 is 45°. The transition slope section 9 is used to carry the soluble ball 1 to complete the pressure test function;

[0041] The maximum outer diameter of the soluble ball seat 2 is φ62.5mm, and there are 10 φ8mm countersunk holes distributed along the circumferential direction on the top surface of the soluble ball seat 2. As a salt storage tank, each salt storage tank is processed with M3.5×0.6 through-hole threads at the bottom, and the through-hole threads 2 are used to cooperate with the fixing screws 4. An annular groove is processed at the junction of the bottom surface of the soluble ball seat 2 and the ball seat body 6, and a sealing ring 5 is arranged in the annular groove.

[0042] The inner liner 3 is made of polyethylene material, the maximum outer diameter of the soluble ball seat 2 is φ8mm, the inner diameter is φ5mm, the wall thickness is 1.5mm, and the length is designed to be 13mm.

[0043] The fixing screw 4 is a "cross head" screw, the screw thread specification is M3.5×0.6, and the length is 20 mm.

[0044] The sealing ring 5 is an "O"-shaped sealing ring, which is made of cyanide nitrile rubber and has a size corresponding to the annular groove.

[0045] The ball seat body 6 has a total length of 200 mm, the first through hole 7 is a φ36 mm through hole structure, both ends of the ball seat body 6 are processed with external oil pipe threads, and the upper end surface is processed with a plurality of threaded holes, the size of which is equal to that of the soluble ball seat, for fixing the soluble ball seat.

[0046] Example 3

[0047] A soluble pressure testing method for an oil pipe string in a wellbore comprises the following steps:

[0048] The sealing ring 5 is arranged in the annular groove, the first threaded hole and the second threaded hole are aligned, the soluble ball seat 2 is fixedly connected to the ball seat body 6 by fixing screws, and the ball seat body 6 is fixedly connected to the oil pipe string. An inner sleeve 3 is arranged in each salt storage tank, and the inner sleeve 3 is filled with NaCl particles. The oil pipe string and the ball seat body 6 are lowered into the well, and the soluble ball 1 is put into the oil pipe string so that the soluble ball 1 seals the second through hole of the soluble ball seat 2. The pressure test of the pipe string is carried out. After the test is completed, the liquid near the ball seat body 6 dissolves the NaCl particles in the inner sleeve 3 to form a Cl-rich - Area, rich in Cl - The soluble ball 1 and the soluble ball seat 2 will be dissolved in the area, and the passage in the oil pipe string will be opened so that it can work normally.

[0049] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A soluble pressure test device for an oil pipe string in a wellbore, characterized in that: The invention comprises a soluble ball (1), a soluble ball seat (2) and a ball seat body (6), wherein a first through hole (7) is provided at the center of the ball seat body (6), the top of the ball seat body (6) is fixedly connected to the top of the soluble ball seat (2), a second through hole (8) is provided at the center of the soluble ball seat (2), the top of the soluble ball seat (2) and the soluble ball (1) form a sealing structure, a plurality of salt storage tanks are provided on the top surface of the soluble ball seat (2), each of the salt storage tanks is provided with an inner sleeve (3), and the soluble ball seat (2) and the soluble ball (1) are both made of magnesium-aluminum alloy material.

2. A soluble pressure testing device for an oil pipe string in a wellbore according to claim 1, characterized in that: A transition slope section (9) is provided above the second through hole (8), the diameter of the transition slope section (9) gradually decreases from top to bottom, and the minimum diameter of the transition slope section (9) is equal to the diameter of the second through hole (8).

3. A soluble pressure testing device for an oil pipe string in a wellbore according to claim 1, characterized in that: A first threaded hole is provided at the bottom of each salt storage tank, and a plurality of second threaded holes are provided on the top surface of the ball seat body (6), and each of the second threaded holes corresponds to a first threaded hole.

4. A soluble pressure testing device for an oil pipe string in a wellbore according to claim 1, characterized in that: The bottom surface of the soluble ball seat (2) is provided with an annular groove, and a sealing ring (5) is provided in the annular groove.

5. The soluble pressure testing device for oil pipe string in a wellbore according to claim 1, characterized in that: The inner liner (3) is made of anti-corrosion material.

6. A soluble pressure testing device for an oil pipe string in a wellbore according to claim 1, characterized in that: The upper part and the lower part of the ball seat body (6) are both provided with external threads.

7. A soluble pressure testing device for an oil pipe string in a wellbore according to claim 1, characterized in that: The diameters of the first through hole (7) and the second through hole (8) are the same.

8. A soluble pressure testing device for an oil pipe string in a wellbore according to claim 3, characterized in that: A fixing screw (4) is arranged in each of the first threaded holes.

9. A soluble pressure testing device for an oil pipe string in a wellbore according to claim 4, characterized in that: The sealing ring (5) is made of cyanide nitrile rubber.

10. A soluble pressure test method for an oil pipe string in a wellbore, characterized in that: The following steps are involved: The soluble ball seat (2) is fixedly connected to the ball seat body (6), and the ball seat body (6) is fixedly connected to the oil pipe column. An inner sleeve (3) is arranged in each salt storage tank, and NaCl particles are filled in the inner sleeve (3). The oil pipe column and the ball seat body (6) are lowered into the well, and the soluble ball (1) is put into the oil pipe column so that the soluble ball (1) seals the second through hole (8) of the soluble ball seat (2). A pressure test of the pipe column is carried out. After the test is completed, the NaCl particles in the inner sleeve (3) are dissolved to generate Cl - , Cl - The soluble ball (1) and the soluble ball seat (2) are dissolved, and the passage in the oil pipe string is opened.

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