Control device for simulating high-temperature and high-pressure cement paste plugging of oil and gas well

Abstract

The invention discloses a control device for simulating oil-gas well high-temperature and high-pressure cement paste plugging, which comprises an outer cylinder, the bottom end of the outer cylinder is provided with a lower base, the top end of the outer cylinder is provided with a pressure-resistant mechanism, the pressure-resistant mechanism comprises a support, the outer wall of the support is provided with a through groove, and the through groove is communicated with the through groove. A hydraulic cylinder is rotationally connected to one side of the inner wall of the support through a rotating shaft, a first transverse rod is rotationally connected to the bottom end of the hydraulic cylinder, one end of a first rotating block is rotationally connected to each of the front end and the rear end of the first transverse rod, and the center of the outer wall of each first rotating block is rotationally connected with the inner wall of the support. According to the control device for simulating high-temperature and high-pressure cement paste plugging of the oil and gas well, the pressure resisting function of the pressure resisting cover is achieved through the connecting rod, the hydraulic cylinder, the pressure resisting cover, a sealing ring, a pressurizer, a first supporting rod, a second rotating block, a first rotating block, a second supporting rod, a first transverse rod, a second transverse rod, a third transverse connecting rod and other structures, and the situation that workers are hurt due to misoperation is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas well plugging, and in particular to a device for simulating high-temperature and high-pressure cement slurry plugging of oil and gas wells. Background Art

[0002] Cementing operations in oil and gas wells are a common method used in oil fields to seal leaking layers, perforation sections, and blastholes. The purpose is to force cement slurry into the formation or blasthole by applying pressure, and then seal the formation or blasthole after the cement slurry solidifies.

[0003] The existing cementing operation in oil and gas wells is as follows: a cement truck injects a certain amount of ultrafine cement slurry through the drill pipe. After the ultrafine cement slurry is injected into the designated position, the drill pipe is pulled above the cement slurry liquid level, and pressure is applied to squeeze the ultrafine cement slurry into the formation or blasthole. The pressure change is used to determine whether the cement slurry has been squeezed into the formation. When the pressure continues to rise to the set value, the squeezing is stopped, the drill pipe is pulled to a safe position, and the cement slurry is allowed to solidify. After the cement slurry solidifies, the formation or blasthole can be sealed.

[0004] However, problems exist in existing operating methods: different formations have different conditions of pore development, and the ability of the plugging cement slurry to enter and penetrate them may vary. At the same time, different plugging cement slurries, due to differences in their components and the physical and chemical properties of their particles, have different abilities to enter formation pores and blastholes under pressure, and their strength after solidification may also vary. Therefore, it is impossible to effectively evaluate whether the cement slurry can enter the formation pores and fractures as expected, form a plugging zone of sufficient thickness, and whether it can form sufficient strength to plug pores of different sizes and achieve the expected plugging effect. As a result, it is impossible to adjust the corresponding extrusion parameters (currently only empirical parameters) according to the specific conditions of the oil and gas wells, resulting in an insufficient plugging effect.

[0005] In the prior art, a device is designed to simulate the high-pressure cement slurry plugging of oil and gas wells. Through indoor simulation experiments and evaluation, the plugging cement slurry components suitable for the size of the formation pores and fractures are selected based on the evaluation results, and the formula of the plugging cement slurry is optimized to ensure that the plugging cement slurry can penetrate into the formation pores and fractures or blastholes to a certain depth to form a plugging zone of sufficient thickness, and has sufficient strength after solidification to achieve the plugging of the predetermined pores and fractures or blastholes.

[0006] However, for the existing device for simulating high-pressure cement slurry plugging of oil and gas wells, the device itself does not have a cover opening function, or requires manual opening, and some cover opening functions are complicated, which makes the device inconvenient to use. The cover of the existing device for simulating high-pressure cement slurry plugging of oil and gas wells does not have the ability to withstand high pressure. The upper limit temperature of the existing device for simulating high-pressure cement slurry plugging of oil and gas wells is generally 200°C, and the upper limit pressure is generally around 30MPa. The machine cover is easily damaged in the experiment, and manual opening of the cover is dangerous, the beneficial effect is not obvious, and the practicality is poor. Summary of the Invention

[0007] The object of the present invention is to provide a device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solution: a device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells, comprising an outer cylinder, a lower base being provided at the bottom end of the outer cylinder, and a pressure-resistant mechanism being provided at the top end of the outer cylinder; The top end face of said sliding arm is fixedly provided with a toothed connecting strip which is cooperatively connected with said toothed connecting strip.

[0009] Preferably, a first inner cylinder is provided at the top end of the inner cavity of the outer cylinder, a second inner cylinder is provided at the bottom end of the first inner cylinder, and a liquid discharge port is provided at the bottom end of the outer cylinder.

[0010] Preferably, a core specimen is placed in the inner cavity of the second inner cylinder, and a gap between the core specimen and the second inner cylinder is sealed with resin.

[0011] Preferably, a transparent graduated tube is fixed to the bottom end of the liquid discharge port of the outer cylinder, and an adjustable high-pressure needle valve is connected to the bottom end of the transparent graduated tube.

[0012] Preferably, a supporting mesh is provided at the inner bottom of the vertical inner cavity of the outer cylinder, and the core specimen is placed on the top of the supporting mesh.

[0013] Preferably, the first inner cylinder is conical with a larger upper portion and a smaller lower portion, and the opening at the upper end of the second inner cylinder is a flared opening with a larger upper portion and a smaller lower portion. The first inner cylinder and the second inner cylinder are adapted to be docked, and butter is applied to the docking joint before docking.

[0014] Preferably, the first rotating block is a "T"-shaped rotating block.

[0015] Preferably, the second rotating block is an "L"-shaped rotating block.

[0016] Preferably, a sealing ring is provided at the bottom end of the pressure-resistant cover.

[0017] Preferably, a sealing ring is provided on the inner side of the second inner cylinder.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: the control device for simulating high-temperature and high-pressure cement slurry plugging of oil and gas wells realizes the pressure-resistant function of the pressure-resistant cover through the structures such as the connecting rod, the hydraulic cylinder, the pressure-resistant cover, the sealing ring, the pressurizer, the first support rod, the second rotating block, the first rotating block, the second support rod, the first cross bar, the second cross bar, and the third cross bar, thereby avoiding harm to the staff due to improper operation, and the device can obtain the formation core conditions through simulation in the laboratory, optimize the plugging cement slurry parameters, and improve the success rate of oil and gas well plugging; this solution simulates the pores and gaps in the actual formation core to form a columnar Core specimens; by conducting plugging cement slurry penetration experiments on cylindrical core specimens in the laboratory; the upper limit temperature of this scheme is 200℃, and the upper limit pressure is 30MPa; it can simulate and evaluate the squeezing effect of cement slurries with different temperatures, squeezing pressures, and particle size distributions, quantify the depth of cement slurry squeezed into the formation, and effectively evaluate the plugging effect of the formation after squeezing ultra-fine cement slurry; in one experiment, the amount of plugging cement slurry squeezed into the cylindrical core specimen can be measured simultaneously, the hydraulic breakdown pressure of the plugging zone can be measured, and the consolidation condition of the plugging cement slurry in the pores and fractures of the formation can be measured, which greatly simplifies the number of experimental operations, has strong practicality, and is beneficial to popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a front cross-sectional view of the pressure-resistant cover structure of the present invention in an open state; Figure 2 This is a front cross-sectional view of the anti-pressure cover structure of the present invention in a closed state; Figure 3 It is the front view of the present invention; Figure 4 It is an enlarged view of point A of the present invention; Figure 5 Schematic diagram of the internal structural connection relationship of the bracket of the present invention.

[0020] In the figure: 1. outer cylinder, 2. bracket, 3. through groove, 4. first inner cylinder, 5. second inner cylinder, 6. resin, 7. sealing ring, 8. support mesh, 9. transparent scale tube, 10. adjustable high-pressure needle valve, 11. lower base, 12. core specimen, 13. connecting rod, 14. hydraulic cylinder, 15. pressure cover, 16. sealing ring, 17. pressurizer, 18. first support rod, 19. second rotating block, 20. first rotating block, 21. second support rod, 22. first cross bar, 23. second cross bar, 24. third cross bar. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] See also Figure 1-5The present invention provides a technical solution: a device for simulating high-temperature and high-pressure cement slurry plugging and control of oil and gas wells, comprising an outer tube 1, a lower base 11 being provided at the bottom end of the outer tube 1, and a pressure-resistant mechanism being provided at the top end of the outer tube 1; the pressure-resistant mechanism comprising a bracket 2, which supports the structure around it, the bracket 2 being fixedly connected to the outer wall of the outer tube 1, a through groove 3 being provided on the outer wall of the bracket 2, which serves to avoid the structure moving on the bracket 2, a hydraulic cylinder 14 being rotatably connected to one side of the inner wall of the bracket 2 through a rotating shaft to retract the hydraulic cylinder 14, and a first crossbar being rotatably connected to the bottom end of the hydraulic cylinder 14 22, the hydraulic cylinder 14 contracts and drives the first cross bar 22 to swing. The front and rear ends of the first cross bar 22 are both rotatably connected to one end of the first rotating block 20. The swing of the first cross bar 22 drives the first rotating block 20 to rotate counterclockwise. The center position of the outer wall of the first rotating block 20 is rotatably connected to the inner wall of the bracket 2. The top of the first rotating block 20 is rotatably connected to the second cross bar 23. The first rotating block 20 rotates counterclockwise to drive the second cross bar 23 to swing. The first rotating block 20 is a "T"-shaped rotating block. The center position of the second cross bar 23 is rotatably connected to one end of the connecting rod 13. The other end of the connecting rod 13 rotates. The second cross bar 23 is rotatably connected to the third cross bar 24, and the second cross bar 23 swings through the connecting rod 13 to drive the third cross bar 24 to swing. Both ends of the third cross bar 24 are rotatably connected to one end of the second rotating block 19. The swing of the third cross bar 24 drives the second rotating block 19 to swing counterclockwise. The center position of the outer wall of the second rotating block 19 is rotatably connected to the inner wall of the bracket 2. The other end of the second rotating block 19 is rotatably connected to the first support rod 18. The second rotating block 19 is an "L"-shaped rotating block. The other end of the first rotating block 20 is rotatably connected to the second support rod 21. The bottom end of the first support rod 18 is rotatably connected to The anti-pressure cover 15, the first rotating block 20 and the second rotating block 19 rotate counterclockwise at the same time through the first support rod 18 and the second support rod 21 to press the anti-pressure cover 15 against the top of the outer cylinder 1. The bottom end of the second support rod 21 is fixedly connected to the anti-pressure cover 15. A pressurizer 17 is provided at the top of the anti-pressure cover 15. The pressurizer 17 adds appropriate pressure to the inner cavity of the outer cylinder 1. A sealing ring 16 is provided at the bottom end of the anti-pressure cover 15. The sealing ring 16 seals the connection between the outer cylinder 1 and the anti-pressure cover 15. Pressurized water, pressurized gas, and normal pressure water can be introduced through the pressurizer 17.

[0023] As a preferred solution, a first inner tube 4 is further provided at the top of the inner cavity of the outer tube 1, and a second inner tube 5 is provided at the bottom of the first inner tube 4. A sealing ring 7 is provided inside the second inner tube 5, and a drain port is provided at the bottom of the outer tube 1 to facilitate disassembly. The second inner tube 5 acts as a feed tube to prevent the sealing cement slurry from adhering to the inner wall of the outer tube 1 and preventing the second inner tube 5 from being removed.

[0024] As a preferred solution, further, a core specimen 12 is placed in the inner cavity of the second inner cylinder 5 , and a gap between the core specimen 12 and the second inner cylinder 5 is sealed with resin 6 .

[0025] As a preferred embodiment, further, a transparent graduated tube 9 is fixed to the bottom end of the discharge port of the outer tube 1, and the bottom end of the transparent graduated tube 9 is connected to an adjustable high-pressure needle valve 10. When the plugging cement slurry seeps out from the lower end surface of the core specimen 12, it will fall into the transparent graduated tube 9, and the reading is taken through the transparent graduated tube 9 to measure the amount of the plugging cement slurry at the seepage point. The outer tube 1 is also provided with a heating device and a pressure gauge for measuring the internal pressure of the outer tube 1.

[0026] As a preferred solution, further, a supporting mesh plate 8 is provided at the inner bottom of the vertical inner cavity of the outer tube 1, and the core specimen 12 is placed on the top of the supporting mesh plate 8. When the blocking cement slurry seeps out from the entire lower end surface of the core specimen 12, it is conducive to flowing downward from the mesh holes of the supporting mesh plate 8 to avoid blockage.

[0027] As a preferred solution, further, the first inner cylinder 4 is conical with a larger upper portion and a smaller lower portion, and the opening at the upper end of the second inner cylinder 5 is an expanded opening with a larger upper portion and a smaller lower portion. The first inner cylinder 4 and the second inner cylinder 5 are adapted for docking, and butter is applied at the docking point before docking.

[0028] The detailed connection means are well-known technologies in this field. The following mainly introduces the working principle and process. The specific operations are as follows.

[0029] When in use, first connect the device to an external power source, then make the hydraulic cylinder 14 contract, the contraction of the hydraulic cylinder 14 drives the first cross bar 22 to swing, the swing of the first cross bar 22 drives the first rotating block 20 to rotate counterclockwise, the first rotating block 20 rotates counterclockwise to drive the second cross bar 23 to swing, the swing of the second cross bar 23 drives the third cross bar 24 to swing through the connecting rod 13, the swing of the third cross bar 24 drives the second rotating block 19 to swing counterclockwise, the first rotating block 20 and the second rotating block 19 rotate counterclockwise at the same time through the first support rod 18 and the second support rod 21, so as to press the pressure cover 15 to the top of the outer tube 1, and when the core specimen 12 is installed in the outer tube 1, the sealing cement slurry is loaded through the second inner tube 5, and then the outer tube 1 allows the sealing cement slurry to penetrate into the core specimen through pressure control and temperature control. 12; by measuring the amount of plugging cement slurry that penetrates into the core specimen 12, the ability of the plugging cement slurry to enter the pores of the core specimen 12 is evaluated; by testing the hydraulic breakdown pressure of the plugging belt, the pressure bearing capacity of the plugging belt is evaluated, and then the plugging effect of the cement slurry used on the experimental formation pores is determined; through CT scanning or dissection observation, the situation of the plugging cement slurry entering the formation pores under different conditions and the situation of its consolidation in the formation pores are analyzed and studied; compared with traditional empirical parameters, this scheme obtains the actual parameters of the plugging cement slurry in the formation based on the evaluation and analysis of the corresponding situation, so as to be more realistic in the core situation of oil and gas wells, and provide reference and guidance for optimizing the plugging cement slurry formula and improving the squeezing and sealing process. This design has a simple structure, obvious beneficial effects and strong practicality.

[0030] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells, comprising an outer cylinder (1), wherein a lower base (11) is provided at the bottom end of the outer cylinder (1), and characterized in that: The top end of the outer cylinder (1) is provided with a pressure-resistant mechanism; The anti-pressure mechanism comprises a bracket (2), an outer wall of the bracket (2) is provided with a through groove (3), one side of the inner wall of the bracket (2) is rotatably connected to a hydraulic cylinder (14) via a rotating shaft, the bottom end of the hydraulic cylinder (14) is rotatably connected to a first cross bar (22), the front and rear ends of the first cross bar (22) are rotatably connected to one end of a first rotating block (20), the center position of the outer wall of the first rotating block (20) is rotatably connected to the inner wall of the bracket (2), the top end of the first rotating block (20) is rotatably connected to a second cross bar (23), the center position of the second cross bar (23) is rotatably connected to one end of a connecting rod (13), and the connecting rod (13) The other end of the third cross bar (24) is rotatably connected to the third cross bar (24), the two ends of the third cross bar (24) are rotatably connected to one end of the second rotating block (19), the center position of the outer wall of the second rotating block (19) is rotatably connected to the inner wall of the bracket (2), the other end of the second rotating block (19) is rotatably connected to the first support rod (18), the other end of the first rotating block (20) is rotatably connected to the second support rod (21), the bottom end of the first support rod (18) is rotatably connected to the pressure-resistant cover (15) through a pin shaft, the bottom end of the second support rod (21) is fixedly connected to the pressure-resistant cover (15), and the top end of the pressure-resistant cover (15) is provided with a pressurizer (17).

2. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 1, characterized in that: A first inner cylinder (4) is provided at the top end of the inner cavity of the outer cylinder (1), a second inner cylinder (5) is provided at the bottom end of the first inner cylinder (4), and a liquid discharge port is provided at the bottom end of the outer cylinder (1).

3. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 2, characterized in that: A core specimen (12) is placed in the inner cavity of the second inner cylinder (5), and a gap between the core specimen (12) and the second inner cylinder (5) is sealed with resin (6).

4. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 2, characterized in that: A transparent graduated tube (9) is fixed to the bottom end of the liquid discharge port of the outer cylinder (1), and an adjustable high-pressure needle valve (10) is connected to the bottom end of the transparent graduated tube (9).

5. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 2, characterized in that: A supporting mesh plate (8) is provided at the inner bottom of the vertical inner cavity of the outer cylinder (1), and the core specimen (12) is placed on the top of the supporting mesh plate (8).

6. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 2, characterized in that: The first inner cylinder (4) is in a conical shape with a larger upper portion and a smaller lower portion, and the opening at the upper end of the second inner cylinder (5) is an expanded opening with a larger upper portion and a smaller lower portion. The first inner cylinder (4) and the second inner cylinder (5) are adapted to be connected, and butter is applied to the connection points before connection.

7. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 1, characterized in that: The first rotating block (20) is a "T"-shaped rotating block.

8. The device for simulating high-temperature and high-pressure cement slurry plugging and control of oil and gas wells according to claim 1, characterized in that: The second rotating block (19) is an "L"-shaped rotating block.

9. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 1, characterized in that: A sealing ring (16) is provided at the bottom end of the pressure-resistant cover (15).

10. The device for simulating high-temperature and high-pressure cement slurry plugging control in oil and gas wells according to claim 1, characterized in that: A sealing ring (7) is provided on the inner side of the second inner cylinder (5).

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