Casing thread fatigue sealing evaluation test device and method under simulated horizontal well environment

Abstract

The invention belongs to the technical field of gas well drilling and completion pipe evaluation, and particularly relates to a sleeve thread fatigue sealing evaluation test device and method under the simulated horizontal well environment. The device is organically composed of a large-size test tube, a connecting piece, a first plug, a test sleeve, a coupling, a sliding sleeve, a centralizing ring, a second plug, an electric pressure test pump, a first acting part, a second acting part and a third acting part. By means of the device and method, the tonnage and frequency data of safe lowering of the horizontal well casing can be obtained, the purpose of safe lowering of the casing on site is achieved, the risk of lowering sealing failure of the horizontal well casing is effectively reduced, and the repair cost of sealing failure of a casing string is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of gas well drilling and completion tubular material evaluation, and in particular relates to a casing thread fatigue seal evaluation test device and method in a simulated horizontal well environment. Background Art

[0002] The shale oil extraction technology of a certain oil field is mainly based on "large well group + long horizontal section + multi-stage volume fracturing", with the purpose of maximizing wellhead production. However, in the development of shale oil horizontal wells, casing seal failures frequently occur due to the large offset distance and long horizontal section of shale oil horizontal wells. Due to the large friction resistance of the casing in the Changqing Oilfield shale oil horizontal wells, the lifting and lowering of the wellhead casing causes the downhole casing to bend repeatedly and suffer complex stress, resulting in local casing thread seal failure, which is the main reason for the casing seal failure.

[0003] In order to avoid casing seal failure, it is necessary to select horizontal well casing with appropriate strength and toughness for lowering. At present, the selection of horizontal well casing is mainly based on the "Drilling Party A Manual" and "Drilling Technology". There are three main technical parameters for measuring casing selection, namely tensile strength, internal pressure resistance, and external squeeze resistance; when the tensile strength, internal pressure resistance, and external squeeze resistance of the casing meet the casing lowering depth, it is sufficient. However, the tonnage requirement for the casing to be lowered when encountering resistance is less than 20-30 tons. This tonnage data is far from the current on-site situation and cannot meet the on-site requirements, resulting in the hidden danger of casing seal failure at the site.

[0004] The author is Xie Shiyuan's "Fatigue Failure Analysis and Life Prediction of Long Round Threads of Casing under Multiaxial Alternating Loads". Through the finite element method, a finite element model of long round threads of casing is established, and the stress and strain of the casing threads under multiaxial alternating loads such as tension, compression, and internal pressure after the thread is made up are analyzed. The life evaluation method based on the Mises yield criterion is used to calculate the life of the casing threads under multiaxial alternating loads. This article takes the casing with an outer diameter of 139.4mm and a wall thickness of 9.17mm as an example.

[0005] The author is Wang Xuan. The article "Mechanical Analysis and Fatigue Life Prediction of Casing Drilling Connection Threads" establishes a thread-related mechanical calculation model and a connection thread fatigue life prediction model based on the overall stress conditions of the tubing in casing drilling and the fatigue damage theory of the connection thread. Then, a finite element numerical model of the connection thread is established to simulate the equivalent stress and deformation of the connection thread under multiple working conditions, and the relationship curve between the equivalent stress and the tensile, compressive and torsion forces is sorted out and fitted; the fatigue damage and fatigue life of the connection thread under multiple working conditions are simulated, and the relationship curve between the fatigue life of the connection thread and the bottom hole drilling pressure and torque is fitted. A method for measuring the integrity of threaded connection joints under different loads based on the finite element analysis method and a prediction formula for the fatigue life of threaded connections are proposed.

[0006] The author is Tang Jiarui's "Research on the Anti-rotational Bending Fatigue Test of New Gas-sealed Special Threaded Joints", which is based on API5C5:2017 and API TR 5SF standards. By conducting a resonant bending fatigue test on a certain type of special threaded casing, the sealing performance of the special threaded joint under fatigue vibration load is evaluated.

[0007] The author is Wu Yingxi's "Study on Multi-axial Fatigue Life of Trapezoidal Casing Threaded Joints", which selects API trapezoidal casing threads as the research object and J55 steel as the material. The stress-strain field of the casing thread connection is analyzed by the elastic-plastic finite element method, and a geometrically similar notched specimen simulating the fatigue performance of the casing thread connection is established through the equivalence of fatigue parameters. A series of tension-torsion combined loading tests are carried out on the specimen, and the stress-strain state of the notched specimen under multi-axial loading is analyzed, and the multi-axial fatigue life curves of the notched parts depicted by the two-parameter method and the three-parameter method are obtained.

[0008] The author Ding Yuqi's "Fatigue Life Analysis and Optimization Design of Drill Tool Connection Threads" establishes a three-dimensional finite element model of the connection thread, describes the stress deformation state and contact state of the internal and external threads under dynamic loads, and can calculate the fatigue life of the thread. The results show that axial force has little effect on drill tool thread fatigue, while torque and bending moment have a greater effect on drill tool thread fatigue.

[0009] The author Shu Bozhao's "Optimal Thread Type Selection of Tight Oil Horizontal Well Casing in Mahu Area, Xinjiang" uses finite element numerical simulation method and full-size casing physical test method to compare and analyze the connection strength and fatigue life of API-LC long round buckle type and TP-G2 special buckle type casing threaded joints during the lifting and lowering process of casing operation. The test results show that the connection performance and fatigue resistance of TP-G2 special buckle type casing threaded joints are better than those of API-L long round buckle type casing threaded joints.

[0010] However, the difficulty of inserting casing varies in different regions and locations of different wells. The above methods cannot conduct targeted evaluation of casing thread fatigue sealing based on the actual location of shale oil horizontal wells. Summary of the invention

[0011] The present invention provides a casing thread fatigue seal evaluation test device and method under a simulated horizontal well environment, with the aim of providing a device and method that can evaluate casing in a targeted manner, thereby selecting suitable casing for production, meeting on-site construction requirements, reducing drilling and completion costs, and providing data basis for subsequent remote technical support.

[0012] To achieve the above object, the technical solution adopted by the present invention is:

[0013] A casing thread fatigue seal evaluation test device under a simulated horizontal well environment comprises a large-size test pipe, a connector, a first plug, a test casing, a coupling, a sleeve, a straightening ring, a second plug, an electric pressure test pump, a first action part, a second action part and a third action part; the test casing is placed in the large-size test pipe, the test casing is composed of a left part and a right part, the left part and the right part are connected by a thread, the outer periphery of the threaded connection is sleeved with a coupling, the outer periphery of the coupling is connected with a sleeve, one end of the first action part passes through the outer wall of the large-size test pipe and contacts with the sleeve, and the other end of the first action part is connected with the electric pressure test pump; the two end surfaces of the test casing are respectively connected with the first plug and the second plug; the outer periphery of one end of the test casing is connected to the inner wall of the large-size test pipe through the straightening ring, the end surface of one end of the test casing is in contact with one end of the second action part through the connected second plug, and the other end of the second action part is connected with the electric pressure test pump; the other end of the test casing is connected to the inner wall of the large-size test pipe through the connector, and the other end of the test casing is connected to the electric pressure test pump through the third action part.

[0014] The connecting piece includes a fixing sleeve, a spring and a positioning block; the fixing sleeve is a circular cup-shaped structure, a through hole is opened at the bottom of the fixing sleeve, and the bottom of the fixing sleeve is connected to the inner wall of the large-sized test tube; the spring is placed in the fixing sleeve, and the top end of the fixing sleeve is slidably connected to the other end of the test sleeve through the positioning block.

[0015] The second plug is a hollow plug.

[0016] The first action part includes a second oil cylinder, a conversion short circuit, a second joint, a third joint, a fourth joint, a first valve, a second valve and a third valve; the second oil cylinder is connected to the middle side wall of the large-size test pipe, one end of the second oil cylinder is the output end, the output end is in contact with the sleeve, the other end of the second oil cylinder is connected to the conversion short circuit, the second joint, the third joint and the fourth joint are respectively connected to the conversion short circuit; the second joint, the third joint and the fourth joint are respectively connected to the electric pressure test pump through the first valve, the second valve and the third valve.

[0017] The second action part includes a piston, a first oil cylinder, a first joint, a side joint, a fourth valve and a fifth valve; the first oil cylinder is fixedly connected to the side wall of one end of the large-size test tube, the first oil cylinder is connected to a piston, and the output end of the piston is in contact with the second plug; the first oil cylinder is connected to a first joint and a side joint; the first joint is connected to the electric pressure test pump through the fifth valve; the side joint is connected to the electric pressure test pump through the fourth valve.

[0018] It also includes a hydraulic cylinder outer tube; the hydraulic cylinder outer tube is sleeved on the outer periphery of the first oil cylinder.

[0019] The third action part includes a pipeline, a telescopic short circuit and a sixth valve; one end of the pipeline passes through the side wall of the other end of the large-size test tube and is connected to the test sleeve; the other end of the pipeline is connected to the electric pressure test pump through the telescopic short circuit and the sixth valve in sequence.

[0020] A casing thread fatigue seal evaluation test method under a simulated horizontal well environment, using a casing thread fatigue seal evaluation test device under a simulated horizontal well environment, comprising the following steps:

[0021] Step 1: Start the electric pressure test pump and perform a stretching operation on the test casing through the second action part;

[0022] Step 2: compress the test sleeve through the second action part, pressurize the inside of the test sleeve through the third action part, bend and reset the middle part of the test sleeve through the first action part, then release the pressure inside the test sleeve, and compress and reset the test sleeve;

[0023] Step 3: Stop the preset duration;

[0024] Step 4: Perform stretching and compression operations on the test sleeve through the second action part;

[0025] Step 5, opening the third action part to apply pressure to the inside of the test sleeve, opening the first action part to bend the test sleeve in the opposite direction of step 2 through the first action part, and keeping the bending state for a preset time;

[0026] Step 6: The bending, internal pressure and compression force on the test sleeve are eliminated through the first action part, the second action part and the third action part, and the test sleeve gradually returns to its original state;

[0027] Step 7: Repeat step 1 to step 6 for 200-500 times of loading test;

[0028] Step 8. Start the first action part, apply external pressure to the test casing, and maintain the pressure for a preset time of minutes; verify the sealing of the casing thread.

[0029] The specific implementation method of the second action part performing the stretching operation on the test sleeve is as follows:

[0030] The first step is to open the fifth valve and the hydraulic pipeline where the first joint is located;

[0031] Step 2: Hydraulic oil enters the first oil cylinder, and the piston in the first oil cylinder drives the second plug at one end of the test sleeve to move away from the center, so that the axial direction of the test sleeve is pulled, thereby driving the test sleeve to move away from the center;

[0032] Step 3: Keep the tension for 1 minute;

[0033] Step 4: Depressurize the hydraulic pipeline where the fifth valve and the first joint are located, and release the tension on the test casing;

[0034] The specific implementation method of the second action part performing the compression operation on the test sleeve is as follows:

[0035] Step 1: Open the fourth valve and the hydraulic pipeline where the side joint is located;

[0036] Step 2: Hydraulic oil enters the first oil cylinder, and the piston in the first oil cylinder drives the second plug at one end of the test sleeve to move toward the center, and the second plug is compressed, so that the test sleeve is compressed in the axial direction;

[0037] Step 3: Keep the tension for 1 minute;

[0038] Step 4: Depressurize the hydraulic pipeline where the fourth valve and the side joint are located to relieve the axial pressure on the test casing.

[0039] The specific method of the third action part applying pressure to the inside of the test sleeve is as follows:

[0040] The first step is to open the sixth valve and the hydraulic pipeline where the telescopic short circuit is located;

[0041] Step 2: hydraulic pressure enters the test casing to apply pressure to the inside of the test casing;

[0042] Step 3: The hydraulic pipeline where the sixth valve and the telescopic short circuit are located is depressurized, and the internal pressure of the test casing gradually disappears;

[0043] The specific implementation method of the first action part performing the bending operation on the middle part of the test sleeve is as follows:

[0044] Step 1: Open the hydraulic pipeline where the fourth joint and the second valve are located;

[0045] Step 2: Hydraulic oil enters the second oil cylinder, and the piston in the second oil cylinder drives the sliding sleeve to move away from the second oil cylinder, so that the coupling in the middle of the test casing is bent;

[0046] Step 3: Keep the bending state for 1 minute;

[0047] Step 4: Depressurize the hydraulic pipeline where the fourth joint and the second valve are located, and the bend produced at the coupling in the middle of the test casing is gradually restored;

[0048] Step 5: Open the hydraulic pipeline where the third joint and the third valve are located; the hydraulic oil enters the second oil cylinder;

[0049] Step 6: The piston in the second oil cylinder drives the sliding sleeve to move toward the second oil cylinder, so that the coupling in the middle of the test casing is bent in the opposite direction to the second step;

[0050] Step 7. Maintain the bending state for 1 minute;

[0051] Step 8. Depressurize the hydraulic pipeline where the third joint and the third valve are located, and the bend in the middle coupling of the test casing in the opposite direction of the second step is gradually restored.

[0052] Beneficial effects:

[0053] (1) The present invention is composed of a large-size test pipe, a connector, a plug, a test casing, a coupling, a sliding sleeve, a stabilizing ring, a plug, an electric pressure test pump, a first action part, a second action part and a third action part. Through the present invention, the tonnage and number of times of safe lowering of the horizontal well casing can be obtained, meeting the purpose of safely lowering the casing on site.

[0054] (2) The present invention effectively reduces the risk of sealing failure during the installation of horizontal well casing.

[0055] (3) The adoption of the present invention greatly reduces the cost of repairing casing string seal failure.

[0056] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0058] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0059] In the figure: 1. large-size test pipe; 2. fixing sleeve; 3. spring; 4. positioning block; 5. first plug; 6. test sleeve; 7. coupling; 8. sliding sleeve; 9. straightening ring; 10. second plug; 11. piston; 12. first oil cylinder; 13. outer tube of liquid cylinder; 14. first joint; 15. side joint; 16. second oil cylinder; 17. conversion short circuit; 18. second joint; 19. third joint; 20. fourth joint; 21. electric pressure test pump; 22. first valve; 23. second valve; 24. third valve; 25. fourth valve; 26. fifth valve; 27. pipeline; 28. telescopic short circuit; 29. ​​sixth valve. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Embodiment 1:

[0062] according to Figure 1 The casing thread fatigue sealing evaluation test device shown in the figure simulates a horizontal well environment, comprising a large-size test pipe 1, a connector, a first plug 5, a test casing 6, a coupling 7, a sleeve 8, a straightening ring 9, a second plug 10, an electric pressure test pump 21, a first action part, a second action part and a third action part; the test casing 6 is placed in the large-size test pipe 1, and the test casing 6 is composed of left and right parts, which are connected by threads, and the outer periphery of the threaded connection is sleeved with a coupling 7, and the outer periphery of the coupling 7 is connected with a sleeve 8, and one end of the first action part passes through the outer wall of the large-size test pipe 1 It contacts with the sliding sleeve 8, and the other end of the first acting part is connected to the electric pressure test pump 21; the two end faces of the test sleeve 6 are respectively connected with the first plug 5 and the second plug 10; the outer periphery of one end of the test sleeve 6 is connected to the inner wall of the large-size test pipe 1 through the straightening ring 9, and the end face of one end of the test sleeve 6 contacts with one end of the second acting part through the connected second plug 10, and the other end of the second acting part is connected to the electric pressure test pump 21; the other end of the test sleeve 6 is connected to the inner wall of the large-size test pipe 1 through a connecting piece, and the other end of the test sleeve 6 is connected to the electric pressure test pump 21 through the third acting part.

[0063] In actual use, the electric pressure test pump 21 is started, and the test sleeve 6 is stretched through the second action part; then, the test sleeve 6 is compressed through the second action part, the inside of the test sleeve 6 is pressurized through the third action part, and the middle of the test sleeve 6 is bent and reset through the first action part, and then the pressure inside the test sleeve 6 is released, and the compression of the test sleeve 6 is reset; the preset time is stopped for one minute; then, the test sleeve 6 is stretched and compressed through the second action part; then, the third action part is turned on to pressurize the test sleeve 6, start the first action part to bend the middle part of the test sleeve 6 in the opposite direction to step 2 through the first action part, and keep the bending state for a preset time; then, through the first action part, the second action part and the third action part, the bending, internal pressure and compression force on the test sleeve 6 disappear, and the test sleeve 6 gradually returns to its original state; repeat steps 1 to 6 for 200-500 loading tests; start the first action part, apply external pressure to the test sleeve 6, and maintain the pressure for 1 minute; verify the sealing of the sleeve thread.

[0064] The present invention can obtain the tonnage and number of times of safe lowering of horizontal well casing, meet the purpose of safe casing lowering on site, effectively reduce the risk of sealing failure during the lowering of horizontal well casing, and greatly reduce the cost of repairing casing string sealing failure.

[0065] Embodiment 2:

[0066] according to Figure 1 The casing thread fatigue sealing evaluation test device shown in the figure simulates the horizontal well environment. The difference from the embodiment 1 is that the connecting piece includes a fixing sleeve 2, a spring 3 and a positioning block 4; the fixing sleeve 2 is a circular cup-shaped structure, and a through hole is opened at the bottom of the fixing sleeve 2. The bottom of the fixing sleeve 2 is connected to the inner wall of one end of the large-size test pipe 1; the spring 3 is placed in the fixing sleeve 2, and the top end of the fixing sleeve 2 is slidably connected to the other end of the test casing 6 through the positioning block 4.

[0067] In actual use, one end of the fixing sleeve 2 is fixedly connected to the inner wall of one end of the large-size test tube 1, and the spring 3 provided therein can ensure that the test sleeve 6 is compressed and reset after the pressure is released under the action of the second action part. The setting of the positioning block 4 ensures that the axis of the test sleeve 6 will not deviate when it moves.

[0068] Embodiment three:

[0069] according to Figure 1 The casing thread fatigue seal evaluation test device shown in the figure under a simulated horizontal well environment is different from the first embodiment in that the second plug 10 is a hollow plug.

[0070] In actual use, the second plug 10 is a hollow plug, which can ensure the bidirectional movement of the piston in the outer cylinder 13 while ensuring the sealing.

[0071] Embodiment 4:

[0072] according to Figure 1 The casing thread fatigue sealing evaluation test device shown in the embodiment of the present invention simulates a horizontal well environment. The difference from the embodiment 1 is that the first action part includes a second oil cylinder 16, a conversion short circuit 17, a second joint 18, a third joint 19, a fourth joint 20, a first valve 22, a second valve 23 and a third valve 24; the second oil cylinder 16 is connected to the middle side wall of the large-size test pipe 1, one end of the second oil cylinder 16 is the output end, and the output end is in contact with the sleeve 8, and the other end of the second oil cylinder 16 is connected to the conversion short circuit 17, and the second joint 18, the third joint 19 and the fourth joint 20 are respectively connected to the conversion short circuit 17; the second joint 18, the third joint 19 and the fourth joint 20 are respectively connected to the electric pressure test pump 21 through the first valve 22, the second valve 23 and the third valve 24.

[0073] In actual use, the first action part is used to apply radial force to the middle part of the test sleeve 6 to bend the test sleeve 6 and release the force to restore the bending.

[0074] The specific implementation process of the first action part performing the bending operation on the middle part of the test sleeve 6 is as follows: first, the hydraulic pipeline where the fourth joint 20 and the second valve 23 are located is opened to allow the hydraulic oil to enter the second oil cylinder 16, and the piston in the second oil cylinder 16 drives the sleeve 8 to move in the direction away from the second oil cylinder 16, so that the coupling 7 in the middle part of the test sleeve 6 is bent; after the bending state is maintained for 1 minute, the hydraulic pipeline where the fourth joint 20 and the second valve 23 are located is depressurized, and the bending generated at the coupling 7 in the middle part of the test sleeve 6 is gradually restored; then, the hydraulic pipeline where the third joint 19 and the third valve 24 are located is opened; the hydraulic oil enters the second oil cylinder 16, and the piston in the second oil cylinder 16 drives the sleeve 8 to move in the direction close to the second oil cylinder 16, so that the coupling 7 in the middle part of the test sleeve 6 is bent in the opposite direction to the second step, and after the bending state is maintained for 1 minute, the hydraulic pipeline where the third joint 19 and the third valve 24 are depressurized, and the bending generated at the coupling 7 in the middle part of the test sleeve 6 is bent in the opposite direction to the second step.

[0075] The design of the first action portion enables the present invention to conveniently obtain the safe number of bending actions of the test sleeve 6 .

[0076] Embodiment five:

[0077] according to Figure 1 The casing thread fatigue sealing evaluation test device shown in the embodiment of a simulated horizontal well environment is different from the embodiment 1 in that: the second action part includes a piston 11, a first oil cylinder 12, a first joint 14, a side joint 15, a fourth valve 25 and a fifth valve 26; the first oil cylinder 12 is fixedly connected to the side wall of one end of the large-size test pipe 1, and the first oil cylinder 12 is connected to the piston 11, and the output end of the piston 11 is in contact with the second plug 10; the first oil cylinder 12 is connected to the first joint 14 and the side joint 15; the first joint 14 is connected to the electric pressure test pump 21 through the fifth valve 26; the side joint 15 is connected to the electric pressure test pump 21 through the fourth valve 25.

[0078] In actual use, the second action part is used to apply tension and compression to the axial direction of the test sleeve 6 and release the two forces.

[0079] The specific implementation method of the second action part to perform the stretching operation on the test sleeve 6 is as follows:

[0080] First, open the hydraulic pipeline where the fifth valve 26 and the first connector 14 are located; the hydraulic oil enters the first cylinder 12, and the piston 11 in the first cylinder 12 drives the second plug 10 at one end of the test sleeve 6 to move away from the center, so that the axial direction of the test sleeve 6 is pulled, thereby driving the test sleeve 6 to move away from the center; the pulling force is maintained for 1 minute; then, the hydraulic pipeline where the fifth valve 26 and the first connector 14 are located is depressurized, and the pulling force on the test sleeve 6 is released.

[0081] The specific implementation method of the second action part performing the compression operation on the test sleeve 6 is as follows:

[0082] First, open the hydraulic pipeline between the fourth valve 25 and the side joint 15; the hydraulic oil enters the first cylinder 12, and the piston 11 in the first cylinder 12 drives the second plug 10 at one end of the test sleeve 6 to move toward the center, and the second plug 10 is pressurized, so that the test sleeve 6 is axially compressed; the tension is maintained for 1 minute; then, the hydraulic pipeline where the fourth valve 25 and the side joint 15 are located is depressurized, and the axial pressure on the test sleeve 6 is released.

[0083] By adopting this technical solution, compression and tension can be easily applied to the test casing 6, effectively simulating the actual production site, and providing strong data support for the subsequent understanding of the risk of sealing failure of horizontal well casing.

[0084] Embodiment six:

[0085] according to Figure 1 The casing thread fatigue seal evaluation test device shown in the figure under a simulated horizontal well environment is different from the fifth embodiment in that it also includes a liquid cylinder outer tube 13; the liquid cylinder outer tube 13 is sleeved on the outer periphery of the first oil cylinder 12.

[0086] In actual use, the arrangement of the liquid cylinder outer tube 13 can ensure the bidirectional movement of the piston in the liquid cylinder outer tube 13 while ensuring the sealing.

[0087] Embodiment seven:

[0088] according to Figure 1 The casing thread fatigue sealing evaluation test device shown in the figure simulates the horizontal well environment. The difference from the embodiment 1 is that: the third action part includes a pipeline 27, a telescopic short circuit 28 and a sixth valve 29; one end of the pipeline 27 passes through the side wall of the other end of the large-size test pipe 1 and is connected to the test casing 6; the other end of the pipeline 27 is connected to the electric pressure test pump 21 through the telescopic short circuit 28 and the sixth valve 29 in sequence.

[0089] In actual use, the function of the third action part is to inject pressure into the test casing 6 to make it closer to the actual production environment of the horizontal well, so that the obtained data is more accurate.

[0090] Embodiment eight:

[0091] according to Figure 1 The casing thread fatigue seal evaluation test device shown in the figure simulates the horizontal well environment, which is different from the embodiment 1 in that: the connecting piece includes a fixing sleeve 2, a spring 3 and a positioning block 4; the fixing sleeve 2 is a circular cup-shaped structure, and a through hole is opened at the bottom of the fixing sleeve 2, and the bottom of the fixing sleeve 2 is connected to the inner wall of the large-size test pipe 1; the spring 3 is placed in the fixing sleeve 2, and the top of the fixing sleeve 2 is slidably connected to the other end of the test sleeve 6 through the positioning block 4; the second plug 10 is a hollow plug; the first action part includes a second oil cylinder 16, a conversion short circuit 17, a second joint 18, a third joint 19, a fourth joint 20, a first valve 22, a second valve 23 and a third valve 24; the second oil cylinder 16 is connected to the middle side wall of the large-size test pipe 1, one end of the second oil cylinder 16 is the output end, and the output end contacts the sliding sleeve 8, and the other end of the second oil cylinder 16 is connected to the conversion short circuit 17, and the second joint 18, the third joint 19 and the fourth joint 20 are respectively connected to the conversion short circuit 17; the second joint 18, the third joint 19 and the fourth joint 20 are respectively connected to the conversion short circuit 17; the second joint 18, the third joint 19 and The fourth joint 20 is connected to the electric pressure test pump 21 through the first valve 22, the second valve 23 and the third valve 24 respectively; the second action part includes a piston 11, a first oil cylinder 12, a first joint 14, a side joint 15, a fourth valve 25, a liquid cylinder outer tube 13 and a fifth valve 26; the first oil cylinder 12 is fixedly connected to the side wall of one end of the large-size test tube 1, the first oil cylinder 12 is connected to the piston 11, and the output end of the piston 11 is in contact with the second plug 10; the first oil cylinder 12 is connected to the first joint 14 and Side joint 15; the first joint 14 is connected to the electric pressure test pump 21 through the fifth valve 26; the side joint 15 is connected to the electric pressure test pump 21 through the fourth valve 25; the liquid cylinder outer tube 13 is sleeved on the outer periphery of the first oil cylinder 12; the third action part includes a pipeline 27, a telescopic short circuit 28 and a sixth valve 29; one end of the pipeline 27 passes through the side wall of the other end of the large-size test tube 1 and is connected to the test sleeve 6; the other end of the pipeline 27 is connected to the electric pressure test pump 21 through the telescopic short circuit 28 and the sixth valve 29 in sequence.

[0092] In actual use, first start the electric pressure test pump 21; open the hydraulic pipeline where the fifth valve 26 and the first joint 14 are located, and the hydraulic oil enters the first cylinder 12. The piston 11 in the first cylinder 12 drives the second plug 10 at one end of the test sleeve 6 to move away from the center, so that the axial direction of the test sleeve 6 is pulled, thereby driving the test sleeve 6 to move away from the center; the test sleeve 6 is pulled axially; the threads on the test sleeve 6 are subjected to tension, and the metal sealing surface tends to separate; the tension is maintained for 1 minute; the hydraulic pipeline where the fifth valve 26 and the first joint 14 are located is depressurized, and the tension on the test sleeve 6 is released. Afterwards, the fourth valve 25 and the hydraulic pipeline where the side joint 15 are located are opened; the hydraulic oil enters the first oil cylinder 12, and the piston 11 in the first oil cylinder 12 drives the second plug 10 at one end of the test sleeve 6 to move toward the center, and the second plug 10 is pressurized, so that the test sleeve 6 is axially pressurized; the hydraulic pipeline where the telescopic short circuit 28 and the sixth valve 29 are located is opened, and the hydraulic pressure enters the inside of the test sleeve 6 to apply internal pressure to the test sleeve 6; afterwards, the fourth joint 20 and the hydraulic pipeline where the second valve 23 are located are opened, and the hydraulic oil enters the second oil cylinder 16, and the second oil The piston in the cylinder 16 drives the sleeve 8 to move away from the second oil cylinder 16, causing the coupling 7 in the middle of the test sleeve 6 to bend; after the bending state is maintained for 1 minute, the hydraulic pipeline where the fourth joint 20 and the second valve 23 are located is depressurized, and the bending of the test sleeve 6 disappears; the hydraulic pipeline where the telescopic short circuit 28 and the sixth valve 29 are located is depressurized, and the internal pressure of the sleeve disappears; the hydraulic pipeline where the fourth valve 25 and the side joint 15 are located is depressurized, so that the compression force on the test sleeve 6 disappears, and the test sleeve 6 gradually returns to a free state, completing a test process.After stopping for 1 minute, the fifth valve 26 and the hydraulic pipeline where the first joint 14 is located are opened, and the hydraulic oil enters the piston 11 in the first oil cylinder 12, which drives the second plug 10 at one end of the test sleeve 6 to move away from the center, so that the axial direction of the test sleeve 6 is pulled, thereby driving the test sleeve 6 to move away from the center, and the pulling force is maintained for 1 minute; then the hydraulic pipeline where the fifth valve 26 and the first joint 14 are located is depressurized; the hydraulic pipeline where the fourth valve 25 and the side joint 15 are located is opened, and the hydraulic oil enters the first oil cylinder 12. The hydraulic oil enters the first oil cylinder 12, and the piston 11 drives the second plug 10 at one end of the test sleeve 6 to move toward the center to compress the sleeve plug; the telescopic short-circuit 28 and the sixth valve 29 are opened. Hydraulic pipeline, hydraulic pressure enters the interior of the test sleeve 6; open the hydraulic pipeline where the third joint 19 and the third valve 24 are located, hydraulic oil enters the second oil cylinder 16, and the piston in the second oil cylinder 16 drives the annular sleeve 8 to move toward the second oil cylinder 16, so that the thread position of the test sleeve 6 bends toward the second oil cylinder 16, and the bending state is maintained for 1 minute; the hydraulic pipeline where the fourth joint 20 and the second valve 23 are located is depressurized, and the bending of the sleeve disappears; the hydraulic pipeline where the telescopic short circuit 28 and the sixth valve 29 are depressurized, and the internal pressure of the test sleeve 6 disappears; the hydraulic pipeline where the fourth valve 25 and the side joint 15 are depressurized, and the compression force on the test sleeve 6 disappears, and the sleeve string gradually returns to a free state, completing the second test process. Repeatedly, after completing 200-500 loading tests, open the hydraulic pipeline where the second joint 18 and the first valve 22 are located, and apply external pressure to the sleeve test piece, maintain pressure for 1 minute, and verify the sealing of the sleeve thread.

[0093] By using the present invention, the tonnage and number of times of safe lowering of horizontal well casing can be obtained, which meets the purpose of safely lowering casing on site, effectively reduces the risk of sealing failure during lowering of horizontal well casing, and greatly reduces the cost of repairing casing string sealing failure.

[0094] Embodiment nine:

[0095] Reference Figure 1 A casing thread fatigue seal evaluation test method under a simulated horizontal well environment, using a casing thread fatigue seal evaluation test device under a simulated horizontal well environment, includes the following steps:

[0096] Step 1: Start the electric pressure test pump 21 to stretch the test casing 6 through the second action part;

[0097] Step 2: compress the test sleeve 6 through the second action part, pressurize the inside of the test sleeve 6 through the third action part, bend and reset the middle part of the test sleeve 6 through the first action part, then release the pressure inside the test sleeve 6, and compress and reset the test sleeve 6;

[0098] Step 3: Stop the preset duration;

[0099] Step 4: Perform stretching and compression operations on the test sleeve 6 through the second action part;

[0100] Step 5, opening the third action part to apply pressure to the inside of the test sleeve 6, opening the first action part to bend the test sleeve 6 in the opposite direction of step 2 through the first action part, and keeping the bending state for a preset time;

[0101] Step 6: The bending, internal pressure and compression force on the test sleeve 6 are eliminated through the first action part, the second action part and the third action part, and the test sleeve 6 gradually returns to its original state;

[0102] Step 7: Repeat step 1 to step 6 for 200-500 times of loading test;

[0103] Step 8: Start the first action part, apply external pressure to the test casing 6, and maintain the pressure for 1 minute; verify the sealing of the casing thread.

[0104] Furthermore, the specific implementation method of the second action part performing the stretching operation on the test sleeve 6 is as follows:

[0105] The first step is to open the fifth valve 26 and the hydraulic pipeline where the first connector 14 is located;

[0106] Step 2: The hydraulic oil enters the first oil cylinder 12, and the piston 11 in the first oil cylinder 12 drives the second plug 10 at one end of the test sleeve 6 to move away from the center, so that the axial direction of the test sleeve 6 is pulled, thereby driving the test sleeve 6 to move away from the center;

[0107] Step 3: Keep the tension for 1 minute;

[0108] Step 4: Depressurize the hydraulic pipeline where the fifth valve 26 and the first joint 14 are located, and release the tension on the test sleeve 6;

[0109] The specific implementation method of the second action part to perform the compression operation on the test sleeve 6 is as follows:

[0110] The first step is to open the fourth valve 25 and the hydraulic pipeline where the side joint 15 is located;

[0111] Step 2: Hydraulic oil enters the first oil cylinder 12, and the piston 11 in the first oil cylinder 12 drives the second plug 10 at one end of the test sleeve 6 to move toward the center, and the second plug 10 is compressed, so that the test sleeve 6 is compressed in the axial direction;

[0112] Step 3: Keep the tension for 1 minute;

[0113] Step 4: depressurize the hydraulic pipeline where the fourth valve 25 and the side joint 15 are located, so that the axial pressure on the test sleeve 6 is released.

[0114] Furthermore, the specific method of the third action part applying pressure to the inside of the test sleeve 6 is as follows:

[0115] The first step is to open the sixth valve 29 and the hydraulic pipeline where the telescopic short circuit 28 is located;

[0116] Step 2: hydraulic pressure enters the test casing 6 to apply pressure to the inside of the test casing 6;

[0117] Step 3: The hydraulic pipeline where the sixth valve 29 and the telescopic short circuit 28 are located is depressurized, and the internal pressure of the test sleeve 6 gradually disappears;

[0118] The specific implementation method of the first action part performing the bending operation on the middle part of the test sleeve 6 is as follows

[0119] The first step is to open the hydraulic pipeline where the fourth joint 20 and the second valve 23 are located;

[0120] Step 2: The hydraulic oil enters the second oil cylinder 16, and the piston in the second oil cylinder 16 drives the sliding sleeve 8 to move away from the second oil cylinder 16, so that the coupling 7 in the middle of the test casing 6 is bent;

[0121] Step 3: Keep the bending state for 1 minute;

[0122] Step 4: Depressurize the hydraulic pipeline where the fourth joint 20 and the second valve 23 are located, and the bend generated at the coupling 7 in the middle of the test casing 6 is gradually restored;

[0123] Step 5: Open the hydraulic pipeline where the third joint 19 and the third valve 24 are located; the hydraulic oil enters the second oil cylinder 16;

[0124] Step 6: The piston in the second oil cylinder 16 drives the sliding sleeve 8 to move toward the second oil cylinder 16, so that the coupling 7 in the middle of the test casing 6 is bent in the opposite direction to the second step;

[0125] Step 7. Maintain the bending state for 1 minute;

[0126] Step 8: Depressurize the hydraulic pipeline where the third joint 19 and the third valve 24 are located, and the bend in the opposite direction of the second step generated at the coupling 7 in the middle of the test casing 6 is gradually restored.

[0127] The use of the technical solution of the present invention can obtain the tonnage and number of times of safe lowering of horizontal well casing, thereby meeting the purpose of safe casing lowering on site, effectively reducing the risk of sealing failure during the lowering of horizontal well casing, and greatly reducing the cost of repairing casing string sealing failure.

[0128] In the absence of conflicts, technicians in this field can combine the relevant technical features in the above examples according to actual conditions to achieve corresponding technical effects. The specific combinations are not described here one by one.

[0129] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0130] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0131] The above are only preferred embodiments of the present invention. The present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A casing thread fatigue seal evaluation test device in a simulated horizontal well environment, characterized by: The invention comprises a large-sized test tube (1), a connecting piece, a first plug (5), a test sleeve (6), a coupling (7), a sliding sleeve (8), a straightening ring (9), a second plug (10), an electric pressure test pump (21), a first action part, a second action part and a third action part; the test sleeve (6) is placed in the large-sized test tube (1), the test sleeve (6) is composed of left and right parts, the left and right parts are connected by a thread, the outer periphery of the threaded connection is sleeved with a coupling (7), the outer periphery of the coupling (7) is connected with a sliding sleeve (8), one end of the first action part passes through the outer wall of the large-sized test tube (1) and contacts with the sliding sleeve (8), and the first action part The other end of the test sleeve (6) is connected to an electric pressure test pump (21); the two end surfaces of the test sleeve (6) are respectively connected to a first plug (5) and a second plug (10); the outer periphery of one end of the test sleeve (6) is connected to the inner wall of the large-sized test pipe (1) through a straightening ring (9), the end surface of one end of the test sleeve (6) contacts one end of the second action part through the connected second plug (10), and the other end of the second action part is connected to the electric pressure test pump (21); the other end of the test sleeve (6) is connected to the inner wall of the large-sized test pipe (1) through a connecting piece, and the other end of the test sleeve (6) is connected to the electric pressure test pump (21) through a third action part.

2. A casing thread fatigue seal evaluation test device in a simulated horizontal well environment as claimed in claim 1, characterized in that: The connecting piece comprises a fixing sleeve (2), a spring (3) and a positioning block (4); the fixing sleeve (2) is a circular cup-shaped structure, a through hole is opened at the bottom of the fixing sleeve (2), and the bottom of the fixing sleeve (2) is connected to the inner wall of the large-sized test tube (1); the spring (3) is placed in the fixing sleeve (2), and the top end of the fixing sleeve (2) is slidably connected to the other end of the test sleeve (6) through the positioning block (4).

3. The casing thread fatigue seal evaluation test device in a simulated horizontal well environment according to claim 1, characterized in that: The second plug (10) is a hollow plug.

4. The casing thread fatigue seal evaluation test device in a simulated horizontal well environment according to claim 1, characterized in that: The first action part comprises a second oil cylinder (16), a conversion short circuit (17), a second joint (18), a third joint (19), a fourth joint (20), a first valve (22), a second valve (23) and a third valve (24); the second oil cylinder (16) is connected to the middle side wall of the large-size test pipe (1); one end of the second oil cylinder (16) is an output end, which contacts the sliding sleeve (8); the other end of the second oil cylinder (16) is connected to the conversion short circuit (17); the second joint (18), the third joint (19) and the fourth joint (20) are respectively connected to the conversion short circuit (17); the second joint (18), the third joint (19) and the fourth joint (20) are respectively connected to the electric pressure test pump (21) through the first valve (22), the second valve (23) and the third valve (24).

5. The casing thread fatigue seal evaluation test device in a simulated horizontal well environment according to claim 1, characterized in that: The second action part comprises a piston (11), a first oil cylinder (12), a first joint (14), a side joint (15), a fourth valve (25) and a fifth valve (26); the first oil cylinder (12) is fixedly connected to the side wall of one end of the large-size test tube (1), the first oil cylinder (12) is connected to the piston (11), and the output end of the piston (11) is in contact with the second plug (10); the first oil cylinder (12) is connected to the first joint (14) and the side joint (15); the first joint (14) is connected to the electric pressure test pump (21) through the fifth valve (26); the side joint (15) is connected to the electric pressure test pump (21) through the fourth valve (25).

6. A casing thread fatigue seal evaluation test device in a simulated horizontal well environment as claimed in claim 5, characterized in that: It also comprises a liquid cylinder outer tube (13); the liquid cylinder outer tube (13) is sleeved on the outer periphery of the first oil cylinder (12).

7. The casing thread fatigue seal evaluation test device in a simulated horizontal well environment according to claim 1, characterized in that: The third action part comprises a pipeline (27), a telescopic short circuit (28) and a sixth valve (29); one end of the pipeline (27) passes through the side wall of the other end of the large-size test tube (1) and is connected to the test sleeve (6); the other end of the pipeline (27) is connected to the electric pressure test pump (21) through the telescopic short circuit (28) and the sixth valve (29) in sequence.

8. A casing thread fatigue seal evaluation test method in a simulated horizontal well environment, characterized by: The casing thread fatigue seal evaluation test device in a simulated horizontal well environment as described in any one of claims 1 to 7 comprises the following steps: Step 1: starting the electric pressure test pump (21) to perform a stretching operation on the test casing (6) through the second action part; Step 2: compressing the test sleeve (6) through the second action part, pressing the inside of the test sleeve (6) through the third action part, bending and resetting the middle part of the test sleeve (6) through the first action part, then relieving the pressure inside the test sleeve (6), and compressing and resetting the test sleeve (6); Step 3: Stop the preset duration; Step 4: Performing stretching and compression operations on the test sleeve (6) through the second action part; Step 5: opening the third action part to apply pressure to the inside of the test sleeve (6), opening the first action part to bend the middle part of the test sleeve (6) in the opposite direction to step 2 through the first action part, and maintaining the bending state for a preset time; Step 6: The bending, internal pressure and compression force on the test sleeve (6) are eliminated by the first action part, the second action part and the third action part, and the test sleeve (6) gradually returns to its original state; Step 7: Repeat step 1 to step 6 for 200-500 times of loading test; Step 8: Start the first action part to apply external pressure to the test casing (6) and maintain the pressure for a preset time of minutes; verify the sealing of the casing thread.

9. A casing thread fatigue seal evaluation test method in a simulated horizontal well environment as claimed in claim 8, characterized in that: The specific implementation method of the second action part performing the stretching operation on the test sleeve (6) is as follows: The first step is to open the fifth valve (26) and the hydraulic pipeline where the first connector (14) is located; In the second step, the hydraulic oil enters the first oil cylinder (12), and the piston (11) in the first oil cylinder (12) drives the second plug (10) at one end of the test sleeve (6) to move away from the center, so that the axial direction of the test sleeve (6) is pulled, thereby driving the test sleeve (6) to move away from the center; Step 3: Keep the tension for 1 minute; Step 4: depressurize the hydraulic pipeline where the fifth valve (26) and the first joint (14) are located, and release the tension on the test sleeve (6); The specific implementation method of the second action part performing the compression operation on the test sleeve (6) is as follows: The first step is to open the fourth valve (25) and the hydraulic pipeline where the side joint (15) is located; In the second step, the hydraulic oil enters the first oil cylinder (12), and the piston (11) in the first oil cylinder (12) drives the second plug (10) at one end of the test sleeve (6) to move toward the center, and the second plug (10) is compressed, so that the test sleeve (6) is compressed in the axial direction; Step 3: Keep the tension for 1 minute; Step 4: Depressurize the hydraulic pipeline where the fourth valve (25) and the side joint (15) are located, and release the axial pressure on the test sleeve (6).

10. A casing thread fatigue seal evaluation test method in a simulated horizontal well environment as claimed in claim 8, characterized in that: The specific method of applying pressure to the interior of the test sleeve (6) by the third action part is as follows: The first step is to open the sixth valve (29) and the hydraulic pipeline where the telescopic short circuit (28) is located; Step 2: hydraulic pressure enters the test casing (6) to apply pressure to the inside of the test casing (6); Step 3: The hydraulic pipeline where the sixth valve (29) and the telescopic short circuit (28) are located is depressurized, and the internal pressure of the test sleeve (6) gradually disappears; The specific implementation method of the first action part performing the bending operation on the middle part of the test sleeve (6) is as follows: The first step is to open the hydraulic pipeline where the fourth joint (20) and the second valve (23) are located; Step 2: Hydraulic oil enters the second oil cylinder (16), and the piston in the second oil cylinder (16) drives the sliding sleeve (8) to move away from the second oil cylinder (16), so that the coupling (7) in the middle of the test casing (6) is bent; Step 3: Keep the bending state for 1 minute; Step 4: depressurize the hydraulic pipeline where the fourth joint (20) and the second valve (23) are located, and the bend generated at the coupling (7) in the middle of the test casing (6) is gradually restored; Step 5: Open the hydraulic pipeline where the third joint (19) and the third valve (24) are located; the hydraulic oil enters the second oil cylinder (16); Step 6: The piston in the second oil cylinder (16) drives the sliding sleeve (8) to move toward the second oil cylinder (16), so that the middle coupling (7) of the test casing (6) is bent in the opposite direction to the second step; Step 7. Maintain the bending state for 1 minute; Step 8: Depressurize the hydraulic pipeline where the third joint (19) and the third valve (24) are located, and gradually restore the bend in the middle coupling (7) of the test casing (6) in the opposite direction to the second step.

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