Sealing performance testing device and method for double-wall drill rod inner pipe connector

Abstract

The invention discloses a sealing performance testing device for a double-wall drill rod inner pipe connector, which comprises a drill rod external thread connector and a drill rod internal thread connector, an external thread connector side inner pipe is arranged in the drill rod external thread connector, an inner pipe connector is arranged in the drill rod internal thread connector, and an inner pipe is inserted into the inner pipe connector. The end portion of the outer thread connector side inner pipe is plugged through an inner pipe plug, and the traction device pushes the outer thread connector side inner pipe to move in a reciprocating mode. The invention further discloses a sealing performance testing method. The method comprises the following steps: pressurizing and maintaining the pressure in the inner pipe on the side of the external thread joint according to the designed pressure; the traction device is started, so that the external thread connector side inner pipe reciprocates; and observing the water pressure drop amplitude of the inner pipe on the external thread joint side within the pressure maintaining time, and evaluating whether the sealing performance is qualified or not. According to the sealing performance testing device, the sealing performance testing problem of the inner pipe connecting part in the axial movement state of the inner pipe in the using process of the double-wall drill pipe is solved, the service life of the drill pipe is prolonged, and the safety and reliability of the drill pipe are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of double-wall drill pipe quality inspection, and specifically relates to a sealing performance test device for the inner pipe connection joint of a double-wall drill pipe, and also relates to a sealing performance test method for the inner pipe connection joint of a double-wall drill pipe. Background Art

[0002] In oil, natural gas, geological, and geothermal drilling operations, it is often encountered that leaky formations are drilled, where drilling fluid leakage will occur, causing huge economic losses to the drilling operation and also bringing great difficulties to the drilling operation. To solve this problem, scholars have developed a special drill pipe - double-wall drill pipe that can establish a double-layer drilling fluid channel in the inner and outer annuli. The double-wall drill pipe consists of an inner and an outer layer of drill pipes (referred to as the inner connecting pipe and the outer drill pipe). An annular gap is formed between the inner and outer pipes, which is the first transmission channel for drilling fluid (or gas); the inner hole of the inner connecting pipe is the second transmission channel for drilling fluid. Each double-wall drill pipe is connected by the threads of the outer drill pipe to form a drill pipe string to transmit torque, drilling pressure, and withstand the pressure of the drilling fluid. After connection, the pipe body of the inner pipe of the double-wall drill pipe is inserted into the lower joint of the inner pipe, thus forming a pipe string of the inner pipe. In the lower joint of the inner pipe, a sealing ring for sealing is provided, so that the connection part of the inner pipe forms a sealing ability to prevent the annulus between the inner pipe string and the outer drill pipe string from communicating. Due to the pressure difference between the annulus between the inner pipe string and the outer drill pipe string, the sealing pressure at the connection part of the inner pipe needs to be greater than the internal and external pressure difference under its service conditions. In the prior art, the sealing pressure test of the connection part of the inner pipe often adopts hydrostatic sealing, that is, the hydrostatic test of the inner pipe connection is carried out in a static state. However, during the use of the double-wall drill pipe, due to the pressure fluctuation of the high-pressure fluid in the inner pipe, the long and slender inner pipe without fixation often vibrates, causing the inner pipe to axially move in the inner pipe joint, changing the sealing state of the inner pipe joint from static to dynamic, and its sealing performance will also change accordingly. Summary of the Invention

[0003] The object of the present invention is to provide a sealing performance test device for the inner pipe connection joint of a double-wall drill pipe, which can not only test the hydrostatic sealing performance of the inner pipe connection part, but also simulate the sealing performance of the inner pipe connection part under the axial movement state of the inner pipe during the use of the double-wall drill pipe.

[0004] Another object of the present invention is to provide a sealing performance test method for the inner pipe connection joint of a double-wall drill pipe.

[0005] The technical solution adopted by the present invention is a sealing performance test device for the inner pipe connection joint of a double-wall drill pipe, which includes a drill pipe external thread joint and a drill pipe internal thread joint. The drill pipe external thread joint and the drill pipe internal thread joint are connected by threads; an external thread joint side inner pipe is arranged inside the drill pipe external thread joint, and an inner pipe joint is arranged inside the drill pipe internal thread joint. The external thread joint side inner pipe is inserted into the inner pipe joint, the end of the inner pipe joint is welded to the sealing partition board, the end of the external thread joint side inner pipe is blocked by an inner pipe plug, a liquid flow channel is arranged on the inner pipe plug, the liquid flow channel is connected to a hydraulic pipeline, the hydraulic pipeline is connected to a water pressure pump, and a hydraulic pressure gauge is arranged on the hydraulic pipeline; a traction device is further included, and the traction device is used to push the external thread joint side inner pipe to perform axial reciprocating motion.

[0006] The characteristics of the present invention also lie in that

[0007] The traction device includes a support plate, a fixed sleeve, a roller, a crankshaft and a motor. The fixed sleeve is arranged on the support plate, the roller is arranged below the support plate, one side of the crankshaft is connected to the support plate, and the other side is connected to the motor; the side of the external thread joint side inner pipe is fixed to the support plate through the fixed sleeve.

[0008] Sealing between the external thread joint side inner pipe and the inner pipe joint is achieved through a sealing ring; a sealing groove matching the sealing ring is arranged on the outer surface of the external thread joint side inner pipe.

[0009] The sealing groove is of a spherical crown type, the radial depth is greater than 1 / 2 of the diameter, and the number of sealing grooves is 2 - 3.

[0010] The sealing partition board is centered and fixed to the inner wall end surface of the inner pipe joint by welding.

[0011] A centering sleeve is sleeved on the outer surface of the inner pipe joint, and the centering sleeve is used to fix the inner pipe joint inside the drill pipe internal thread joint.

[0012] Another technical solution adopted by the present invention is a sealing performance test method for the inner pipe connection joint of a double-wall drill pipe, which is specifically implemented according to the following steps:

[0013] S1: Check whether the sealing ring on the outer surface of the external thread joint side inner pipe is in good condition, and connect the drill pipe external thread joint and the drill pipe internal thread joint;

[0014] S2: Assemble the inner pipe joint inside the drill pipe internal thread joint, and insert the external thread joint side inner pipe into the inner pipe joint;

[0015] S3: Block and fix the inner pipe joint with the sealing partition board; block the external thread joint side inner pipe with the inner pipe plug;

[0016] S4: Fix the external thread joint side inner pipe on the traction device, pressurize the inside of the external thread joint side inner pipe according to the designed pressure, and maintain the pressure after reaching the designed pressure;

[0017] S5: Start the traction device to reciprocate the inner pipe on the external thread joint side axially;

[0018] S6: Observe the water pressure drop of the inner pipe on the external thread joint side within the 5-minute pressure holding time, and evaluate whether the sealing performance is qualified.

[0019] The design pressure of the inner pipe on the external thread joint side is greater than or equal to 60% of the internal pressure resistance strength of the inner pipe on the external thread joint side.

[0020] The beneficial effects of the present invention are as follows:

[0021] Aiming at the lack of a dynamic sealing ability test method for the inner pipe connection part of the existing double-wall drill pipe, which cannot simulate the influence of the axial movement of the inner pipe on the sealing pressure during the service process of the drill pipe, the sealing performance test device for the inner pipe connection joint of the double-wall drill pipe of the present invention solves the problem of testing the sealing ability of the inner pipe connection part under the axial movement state of the inner pipe during the use of the double-wall drill pipe, provides a detection device and a test method for the quality evaluation of the double-wall drill pipe, thereby effectively ensuring the quality of the double-wall drill pipe and improving the service life and safety reliability of the drill pipe. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram (1) of the sealing performance test device for the inner pipe connection joint of the double-wall drill pipe of the present invention;

[0023] Figure 2 It is a schematic structural diagram of the sealing groove on the outer surface of the inner pipe in the sealing performance test device for the inner pipe connection joint of the double-wall drill pipe of the present invention;

[0024] Figure 3 It is a schematic structural diagram (2) of the sealing performance test device for the inner pipe connection joint of the double-wall drill pipe of the present invention.

[0025] In the figure, 1. Drill pipe external thread joint, 2. Drill pipe internal thread joint, 3. Inner pipe on the external thread joint side, 3-1. Sealing groove, 4. Inner pipe joint, 5. Sealing ring, 6. Centering sleeve, 7. Sealing partition board, 8. Inner pipe plug, 9. Water pressure pump, 10. Hydraulic pipeline, 11. Hydraulic pressure gauge, 12. Traction device, 12-1. Support plate, 12-2. Fixed sleeve, 12-3. Roller, 12-4. Crankshaft, 12-5. Motor, 13. Metal round pipe. Detailed Embodiments

[0026] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0027] Embodiment 1

[0028] The sealing performance test device for the inner pipe connection joint of the double-wall drill pipe of the present invention, as Figure 1As shown, it includes an external screw joint 1 of the drill pipe and an internal screw joint 2 of the drill pipe. The external screw joint 1 of the drill pipe and the internal screw joint 2 of the drill pipe are connected together by a threaded connection method to truly simulate the working conditions of the double-wall drill pipe.

[0029] An inner pipe 3 on the side of the external screw joint is arranged inside the external screw joint 1 of the drill pipe, and an inner pipe joint 4 is arranged inside the internal screw joint 2 of the drill pipe. The inner pipe 3 on the side of the external screw joint is inserted into the inner pipe joint 4, and a seal is achieved between the inner pipe 3 on the side of the external screw joint and the inner pipe joint 4 through a sealing ring 5; a sealing groove 3-1 matching the sealing ring 5 is provided on the outer surface of the inner pipe 3 on the side of the external screw joint, as Figure 2 shown. The sealing groove 3-1 is of a spherical crown type, and the radial depth is greater than 1 / 2 of the diameter. Preferably, the depth of the sealing groove 3-1 is 4 / 7 of the diameter, and the number is 2-3.

[0030] A centering sleeve 6 is sleeved on the outer surface of the inner pipe joint 4. The centering sleeve 6 is made of rubber material to center and fix the inner pipe joint 4 in the Y and Z directions inside the internal screw joint 2 of the drill pipe; the end of the inner pipe joint 4 is welded and sealed with a sealing partition plate 7, and the sealing partition plate 7 is centered and fixed on the inner wall end surface of the internal screw joint 2 of the drill pipe by welding.

[0031] The end of the inner pipe 3 on the side of the external screw joint is blocked by an inner pipe plug 8. A liquid flow channel is provided on the inner pipe plug 8. The liquid flow channel on the inner pipe plug 8 is connected to a hydraulic pipeline 10, and the hydraulic pipeline 10 is connected to a water pressure pump 9. A pressure test medium (the medium is clean water or other liquid) is injected into the inner pipe 3 on the side of the external screw joint through the water pressure pump 9; a hydraulic pressure gauge 11 is provided on the hydraulic pipeline 10;

[0032] It also includes a traction device 12, and the traction device 12 is used to push the inner pipe 3 on the side of the external screw joint to perform axial reciprocating motion;

[0033] The traction device 12 includes a support plate 12-1, a fixed sleeve 12-2, rollers 12-3, a crankshaft 12-4 and a motor 12-5. The fixed sleeve 12-2 is arranged on the support plate 12-1, and the rollers 12-3 are arranged under the support plate 12-1. The number of rollers is 2-3 groups; one side of the crankshaft 12-4 is connected to the support plate 12-1, and the other side is connected to the motor 12-5; when the motor 12-5 rotates, it drives the crankshaft 12-4 to rotate, so that the front of the support plate 12-1 reciprocates. The side of the inner pipe 3 on the side of the external screw joint is fixed on the support plate 12-1 through the fixed sleeve 12-2.

[0034] Embodiment 2

[0035] The method for testing the sealing performance of the inner pipe connection joint of the double-wall drill pipe of the present invention is specifically implemented according to the following steps:

[0036] S1: Check whether the sealing ring 5 on the outer surface of the inner pipe 3 on the external thread joint side is in good condition, and whether the inner pipe 3 on the external thread joint side can be smoothly inserted into the inner pipe joint 4; connect the drill pipe external thread joint 1 and the drill pipe internal thread joint 2;

[0037] S2: Assemble the inner pipe joint 4 inside the drill pipe internal thread joint 2, and insert the inner pipe 3 on the external thread joint side into the inner pipe joint 4;

[0038] S3: Seal and fix the inner pipe joint 4 with the sealing partition plate 7; seal the inner pipe 3 on the external thread joint side with the inner pipe plug 8;

[0039] S4: Fix the inner pipe 3 on the external thread joint side on the traction device 12, apply pressure inside the inner pipe 3 on the external thread joint side according to the designed pressure, and maintain the pressure after reaching the designed pressure;

[0040] The designed pressure of the inner pipe 3 on the external thread joint side should be greater than or equal to 60% of the internal pressure resistance strength of the inner pipe;

[0041] S5: Start the traction device 12 to make the inner pipe 3 on the external thread joint side reciprocate axially;

[0042] The moving speed of the traction device is less than 3 m / min, and the reciprocating moving amplitude is ±25 mm.

[0043] S6: Observe the water pressure drop of the inner pipe 3 on the external thread joint side within the 5-minute pressure holding time, and record the data;

[0044] If the pressure drop of the inner pipe 3 on the external thread joint side within 5 minutes of pressure holding is less than 0.3 MP, it is qualified, which proves its good sealing performance;

[0045] As Figure 3 shown, the drill pipe internal thread joint 2 and the drill pipe external thread joint 1 can also be replaced by the metal round pipe 13 with a smooth inner wall. In addition, in this embodiment Figure 2 the connection and sealing form of the inner pipe 3 on the external thread joint side and the inner pipe joint 4 is only a specific structural form for explaining the use of the test device.

[0046] Example 3

[0047] The method for testing the sealing performance of the connection joint of the inner pipe of the double-wall drill pipe of the present invention has the following procedures:

[0048] S1: Check whether the seal 5 on the outer surface of the inner pipe 3 on the external thread joint side is in good condition, and whether the inner pipe 3 on the external thread joint side can be smoothly inserted into the inner pipe joint 4; connect the drill pipe external thread joint 1 and the internal thread joint 2;

[0049] S2: Assemble the inner pipe joint 4 inside the drill pipe internal thread joint 2, and insert the inner pipe 3 on the external thread joint side into the inner pipe joint 4;

[0050] S3: Seal and fix the inner pipe joint 4 with the sealing partition plate 7; seal the inner pipe 3 on the side of the external thread joint with the inner pipe plug 8;

[0051] S4: Fix the inner pipe 3 on the side of the external thread joint on the traction device 12, pressurize the inner pipe 3 on the side of the external thread joint according to the designed pressure, and keep the pressure after reaching the designed pressure;

[0052] In this embodiment, the internal pressure resistance strength of the inner pipe 3 on the side of the external thread joint is 50 MPa, and the measured water pressure value is 35 MPa;

[0053] S5: Start the traction device 12 to make the inner pipe 3 on the side of the external thread joint move axially back and forth;

[0054] During the pressure test, the moving speed of the traction device 12 is 2.7 m / min, and the reciprocating moving amplitude is ±25 mm.

[0055] S6: Observe the water pressure drop of the inner pipe 3 on the side of the external thread joint within the 5-minute pressure holding time and record the data;

[0056] During the test process, when there is no leakage in the sealing partition plate 7, the inner pipe plug 8 and the hydraulic pipeline 10, the pressure value of the pressure gauge 11 of the water pressure of the inner pipe 3 on the side of the external thread joint drops from 35 MPa to 34 MPa within 5 minutes of pressure holding, and the drop is 1 MPa, which does not meet the requirement of less than 0.3 MPa, and the test result is unqualified.

[0057] The sealing performance test device and method for the inner pipe connection joint of the double-wall drill pipe of the present invention solve the problem of detecting the actual sealing ability that the inner pipe sealing connection can withstand under the service conditions, especially the influence of the axial crosstalk of the inner pipe on the sealing ability of the inner pipe connection part during the service process of the double-wall drill pipe.

Claims

1. A sealing performance testing device for the inner pipe connection joint of a double-wall drill pipe, characterized in that, it includes a drill pipe external thread joint (1) and a drill pipe internal thread joint (2), and the drill pipe external thread joint (1) and the drill pipe internal thread joint (2) are connected by threads; an external thread joint side inner pipe (3) is arranged inside the drill pipe external thread joint (1), an inner pipe joint (4) is arranged inside the drill pipe internal thread joint (2), the external thread joint side inner pipe (3) is inserted into the inner pipe joint (4), the end of the inner pipe joint (4) is welded to a sealing partition plate (7), the end of the external thread joint side inner pipe (3) is blocked by an inner pipe plug (8), a liquid flow channel is arranged on the inner pipe plug (8), the liquid flow channel is connected to a hydraulic pipeline (10), the hydraulic pipeline (10) is connected to a water pressure pump (9), and a hydraulic pressure gauge (11) is arranged on the hydraulic pipeline (10); it further includes a traction device (12), and the traction device (12) is used to push the external thread joint side inner pipe (3) to perform axial reciprocating motion.

2. The sealing performance testing device for the inner pipe connection joint of a double-wall drill pipe according to claim 1, characterized in that, the traction device (12) includes a support plate (12-1), a fixed sleeve (12-2), a roller (12-3), a crankshaft (12-4) and a motor (12-5), the fixed sleeve (12-2) is arranged on the support plate (12-1), the roller (12-3) is arranged below the support plate (12-1), one side of the crankshaft (12-4) is connected to the support plate (12-1), and the other side is connected to the motor (12-5); when the motor (12-5) rotates, it drives the crankshaft (12-4) to rotate, so that the support plate (12-1) reciprocates, and the side part of the external thread joint side inner pipe (3) is fixed to the support plate (12-1) through the fixed sleeve (12-2).

3. The sealing performance testing device for the inner pipe connection joint of a double-wall drill pipe according to claim 1, characterized in that, sealing between the external thread joint side inner pipe (3) and the inner pipe joint (4) is achieved through a sealing ring (5); a sealing groove (3-1) matching the sealing ring (5) is arranged on the outer surface of the external thread joint side inner pipe (3).

4. The sealing performance testing device for the inner pipe connection joint of a double-wall drill pipe according to claim 3, characterized in that, the sealing groove (3-1) is of a spherical crown type, the radial depth is greater than 1 / 2 of the diameter, and the number of the sealing grooves (3-1) is 2-3.

5. The sealing performance testing device for the inner pipe connection joint of a double-wall drill pipe according to claim 1, characterized in that, the sealing partition plate (7) is centrally fixed to the inner wall end face of the drill pipe internal thread joint (2) by welding.

6. The sealing performance testing device for the inner pipe connection joint of a double-wall drill pipe according to claim 1, characterized in that, a centering sleeve (6) is sleeved on the outer surface of the inner pipe joint (4), and the centering sleeve (6) is used to fix the inner pipe joint (4) inside the drill pipe internal thread joint (2).

7. A sealing performance testing method for the inner pipe connection joint of a double-wall drill pipe, characterized in that, The implementation is specifically carried out according to the following steps: S1: Check whether the sealing ring (5) on the outer surface of the inner pipe (3) on the external thread joint side is in good condition, and connect the external thread joint (1) of the drill pipe and the internal thread joint (2) of the drill pipe; S2: Assemble the inner pipe joint (4) inside the internal thread joint (2) of the drill pipe, and insert the inner pipe (3) on the external thread joint side into the inner pipe joint (4); S3: Block and fix the inner pipe joint (4) with a sealing partition plate (7); block the inner pipe (3) on the external thread joint side with an inner pipe plug (8); S4: Fix the inner pipe (3) on the external thread joint side on the traction device (12), pressurize the inside of the inner pipe (3) on the external thread joint side according to the design pressure, and maintain the pressure after reaching the design pressure; S5: Start the traction device (12) to make the inner pipe (3) on the external thread joint side reciprocate axially; S6: Observe the water pressure drop of the inner pipe (3) on the external thread joint side within the 5-minute pressure holding time, and evaluate whether the sealing performance is qualified.

8. The method for testing the sealing performance of the connection joint of the inner pipe of the double-wall drill pipe according to claim 7, wherein, the design pressure of the inner pipe (3) on the external thread joint side is greater than or equal to 60% of the internal pressure resistance strength of the inner pipe (3) on the external thread joint side.

9. The method for testing the sealing performance of the connection joint of the inner pipe of the double-wall drill pipe according to claim 7, wherein, the moving speed of the traction device (12) is not greater than 3 m / min, and the reciprocating moving amplitude is ±25 mm.

10. The method for testing the sealing performance of the connection joint of the inner pipe of the double-wall drill pipe according to claim 7, wherein, in step S6, if the pressure drop of the inner pipe (3) on the external thread joint side within 5 minutes of pressure holding is less than 0.3 MP, it proves that the sealing performance is qualified; otherwise, the sealing performance is unqualified.

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