High-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device and testing method

Abstract

The present application relates to triaxial fracturing technical field, it is a kind of high temperature high stress high pore pressure triaxial hydraulic fracturing device and testing method, the former includes test jar and pressurizing pump, test jar outside is equipped with heat preservation heating jacket, heat preservation heating jacket is connected with temperature controller, test jar is equipped with sample, sample lower side is equipped with pore pressure plate, pore pressure plate is equipped with several up-and-down through flow holes, pore pressure plate is sealed together with sample by sealing glue.The present application is reasonable and compact in structure, easy to use, it seals sample by sealing glue, sets up heat preservation heating jacket to heat test jar as a whole to heat sample, controls the confining pressure outside sample by setting up hydraulic pipeline, carries out fracturing and pore pressure test to sample respectively by setting up fracturing pipeline and pore pressure pipeline, sample heating insulation effect is good when testing, and can realize fracturing and pore pressure, the effect of simulating reservoir temperature stress pore pressure is better, with safe, labor-saving, simple and efficient characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of triaxial fracturing, and is a high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device and a testing method. BACKGROUND

[0002] At present, with the exploration and development of each oilfield, the exploration and development objects gradually evolve from conventional sandstone reservoirs into low-grade tight oil, shale oil and other unconventional reservoirs, and the reservoir properties gradually deteriorate. In order to realize the economic benefit development of low-grade oil layers, fracturing has become a main technical means for stable and increased production of each oilfield. In addition to rock mechanics parameters and natural fracture systems, reservoir temperature, formation stress, pore pressure, liquid performance and construction displacement are all key factors affecting the formation cracking. Research on rock mechanics properties and fracturing fluid rheological properties under reservoir conditions is of great significance for guiding field fracturing construction.

[0003] The cracks of homogeneous rocks generally open perpendicular to the direction of the minimum principal stress, and are most affected by the minimum principal stress, while the stresses in the other two directions mainly affect the expansion of the cracks. If only the cracking is studied, the minimum principal stress of the formation can be met. At present, the indoor research on rock cracking and crack expansion morphology mainly focuses on true triaxial hydraulic fracturing experiments. Due to the limitation of sample size, the samples used are mostly artificial rocks, and downhole cored rocks cannot be used. The conventional true triaxial hydraulic fracturing device cannot seal the rock samples and apply pore pressure to the inside of the rock. The heating of the true triaxial sample is currently mostly conducted by heating the metal plate on the surface of the rock for heat conduction, which has slow warming and low heat energy utilization rate, and poor heat preservation effect. Or the fracturing fluid is preheated in the middle container to the formation temperature, and then injected into the inside of the rock through the pipeline, which also causes the temperature of the fracturing fluid to decrease due to heat exchange with the pipe wall and well wall during pumping, and the rock is only locally heated at the bottom of the wellbore, so the test results cannot truly reflect the strength of the core in the formation and the performance of the fracturing fluid in the well. Once the pressure leaks, the fracturing fluid under high temperature and high pressure will rapidly vaporize in the atmosphere, which may cause potential danger. The current pseudo-triaxial hydraulic fracturing equipment can only achieve high stress, and a few can additionally apply pore pressure. The sample size is constant and small. SUMMARY

[0004] The present application provides a high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device and a testing method, which overcomes the shortcomings of the prior art and effectively solves the problem of poor sample heating effect and safety hazards during high-temperature testing of the existing pseudo-triaxial hydraulic fracturing equipment.

[0005] One of the technical solutions of the present application is realized by the following measures: a high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device, comprising a test tank and a pressurizing pump, the test tank is provided with a heat preservation heating jacket outside, a sample is arranged in the test tank, a pore pressure plate is arranged at the lower side of the sample, a plurality of up-and-down through flow holes are arranged on the pore pressure plate, the pore pressure plate and the sample are sealed together by sealing glue, an upward opening test port is arranged in the middle of the sample, a wellbore is arranged on the upper inner side of the test port, a bare hole section is arranged between the lower side of the wellbore and the lower end of the test port, a detachable top cover is arranged on the upper side of the test tank, a plurality of up-and-down through holes are arranged on the top cover in a circumferential interval, the outlet of the pressurizing pump is communicated with the inside of the test tank through hydraulic pipelines, pore pressure pipelines and fracturing pipelines, the outlet of the pore pressure pipeline passes through the through hole and is communicated with the pore pressure plate, the outlet of the fracturing pipeline passes through the through hole and is communicated with the wellbore, a temperature sensor is connected with a temperature controller, the temperature controller is connected with the heat preservation heating jacket, an electronic hydraulic pressure gauge is arranged on the fracturing pipeline, and a direct-reading hydraulic pressure gauge for measuring the pressure in the test tank is arranged on the top cover.

[0006] The following is a further optimization or / and improvement of the above-mentioned technical solutions of the present application:

[0007] The above-mentioned can further include an acoustic emission sensor, the acoustic emission sensor is fixedly installed on the upper side of the top cover, the acoustic emission sensor is connected with an acoustic emission instrument for collecting sound signals, and the acoustic emission instrument and the electronic hydraulic pressure gauge are respectively connected with a client.

[0008] The above-mentioned can further include a back pressure valve and a pressure relief valve, the pressure relief valve is arranged on the top cover and communicated with the test tank, the pressure relief valve is communicated with the back pressure valve through a pipeline, the back pressure valve is communicated with a back pressure limiting valve through a pipeline, and the back pressure valve is provided with a pressure relief pipeline.

[0009] The above-mentioned can further include a safety valve, the safety valve is arranged on the top cover and fixedly communicated with the test tank.

[0010] The second technical solution of the present application is realized by the following measures: a test method of a high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device, comprising a stress test method, a pore pressure test method and a high-temperature test method:

[0011] The stress test method is performed according to the following method: the whole sample is sealed with sealant, only the open hole section is in contact with air, the wellbore in the sample is connected with the fracturing pipeline, the sample is placed in the test tank, the top cover is sealed with the tank body, the hole pressure pipeline is closed, the pressure pump injects liquid into the tank through the hydraulic pipeline until the discharge pipeline on the back pressure valve stabilizes the liquid, the specified pressure is applied to the back pressure valve through the back pressure limiting valve, the liquid is continuously injected into the test tank through the hydraulic pipeline until the pressure reaches the specified pressure of the back pressure valve, the hydraulic pipeline is closed, the fracturing pipeline is opened, the pressure pump pumps fracturing fluid and temporary plugging agent into the wellbore through the fracturing pipeline, the pressure signals of the pressure pump and the electronic hydraulic gauge and the acoustic wave signals of the acoustic emission sensor are recorded during the test process, the electronic hydraulic gauge monitors the sudden drop of pressure, indicating that the sample is damaged, the pressure pump is stopped to pressurize the fracturing pipeline, the fracturing is completed, the test tank is depressurized through the back pressure valve, the device is disassembled, the sample is taken out, and the test is completed;

[0012] The hole pressure test method is performed according to the following method: first, the sample is vacuumized and pressurized saturated, the hole pressure plate is arranged at the bottom of the sample and the whole sample and hole pressure plate are sealed with sealant, only the open hole section is in contact with air, the wellbore in the sample is connected with the fracturing pipeline, the sample is placed in the test tank, the top cover is sealed with the tank body, the hole pressure pipeline is closed, the pressure pump injects liquid into the tank through the hydraulic pipeline until the discharge pipeline on the back pressure valve stabilizes the liquid, the specified pressure is applied to the back pressure valve through the back pressure limiting valve, the liquid is continuously injected into the test tank through the hydraulic pipeline until the pressure reaches the specified pressure of the back pressure valve, the hydraulic pipeline is closed, the hole pressure pipeline is opened, the pressure pump injects pressure into the gap of the sample through the hole pressure pipeline and the hole pressure plate, the high-pressure liquid in the hole pressure pipeline enters the fracturing pipeline along the wellbore, the electronic hydraulic gauge detects the pressure of the liquid in the fracturing pipeline, when the pressure of the electronic hydraulic gauge is the same as the pressure of the pressure pump, the hole pressure pipeline is closed, the fracturing pipeline is opened to pump fracturing fluid and temporary plugging agent into the wellbore, the pressure signals of the pressure pump and the electronic hydraulic gauge and the acoustic wave signals of the acoustic emission sensor are recorded during the test process, the electronic hydraulic gauge monitors the sudden drop of pressure, indicating that the sample is damaged, the pressure pump is stopped to pressurize the fracturing pipeline, the fracturing is completed, the test tank is depressurized through the back pressure valve, the device is disassembled, the sample is taken out, and the test is completed;

[0013] The high-temperature test method is performed according to the following method: the sample is sealed as a whole on the outside by sealing glue, only the bare section is kept in contact with air, the wellbore in the sample is connected with the fracturing pipeline, the sample is placed in a test tank, the top cover is sealed with the tank body, the hole pressure pipeline is closed, the pressure pump injects liquid into the tank body through the hydraulic pipeline until the discharge pressure pipeline on the back pressure valve stably discharges liquid, the specified pressure is applied to the back pressure valve through the back pressure limiting valve, the heating jacket is turned on for heating, the temperature controller controls the heating jacket to heat and disconnect, the temperature in the test tank body is maintained in the set range, the liquid is continuously injected into the test tank body through the hydraulic pipeline until the pressure reaches the specified pressure of the back pressure valve, the hydraulic pipeline is closed, the fracturing pipeline is opened, the pressure pump pumps fracturing fluid and temporary plugging agent into the wellbore through the fracturing pipeline, the pressure signal of the pressure pump and the acoustic wave signal of the acoustic emission sensor are recorded during the test process, the electronic hydraulic gauge monitors the pressure drop, which indicates that the sample is damaged, the pressure pump is stopped to pressurize the fracturing pipeline, the fracturing is completed, the test tank body is depressurized through the back pressure valve, and the device is disassembled after the temperature drops below 60 degrees Celsius, the sample is taken out, and the test is completed.

[0014] The application has the advantages of reasonable and compact structure, convenient use, sealing of the sample by sealing glue, overall heating of the test tank by the heat preservation heating jacket, control of the confining pressure on the outside of the sample by the hydraulic pipeline, and fracturing and hole pressure test of the sample by the fracturing pipeline and the hole pressure pipeline. BRIEF DESCRIPTION OF DRAWINGS

[0015] ATTACHED Figure 1 It is a schematic view of the front view and partial section structure of the best embodiment of the application.

[0016] The codes in the drawings are as follows: 1 is a test tank, 2 is a pressure pump, 3 is a heat preservation heating jacket, 4 is a sample, 5 is a hole pressure plate, 6 is sealing glue, 7 is a wellbore, 8 is a top cover, 9 is a hydraulic pipeline, 10 is a hole pressure pipeline, 11 is a fracturing pipeline, 12 is a temperature sensor, 13 is a direct-reading hydraulic gauge, 14 is an electronic hydraulic gauge, 15 is an acoustic emission sensor, 16 is a back pressure valve, 17 is a discharge pressure valve, 18 is a discharge pressure pipeline, 19 is a safety valve, and 20 is a sealing joint. DETAILED DESCRIPTION

[0017] The application is not limited by the following examples, and the specific implementation mode can be determined according to the technical scheme of the application and the actual situation.

[0018] In the application, the relative position relationship of each component is described according to the schematic view of the front view and partial section structure of the best embodiment of the application. Figure 1The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0019] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0020] Example 1: As shown in the attached document Figure 1 As shown, the high-temperature, high-stress, high-pore-pressure triaxial hydraulic fracturing device includes a test tank 1 and a pressurizing pump 2. The test tank 1 is equipped with an insulation and heating jacket 3 on its outer side. A sample 4 is placed inside the test tank 1. A pore pressure plate 5 is located below the sample 4, and the pore pressure plate 5 has several vertically penetrating flow holes. The pore pressure plate 5 and the sample 4 are sealed together with sealant 6. A test port with an upward opening is located in the middle of the sample 4. A wellbore 7 is located on the inner side of the upper part of the test port. The area between the lower side of the wellbore 7 and the lower end of the test port is an open-hole section. A removable top cover 8 is installed on the upper side of the test tank 1. The top cover 8 has multiple through holes spaced along its circumference. The outlet of the pressurization pump 2 is connected to the inside of the test tank 1 through the hydraulic line 9, the borehole pressure line 10, and the fracturing line 11 inlet. The outlet of the borehole pressure line 10 passes through the through hole and is connected to the borehole pressure plate 5. The outlet of the fracturing line 11 passes through the through hole and is connected to the wellbore 7. The temperature sensor 12 is connected to the temperature controller, which is connected to the heat insulation jacket 3. The fracturing line 11 is equipped with an electronic hydraulic gauge 14, and the top cover 8 is equipped with a direct-reading hydraulic gauge 13 for measuring the pressure inside the test tank 1.

[0021] According to the requirements, multiple screws are arranged at intervals along the circumference at the upper end of the test tank 1. A fixing hole is provided on the top cover 8 corresponding to each screw position. The screw passes through the fixing hole and is fixed together with the nut, thereby sealing the test tank 1 and the top cover 8 together. Each through hole and pipeline is sealed by a sealing joint 20. The fracturing pipeline 11 is connected to the well barrel 7 through the well barrel 7 joint.

[0022] As required, silicone sealant 6 is used to seal the outside of the pressure plate 5 and the sample 4. Elastic rubber is also fitted on the outside of the silicone sealant 6 for further sealing.

[0023] As required, the booster pump 2 is a Teledyne Isco 500D model, which has a programmable controller and can meet the requirements of pumping high-temperature and high-pressure corrosive solutions.

[0024] When the fracturing test is performed, the heating jacket is closed, the pressurizing pump 2 is connected with the hydraulic pipeline 9 first, the hydraulic pipeline 9 is filled with liquid in the tank body, and then the pressurizing pump 2 continues to inject pressure, so that the pressure in the test tank 1 reaches the minimum principal stress, the pressure in the tank is read by the direct-reading hydraulic pressure gauge 13, the rock confining pressure is simulated, then the hydraulic pipeline 9 is closed, the pressurizing pump 2 is connected with the fracturing pipeline 11, the fracturing pipeline 11 pumps the fracturing fluid and the temporary plugging agent into the wellbore 7, the high pressure is built up in the rock, until the rock tensile strength is reached, the sample 4 is damaged, and the pressure in the fracturing pipeline 11 during the fracturing is read by the electronic hydraulic pressure gauge 14, when the rock appears micro cracks or larger cracks, the pressure will suddenly decrease, so whether the rock is damaged can be judged; when the pore pressure test is performed, the rock sample 4 is first vacuumized and pressurized and saturated, the heating jacket is closed, the pressurizing pump 2 is connected with the hydraulic pipeline 9 first to inject liquid, so that the pressure in the tank reaches the minimum principal stress, then the pressurizing pump 2 is connected with the pore pressure pipeline 10, liquid is injected into the lower end of the rock sample 4, the rock is filled with liquid, so that the fluid in the rock sample 4 reaches the set pore pressure, until the rock sample 4 is damaged; when the high-temperature test is performed, the pressurizing pump 2 is connected with the hydraulic pipeline 9 first, the hydraulic pipeline 9 is filled with liquid in the tank body, the heating jacket is opened to heat, the temperature control instrument controls the heating jacket to heat intermittently, so that the temperature in the test tank 1 is always maintained in the specified range, then the pressurizing pump 2 continues to inject pressure, so that the pressure in the test tank 1 reaches the minimum principal stress, the rock confining pressure is simulated, then the hydraulic pipeline 9 is closed, the pressurizing pump 2 is connected with the fracturing pipeline 11, the fracturing pipeline 11 pumps the fracturing fluid and the temporary plugging agent into the wellbore 7, until the sample 4 is damaged; the rock breaking condition is observed according to the pressure, temperature and other parameters during the test.

[0025] The present application can use downhole cored rock, simulate the temperature, pore pressure and ground stress conditions of the actual formation, evaluate the fracturing fluid construction effect in the well, analyze the influence of the external environment on the rock breaking strength, and analyze the temporary plugging and steering rules of the cracks. The device plays a good guiding role in the selection of the fracturing fluid and the temporary plugging material on site and the evolution evaluation of the reservoir rock mechanics properties, and the size combination of the rock sample 4 during the test is more flexible, the diameter range is 25mm-250mm, and the length range is 50mm-300mm, which can meet the specifications of most samples 4.

[0026] The high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device can be further optimized or / and improved according to actual needs.

[0027] As shown in the accompanying drawings, Figure 1 The acoustic emission sensor 15 is further included, the acoustic emission sensor 15 is fixedly installed on the upper side of the top cover 8, the acoustic emission sensor 15 is connected with the acoustic emission instrument for collecting sound signals, and the acoustic emission instrument and the electronic hydraulic pressure gauge 14 are respectively connected with the client.

[0028] During use, when conducting pore pressure tests, as liquid flows from the lower end of the rock into the wellbore 7 and along the wellbore 7 into the fracturing pipeline 11, the electronic hydraulic gauge 14 monitors the pressure in the pipeline. When the pressure monitored by the electronic hydraulic gauge 14 is the same as the pressure applied by the booster pump 2, it indicates that the rock fissures are filled with liquid, and the pore pressure pumping can be stopped. The electronic hydraulic gauge 14 can monitor the pressure during fracturing, and it is connected to the client, which can be a computer. The computer can monitor the pressure changes during fracturing. During the fracturing process, relying solely on the pressure signal is insufficient to determine the damage status of the rock sample 4 inside the equipment. Therefore, two acoustic emission probes are added to the surface of the top cover 8 to monitor the sound of rock fracturing and verify the changes in the pressure signal.

[0029] As attached Figure 1 As shown, it also includes a backpressure valve 16 and a pressure relief valve 17. The top cover 8 is equipped with a pressure relief valve 17 connected to the test tank 1. The pressure relief valve 17 is connected to the backpressure valve 16 via a pipeline, and the backpressure valve 16 is connected to a backpressure limiting valve via a pipeline. A pressure relief pipeline 18 is provided on the backpressure valve 16. In the high-temperature crack initiation experiment, the liquid pressure gradually increases as the temperature inside the equipment rises. To avoid experimental errors caused by stress changes applied to the rock skeleton and to ensure experimental safety, a backpressure valve 16 is added at the outlet of the pressure relief valve 17 to limit the upper pressure limit inside the test tank 1.

[0030] As attached Figure 1 As shown, it also includes a safety valve 19, which is fixedly connected to the test tank 1 on the top cover 8. During use, a safety pressure limit is set to ensure safety. If the safety pressure limit is exceeded, the safety valve 19 will rupture and release pressure.

[0031] Example 2: Testing methods for this high-temperature, high-stress, high-pore-pressure triaxial hydraulic fracturing device, including stress testing methods, pore-pressure testing methods, and high-temperature testing methods:

[0032] The stress test method is performed according to the following method: the whole sample 4 is sealed by sealant 6, only the open hole section is in contact with air, the wellbore 7 inside the sample 4 is connected with the fracturing pipeline 11, the sample 4 is placed in the test tank 1, the top cover 8 is sealed with the tank body, the hole pressure pipeline 10 is closed, the pressurizing pump 2 injects liquid into the tank body through the hydraulic pipeline 9 until the discharge pipeline 18 on the back pressure valve 16 stabilizes the liquid, a specified pressure is applied to the back pressure valve 16 through the back pressure limiting valve, the pressurizing pump 2 continues to inject liquid into the test tank 1 through the hydraulic pipeline 9 until the pressure reaches the specified pressure of the back pressure valve 16, the hydraulic pipeline 9 is closed, the fracturing pipeline 11 is opened, the pressurizing pump 2 pumps fracturing fluid and temporary plugging agent into the wellbore 7 through the fracturing pipeline 11, the pressure signal of the pressurizing pump 2 and the electronic hydraulic gauge 14 and the acoustic wave signal of the acoustic emission sensor 15 are recorded during the test process, the electronic hydraulic gauge 14 monitors a sudden drop in pressure, indicating that the sample 4 is damaged, the pressurizing pump 2 is stopped to pressurize the fracturing pipeline 11, the fracturing is completed, the test tank 1 is depressurized through the back pressure valve 16, the device is disassembled, the sample 4 is taken out, and the test is completed;

[0033] The hole pressure test method is performed according to the following method: first, the sample 4 is vacuumized and pressurized saturated, the hole pressure plate 5 is arranged at the bottom of the sample 4 and the whole sample 4 and hole pressure plate 5 are sealed by sealant 6, only the open hole section is in contact with air, the wellbore 7 inside the sample 4 is connected with the fracturing pipeline 11, the sample 4 is placed in the test tank 1, the top cover 8 is sealed with the tank body, the hole pressure pipeline 10 is closed, the pressurizing pump 2 injects liquid into the tank body through the hydraulic pipeline 9 until the discharge pipeline 18 on the back pressure valve 16 stabilizes the liquid, a specified pressure is applied to the back pressure valve 16 through the back pressure limiting valve, the pressurizing pump 2 continues to inject liquid into the test tank 1 through the hydraulic pipeline 9 until the pressure reaches the specified pressure of the back pressure valve 16, the hydraulic pipeline 9 is closed, the hole pressure pipeline 10 is opened, the pressurizing pump 2 injects pressure into the gap of the sample 4 through the hole pressure pipeline 10 and the hole pressure plate 5, the high-pressure liquid in the hole pressure pipeline 10 enters the fracturing pipeline 11 along the wellbore 7, the electronic hydraulic gauge 14 detects the pressure of the liquid in the fracturing pipeline 11, the hole pressure pipeline 10 is closed when the pressure of the electronic hydraulic gauge 14 is the same as the pressure of the pressurizing pump 2, the fracturing pipeline 11 is opened to pump fracturing fluid and temporary plugging agent into the wellbore 7, the pressure signal of the pressurizing pump 2 and the electronic hydraulic gauge 14 and the acoustic wave signal of the acoustic emission sensor 15 are recorded during the test process, the electronic hydraulic gauge 14 monitors a sudden drop in pressure, indicating that the sample 4 is damaged, the pressurizing pump 2 is stopped to pressurize the fracturing pipeline 11, the fracturing is completed, the test tank 1 is depressurized through the back pressure valve 16, the device is disassembled, the sample 4 is taken out, and the test is completed;

[0034] The high-temperature test method is performed according to the following method: the whole outside of the sample 4 is sealed by the sealant 6, only the bare section is kept in contact with the air, the wellbore 7 inside the sample 4 is communicated with the fracturing pipeline 11, the sample 4 is placed in the test tank 1, the top cover 8 is sealed with the tank body, the hole pressure pipeline 10 is closed, the pressurizing pump 2 injects liquid into the tank body through the hydraulic pipeline 9 until the discharge pressure pipeline 18 on the back pressure valve 16 stably discharges liquid, the specified pressure is applied to the back pressure valve 16 through the back pressure limiting valve, the heating jacket is heated, the temperature controller controls the heating and disconnection of the heating jacket, the temperature in the test tank 1 is maintained in the set range, the liquid is continuously injected into the test tank 1 through the hydraulic pipeline 9 until the pressure reaches the specified pressure of the back pressure valve 16, the hydraulic pipeline 9 is closed, the fracturing pipeline 11 is opened, the pressurizing pump 2 pumps the fracturing fluid and the temporary plugging agent into the wellbore 7 through the fracturing pipeline 11, the pressure signals of the pressurizing pump 2 and the electronic hydraulic gauge 14 and the acoustic wave signals of the acoustic emission sensor 15 are recorded during the test process, the electronic hydraulic gauge 14 monitors the sudden drop of pressure, which indicates that the sample 4 is damaged, the pressurizing pump 2 is stopped to pressurize the fracturing pipeline 11, the fracturing is completed, the test tank 1 is depressurized through the back pressure valve 16, and the device is disassembled after the temperature drops below 60 degrees Celsius, the sample 4 is taken out, and the test is completed.

[0035] During the test process, the pressure signals of the pressurizing pump 2 and the electronic hydraulic gauge 14 and the acoustic wave signals of the acoustic emission sensor 15 are recorded by the client, and the pressure, acoustic emission quantity and time curves are drawn, and according to the pressure and sound changes, it can be judged that the rock appears micro cracks or the rock is broken under a certain pressure. The present application can evaluate the effectiveness of the fracturing fluid and the temporary plugging material, and study the influence law of high-temperature hole pressure and other external conditions on rock fracture, and provide technical guidance for field fracturing reconstruction.

[0036] The above technical features constitute the best embodiment of the present application, which has strong adaptability and best implementation effect, and unnecessary technical features can be added or reduced according to actual needs to meet the needs of different situations.

Claims

1. A test method based on a high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device, characterized by The application relates to a high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device, a high-temperature high-stress high-pore-pressure triaxial hydraulic fracturing device, a test tank and a pressurizing pump, a heat preservation heating jacket is arranged outside the test tank, a sample is arranged in the test tank, a pore pressure plate is arranged at the lower side of the sample, a plurality of up-and-down through flow holes are arranged on the pore pressure plate, the pore pressure plate is sealed together with the sample through sealing glue, a test port opening upwards is arranged in the middle of the sample, a well shaft is arranged at the upper side of the test port, a bare hole section is arranged between the lower side of the well shaft and the lower end of the test port, a detachable top cover is arranged on the upper side of the test tank, a plurality of up-and-down through holes are arranged on the top cover at intervals along the circumference, the outlet of the pressurizing pump is communicated with the inside of the test tank through hydraulic pipelines, pore pressure pipelines and fracturing pipelines, the outlet of the pore pressure pipeline is communicated with the pore pressure plate through the through holes, the outlet of the fracturing pipeline is communicated with the well shaft through the through holes, a temperature sensor is connected with a temperature controller, the temperature controller is connected with the heat preservation heating jacket, an electronic hydraulic pressure gauge is arranged on the fracturing pipeline, a direct-reading hydraulic pressure gauge for measuring the pressure in the test tank is arranged on the top cover; the application further comprises an acoustic emission sensor, the acoustic emission sensor is fixedly arranged on the upper side of the top cover, the acoustic emission sensor is connected with an acoustic emission instrument for collecting sound signals, the acoustic emission instrument and the electronic hydraulic pressure gauge are connected with a client respectively; the application further comprises a back pressure valve and a pressure relief valve, the pressure relief valve is arranged on the top cover and communicated with the test tank, the pressure relief valve is communicated with the back pressure valve through a pipeline, the back pressure valve is communicated with a back pressure limiting valve through a pipeline, and a pressure relief pipeline is arranged on the back pressure valve; the application further comprises a safety valve, the safety valve is arranged on the top cover and fixedly communicated with the test tank; The test method comprises a stress test method, a pore pressure test method and a high-temperature test method: The stress test method is carried out according to the following method: the whole sample outside is sealed by sealing glue, only the bare hole section is kept in contact with air, the well shaft in the sample is communicated with the fracturing pipeline, the sample is put into the test tank, the top cover is sealed with the tank body, the pore pressure pipeline is closed, the pressurizing pump injects liquid into the tank body through the hydraulic pipeline until the pressure relief pipeline on the back pressure valve stably discharges liquid, a specified pressure is applied to the back pressure valve through the back pressure limiting valve, the pressurizing pump continues to inject liquid into the test tank through the hydraulic pipeline until the pressure reaches the specified pressure of the back pressure valve, the hydraulic pipeline is closed, the fracturing pipeline is opened, the pressurizing pump pumps fracturing fluid and temporary plugging agents into the well shaft through the fracturing pipeline, the pressure signals of the pressurizing pump and the electronic hydraulic pressure gauge and the sound wave signals of the acoustic emission sensor are recorded during the test process, the pressure is suddenly reduced when the electronic hydraulic pressure gauge is monitored, which indicates that the sample is damaged, the pressurizing pump is stopped to pressurize the fracturing pipeline, the fracturing is completed, the test tank body is depressurized through the back pressure valve, the device is disassembled, the sample is taken out, and the test is completed. The hole pressure test method is performed according to the following method: first, the sample is vacuumized and pressurized to saturation, the hole pressure plate is arranged at the bottom of the sample, and the sample and the hole pressure plate are integrally sealed by using sealing glue, only the open hole section is in contact with air, the wellbore in the sample is connected with the fracturing pipeline, the sample is placed in the test tank, the top cover is sealed with the tank body, the hole pressure pipeline is closed, the pressurizing pump injects liquid into the tank body through the hydraulic pipeline until the discharge pipeline of the back pressure valve stably discharges liquid, the specified pressure of the back pressure valve is applied through the back pressure limiting valve, the pressurizing pump continues to inject liquid into the test tank through the hydraulic pipeline until the pressure reaches the specified pressure of the back pressure valve, the hydraulic pipeline is closed, the hole pressure pipeline is opened, the pressurizing pump injects pressure into the gap of the sample through the hole pressure pipeline and the hole pressure plate, the high-pressure liquid in the hole pressure pipeline enters the fracturing pipeline along the wellbore, the electronic hydraulic pressure gauge detects the pressure of the liquid in the fracturing pipeline, when the pressure of the electronic hydraulic pressure gauge is the same as the pressure of the pressurizing pump, the hole pressure pipeline is closed, the fracturing pipeline is opened to pump the fracturing fluid and the temporary plugging agent into the wellbore, the pressure signals of the pressurizing pump and the electronic hydraulic pressure gauge and the acoustic wave signals of the acoustic emission sensor are recorded during the test process, when the electronic hydraulic pressure gauge detects a sudden drop in pressure, it indicates that the sample is damaged, the pressurizing pump is stopped to pressurize the fracturing pipeline, the fracturing is completed, the test tank is depressurized through the back pressure valve, the device is disassembled, the sample is taken out, and the test is completed. The high-temperature test method is performed according to the following method: the sample is integrally sealed by using sealing glue, only the open hole section is in contact with air, the wellbore in the sample is connected with the fracturing pipeline, the sample is placed in the test tank, the top cover is sealed with the tank body, the hole pressure pipeline is closed, the pressurizing pump injects liquid into the tank body through the hydraulic pipeline until the discharge pipeline of the back pressure valve stably discharges liquid, the specified pressure of the back pressure valve is applied through the back pressure limiting valve, the heating jacket is heated, the temperature controller controls the heating and disconnection of the heating jacket, the temperature in the test tank is maintained within the set range, the pressurizing pump continues to inject liquid into the test tank through the hydraulic pipeline until the pressure reaches the specified pressure of the back pressure valve, the hydraulic pipeline is closed, the fracturing pipeline is opened, the pressurizing pump pumps the fracturing fluid and the temporary plugging agent into the wellbore through the fracturing pipeline, the pressure signals of the pressurizing pump and the electronic hydraulic pressure gauge and the acoustic wave signals of the acoustic emission sensor are recorded during the test process, when the electronic hydraulic pressure gauge detects a sudden drop in pressure, it indicates that the sample is damaged, the pressurizing pump is stopped to pressurize the fracturing pipeline, the fracturing is completed, the test tank is depressurized through the back pressure valve, and after the temperature drops to below 60 degrees Celsius, the device is disassembled, the sample is taken out, and the test is completed.

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