Casing compressive strength testing device and testing method

Abstract

The invention discloses a casing compressive strength testing device which comprises a supporting frame, a bottom plate is horizontally arranged in the supporting frame, a plurality of guide rails are fixedly connected to the bottom plate, the ends, away from the bottom plate, of the guide rails penetrate through a cover plate, the bottom plate is parallel to the plate face of the cover plate, a hydraulic jack is arranged at the end, away from the bottom plate, in the supporting frame, and the hydraulic jack is in communication connection with an upper computer. The casing compressive strength testing method comprises the following steps: acquiring a casing sample; placing a sleeve sample between the bottom plate and the guide rail, and covering the cover plate; lowering the hydraulic jack and the hydraulic ram, and entering the next step when the hydraulic flashboard is attached to the surface of the cover plate; the reading of the detection instrument is set to be zero, and the detachable handle is inserted into a low-speed loading clamping groove of the hydraulic device; starting a strength test, and enabling the hydraulic flashboard to move downwards; a calculation button is clicked to calculate the compressive strength of the casing, and the test is completed. According to the device and the method for testing the compressive strength of the casing, the cost of testing the compressive strength is lower, and the operation process is simpler and more convenient.

Description

Technical Field

[0001] This invention belongs to the technical field of casing strength testing equipment, and relates to a casing compressive strength testing device and a casing compressive strength testing method. Background Technology

[0002] In the oil and gas industry, casing is widely used in well construction during the drilling and production phases. As reservoir depth increases, well depths become greater, and the loads on casing become increasingly complex. Especially in the high-temperature, high-pressure environment at the bottom of the well, casing will withstand extremely high temperature and pressure loads throughout its entire lifespan. The yield strength of the casing is a crucial indicator affecting well construction costs and subsequent safety. Due to the increasing failure rate of casing downhole, its strength is receiving increasing attention. The internal pressure resistance and external extrusion resistance of the casing string are the main parameters for evaluating casing performance; currently, the yield strength of casing is calculated using the API standard.

[0003] The API standard yield strength test involves cutting the specimen out of the casing and performing an axial test. However, the yield strength of the casing is mainly affected by the circumferential material properties. Studies have shown that as the casing length increases, the non-uniform load-bearing capacity of the casing also increases, making the casing's resistance to external extrusion strength testing difficult and resulting in low prediction accuracy.

[0004] In summary, existing technologies suffer from problems such as complex testing procedures and high testing costs for casing resistance to external extrusion. Summary of the Invention

[0005] The purpose of this invention is to provide a casing compressive strength testing device, which solves the problems of complex testing procedures and high testing costs in the existing technology for casing external extrusion strength testing.

[0006] Another objective of this invention is to provide a method for testing the compressive strength of casing.

[0007] The technical solution adopted in this invention is a casing compressive strength testing device, including a support frame, a base plate horizontally arranged inside the support frame, several guide rails fixedly connected to the base plate, the end of the guide rail away from the base plate passing through a cover plate, the base plate and the cover plate being arranged parallel to each other, a hydraulic jack being arranged inside the support frame away from the base plate, and the hydraulic jack being communicatively connected to a host computer.

[0008] The invention is further characterized by:

[0009] The guide rail structure is cylindrical, and the axes of several guide rails are parallel; a displacement sensor is installed on one side of the hydraulic jack, and the displacement sensor is connected to the host computer for communication.

[0010] A hydraulic ram is installed on the side of the hydraulic jack near the base plate. The hydraulic ram is embedded in the hydraulic jack, and the hydraulic jack and the hydraulic ram are respectively connected to hydraulic devices via pipelines.

[0011] The hydraulic device has several slots, and a detachable handle is provided in each slot. A hydraulic gate is fixed to the side of the hydraulic ram away from the hydraulic jack, and the surface of the hydraulic gate is parallel to the surface of the base plate.

[0012] A torque meter is installed on the side of the cover plate near the hydraulic gate, and the torque meter is connected to the host computer for communication.

[0013] The host computer is equipped with a compressive strength test control module, which has a "start" button and a "calculate" button.

[0014] Another technical solution adopted in this invention is a method for testing the compressive strength of a casing, comprising the following steps:

[0015] S1. Obtain a sleeve sample and measure its inner diameter, outer diameter, and length;

[0016] S2. Place the sleeve sample between the base plate and the guide rail, and cover it with the cover plate to make the sleeve sample fit with the cover plate, the base plate, and the guide rail.

[0017] S3. Lower the hydraulic jack and hydraulic slide block. When the hydraulic gate plate is in contact with the surface of the cover plate, proceed to the next step.

[0018] S4. In the upper computer's compressive strength test control module, set the reading of the testing instrument to zero, and insert the detachable handle into the slow loading slot of the hydraulic device.

[0019] S5. Click the "Start" button in the host computer to start the strength test. The hydraulic gate will move downwards and stop moving when the displacement distance of the hydraulic gate is equal to 25% of the outer diameter of the sleeve sample.

[0020] S6. Click the "Calculate" button to calculate the casing compressive strength. The test is now complete.

[0021] Another feature of the technical solution of this invention is that:

[0022] The testing instruments include position sensors and torque meters;

[0023] The formula for calculating the compressive strength of the casing is as follows:

[0024]

[0025] Where, σ y The value represents the compressive strength of the casing, D represents the outer diameter of the casing, t represents the wall thickness of the casing, F1 represents half of the external load applied to the elastic limit of the casing, and l represents the length of the casing sample.

[0026] The beneficial effects of this invention are: lower cost of crush resistance testing and simpler and more convenient operation process; this invention accurately tests the crush resistance of casing and evaluates each manufactured casing, which helps to select appropriate casing in drilling design schemes, and ensures the integrity of gas wells while solving local abnormal pressure in specific gas wells, rather than using the API conservative method to estimate the crush resistance of casing using minimum attributes and experience, making casing selection more accurate and faster. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the casing compressive strength testing device of the present invention;

[0028] Figure 2 This is a partially enlarged schematic diagram of the casing compressive strength testing device of the present invention.

[0029] In the diagram, 1. Cover plate; 2. Base plate; 3. Guide rail; 4. Hydraulic device; 5. Hydraulic gate; 6. Hydraulic jack; 7. Hydraulic slide; 8. Detachable handle; 9. Displacement sensor; 10. Host computer; 11. Torque meter; 12. Support frame. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] Casing compressive strength testing device, such as Figure 1 As shown, it includes a support frame 12, a base plate 2 is horizontally arranged inside the support frame 12, several guide rails 3 are fixedly connected to the base plate 2, the end of the guide rail 3 away from the base plate 2 passes through the cover plate 1, the base plate 2 and the cover plate 1 are arranged parallel to each other, a hydraulic jack 6 is arranged inside the support frame 12 away from the base plate 2, and the hydraulic jack 6 is communicatively connected to the host computer 10.

[0032] The guide rail 3 has a cylindrical structure, and the axes of several guide rails 3 are parallel; a displacement sensor 9 is installed on one side of the hydraulic jack 6, and the displacement sensor 9 is connected to the host computer 10 for communication.

[0033] A hydraulic jack 6 is provided with a hydraulic slide 7 on the side near the base plate 2. The hydraulic slide 7 is embedded in the hydraulic jack 6. The hydraulic jack 6 and the hydraulic slide 7 are respectively connected to hydraulic devices 4 by pipelines.

[0034] The hydraulic device 4 has several slots, and a detachable handle 8 is provided in the slots of the hydraulic device 4; a hydraulic gate 5 is fixed to the side of the hydraulic ram 7 away from the hydraulic jack 6, and the surface of the hydraulic gate 5 is parallel to the surface of the base plate 2.

[0035] A torque meter 11 is installed on the side of the cover plate 1 near the hydraulic gate 5, and the torque meter 11 is connected to the host computer 10 for communication.

[0036] The host computer 10 is equipped with a compressive strength test control module, which has a "start" button and a "calculate" button.

[0037] The method for testing the compressive strength of casing includes the following steps:

[0038] S1. Obtain a sleeve sample and measure its inner diameter, outer diameter, and length;

[0039] S2. Place the sleeve sample between the base plate 2 and the guide rail 3, and cover it with the cover plate 1. Figure 2 As shown, the sleeve sample is made to fit against the cover plate 1, the base plate 2, and the guide rail 3;

[0040] S3. Lower the hydraulic jack 6 and hydraulic slide 7. When the hydraulic gate 5 is in contact with the surface of the cover plate 1, proceed to the next step.

[0041] S4. In the compressive strength test control module of the host computer 10, set the reading of the test instrument to zero, and insert the detachable handle 8 into the slow loading slot of the hydraulic device 4.

[0042] S5. Click the "Start" button in the host computer 10 to start the strength test. The hydraulic gate 5 will move downwards and stop moving when the displacement distance of the hydraulic gate 5 is equal to 25% of the outer diameter of the sleeve sample.

[0043] S6. Click the "Calculate" button to calculate the casing compressive strength. The test is now complete.

[0044] The testing instruments include a position sensor 9 and a torque meter 11;

[0045] The formula for calculating the compressive strength of the casing is as follows:

[0046]

[0047] Where, σ y The value represents the compressive strength of the casing, D represents the outer diameter of the casing, t represents the wall thickness of the casing, F1 represents half of the external load applied to the elastic limit of the casing, and l represents the length of the casing sample.

[0048] This invention refines and optimizes the original formula for calculating resistance to external extrusion into a simpler calculation form without reducing its accuracy, and proposes a new testing method to obtain circumferential resistance to external extrusion. This invention simplifies the testing procedure and reduces testing costs. Multiple casing samples are selected, and their compressive strength is calculated separately, then the average value is taken. The error rate is reduced by increasing the testing frequency. This invention avoids the casing failure mechanism, using a simple fracture test to obtain relevant data, resulting in faster and simpler testing procedures for obtaining the casing's resistance to external extrusion.

[0049] Example 1

[0050] This embodiment proposes a casing compressive strength testing device, such as... Figure 1 As shown, it includes a support frame 12, a base plate 2 is horizontally arranged inside the support frame 12, several guide rails 3 are fixedly connected to the base plate 2, the end of the guide rail 3 away from the base plate 2 passes through the cover plate 1, the base plate 2 and the cover plate 1 are arranged parallel to each other, a hydraulic jack 6 is arranged inside the support frame 12 away from the base plate 2, and the hydraulic jack 6 is communicatively connected to the host computer 10.

[0051] Example 2

[0052] This embodiment proposes a casing compressive strength testing device, such as... Figure 1 As shown, the system includes a support frame 12, within which a base plate 2 is horizontally mounted. Several guide rails 3 are fixedly connected to the base plate 2, with one end of each guide rail passing through a cover plate 1. The base plate 2 and cover plate 1 are parallel to each other. A hydraulic jack 6 is mounted on the support frame 12 at the end furthest from the base plate 2, and the hydraulic jack 6 is communicatively connected to a host computer 10. The guide rails 3 are cylindrical, and their axes are parallel. A displacement sensor 9 is mounted on one side of the hydraulic jack 6, and is communicatively connected to the host computer 10. A hydraulic slide 7 is mounted on the side of the hydraulic jack 6 closest to the base plate 2, and is embedded in the hydraulic jack 6. Both the hydraulic jack 6 and the hydraulic slide 7 are connected to hydraulic devices 4 via pipelines. Several slots are formed on the hydraulic devices 4, and detachable handles 8 are fitted into these slots. A hydraulic gate 5 is fixedly connected to the side of the hydraulic slide 7 furthest from the hydraulic jack 6, and the surface of the hydraulic gate 5 is parallel to the surface of the base plate 2.

[0053] Example 3

[0054] This embodiment proposes a casing compressive strength testing device, such as... Figure 1 As shown, the system includes a support frame 12, within which a base plate 2 is horizontally mounted. Several guide rails 3 are fixed to the base plate 2, with one end of each guide rail 3 passing through a cover plate 1. The base plate 2 and cover plate 1 are parallel to each other. A hydraulic jack 6 is mounted within the support frame 12 at the end furthest from the base plate 2, and the hydraulic jack 6 is communicatively connected to a host computer 10. The guide rails 3 are cylindrical, and their axes are parallel. A displacement sensor 9 is mounted on one side of the hydraulic jack 6, and the displacement sensor 9 is communicatively connected to the host computer 10. A hydraulic ram 7 is mounted on the side of the hydraulic jack 6 closest to the base plate 2, and the hydraulic ram 7 is embedded in the hydraulic jack 6. Both the hydraulic jack 6 and the hydraulic ram 7 are connected to hydraulic devices 4 via pipelines.

[0055] The hydraulic device 4 has several slots, and a detachable handle 8 is fitted into these slots. A hydraulic gate 5 is fixed to the side of the hydraulic ram 7 away from the hydraulic jack 6, and the surface of the hydraulic gate 5 is parallel to the surface of the base plate 2. A torque meter 11 is installed on the surface of the cover plate 1 near the hydraulic gate 5, and the torque meter 11 is communicatively connected to the host computer 10. The host computer 10 contains a compressive strength test control module, which has a "start" button and a "calculate" button.

[0056] Example 4

[0057] This embodiment proposes a method for testing the compressive strength of casing, including the following steps:

[0058] S1. Obtain a sleeve sample and measure its inner diameter, outer diameter, and length;

[0059] S2. Place the sleeve sample between the base plate 2 and the guide rail 3, and cover it with the cover plate 1 so that the sleeve sample fits against the cover plate 1, the base plate 2, and the guide rail 3.

[0060] S3. Lower the hydraulic jack 6 and hydraulic slide 7. When the hydraulic gate 5 is in contact with the surface of the cover plate 1, proceed to the next step.

[0061] S4. In the compressive strength test control module of the host computer 10, set the reading of the test instrument to zero, and insert the detachable handle 8 into the slow loading slot of the hydraulic device 4.

[0062] S5. Click the "Start" button in the host computer 10 to start the strength test. The hydraulic gate 5 will move downwards and stop moving when the displacement distance of the hydraulic gate 5 is equal to 25% of the outer diameter of the sleeve sample.

[0063] S6. Click the "Calculate" button to calculate the casing compressive strength. The test is now complete.

Claims

1. A casing compressive strength testing device, characterized in that, The system includes a support frame (12), a base plate (2) is horizontally arranged inside the support frame (12), several guide rails (3) are fixedly connected to the base plate (2), the end of the guide rail (3) away from the base plate (2) passes through the cover plate (1), the base plate (2) and the cover plate (1) are arranged parallel to each other, a hydraulic jack (6) is arranged inside the support frame (12) away from the base plate (2), and the hydraulic jack (6) is communicatively connected to a host computer (10).

2. The casing compressive strength testing device according to claim 1, characterized in that, The guide rail (3) has a cylindrical structure, and the axes of several guide rails (3) are parallel; a displacement sensor (9) is provided on one side of the hydraulic jack (6), and the displacement sensor (9) is communicatively connected to the host computer (10).

3. The casing compressive strength testing device according to claim 2, characterized in that, The hydraulic jack (6) is provided with a hydraulic slide (7) on the side near the base plate (2). The hydraulic slide (7) is embedded in the hydraulic jack (6). The hydraulic jack (6) and the hydraulic slide (7) are respectively connected to a hydraulic device (4) via pipelines.

4. The casing compressive strength testing device according to claim 3, characterized in that, The hydraulic device (4) has several slots, and a detachable handle (8) is provided on the slots of the hydraulic device (4); a hydraulic gate (5) is fixedly connected to the side of the hydraulic ram (7) away from the hydraulic jack (6), and the surface of the hydraulic gate (5) is parallel to the surface of the base plate (2).

5. The casing compressive strength testing device according to claim 4, characterized in that, A torque meter (11) is installed on the side of the cover plate (1) near the hydraulic gate (5), and the torque meter (11) is connected to the host computer (10) for communication.

6. The casing compressive strength testing device according to claim 5, characterized in that, The host computer (10) is equipped with a compressive strength test control module, which is equipped with a "start" button and a "calculate" button.

7. A method for testing the compressive strength of a casing, characterized in that, Includes the following steps: S1. Obtain a sleeve sample and measure its inner diameter, outer diameter, and length; S2. Place the sleeve sample between the base plate (2) and the guide rail (3), and cover it with the cover plate (1) so that the sleeve sample fits against the cover plate (1), the base plate (2), and the guide rail (3); S3. Lower the hydraulic jack (6) and hydraulic slide (7), and proceed to the next step when the hydraulic gate (5) and the cover plate (1) are in contact. S4. In the compressive strength test control module of the host computer (10), set the reading of the test instrument to zero, and insert the detachable handle (8) into the slow loading slot of the hydraulic device (4). S5. Click the "Start" button in the host computer (10) to start the strength test. The hydraulic gate (5) moves downward. The displacement of the hydraulic gate (5) stops when the displacement distance is equal to 25% of the outer diameter of the sleeve sample. S6. Click the "Calculate" button to calculate the casing compressive strength. The test is now complete.

8. The method for testing the compressive strength of a casing according to claim 7, characterized in that, The detection instruments include a position sensor (9) and a torque meter (11); The formula for calculating the compressive strength of the casing is as follows: Where, σ y The value represents the compressive strength of the casing, D represents the outer diameter of the casing, t represents the wall thickness of the casing, F1 represents half of the external load applied to the elastic limit of the casing, and l represents the length of the casing sample.

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