CN110005400A - Device for testing cementing surface of shaft sleeve-cement sheath in high-temperature and high-pressure environment of dry hot rock stratum - Google Patents

Abstract

The hot-dry rock formation high temperature and high pressure environment wellbore casing-cement sheath cementation surface testing device of the present invention takes the casing as the center in the horizontal direction, and includes the casing, the cement sheath, the formation rock, and the horizontally loaded force transmission member from the inside to the outside. and an insulating layer; a heating device is evenly arranged on the inner side of the insulating layer. The heating device adopts electric heating alloy wire as heating element, and the thermal insulation layer adopts ceramic fiber board-microporous thermal insulation board as thermal insulation material. The horizontal loading force transmission member is connected with the hydraulic cylinder to obtain the pressure in the horizontal direction; the vertical loading force transmission member is connected with the universal testing machine to obtain the vertical pressure. The casing is connected with the water pump through the water pipe to form a circulation system. The testing apparatus also includes a leak testing system for monitoring the rupture of the cemented surface. The testing device can not only meet the requirements of the temperature of the dry-hot rock formation in the ambient temperature, but also provide accurate non-uniform in-situ stress field load application, so as to obtain the real dry-hot rock laboratory test data.

Description

High temperature and high pressure environment wellbore casing-cement ring cementation surface test device in hot dry rock formation

technical field

The invention belongs to the field of dry-hot rock engineering cementing, and in particular relates to a device and method for testing the bonding strength of a wellbore casing and a cement sheath under a high-temperature and high-pressure environment of a dry-hot rock formation.

Background technique

Geothermal resources are a new type of clean renewable energy, and one of the green new energy sources that can effectively solve traditional fossil fuels, energy shortages and air pollution. A large amount of geothermal energy is stored in the hot dry rock (HDR) geothermal resource thousands of meters deep, so the hot dry rock is also called enhanced geothermal resource. Hot dry rock itself is a high-temperature rock mass with no internal fluid or only a small amount of underground fluid. There are few pores or fissures, and the permeability is extremely poor. , but it can also be Mesozoic and Cenozoic metamorphic rocks, or even massive sedimentary rocks with huge thickness. Therefore, the commercial development of geothermal resources can only be achieved with the aid of reservoir stimulation technologies such as external hydraulic fracturing.

At present, the most important method for developing hot dry rock resources is hydraulic fracturing. "Hydraulic fracturing method" achieves the purpose of fracturing hot dry rock geothermal reservoirs by injecting fracturing fluid at normal temperature at high pressure in the injection well; with the help of hydraulic fracturing fractures, the reservoir geothermal exchange channel can be established, thereby expanding the reservoir heat exchange area , to accelerate the heat exchange rate between the injected fluid and the surrounding rock mass. At the same time, it is necessary to drill production wells in the fracture stimulation area to realize fluid circulation extraction. The high-temperature fluid produced by the production well can be re-injected into the injection well after being cooled in the production process, and it will be used as the injection fluid again, so as to achieve the purpose of recycling.

However, the casing-cement sheath cemented surface and other structures in the wellbore system have a very harsh environment in the hot dry rock reservoir. Since the cemented surface structure is the weakest structure of the wellbore system, the cemented surface is easily ruptured during use, resulting in bring huge economic losses. Therefore, it is of great significance for the utilization of hot dry rock resources to study the cementation strength of casing-cement sheath cementation surface in hot dry rock formations. The invention patent application 201710916807.3 discloses the "hydraulic fracturing simulation experiment device and method of hot dry rock enhanced geothermal system", which simulates the high pressure and high temperature generation environment of hot dry rock, and applies precise stress to the core by designing multi-stage pistons, and Pressure-resistant and temperature-resistant porous plates are used to maintain the permeability of hot dry rock fluid, and are connected to the fluid collection chamber through the diversion groove. At the same time, an adjustable acoustic emission probe is embedded in the true triaxial high-pressure axe to monitor cracks during hydraulic fracturing. Acoustic emission events during expansion, the device can realize the integrated collection of rock hydraulic fracturing-acoustic emission-thermal energy recovery efficiency and other information under triaxial confining pressure conditions, and study the initiation and propagation of hot dry rock hydraulic fractures. The application relies on the hydraulic fracturing chamber and realizes three-dimensional pressure by applying pressure through multi-stage pistons; 8 pistons are used to apply pressure, which solves the problem of uneven pressure to a certain extent. The fracturing chamber itself will share a certain pressure, and at the same time, it will also produce a certain degree of deformation, so that the pressures in the three directions interfere with each other, thereby reducing the accuracy of applying the in-situ stress in the three directions. As a simulation device, whether it can accurately simulate a specific experimental environment is an important indicator to measure the simulation device; it is also the key to study the bonding strength of wellbore casing and cement sheath in hot dry rock formations.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the simulation devices in the prior art, the present invention provides a wellbore casing-cement sheath cementation surface testing device in a high temperature and high pressure environment for hot dry rock formations, which can not only meet the requirements of the temperature of the hot dry rock formation, but also provide Precise application of non-uniform ground stress field loads to obtain real hot dry rock laboratory test data.

Technical scheme of the present invention:

A test device for wellbore casing-cement sheath cementation surface in a high temperature and high pressure environment in dry and hot rock formations, the test device is centered on the casing in the horizontal direction, and sequentially includes casing, cement sheath, formation rock, horizontal loading force transmission from inside to outside A component and a thermal insulation layer; a heating device is evenly arranged on the inner side of the thermal insulation layer. The heating device adopts electrothermal alloy wire as the heating element, and the thermal insulation device adopts ceramic fiber board-microporous thermal insulation board as the thermal insulation material.

The horizontally loaded force transmission member is a square structure with an I-shaped section, and the horizontally loaded force transmission member includes a square member I, a square member III, and a connecting member II connecting the two. The square member I is located inside the thermal insulation layer, the square member III is located outside the thermal insulation layer, and the connecting member II penetrates the thermal insulation layer. The horizontal loading force transmission member is connected with the hydraulic cylinder through the square member III to obtain the pressure in the horizontal direction; and then the square member I exerts pressure on the formation rock. The outer periphery of the horizontal section of the formation rock is square, and the dimensions of the four sides of the formation rock in the vertical direction match the square member II of the horizontally loaded force transmission member, so as to achieve uniform application of pressure in the horizontal direction. The hydraulic oil cylinder is fixedly connected with the T-shaped steel beam through the oil cylinder fixing structure. The number of the T-shaped steel beams is two, which are not related to each other. The structural design of the T-shaped steel beam can minimize the deformation of the steel beam caused by the horizontal load applied by the hydraulic cylinder.

The upper and lower ends of the test device are provided with vertically loaded force-transmitting members, which include a square member IV, a square member VI and a connecting member V connecting the two, and the connecting member V is composed of four Columnar structure. The square member IV is located inside the thermal insulation layer, the square member VI is located outside the thermal insulation layer, and the connecting member V penetrates the thermal insulation layer. The vertically loaded force transmission member is connected with the universal testing machine through the square member VI to obtain the pressure in the vertical direction, and then is connected with the cement sheath and the formation rock through the square member IV to apply the vertical pressure. The square member IV of the vertically loaded force-transmitting member matches the shapes of the cement sheath and the upper and lower end faces of the formation rock, thereby realizing uniform application of pressure in the vertical direction. It should be particularly emphasized that there is no relationship between the two T-shaped steel beams and the vertical loading, so as to avoid mutual interference between the applied pressures.

Wherein, the upper and lower ends of the casing are connected with water pipes, which are connected with the water pump to form a circulation system; the pressure is provided by the water pump to apply the inner pressure of the casing, and the temperature of the high-speed circulating water is used to control the temperature of the inner wall of the casing.

The testing apparatus also includes a leak testing system for monitoring the rupture of the cemented surface. The leak test system includes a leak test interface, a pressure gauge, a valve and a pressure pump; the leak test interface is set in the cement ring and is connected to the pressure gauge, the valve and the pressure pump in sequence through a pipeline.

Preferably, the testing device includes upper and lower parts with symmetrical structure and detachable structure; specifically, the incubator is divided into upper and lower movable parts, and the horizontal load is also divided into two parts along the shaft axis of the wellbore, and the loading is carried out at the same time. ; It is convenient to use CT machine to scan the cemented surface of casing-cement sheath and the crack propagation process of cement sheath in real time.

A preparation method of a wellbore casing-cement sheath cementation surface testing device in a high-temperature and high-pressure environment in a dry-hot rock stratum specifically includes the following steps: preparing a cuboid rock sample, drilling a hole in the middle of the sample, placing a casing in the center of the hole, and mixing cement Stir and pour into the annular area between the rock and the casing; drill a hole on the side of the rock sample, and bury the leakage test interface through the hole into the annular area near the outer wall of the casing; then put the sample into the environmental chamber Inside, it is fixed with a horizontal loading force transmission member and a vertical loading force transmission member; the environmental box includes a thermal insulation layer and a heating device arranged inside the thermal insulation layer; the horizontal loading force transmission member is connected with the hydraulic cylinder to obtain the horizontal direction. pressure; the vertical loading force transmission member is connected with the universal pressure testing machine to obtain the pressure in the vertical direction. The temperature range that the test device can achieve is 150°C to 500°C.

The method of using the wellbore casing-cement sheath cementation surface testing device in the high temperature and high pressure environment of the hot dry rock formation includes the following steps:

(1) Start the heating device, heat the ambient temperature to the temperature of the dry hot rock formation, keep the temperature constant, and perform sample maintenance;

(2) Start the hydraulic cylinder, and apply the two principal stresses in the horizontal direction of the formation by loading the force-transmitting member horizontally; start the universal pressure testing machine, and apply the vertical stress by vertically loading the force-transmitting member; Simultaneously apply slowly until the test requirements are met;

(3) Use the leakage test system to test the bonding strength of the cemented surface between the casing and the cement sheath, specifically: open the valve, fill the end of the leakage test interface with the gas in the pressure pump, observe the change of the pressure gauge, and Record the pressure value P1;

(4) Turn off the valve, set the temperature of the water in the water tank, open the water pump connection valve, turn on the water pump, circulate the water in the casing, realize the temperature change of the casing, turn off the water pump after a period of time, and close the water pump connection valve; repeat the above Operate until the design number of experiments is reached;

(5) According to step (3), open the valve, and fill the gas in the pressure pump through the buried end of the leakage test interface to the position of the cemented surface of the casing and the cement ring, observe the change of the pressure gauge, and record the pressure value P2;

(6) Turn off the valve, set the temperature of the water in the water tank, open the connection valve of the water pump, turn on the water pump, set the output power of the water pump, and meet the internal pressure of the casing required by the test; adjusting the output power of the water pump can realize the change of the internal pressure of the casing;

(7) According to step (3), open the valve, fill the gas in the pressure pump through the buried end of the leakage test interface to the position where the casing and the cement ring are cemented, observe the change of the pressure gauge, and record the pressure value P3;

(8) During the test, separate the upper and lower parts of the environmental box, and place the X-ray emitting end of the X-CT machine in the middle of the sample, so as to scan the casing-cement sheath bonding surface and the cement sheath crack propagation process in real time .

Beneficial effects of the present invention:

(1) The hot-dry rock formation high temperature and high pressure environment cementing cement sheath testing device according to the present invention can not only meet the requirements of the temperature of the dry and hot rock formation, but also provide accurate non-uniform in-situ stress field load application, thereby Obtain real hot dry rock laboratory test data.

(2) The test device is designed as a detachable upper part and a lower part, so as to realize the real-time scanning of the casing-cement sheath cementation surface and the cement sheath crack propagation process; combined with the leakage test system to monitor the cemented surface rupture It can comprehensively simulate the various challenges of the cemented surface in the actual environment, so as to find countermeasures to avoid the huge economic losses caused by it.

Description of drawings

Accompanying drawing 1 is the structural schematic diagram of the high temperature and high pressure environment cementing cement sheath testing device of hot dry rock formation;

Fig. 2 is a schematic structural diagram of the section A-A' in Fig. 1 .

Among them: 1. Formation rock, 2. Cement sheath, 3. Casing, 4. Insulation layer, 5. Heating device, 6. T-beam, 7. Vertically loaded force transmission member, 8. Horizontally loaded force transmission member , 9. Hydraulic cylinder, 10. Cylinder fixed structure, 11. Gasket, 12. Leakage test interface, 13. Pressure gauge, 14. Valve, 15. Pressure pump, 16. Water pump, 17. Water tank, 18. CT scan window.

Detailed ways

The present invention will be further described below in conjunction with the embodiments.

A preparation method of a wellbore casing-cement sheath cementation surface testing device in a high-temperature and high-pressure environment in a dry-hot rock stratum specifically includes the following steps: preparing a cuboid rock sample and drilling a hole in the middle of the sample, placing the casing 3 in the center of the hole, and placing the cement The mixture is poured into the annulus area between the rock and casing 3. Drill a hole on the side of the rock sample, and bury the leakage test interface 12 through the hole into the annulus area near the outer wall of the casing; then put the sample into the environment box, load the force transmission member 8 horizontally and load it vertically The force transmission member 7 is fixed; the environmental box includes a thermal insulation layer 4 and a heating device 5 arranged inside the thermal insulation layer 4 . The horizontal loading force transmission member 8 is connected with the hydraulic cylinder 9 to obtain the pressure in the horizontal direction; the vertical loading force transmission member 7 is connected with the universal pressure testing machine to obtain the pressure in the vertical direction. The temperature range that the test device can achieve is 150°C to 500°C.

A test device for wellbore casing-cement sheath cementation surface in a high temperature and high pressure environment in hot dry rock formation, the test device is centered on the casing 3 in the horizontal direction, and includes the casing 3, cement sheath 2, formation rock 1, The force transmission member 8 and the thermal insulation layer 4 are loaded horizontally; the heating device 5 is evenly arranged on the inner side of the thermal insulation layer 4 . The heating device 5 uses an electrothermal alloy wire as a heating element, and the thermal insulation device 4 uses a ceramic fiber board-microporous thermal insulation board as a thermal insulation material.

The horizontally loaded force transmission member 8 is a square structure with an I-shaped section, and the horizontally loaded force transmission member 8 includes a square member I, a square member III and a connecting member II connecting the two. The square member I is located inside the thermal insulation layer 4 , the square member III is located outside the thermal insulation layer 4 , and the connecting member II penetrates the thermal insulation layer 4 . The horizontal loading force transmission member 8 is connected to the hydraulic cylinder 9 through the square member III to obtain pressure in the horizontal direction; and then the square member I exerts pressure on the formation rock 1 . The outer periphery of the horizontal section of the formation rock 3 is square, and the dimensions of the four vertical sides of the formation rock 3 match the square member II of the horizontally loaded force transmission member 8, thereby realizing the uniform application of pressure in the horizontal direction. The hydraulic cylinder 9 is fixedly connected to the T-shaped steel beam 6 through the cylinder fixing structure 10 and the gasket 11 . The number of the T-shaped steel beams 6 is two, which are not related to each other. The cross section of the T-shaped steel beam as shown in FIG. 2 is T-shaped, and the two T-shaped steel beams both surround the thermal insulation layer 4 along the square member III (as shown in FIG. 1 ).

The upper and lower ends of the test device are provided with vertically loaded force transmission members 7, and the vertically loaded force transmission members 7 include a square member IV, a square member VI and a connecting member V connecting the two, and the connecting member V is composed of It consists of four columnar structures. The square member IV is located inside the thermal insulation layer 4 , the square member VI is located outside the thermal insulation layer 4 , and the connecting member V penetrates the thermal insulation layer 4 . The vertical load transmission member 7 is connected to the universal testing machine through the square member VI to obtain the vertical pressure, and then connected to the cement sheath 2 and the formation rock 1 through the square member IV to apply vertical pressure. The square member IV of the vertically loaded force-transmitting member 7 matches the shapes of the cement sheath and the upper and lower end faces of the formation rock 1, so as to achieve uniform application of pressure in the vertical direction.

Wherein, the upper and lower ends of the casing 3 are connected with water pipes, which are connected with the water pump 16 and the water tank 17 through the water pipes to form a circulation system; the pressure is provided by the water pump 16 to apply the inner pressure of the casing, and the temperature of the high-speed circulating water is used to control the The temperature of the inner wall of the casing 3.

The testing apparatus also includes a leak testing system for monitoring the rupture of the cemented surface. The leak test system includes a leak test interface 12, a pressure gauge 13, a valve 14 and a pressure pump 15; the leak test interface 12 is arranged in the cement sheath 2, and is connected to the pressure gauge 13, the valve 14 and the pressure gauge 13 in turn through the pipeline. A pressure pump 15 is connected.

The test device includes upper and lower parts that are symmetrical in structure and can be separated, and a CT scanning window 18 is provided; specifically, the environmental chamber is divided into upper and lower movable parts, and the horizontal load is also divided into two parts along the shaft axis of the wellbore. , Simultaneous loading; it is convenient to use CT machine to scan the cemented surface of casing-cement sheath and the crack propagation process of cement sheath in real time.

The method of using the wellbore casing-cement sheath cementation surface testing device in the high temperature and high pressure environment of the hot dry rock formation includes the following steps:

(1) Start the heating device 5, heat the ambient temperature to the temperature of the dry hot rock formation, keep the temperature constant, and perform sample maintenance.

(2) Activate the hydraulic cylinder 9, and apply the two principal stresses in the horizontal direction of the formation through the horizontal loading of the force-transmitting member 8; The principal stress is applied slowly at the same time until the test requirements are met.

(3) Use the leakage test system to test the bonding strength of the cemented surface between the casing and the cement sheath, specifically: open the valve 14, fill the gas in the pressure pump 15 with the end of the leakage test interface 12, observe the pressure gauge 13 and record the initial pressure value P1, that is, the pressure at the initial casing-cement bonding surface.

(4) Turn off the valve 14, set the temperature of the water in the water tank 17, open the water pump connection valve, turn on the water pump 16, circulate the water in the casing 3, realize the temperature change of the casing, turn off the water pump 16 after a period of time, close the The water pump is connected to the valve; the above operation is repeated until the design number of experiments is reached.

(5) According to step (3), open the valve 14, and fill the gas in the pressure pump 15 through the embedded end of the leakage test interface 12 to the position where the casing 3 and the cement ring 2 are bonded, and observe the pressure of the pressure gauge 13. change, and record the pressure value P2, that is, the pressure at the casing-cement bonding surface after the casing temperature is changed. If the cemented surface is broken, then P2<P1; at the same time, the degree of damage of the cemented surface can be judged according to the reduced pressure value, the more the decrease is, the more serious the damage of the cemented surface is.

(6) Turn off the valve 14, set the temperature of the water in the water tank 17, open the water pump connection valve, turn on the water pump 16, set the output power of the pump to meet the internal pressure of the casing required by the test; adjust the output power of the pump to achieve the internal pressure of the casing. Variety.

(7) According to step (3), open the valve 14, and fill the gas in the pressure pump 15 through the embedded end of the leakage test interface 12 to the position where the casing 3 and the cement ring 2 are cemented, and observe the pressure gauge 13. change, and record the pressure value P3, that is, the pressure at the casing-cement bonding surface after the change in the casing internal pressure. If the cemented surface is broken, then P3<P1; at the same time, the degree of damage of the cemented surface can be judged according to the reduced pressure value, the more the decrease is, the more serious the damage of the cemented surface is.

(8) During the test, the upper and lower parts of the temperature environment box were separated, and the X-ray emission end of the X-CT machine was placed in the middle of the sample, so as to scan the casing-cement ring bonding surface and the cement ring crack propagation in real time. process.

Claims (10)

1. The high temperature and high pressure environment wellbore casing of hot dry rock formation-cement sheath cementation surface testing device is characterized in that: the testing device is centered on the casing (3) in the horizontal direction, and sequentially comprises the casing (3) from the inside to the outside. ), cement sheath (2), formation rock (1), horizontal loading force transmission member (8) and thermal insulation layer (4); heating devices (5) are evenly arranged on the inner side of the thermal insulation layer (4); the horizontal loading The force transmission member (8) is a square structure with an I-shaped section, and the horizontally loaded force transmission member (8) includes a square member I, a square member III, and a connecting member II connecting the two; the square member I is located in the thermal insulation. Inside the layer (4), the square member III is located outside the thermal insulation layer (4), and the connecting member II penetrates the thermal insulation layer (4); the horizontal loading force transmission member (8) passes the square member I to the formation rock ( 1) Apply pressure; the upper and lower ends of the test device are provided with vertically loaded force transmission members (7), and the vertically loaded force transmission members (7) include a square member IV, a square member VI and a connection connecting the two Component V, the connecting component V consists of four columnar structures; the square component IV is located inside the thermal insulation layer (4), the square component VI is located outside the thermal insulation layer (4), and the connecting component V penetrates the thermal insulation layer (4). ); the vertical loading force transmission member (7) is connected with the cement sheath (2) and the formation rock (1) through the square member IV to exert vertical pressure. 2. The device for testing the wellbore casing-cement sheath cemented surface in a high temperature and high pressure environment in hot dry rock formation according to claim 1, wherein the horizontal loading force transmission member (8) passes through the square member III and the hydraulic cylinder (9). ) is connected to obtain the pressure in the horizontal direction; the vertically loaded force transmission member (7) is connected with the universal testing machine through the square member VI to obtain the pressure in the vertical direction. 3. The wellbore casing-cement sheath cementation surface testing device in a high temperature and high pressure environment in hot dry rock formation according to claim 2, characterized in that: the outer periphery of the horizontal section of the formation rock (3) is a square, and the formation rock (3) 3) The dimensions of the four sides in the vertical direction are matched with the square member II of the horizontally loaded force transmission member (8) to achieve uniform application of pressure in the horizontal direction; the square member IV of the vertically loaded force transmission member (7) is the same as the The shapes of the upper and lower end faces of the cement sheath and formation rock (1) are matched to achieve uniform application of pressure in the vertical direction. 4. The wellbore casing-cement sheath cementation surface testing device in a high temperature and high pressure environment in hot dry rock formation according to claim 2, characterized in that: the hydraulic cylinder (9) is fixed by the cylinder (10) and the gasket (11) ) is fixedly connected to the T-shaped steel beam (6). 5. The hot-dry rock formation high temperature and high pressure environment wellbore casing-cement sheath cementation surface testing device according to claim 3 or 4, characterized in that: the upper and lower ends of the casing (3) are connected to water pipes, and the water pipes pass through them. It is connected with the water pump to form a circulation system. 6 . The wellbore casing-cement sheath cementation surface testing device in a high temperature and high pressure environment of hot dry rock formation according to claim 5 , wherein the testing device comprises upper and lower parts with symmetrical structure and detachable structure. 7 . 7 . The wellbore casing-cement sheath cementation surface testing device in a high temperature and high pressure environment in hot dry rock formation according to claim 5 , wherein the heating device ( 5 ) uses an electrothermal alloy wire as a heating element, and the thermal insulation layer (4) The ceramic fiber board-microporous thermal insulation board is used as the thermal insulation material. 8 . The wellbore casing-cement sheath cementation surface testing device in a high temperature and high pressure environment in hot dry rock formation according to claim 5 , wherein the testing device further comprises a leakage testing system, and the leakage testing system includes a leakage testing system. 9 . A leak test interface (12), a pressure gauge (13), a valve (14) and a pressure pump (15); the leak test interface (12) is set in the cement ring (2), and is connected to the pressure gauge ( 13), the valve (14) is connected with the pressure pump (15). 9. The method for preparing a wellbore casing-cement sheath cementation surface testing device in a high-temperature and high-pressure environment of hot dry rock formation as claimed in claim 1-8, characterized in that: it specifically comprises the following steps: preparing a cuboid rock sample and placing it in the middle of the sample. Drill a hole, put the casing (3) in the center of the hole, and pour the cement into the annular space between the rock and the casing (3); ) is buried in the annulus area near the outer wall of the casing through the hole; then the sample is placed inside the environmental box and fixed with the horizontal loading force transmission member (8) and the vertical loading force transmission member (7); the environmental box It comprises an insulating layer (4) and a heating device (5) arranged inside the insulating layer (4); the horizontal loading force transmission member (8) is connected with the hydraulic cylinder (9) to obtain pressure in the horizontal direction; The loading force transmission member (7) is connected with the universal pressure testing machine to obtain the pressure in the vertical direction. 10. The using method of the hot dry rock formation high temperature and high pressure environment wellbore casing-cement sheath cementation surface testing device as claimed in claim 9, characterized in that: comprising the following steps: (1) Start the heating device (5), heat the ambient temperature to the temperature of the dry hot rock formation, keep the temperature constant, and perform sample maintenance; (2) Activate the hydraulic cylinder (9), and apply the two principal stresses in the horizontal direction of the formation by horizontally loading the force-transmitting member (8); The principal stress in three directions is applied slowly at the same time until the test requirements are met; (3) Use the leakage test system to test the bonding strength of the cemented surface between the casing and the cement sheath, specifically: open the valve (14), fill the gas in the pressure pump (15) with the end of the leakage test interface (12) part, observe the change of the pressure gauge (13), and record the pressure value P1; (4) Turn off the valve (14), set the temperature of the water in the water tank (17), open the water pump connection valve, turn on the water pump (16), circulate the water in the casing (3), and realize the temperature change of the casing for a period of time. After the time, turn off the water pump (16), and close the water pump connection valve; repeat the above operations until the number of test designs is reached; (5) According to step (3), open the valve (14), and fill the gas in the pressure pump (15) through the buried end of the leakage test interface to the position where the casing and the cement ring are cemented, and observe the pressure gauge ( 13) changes, and record the pressure value P2; (6) Turn off the valve (14), set the temperature of the water in the water tank (17), open the connection valve of the water pump, turn on the water pump (16), set the output power of the water pump to meet the internal pressure of the casing required by the test; adjust the output power of the water pump The change of the internal pressure of the casing can be realized; (7) According to step (3), open the valve (14), and fill the gas in the pressure pump (15) through the embedded end of the leakage test interface to the position where the casing and the cement ring are bonded, and observe the pressure gauge ( 13) changes, and record the pressure value P3; (8) During the test, separate the upper and lower parts of the environmental box, and place the X-ray emitting end of the X-CT machine in the middle of the sample, so as to scan the casing-cement sheath bonding surface and the cement sheath crack propagation process in real time .