A formwork for testing the compressive strength of oil well cement with confining pressure

Abstract

The utility model discloses an oil well cement compressive strength test mold frame with confining pressure, comprising a pressure device, a confining pressure mold frame, and a hydraulic pump assembly, wherein the pressure device comprises a base, a group of columns are connected to the base, a group of upper ends of the columns are connected to a crossbeam, a hydraulic cylinder is installed at the lower part of the crossbeam, the confining pressure mold frame comprises a cylinder body, a flexible sleeve is arranged in the cylinder body, the outer wall of the flexible sleeve and the inner wall of the cylinder body together form a hydraulic cavity, a test cavity is inside the flexible sleeve, a top cover is arranged at the upper end of the cylinder body, a pressure head is slidably installed on the top cover, the pressure head contacts the telescopic end of the hydraulic cylinder, a hydraulic pipeline is connected between the cylinder body and the hydraulic pump assembly, the device fills rock and soil particles around the test sample in the test cavity, and uses the hydraulic pump assembly to make the flexible sleeve squeeze the rock and soil particles in the test cavity, thereby realizing accurate simulation of the confining pressure effect of the rock and soil layer under the actual use environment.

Description

Technical Field

[0001] The utility model relates to the technical field of a compressive strength test device with confining pressure, in particular to an oil well cement compressive strength test mold frame with confining pressure. Background Art

[0002] Oil well cement is specially used for cementing projects of oil wells and gas wells, also known as plugging cement. Its main purpose is to cement and seal the casing with the surrounding rock formations, so as to form an oil flow channel in the well that flows from the oil layer to the ground and is well isolated. Therefore, when testing the compressive strength of oil well cement, it is necessary to consider the effect of the confining pressure of the rock and soil layer on the oil well cement. The existing triaxial test instrument provides confining pressure to the sample by water injection. Considering that there are usually many small holes in the cement sample, the confining pressure simulated by water injection may be high-pressure water injected into the cement sample, and thus cannot effectively simulate the confining pressure of the rock and soil layer on the cement.

[0003] For example, the prior art with publication number CN114486522A provides a mechanical triaxial test instrument with controllable confining pressure, a load frame, a confining pressure applying device, an axial pressure applying device, a confining pressure stabilizing device and an axial strain measuring device; a pressure steel belt is wrapped around the test sample, and the confining pressure is applied by rotating and contracting the pressure steel belt. A one-way gear is provided under the rotating cylinder, and the confining pressure stabilizing device ensures that the rotating cylinder will not rotate in the opposite direction and cause a pressure drop. The mechanical triaxial test instrument with controllable confining pressure strengthens the strength of axial pressure, which is sufficient to reach the ultimate stress of soft rock, and the confining pressure is accurate and adjustable, so that triaxial tests under high confining pressure can be performed. The mechanical triaxial test instrument with controllable confining pressure has the advantages of accurate and controllable confining pressure, high confining pressure, and convenient carrying. However, one disadvantage of the device is that the shape of the sample is required to be high when the device is used for experiments, that is, the shape of the sample needs to be processed into a relatively standard cylinder so that the pressure steel belt of the device can fully and evenly contact the sample, otherwise it cannot accurately simulate the confining pressure of the rock and soil layer, thereby affecting the accuracy of the experiment.

[0004] Based on the above reasons, it is necessary to introduce an oil well cement compressive strength test formwork with confining pressure, which can more accurately simulate the confining pressure effect of the rock and soil layer in the actual use environment. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides an oil well cement compressive strength test formwork with confining pressure, which solves the problem that the existing compressive strength test device with confining pressure cannot accurately simulate the confining pressure effect of the rock and soil layer in the actual use environment.

[0006] To achieve the above objectives, the utility model is implemented through the following technical solutions: an oil well cement compressive strength test mold frame with confining pressure, comprising a pressure device, a confining pressure mold frame, and a hydraulic pump assembly, the pressure device comprising a base, a group of columns connected to the base, a group of columns upper ends connected to a beam, a hydraulic cylinder is installed at the lower part of the beam, the confining pressure mold frame comprises a cylinder body, the cylinder body is placed on the base, a flexible sleeve is arranged in the cylinder body, the outer wall of the flexible sleeve and the inner wall of the cylinder body together constitute a hydraulic cavity, the flexible sleeve is a test cavity, the upper end of the cylinder body is provided with a top cover, a pressure head is slidably installed on the top cover, the pressure head is in contact with the telescopic end of the hydraulic cylinder, and a hydraulic pipeline is connected between the cylinder body and the hydraulic pump assembly.

[0007] Preferably, the hydraulic pipeline includes an oil delivery pipe, one end of which is connected to the side wall of the cylinder body and communicated with the hydraulic chamber, and the other end is connected to and communicated with the hydraulic pump assembly, and a pressure gauge is connected to the oil delivery pipe.

[0008] Preferably, a spring is connected between the pressure head and the top cover.

[0009] Preferably, the material of the flexible sleeve is oil-resistant rubber.

[0010] Preferably, a pair of mold frame fixing mechanisms are provided on the base, and the mold frame fixing mechanisms include a fixing plate, and a threaded rod is rotatably connected to the fixing plate. A support is provided on the base, and the threaded rod is threadedly connected to the support, and a handle is connected to one end of the threaded rod.

[0011] Beneficial Effects

[0012] The utility model provides an oil well cement compressive strength test formwork with confining pressure, which has the following beneficial effects:

[0013] 1. This device fills rock and soil particles around the test sample in the test cavity, injects hydraulic oil into the hydraulic cavity through the hydraulic pump assembly, and causes the flexible casing to squeeze the rock and soil particles in the test cavity, thereby causing the rock and soil particles to squeeze the test sample, thereby accurately simulating the confining pressure of the rock and soil layer in the actual use environment.

[0014] 2. At the same time, the rock and soil particles used for filling in this device can be selected from rock and soil particles with the same components as those in the actual use environment, which further improves the accuracy of the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the front view of the utility model.

[0016] Figure 2 It is a schematic diagram of the confining and pressing mold frame structure of the utility model.

[0017] In the figure: 1. base; 2. handle; 3. support; 4. threaded rod; 5. fixing plate; 6. cylinder body; 7. column; 8. crossbeam; 9. hydraulic cylinder; 10. hydraulic chamber; 11. oil pipeline; 12. pressure gauge; 13. spring; 14. hydraulic pump assembly; 15. flexible casing; 16. hydraulic chamber; 17. top cover; 18. pressure head. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0019] See also Figure 1-2 The utility model provides a technical solution: a test mold frame for the compressive strength of oil well cement with confining pressure, comprising a pressure device, a confining pressure mold frame, and a hydraulic pump assembly 14, wherein the pressure device comprises a base 1, a group of columns 7 are connected to the base 1, a group of the upper ends of the columns 7 are connected to a crossbeam 8, a hydraulic cylinder 9 is installed at the lower part of the crossbeam 8, the confining pressure mold frame comprises a cylinder body 6, the cylinder body 6 is placed on the base 1, a flexible sleeve 15 is arranged in the cylinder body 6, the outer wall of the flexible sleeve 15 and the inner wall of the cylinder body 6 together form a hydraulic cavity 16, the flexible sleeve 15 is a test cavity 10, a top cover 17 is arranged at the upper end of the cylinder body 6, a pressure head 18 is slidably installed on the top cover 17, the pressure head 18 is in contact with the telescopic end of the hydraulic cylinder 9, and a hydraulic pipeline is connected between the cylinder body 6 and the hydraulic pump assembly 14;

[0020] When in use, the test sample is placed in the test cavity 10, and rock particles or powder are filled around the test sample in the test cavity 10. The hydraulic pump assembly 14 injects hydraulic oil into the hydraulic cavity 16 in the cylinder body 6, so that the flexible casing 15 squeezes the rock particles or powder in the test cavity 10, and then the rock particles or powder form an extrusion effect on the test sample, so as to simulate the confining pressure of the rock layer on the oil well cement in the actual use environment. At the same time, the telescopic end of the hydraulic cylinder 9 squeezes the pressure head 18 downward, and the lower end of the pressure head 18 applies a pressure load to the test sample, so as to test the compressive strength of the cement sample under the confining pressure.

[0021] Furthermore, the hydraulic pipeline includes an oil delivery pipe 11, one end of which is connected to the side wall of the cylinder body 6 and communicates with the hydraulic chamber 16, and the other end is connected to and communicates with the hydraulic pump assembly 14, and a pressure gauge 12 is connected to the oil delivery pipe 11;

[0022] The hydraulic pump assembly 14 can inject hydraulic oil into the hydraulic chamber 16 through the oil pipe 11, and control the pressure in the hydraulic chamber 16 by the amount of hydraulic oil injected. The pressure value in the hydraulic chamber can be displayed by the pressure gauge 12. After the test, the hydraulic oil in the hydraulic chamber can also flow back to the hydraulic pump assembly 14 through the oil pipe 11.

[0023] Furthermore, a spring 13 is connected between the pressure head 18 and the top cover 17;

[0024] The spring 13 is a compression spring, which is used to keep the pressure head 18 at the initial position when the experiment ends.

[0025] Furthermore, the material of the flexible sleeve 15 is oil-resistant rubber;

[0026] The material of the flexible sleeve 15 may be oil-resistant rubber, so that the flexible sleeve 15 can be less susceptible to corrosion from hydraulic oil while having good flexibility.

[0027] Furthermore, the base 1 is provided with a pair of mold frame fixing mechanisms, the mold frame fixing mechanisms include a fixing plate 5, a threaded rod 4 is rotatably connected to the fixing plate 5, a support 3 is provided on the base 1, the threaded rod 4 is threadedly connected to the support 3, and one end of the threaded rod 4 is connected to a handle 2;

[0028] The threaded rod 4 is rotated on the support 3 by rotating the handle 2, and then the threaded rod 4 pushes the fixing plate 5 to clamp the cylinder body 6, so that the confining pressure mold frame remains stable during the experiment.

[0029] By those skilled in the art, the components in this case are connected in sequence. The specific connection and operation sequence should refer to the following working principle. The detailed connection means are well-known technologies in the field. The following mainly introduces the working principle and process.

[0030] Embodiment: When in use, first remove the top cover 17 of the confining pressure mold frame cylinder body 6, put the test sample into the test cavity 10, and fill the rock and soil particles or powder around the test sample in the test cavity 10, cover the top cover 6, place the confining pressure mold on the base 1, turn the handle 2 to rotate the threaded rod 4 on the support 3, and then make the threaded rod 4 push the fixed plate 5 to clamp the cylinder body 6, start the hydraulic pump assembly 14, the hydraulic pump assembly 14 injects hydraulic oil into the hydraulic cavity 16 through the oil pipe 11, and controls the pressure in the hydraulic cavity 16 by the amount of injected hydraulic oil. The pressure value in the hydraulic cavity can be displayed by the pressure gauge 12, and the flexible sleeve 15 squeezes the rock and soil particles or powder in the test cavity 10, so that the rock and soil particles or powder form an extrusion effect on the test sample, so as to simulate the confining pressure effect of the rock and soil layer on the oil well cement under the actual use environment. At the same time, the telescopic end of the hydraulic cylinder 9 squeezes the pressure head 18 downward, and the lower end of the pressure head 18 applies a pressure load to the test sample, so as to test the compressive strength of the cement sample under the confining pressure.

[0031] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Although the embodiments of the utility model have been shown and described, it is understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the utility model, and the scope of the utility model is defined by the attached claims and their equivalents.

Claims

1. A mold frame for testing the compressive strength of oil well cement with confining pressure, comprising a pressure device, a confining pressure mold frame, and a hydraulic pump assembly (14), characterized in that: The pressure device comprises a base (1), the base (1) is connected to a group of columns (7), the upper ends of the group of columns (7) are connected to a crossbeam (8), a hydraulic cylinder (9) is installed at the lower part of the crossbeam (8), the confining pressure mold frame comprises a cylinder body (6), the cylinder body (6) is placed on the base (1), a flexible sleeve (15) is arranged inside the cylinder body (6), the outer wall of the flexible sleeve (15) and the inner wall of the cylinder body (6) together form a hydraulic chamber (16), the flexible sleeve (15) is inside a test chamber (10), a top cover (17) is arranged at the upper end of the cylinder body (6), a pressure head (18) is slidably installed on the top cover (17), the pressure head (18) is in contact with the telescopic end of the hydraulic cylinder (9), and a hydraulic pipeline is connected between the cylinder body (6) and the hydraulic pump assembly (14).

2. The oil well cement compressive strength test formwork with confining pressure according to claim 1, characterized in that: The hydraulic pipeline comprises an oil delivery pipe (11), one end of which is connected to the side wall of the cylinder body (6) and communicates with the hydraulic chamber (16), and the other end of which is connected to and communicates with the hydraulic pump assembly (14). A pressure gauge (12) is connected to the oil delivery pipe (11).

3. The oil well cement compressive strength test formwork with confining pressure according to claim 1, characterized in that: A spring (13) is connected between the pressure head (18) and the top cover (17).

4. The oil well cement compressive strength test formwork with confining pressure according to claim 1, characterized in that: The material of the flexible sleeve (15) is oil-resistant rubber.

5. The oil well cement compressive strength test formwork with confining pressure according to claim 1, characterized in that: The base (1) is provided with a pair of mold frame fixing mechanisms, the mold frame fixing mechanisms comprising a fixing plate (5), a threaded rod (4) being rotatably connected to the fixing plate (5), a support (3) being provided on the base (1), the threaded rod (4) being threadedly connected to the support (3), and a handle (2) being connected to one end of the threaded rod (4).

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