Fracturing and sealing device and method for injecting basalt based on supercritical CO2

Abstract

The invention discloses a fracturing sealing device and method based on injecting supercritical CO2 into basalt. The fracturing and sealing device comprises: a test main body module comprising a basalt sample; the injection module is used for injecting required gas, liquid or gas-liquid mixture into the test main body module; the pressure loading module is communicated with the test main body and is used for applying axial pressure and / or confining pressure to the test main body module; wherein the injection module and the pressure loading module are configured to realize the fracturing of the basalt sample, the radial permeability of the fractured basalt sample and the storage of CO2 by the fractured basalt sample. The use limitation that a traditional indoor test device is single in function can be overcome, and comprehensive understanding of the fracturing sealing process under the complex stratum environment condition can be achieved; and the formation rule of the crack net caused by basalt can be analyzed conveniently, the permeability of the crack net can be evaluated, and the feasibility and effectiveness of mineralizing and sealing CO2 by basalt in different injection modes can be compared.

Description

Technical Field

[0001] The present invention relates to CO 2 The field of storage technology particularly relates to a method based on supercritical CO 2 A fracturing and sealing device and method for injecting basalt. Background Art

[0002] Basalt is a volcanic rock rich in alkaline elements and is widely distributed. It has the ability to rapidly mineralize and store CO 2 It is well known that some basalt formations are located in active rift zones and have porous and high permeability characteristics, which are suitable for direct injection of CO 2 and water (or mixed H 2 However, the eruption time and geological environment affect the density and porosity of basalt. In other words, some basalt formations are denser and stronger. In order to effectively use these dense basalt formations to store CO 2 , it is necessary to stimulate fracturing to form a large-scale complex fracture network and provide abundant mineralization reaction space. 2 It is a water-free fracturing fluid with unique thermophysical properties that enables it to reduce fracture pressure, increase formation permeability, and reduce formation damage. In the field of efficient exploitation of oil and gas fields, supercritical CO 2 Fracking has emerged as a promising technology with the potential to replace hydraulic fracturing. 2 The combined application of fracturing stimulation and mineralized storage in tight basalt formations can help achieve the "dual carbon" goals and is a sustainable solution.

[0003] In the above application scenarios, compared with the cost of the engineering site, the physical simulation test is the most effective way to analyze the fracturing storage of CO2. 2 It is one of the economical and effective means to improve performance. 2 The indoor test device for fracturing and sealing has two main application limitations: the device has a single function and has not yet combined the fracturing and sealing processes; and due to the previous problem, the selection of samples has application limitations. For example, if the sample is particulate matter such as fly ash, it cannot meet the prerequisites for fracturing and cannot simulate actual formation application requirements. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] In view of this, the present invention provides a method based on supercritical CO 2The fracturing and sealing device and method for injecting basalt, wherein the fracturing and sealing device can overcome the limitation of single function of traditional indoor test devices, and can realize a comprehensive understanding of complex formation environmental conditions and sealing processes; it is also convenient to analyze the formation law of basalt fracture network, evaluate the permeability of the fracture network, and compare the mineralization and CO storage of basalt under different injection modes. 2 feasibility and effectiveness.

[0006] Specifically, the following technical solutions are included:

[0007] An embodiment of the first aspect of the present invention provides a fracturing and sealing device based on supercritical CO2 injection into basalt, the fracturing and sealing device comprising:

[0008] The test body module includes a basalt assembly, and the basalt assembly includes a basalt sample;

[0009] An injection module is used to inject the required gas, liquid or gas-liquid mixture into the test main module;

[0010] A pressure loading module, connected to the test body, applying axial pressure and / or confining pressure to the test body module;

[0011] The injection module and the pressure loading module are configured to achieve the fracturing of the basalt sample, and the radial permeability of the basalt sample after fracturing and the CO 2 of storage.

[0012] Optionally, the injection module includes supercritical CO 2 preparation unit, water injection unit and mixed solution injection unit; the supercritical CO 2 The preparation unit is configured to achieve the fracturing of the basalt sample and the radial permeability of the basalt sample after fracturing; the supercritical CO 2 The preparation unit, the water injection unit and the mixed solution injection unit are configured to realize the basalt sample after fracturing to CO 2 wherein the supercritical CO 2 The preparation unit, the water injection unit and the mixed solution injection unit are connected in parallel and communicated with the test main module.

[0013] Optionally, the supercritical CO 2 The preparation unit includes:

[0014] CO 2 Gas cylinders;

[0015] CO 2 Injection pump, the CO 2 One end of the injection pump is connected to the CO 2The outlet connection of the gas cylinder, the CO 2 Gas cylinders and the CO 2 A pressure reducing valve is provided between the injection pumps. 2 The other end of the injection pump is communicated with the test main body module and the mixed solution injection unit respectively;

[0016] A booster is provided between the pressure reducing valve and the CO 2 Between the injection pumps, the supercharger is connected to the air compressor via a driving gas inlet.

[0017] Optionally, the water injection unit comprises:

[0018] A water injection pump, one end of which is connected to the water tank, and the other end of which is respectively connected to the test main body module and the mixed solution injection unit.

[0019] Optionally, the mixed solution injection unit comprises:

[0020] The mixed solution displacement container, the first end of the mixed solution displacement container is respectively connected to the supercritical CO 2 The preparation unit is communicated with the water injection unit, the second end of the mixed solution displacement container is communicated with the test main body module, and the third end of the mixed solution displacement container is connected to a mixed solution displacement pump.

[0021] Optionally, the test subject module further includes:

[0022] Three-axle load-bearing frame;

[0023] A three-axis loading frame base, located in the three-axis loading frame;

[0024] A basalt assembly is arranged in a triaxial cavity, a heating and heat preservation component is arranged outside the triaxial cavity, the triaxial cavity is located on the triaxial loading frame base, and the heating and heat preservation component is located in the triaxial loading frame;

[0025] An axial top cylinder, comprising a piston and an oil chamber, wherein the axial top cylinder is arranged below the base of the three-axis loading frame;

[0026] The ball-correcting force-transmitting top is arranged above the three-axis cavity, and the ball-correcting force-transmitting top abuts against the upper side of the basalt assembly through a force-transmitting column.

[0027] Optionally, the basalt assembly further comprises: a central through hole provided on the basalt sample, an upper packing assembly and a lower packing assembly located in the central through hole, and a fracturing hole section enclosed by the central through hole, the upper packing assembly and the lower packing assembly, wherein a high-pressure resistant pipe is provided in the lower packing assembly, and the high-pressure resistant pipe is used to connect the injection module and the pressure hole section;

[0028] A thin film heat shrink tube is jacketed on the outside of the basalt sample, an acoustic emission probe positioning sleeve is jacketed on the thin film heat shrink tube, and an acoustic emission probe is arranged between the thin film heat shrink tube and the acoustic emission probe positioning sleeve;

[0029] A radial deformation meter, comprising a test probe, the test probe abutting against the outer wall of the basalt sample through the film heat shrink tube, the test probe penetrating the acoustic emission probe positioning sleeve, a plurality of radial deformation meters evenly arranged in the circumferential direction at the same height of the basalt sample, the radial deformation meter and the acoustic emission probe being staggered;

[0030] Wherein, the triaxial cavity and the basalt assembly enclose a confining pressure medium cavity.

[0031] Optionally, the basalt assembly further comprises: a central through hole provided on the basalt sample; and

[0032] An upper pressure pad is arranged above the basalt sample, and a central through hole is provided on the upper pressure pad;

[0033] A lower pressure pad is arranged below the basalt sample;

[0034] Wherein, the triaxial cavity and the basalt assembly enclose a radial seepage cavity.

[0035] Optionally, the basalt assembly further comprises: a central through hole provided on the basalt sample; and

[0036] CO2 resistant 2 The sealing rubber cylinder is placed outside the basalt sample, and the CO 2 The sealing rubber cylinder and the three-axis cavity enclose a pressure medium cavity.

[0037] Optionally, the basalt assembly further comprises:

[0038] An upper plug is arranged above the triaxial cavity, and an outlet is arranged on the upper plug, and the outlet is communicated with the confining pressure medium cavity, and the confining pressure medium cavity is communicated with the oil collecting tank through a pipeline;

[0039] An upper pressure head is arranged between the upper plug and the basalt sample, a seepage groove is arranged inside the upper pressure head, a liquid injection pipe is arranged on the upper pressure head, and the liquid injection pipe is communicated with the seepage groove;

[0040] A lower plug is arranged below the triaxial cavity, and a data line terminal, a confining pressure medium channel, a seepage medium channel and a mixed solution channel are arranged on the lower plug, the wiring terminal is connected to the data integration box, and the confining pressure medium channel, the seepage medium channel and the mixed solution channel are connected to the injection module;

[0041] The lower pressure head is arranged between the basalt sample and the lower plug.

[0042] Optionally, the pressure loading module includes:

[0043] An axial pressure servo pump is connected to the oil chamber of the axial top cylinder, and the axial pressure servo pump provides axial pressure for the basalt assembly;

[0044] A confining pressure servo pump is connected to the basalt assembly, and the confining pressure servo pump provides confining pressure for the basalt assembly.

[0045] Optionally, the fracturing and sealing device further includes a metering component, which is in communication with the test main module and includes:

[0046] A gas-liquid separator, a back pressure valve is provided between the gas-liquid separator and the test main body module, the gas outlet of the gas-liquid separator is connected to a gas flow meter, the liquid outlet of the gas-liquid separator is connected to a liquid collecting bottle, and an electronic balance is provided under the liquid collecting bottle;

[0047] The fracturing and sealing device further comprises a fluid channel, and the fluid channel is used to connect the injection module and the test main module.

[0048] The second aspect of the present invention provides a method based on supercritical CO 2 A fracturing and sealing method for injecting basalt, using the above-mentioned fracturing and sealing device, comprises the following steps:

[0049] Install the test main module;

[0050] Starting the pressure loading module to apply pressure to the test main module and monitoring the change of the pressure;

[0051] According to the requirements of fracturing, seepage and sealing, the injection module is started to realize the fracturing, seepage and sealing tests on the main test module;

[0052] After the sealing test is completed, the basalt sample in the test main module is taken out to observe the surface morphology of the fracture and the distribution of mineral components on the test surface.

[0053] The embodiment of the present invention provides a supercritical CO 2A fracturing and sealing device and a fracturing method for injecting basalt, wherein the fracturing and sealing device comprises a test main body module, the test main body module comprises a basalt sample, the required gas, liquid or gas-liquid mixture is injected into the test main body module through the injection module, and the axial pressure and confining pressure of the test subject module are applied through the pressure loading module, so that the test main body module can meet the test requirements, and after the basalt sample is fractured by the fracturing and sealing device of the present application, the permeability of the basalt sample after fracturing is obtained, and the CO 2 It can be seen that this application overcomes the limitation of the single function of traditional indoor test equipment and can obtain a comprehensive understanding of complex formation environmental conditions and the sealing process; at the same time, through the three test angles of fracturing, seepage and sealing of basalt samples, it can not only analyze the formation law of basalt fracture network, but also evaluate the permeability of the fracture network, and can also compare the basalt mineralization storage of CO under different injection modes. 2 At the same time, the fracturing storage device of this application can help researchers in the fields of geological engineering, environmental science and energy to better understand CO 2 behavior in basalt formation environments, thereby optimizing CO 2 Injection strategy to achieve CO from both fracturing and storage perspectives 2 The effective management and utilization of carbon dioxide will provide technical support for achieving the “dual carbon” goals.

[0054] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0056] Figure 1 A schematic diagram of a fracturing and sealing device according to an embodiment of the present invention;

[0057] Figure 2 is a schematic diagram of a lower plug according to an embodiment of the present invention;

[0058] Figure 3 A schematic diagram of a basalt assembly for fracturing according to an embodiment of the present invention;

[0059] Figure 4A schematic diagram of a basalt assembly for radial seepage according to an embodiment of the present invention;

[0060] Figure 5 A schematic diagram of a basalt assembly for storage according to an embodiment of the present invention;

[0061] Figure 6 The figure is a schematic flow chart of the steps of a fracturing sealing method according to an embodiment of the present invention.

[0062] in, Figures 1 to 5 The corresponding relationship between the reference numerals and the component names is as follows:

[0063] 01CO 2 Gas cylinder, 02 pressure reducing valve, 0301-0315 first stop valve - fifteenth stop valve, 04 air compressor, 05 booster, 06 water injection pump, 07 water tank, 08CO 2 injection pump, 09 mixed solution displacement container, 10 mixed solution displacement pump, 11 pressure loading module, 12 axial pressure servo pump, 13 confining pressure servo pump, 14 axial top cylinder, 1501-1506 first pressure sensor-sixth pressure sensor, 16 three-axis loading frame base, 17 ball correction force top, 18 three-axis load frame, 19 lower plug, 1901 data line terminal, 1902 confining pressure medium channel, 1903 seepage medium channel, 1904 mixed solution channel, 20 upper plug head, 21 upper pressure head, 22 injection pipeline, 23 sealing groove, 24 triaxial cavity, 25 basalt assembly, 2501 upper packing assembly, 2502 lower packing assembly, 2503 basalt sample, 2504 fracturing hole section, 2505 film heat shrink tube, 2506 confining pressure medium cavity, 2507 central through hole, 2508 acoustic emission probe, 2509 acoustic emission probe positioning sleeve, 2510 radial seepage cavity, 2511 upper pressure pad, 2512 lower pressure pad, 2513 CO2 resistant 2 Sealing rubber cylinder, 2514 strain gauge, 2515 radial deformation meter, 26 lower pressure head, 27 oil collecting tank, 28 gas flow meter, 29 data integration box, 30 heating and insulation components, 31 back pressure valve, 32 gas-liquid separator, 33 liquid collecting bottle, 34 electronic balance, 35 fluid channel, 36 force transmission column. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] Before further describing the embodiments of the present invention in detail, the directional nouns involved in the embodiments of the present invention, such as "upper part", "lower part" and "side part", do not have the meaning of limiting the protection scope of the present invention.

[0066] To make the technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0067] Figure 1 FIG. 1 is a schematic diagram of a fracturing sealing device according to an embodiment of the present invention.

[0068] like Figure 1 As shown, one embodiment of the present invention provides a method based on supercritical CO 2 A fracturing and sealing device for injecting basalt, the fracturing and sealing device includes:

[0069] The test main body module includes a basalt assembly 25, and the basalt assembly 25 includes a basalt sample 2503;

[0070] Injection module, injecting required gas, liquid or gas-liquid mixture into the test main module;

[0071] The pressure loading module 11 is connected to the test body and applies axial pressure and / or confining pressure to the test body module;

[0072] The injection module and the pressure loading module 11 are configured to realize the fracturing of the basalt sample 2503, and the radial permeability of the basalt sample 2503 after fracturing and the CO 2 of storage.

[0073] It should be noted that the fracturing and sealing device includes a test main body module, which includes a basalt sample 2503. The required gas, liquid or gas-liquid mixture is injected into the test main body module through the injection module, and the axial pressure and confining pressure of the test subject module are applied through the pressure loading module 11, so that the test main body module can meet the test requirements, and after the basalt sample 2503 is fractured by the fracturing and sealing device of the present application, the permeability of the basalt sample 2503 after fracturing is obtained, and the CO 2 It can be seen that this application overcomes the limitation of the single function of traditional indoor test equipment and can obtain a comprehensive understanding of complex formation environmental conditions and the sealing process; at the same time, through the three test angles of fracturing, seepage and sealing of basalt sample 2503, it can not only analyze the formation law of basalt fracture network, but also evaluate the permeability of the fracture network, and can also compare the basalt mineralization storage of CO under different injection modes. 2At the same time, the fracturing storage device of this application can help researchers in the fields of geological engineering, environmental science and energy to better understand CO 2 behavior in basalt formation environments, thereby optimizing CO 2 Injection strategy to achieve CO from both fracturing and storage perspectives 2 The effective management and utilization of carbon dioxide will provide technical support for achieving the “dual carbon” goals.

[0074] In one possible embodiment, the injection module includes supercritical CO 2 Preparation unit, water injection unit and mixed solution injection unit; supercritical CO 2 The preparation unit is configured to achieve fracturing of the basalt sample 2503 and radial permeability of the basalt sample 2503 after fracturing; supercritical CO 2 The preparation unit, water injection unit and mixed solution injection unit are configured to achieve the effect of CO 2 of storage; among them, supercritical CO 2 The preparation unit, the water injection unit and the mixed solution injection unit are connected in parallel and communicated with the test main module.

[0075] The injection module includes supercritical CO 2 Preparation unit, water injection unit and mixed solution injection unit. Supercritical CO 2 The preparation unit and the water injection unit are connected to the mixed solution injection unit through pipelines to inject CO into the mixed solution injection unit. 2 A circulating agitator is arranged at the top upstream of the mixed solution injection unit, which can adjust the speed to mix different solutions.

[0076] In one possible embodiment, supercritical CO 2 The preparation unit includes:

[0077] CO 2 Gas cylinder 01;

[0078] CO 2 Injection pump 08, CO 2 One end of the injection pump 08 is connected to the CO 2 Outlet connection of gas cylinder 01, CO 2 Gas cylinder 01 and CO 2 A pressure reducing valve 02 is provided between the injection pump 08, CO 2 The other end of the injection pump 08 is connected to the test main body module and the mixed solution injection unit respectively;

[0079] Booster 05, installed between pressure reducing valve 02 and CO 2Between the injection pumps 08, the supercharger 05 is connected to the air compressor 04 via the driving gas inlet.

[0080] It should be noted that by adjusting the supercritical CO 2 The supercharger 05 in the preparation unit has a pressure ratio, and in combination with the heating and heat preservation component 30 outside the triaxial cavity 24 in the test main module, it is possible to prepare supercritical CO at a specified pressure and temperature. 2 .

[0081] It is understandable that in order to achieve supercritical CO 2 The parallel connection of the preparation unit, water injection unit and mixed solution injection unit requires the installation of a stop valve on the connecting pipeline. 2 A first stop valve 0301 is provided between the injection pump 08 and the pressure valve. 2 A second stop valve 0302 is provided on the pipe connected to the outlet of the injection pump 08. 2 The third stop valve 0303 and the fourth stop valve 0304 are respectively provided on the pipelines at both ends of the injection pump 08. 2 Injection pump 08 and CO 2 A fourth pressure sensor 1504 is provided between the gas cylinders 01 .

[0082] In a feasible implementation manner, the water injection unit includes:

[0083] A water injection pump 06, one end of which is connected to the water tank 07, and the other end of which is connected to the test main body module and the mixed solution injection unit respectively.

[0084] Among them, a fifth stop valve 0305 is provided between the water tank 07 and the water injection pump 06, a sixth stop valve 0306 is provided on the water injection pump 06, a seventh stop valve 0307 is provided between the water injection pump 06 and the mixed solution displacement container 09, and an eighth stop valve 0308 is provided between the water injection pump 06 and the CO2 injection pump 08. At the same time, a fifth pressure sensor 1505 is provided at the outlet of the water injection pump 06.

[0085] In a feasible implementation manner, the mixed solution injection unit includes:

[0086] The mixed solution displacement container 09 has a first end connected to a supercritical CO 2 The preparation unit is connected to the water injection unit, the second end of the mixed solution displacement container 09 is connected to the test main module, and the third end of the mixed solution displacement container 09 is connected to the mixed solution displacement pump 10 .

[0087] The mixed solution displaces the inlet of container 09 and CO 2A ninth stop valve 0309 is provided between the injection pump 08, a tenth stop valve 0310 is provided between the outlet of the mixed solution displacement container 09 and the test main module, and an eleventh stop valve 0311 is provided between the mixed solution displacement pump 10 and the mixed solution displacement container 09. At the same time, a sixth pressure sensor 1506 is provided between the mixed solution displacement pump 10 and the mixed solution displacement container 09.

[0088] It should be noted that CO 2 The injection pump 08, water injection pump 06 and mixed solution displacement pump 10 are all equipped with the functions of constant injection displacement and constant injection volume, and are divided into two operating modes: manual control and automatic control. They can record and save data such as fluid pressure, displacement, injection volume, etc. in real time. Different injection schemes can be designed by adjusting the displacement and pressure, such as constant type, step type, circulation type, etc. 2 A temperature sensor is installed inside the pump chamber of the injection pump 08, and the CO 2 The output port of the injection pump 08 is equipped with a fourth pressure sensor 1504 for monitoring the front-end CO of different injection schemes. 2 the output port of the water injection pump 06 is equipped with a fifth pressure sensor 1505, and the output port of the mixed solution displacement pump 10 is equipped with a sixth pressure sensor 1506 for monitoring the pressure changes of the injected fluid.

[0089] Optionally, a circulating agitator is provided at the upstream top of the mixed solution displacement container 09, which can adjust the rotation speed to mix different solutions, and the downstream displacement medium is the water in the mixed solution displacement pump 10. A high-sealing and low-inertia suspended piston is provided in the middle of the mixed solution displacement container 09 to allow the downstream displacement medium to drive the upstream mixed solution and then inject it into the basalt sample 2503.

[0090] In a feasible implementation, the test subject module includes:

[0091] Three-axis load-bearing frame 18;

[0092] A three-axis loading frame base 16, located within the three-axis loading frame 18;

[0093] The basalt assembly 25 is disposed in the triaxial cavity 24. A heating and heat preservation component 30 is disposed outside the triaxial cavity 24. The triaxial cavity 24 is located on the triaxial loading frame base 16. The heating and heat preservation component 30 is located in the triaxial loading frame 18.

[0094] An axial top cylinder 14, including a piston and an oil chamber, is disposed below a triaxial loading frame base 16;

[0095] The ball-correcting force-transmitting top 17 is disposed above the triaxial cavity 24 , and the ball-correcting force-transmitting top 17 abuts against the upper side of the basalt assembly 25 through the force-transmitting column 36 .

[0096] Among them, it is necessary to carry out fracturing test, seepage test and sealing test on the main test module. When conducting the fracturing test, the hydraulic oil is driven by the axial pressure servo pump 12 in the pressure loading module 11, input into the oil tank of the axial top cylinder 14, push the piston upward, apply force to the triaxial loading frame base 16, and set the upward speed or displacement as needed to complete the axial pressure loading. At the same time, the hydraulic oil is driven by the confining pressure servo pump 13 in the pressure loading module 11 to fill the confining pressure medium cavity 2506 with oil until the hydraulic oil flows out from the outlet of the upper plug 20 to the oil collecting tank 27 to realize the loading of the confining pressure. The confining pressure medium cavity 2506 is enclosed by the basalt assembly 25 and the triaxial cavity 24. A temperature sensor is installed in the confining pressure medium cavity 2506 to monitor the formation temperature of the simulated basalt, and the temperature change control is realized by heating the insulation component 30. The upper plug 20 and the lower plug 19 are connected to the triaxial cavity 24 through a plurality of sealing grooves 23. The sealing grooves are arranged on the outer periphery of the upper plug 20 and the lower plug 19. O-rings are arranged in the sealing grooves. When the upper plug 20 and the lower plug 19 are inserted into the triaxial cavity 24, the O-rings will be compressed between the contact surfaces of the plugs and the triaxial cavity 24, realizing the system sealing function and ensuring that the medium in the confining pressure medium cavity 2506 does not leak and the pressure is maintained. The ball correction force transmission top 17 above the triaxial load frame 18 can ensure that the end face of the upper pressure head 21 is in close contact with the end face of the basalt sample 2503. After waiting for the temperature in the fracturing hole section 2504 to reach the experimental design value and stabilize, the supercritical CO is turned on. 2 CO in the preparation module 2 Injection pump 08, basalt sample 2503 supercritical CO 2 It should be noted that the depth and size of the sealing groove 23 only need to match the size of the O-ring to ensure that the O-ring is neither over-compressed during installation, resulting in damage or aging of the O-ring, nor too loose to form an effective seal.

[0097] After the fracturing test, the axial pressure and confining pressure are unloaded alternately, and the seepage test is carried out. The acoustic emission probe positioning sleeve 2509 on the outside of the cylindrical sample is slid out, and the surface film heat shrink tube 2505 is removed. The upper isolation assembly 2501 and the lower isolation assembly 2502 are removed, and the upper pressure pad 2511 with the central through hole 2507 and the lower pressure pad 2512 without the central through hole 2507 are installed to form a basalt assembly 25 for radial seepage test. At this time, the axial pressure servo pump 12 is started to apply axial pressure to the basalt assembly 25 to ensure that the seepage medium only flows out from the central through hole 2507 to the injection pipe 22 of the upper pressure head 21. Supercritical CO 2 The preparation unit is connected to the confining pressure medium channel 1902 on the lower plug 19, and the CO 2 Injection pump 08, set the constant pressure injection mode to ensure that the radial seepage cavity 2510 is filled with the seepage medium CO 2, and then the radial permeability is calculated based on the monitoring data of the gas flow meter 28 in the metering component.

[0098] After the radial seepage test is completed, the axial pressure is unloaded and then the sealing test is carried out. The upper pressure pad 2511 and the lower pressure pad 2512 are removed and the CO2-resistant 2 The sealing rubber cylinder 2513 forms a basalt assembly 25 for the seam network mineralization storage test. 2 The preparation unit is connected to the confining pressure medium channel 1902 of the lower plug 19 to pass supercritical CO 2 The preparation unit is connected to the mixed solution injection unit and connected as a whole to the mixed solution channel 1904 on the lower plug 19, and then connected to the injection pipe 22 of the upper pressure head 21, and the metering component is moved to the interface of the fluid channel 35, so as to realize the injection and extraction of the sealing solution. Axial pressure and confining pressure are applied alternately to the basalt assembly 25, and the water injection pump 06 and CO are turned on. 2 Injection pump 08, CO 2 and water are input into the mixed solution displacement container 09, the mixed solution displacement pump 10 is started, the injection mode is set, the sealing solution is injected into the basalt assembly 25 after fracturing, and the sealing test is started. During the test, the mineralized solution is measured in time, weighed and ion analysis is performed, that is, after the assembly 25 is depressurized, the sealing medium is extracted from the confining pressure medium cavity 2506. After the sealing medium is extracted, the original sealing test conditions are restored to continue sealing. After the sealing test, the axial pressure and confining pressure are alternately unloaded, the basalt sample 2503 is taken out, and the surface morphology of the fracture is observed and the distribution of mineral components on the test surface is tested.

[0099] Figure 3 FIG. 1 is a schematic diagram of a basalt assembly for fracturing according to an embodiment of the present invention.

[0100] In a possible implementation, Figure 3 As shown, the basalt assembly 25 further includes: a central through hole 2507 disposed on the basalt sample 2503, an upper packing assembly 2501 and a lower packing assembly 2502 located in the central through hole 2507, and a fracturing hole section 2504 surrounded by the central through hole 2507, the upper packing assembly 2501 and the lower packing assembly 2502, and a high-pressure resistant pipe is disposed in the lower packing assembly 2502, and the high-pressure resistant pipe is used to connect the injection module and the pressure hole section 2504;

[0101] A thin film heat shrink tube 2505 is jacketed on the outside of the basalt sample 2503, an acoustic emission probe positioning sleeve 2509 is jacketed on the thin film heat shrink tube 2505, and an acoustic emission probe 2508 is arranged between the thin film heat shrink tube 2505 and the acoustic emission probe positioning sleeve 2509;

[0102] The radial deformation meter 2515 includes a test probe, which is in contact with the outer wall of the basalt sample 2503 through a thin film heat shrink tube 2505. The test probe passes through the acoustic emission probe positioning sleeve 2509. A plurality of radial deformation meters 2515 are evenly arranged in the circumferential direction at the same height of the basalt sample 2503. The radial deformation meter 2515 and the acoustic emission probe 2508 are staggered.

[0103] The strain gauge 2514 is provided on the basalt sample 2503;

[0104] The triaxial cavity 24 , the upper pressure head 21 , the lower pressure head 26 , the upper plug 20 , the lower plug 19 , and the basalt assembly 25 enclose a confined pressure medium cavity 2506 .

[0105] Specifically, in order to ensure that the basalt sample 2503 is isolated from the confining pressure medium (hydraulic oil) during the fracturing test, the basalt assembly 25 needs to be realized through the cooperation of the sealing groove 23 and the thin film heat shrink tube 2505 opened on the upper pressure head 21 and the lower pressure head 26. The sealing groove 23 is provided on the outer periphery of the upper pressure head 21 and the lower pressure head 26, and the sealing groove 23 is provided with an O-ring. When the upper pressure head 21 and the lower pressure head 26 are inserted into the triaxial cavity 24, the system sealing of the fracturing test is realized. The upper pressure head 21 and the lower pressure head 26 are provided with seepage grooves on the end faces, and the seepage grooves are located in the upper pressure head 21 and the lower pressure head 26. The seepage groove on the upper pressure head 21 is connected to the injection pipeline, and the seepage groove of the lower pressure head 26 is connected to the fluid channel. At the same time, in order to ensure the reception of the sound wave signal of the acoustic emission probe 2508, after a layer of coupling agent is applied on the outer side of the basalt sample 2503, the thin film heat shrink tube 2505 shrinks the basalt sample 2503 and slides into the acoustic emission probe positioning sleeve 2509 from top to bottom. The outer wall of the acoustic emission probe positioning sleeve 2509 is provided with a plurality of probe holes and through grooves. The probe holes are used to place the acoustic emission probe 2508, and the through groove is used to place the test probe of the radial deformation meter 2515. A layer of coupling agent is applied again in the probe holes, and then the acoustic emission probe 2508 is inserted and fixed with a spring clip. Finally, the acoustic emission probe positioning sleeve 2509 is penetrated, and the radial deformation meter 2515 is installed in the through groove so that the test probe of the radial deformation meter 2515 is in contact with the basalt sample. In this embodiment, four radial deformation marks 2515 are provided, and the angle between two adjacent radial deformation meters 2515 is 90°. In this embodiment, the thickness of the thin film heat shrink tube 2505 is 0.1 mm to 0.2 mm. The thin film heat shrink tube 2505 is provided to prevent the confining pressure medium in the confining pressure medium cavity 2606 from directly contacting the basalt sample 2503, that is, the hydraulic oil cannot directly contact the basalt sample 2503. It is understandable that the thickness of the thin film heat shrink tube 2505 will affect the transmission of the acoustic wave signal, and the density and elastic modulus of the thin film heat shrink tube 2505 will affect the propagation speed and attenuation of the acoustic wave inside it; the thicker thin film heat shrink tube 2505 usually has a higher mass, which may lead to increased attenuation of the acoustic wave signal. When the acoustic wave propagates from the sample to the interface of the heat shrink tube, partial reflection and refraction may occur, especially when the acoustic impedance difference of the interface material is large; if the thickness of the thin film heat shrink tube 2505 increases, the interface area increases, which may introduce more signal loss; the larger thickness of the thin film heat shrink tube 2505 will cause the acoustic wave to experience a longer path during transmission, thereby increasing the attenuation of the acoustic wave; when the sound signal propagates in the material, as the propagation distance increases, the signal strength will gradually weaken, that is, the greater the thickness of the thin film heat shrink tube 2505, the worse the transmission effect. Therefore, a thinner thin film heat shrink tube 2505 should be selected as much as possible to reduce acoustic wave attenuation and signal distortion.Normally, the thickness of the film heat shrink tube 2505 should be controlled between 0.1mm and 0.2mm to minimize the impact on the acoustic emission signal, and a suitable coupling agent is used to improve the transmission efficiency of the sound wave. Among them, the coupling agent is a medium for ensuring the transmission of sound waves between the acoustic emission probe 2508 and the material to be tested (such as the basalt sample 2503). Its main function is to eliminate the air gap between the acoustic emission probe 2508 and the surface of the basalt sample 2503, to ensure that the sound wave can be effectively transmitted, thereby ensuring the accurate reception of the acoustic emission signal. The coupling agent is preferably high vacuum silicone grease, which has good chemical stability, high temperature resistance and high adhesion, especially when good contact needs to be maintained for a long time in acoustic emission or ultrasonic testing. The spring is hinged to the outer wall of the acoustic emission probe positioning sleeve 2509 and is located near the probe hole slot. The spring is rotated so that the acoustic emission probe 2508 is pressed against the basalt sample 2503.

[0106] It should be noted that the acoustic emission probe 2508 is used to monitor the formation and expansion of cracks; analyze the failure mechanism of the basalt sample 2503, infer the fracture characteristics of the basalt; locate the crack position, clarify the crack starting point and network distribution; and evaluate the fracture and permeability of the basalt to which the basalt sample 2503 belongs. The radial deformation meter 2515 also includes a support base, and the test probe is fixed to the support base by bolts. The test probes are evenly distributed and fit on the outer surface of the basalt sample 2503 to measure the strain of the basalt sample 2503 at multiple radial positions. A complete radial measurement network can be formed by multiple test probes to ensure accurate evaluation of the overall deformation of the sample.

[0107] The basalt sample 2503 is usually cylindrical, and is provided with a central through hole 2507. The diameter of the central through hole 2507 is 1 / 5 of the diameter of the basalt sample 2503, the diameter of the basalt sample 2503 is within an allowable error of ±0.1 mm, and the inner wall of the central through hole 2507 is smooth. The fracturing hole section 2504 is enclosed by the upper packing assembly 2501 and the lower packing assembly 2502. The height of the fracturing hole section 2504 is 1 / 10 of the height of the basalt sample 2503, and the height of the fracturing hole section 2504 is within an allowable error of ±0.2 mm. The above error range is based on the International Society for Rock Mechanics and related ISO standards, which helps to ensure the accuracy and consistency of the test so that the data between different tests are comparable.

[0108] It should be noted that during the fracturing test, it is necessary to collect the axial deformation, radial deformation, and acoustic emission signals of the basalt sample 2503, as well as the axial strain and radial strain of the outside of the basalt sample 2503 around the fracturing hole section 2504, the temperature and pressure of the fluid inside the fracturing hole section 2504, and the temperature inside the triaxial cavity 24, and transmit the above-collected parameter data to the data integration box 29 through the data line terminal 1901. During the fracturing test, collecting data such as temperature, pressure, deformation, strain, and acoustic emission signals is crucial for studying the mechanical behavior of the material (basalt sample 2503) and the process of crack formation. These data not only help to understand the physical mechanism of the test, but also provide important information for optimizing the fracturing scheme and practical application. In other words, these data work together to help fully understand the formation and expansion of cracks during basalt fracturing and the response behavior of basalt; they provide important experimental basis for evaluating the formation mechanism of the fracture network, optimizing fracturing technology, and predicting the failure mode of the material.

[0109] It is understandable that a fourteenth stop valve 0314 is provided between the upper plug 20 and the oil collecting tank 27, and a second pressure sensor 1502 is provided between the upper plug 20 and the oil collecting tank 27, and the second pressure sensor 1502 is used to monitor the confining pressure data of the fracturing sealing device.

[0110] Figure 4 FIG. 1 is a schematic diagram of a basalt assembly for radial seepage according to an embodiment of the present invention.

[0111] In a possible implementation, Figure 4 As shown, the basalt assembly 25 further includes: a central through hole 2507 disposed on the basalt sample 2503; and

[0112] An upper pressure pad 2511 is disposed above the basalt sample 2503, and a central through hole 2507 is provided on the upper pressure pad 2511;

[0113] A lower pressure pad 2512 is disposed below the basalt sample 2503;

[0114] The triaxial cavity 24 and the basalt assembly 25 enclose a radial seepage cavity 2510 .

[0115] Specifically, during the seepage test, the radial seepage cavity 2510 is enclosed by the upper pressure head 21, the lower pressure head 26, the upper plug 20 and the lower plug 19 of the triaxial cavity 24 basalt assembly 25, the upper pressure pad 2511 with the central through hole 2507 is arranged between the upper pressure head 21 and the basalt sample 2503, and the lower pressure pad 2512 without the central through hole 2507 is arranged between the lower pressure head 26 and the basalt sample 2503. The axial end is sealed by loading with the axial pressure servo pump 12 to ensure that the flow path of the seepage medium is the radial seepage cavity 2510 through the pressure fracture to reach the central through hole 2507 of the sample.

[0116] Among them, the seepage test selected supercritical CO 2 The preparation unit serves as the input of the seepage medium, and a seepage groove is provided in the upper pressure head 21. The seepage groove is connected to the injection pipe 22. The injection pipe 22 is arranged perpendicular to the central axis of the upper pressure head 21. At the same time, the connection combination of the seepage medium channel 1903 inside the lower plug 19 serves as the output of the seepage medium, and is connected to the metering component to monitor the flow change and calculate the radial permeability. It should be noted that radial permeability refers to the ability of the fluid medium to penetrate in the material along the radial direction (usually from the center to the outside), which is an important physical parameter for characterizing porous media materials such as rocks. In basalt fracturing tests and other fields such as underground fluid storage, oil and gas extraction, geothermal development, etc., monitoring flow changes and calculating radial permeability can be used to evaluate the permeability of materials and understand the flow characteristics of fluid media in materials; optimize the fracture network and fracturing process, improve the connectivity and permeability of fractures; improve the efficiency of fluid storage, and ensure that the fluid effectively penetrates and is sealed in the rock.

[0117] Figure 5 FIG. 2 is a schematic diagram of a basalt assembly 25 for storage according to an embodiment of the present invention.

[0118] In a possible implementation, Figure 5 As shown, the basalt assembly 25 further includes: a central through hole 2507 disposed on the basalt sample 2503; and

[0119] CO2 resistant 2 Sealing rubber tube 2513, jacketed on the outside of basalt sample 2503, resistant to CO 2 The sealing rubber tube 2513 and the three-axis cavity 24 enclose a pressure medium cavity 2506 .

[0120] In the storage test, the entire CO 2 The sealing rubber cylinder 2513 wraps the basalt sample 2503, the upper pressure head 21, and the lower pressure head 26, so as to ensure that the confining pressure medium does not directly contact the basalt sample 2503. 2The function of the sealing rubber tube 2513 is the same as that of the thin film heat shrink tube 2505 in the fracturing test. That is, through the triaxial cavity 24 and the upper pressure head 21, the lower pressure head 26, the upper plug 20, the lower plug 19 and the CO resistant 2 The sealing rubber tube 2513 encloses the pressure medium cavity 2506 .

[0121] Among them, the radial seepage chamber 2510 and the confining pressure medium chamber 2506 are similar in space, but the purpose of each chamber is different under different test conditions. It can be understood that in the fracturing test, the confining pressure medium chamber 2506 is surrounded by the triaxial chamber 24, the upper pressure head 21, the lower pressure head 26, the upper plug 20, the lower plug 19 and the thin film heat shrink tube 2505; in the seepage test, the radial seepage chamber 2510 is surrounded by the triaxial chamber 24, the upper pressure head 21, the lower pressure head 26, the upper plug 20, the lower plug 19 and the basalt sample 2503; in the sealing test, the confining pressure medium chamber 2506 is surrounded by the triaxial chamber 24, the upper pressure head 21, the lower pressure head 26, the upper plug 20, the lower plug 19 and the CO resistant 2 The sealing rubber tube 2513 is enclosed.

[0122] Specifically, during the sealing test, the mixed solution injection unit is used as the input end, and the output end is connected to the metering component, through the mixed solution channel 1904 on the lower plug 19, through the seepage groove in the lower pressure head 26, to the basalt sample 2503, and then through the seepage groove in the upper pressure head 21 to the injection pipe 22. The injection pipe 22 is connected to the seepage medium channel 1903 of the lower plug 19 through pipelines and joints to the metering component. According to the sealing time and injection plan, the sampling time of the mineralized solution is selected, the liquid is quantitatively taken, the ion concentration in the solution is detected and analyzed, the basalt sample 2503 is removed, the sample morphology and mineral distribution are observed and analyzed, and the effectiveness of the basalt mineralization sealing is evaluated. Among them, after the basalt sample 2503 is removed, in order to observe and analyze the morphology and mineral distribution of the basalt sample 2503 and evaluate the effectiveness of the basalt mineralization sealing, it is necessary to use a variety of experimental means and analysis methods to conduct a detailed study of the basalt sample 2503. These are all based on some external detection instruments not mentioned in this patent. For example: observe the sample morphology: observe the morphological changes of the sealed basalt sample 2503 by SEM, optical microscope, CT and other methods, and analyze the morphology after the mineral reaction; mineral distribution analysis: use XRD, EPMA, EDS and other methods to analyze the mineral phase distribution and chemical composition, and evaluate the progress of the mineralization reaction; evaluate the effectiveness of the storage: through the determination of the amount of mineralized products, porosity changes, CO 2 The absorption capacity and mineral stability are used to evaluate the extent of mineralization reaction and storage efficiency.

[0123] It is understandable that the choice of sampling timing is based on the sealing time and the injection scheme, and usually includes sampling in the early, middle and final stages, with the purpose of monitoring the dynamic changes of the mineralization reaction. Quantitative liquid sampling can accurately control the volume of each sample through equipment such as a measuring cylinder, a sampling tube, and a syringe. For example, the liquid volume can be set to 5 ml, 10 ml or other specific volumes per sampling, and the liquid volume can be adjusted according to the needs of the experiment. Although the mineralization solution is injected through the mixed solution injection unit, the components in the solution will change over time during the reaction process after injection. Therefore, sampling is not carried out during the injection process, but at different time points after the injection to monitor the progress of the reaction. Through multiple sampling, the changes in the chemical composition of the mixed solution can be captured and the dynamic process of the mineralization reaction can be analyzed.

[0124] Figure 2 Schematic diagram of a lower plug according to an embodiment of the present invention.

[0125] In a possible implementation, Figure 2 As shown, the basalt assembly 25 also includes:

[0126] The upper plug 20 is disposed above the triaxial cavity 24. An outlet is provided on the upper plug 20. The outlet is communicated with the confining pressure medium cavity 2506. The confining pressure medium cavity 2506 is communicated with the oil collecting tank 27 through a pipeline.

[0127] An upper pressure head 21 is disposed between the upper plug 20 and the basalt sample 2503. A seepage groove is disposed in the upper pressure head 21. A liquid injection pipe 22 is disposed on the upper pressure head 21. The liquid injection pipe 22 is connected to the seepage groove.

[0128] The lower plug 19 is arranged below the triaxial cavity 24. The lower plug 19 is provided with a data line terminal 1901, a confining pressure medium channel 1902, a seepage medium channel 1903 and a mixed solution channel 1904. The terminal is connected to the data integration box 29. The confining pressure medium channel 1902, the seepage medium channel 1903 and the mixed solution channel are connected to the injection module.

[0129] The lower pressure head 26 is arranged between the basalt sample 2503 and the lower plug 19 .

[0130] Among them, the upper pressure head 21 is provided with an injection pipe 22, and the injection pipe 22 is arranged perpendicularly to the axis of the upper pressure head. The injection pipe 22 is used to connect the seepage groove in the upper pressure head 21, so that the seepage medium can be input into the seepage groove through the injection pipe 22. The injection pipe 22 can be selectively connected to multiple places, such as a mixed solution injection unit, a metering component, etc., only through corresponding pipelines. The injection pipe 22 has a threaded interface, and the threaded interface can be connected to different components such as valves, joints, etc., and a sealed and stable connection is achieved through threads. It is understandable that when the injection pipe 22 is not used, a thread plug (usually a threaded plug for closing a port) can be used for temporary closure.

[0131] In a feasible implementation, the pressure loading module 11 includes:

[0132] The axial pressure servo pump 12 is connected to the oil chamber of the axial top cylinder 14, and the axial pressure servo pump 12 provides axial pressure for the basalt assembly 25;

[0133] The confining pressure servo pump 13 is in communication with the basalt assembly 25 , and the confining pressure servo pump 13 provides confining pressure for the basalt assembly 25 .

[0134] Among them, a twelfth stop valve 0312 is set between the axial pressure servo pump 12 and the axial top cylinder 14 to control the opening and closing of the axial pressure servo pump 12, and a thirteenth stop valve 0313 is set between the confining pressure servo pump 13 and the basalt assembly 25 to control the opening and closing of the confining pressure servo pump 13.

[0135] It should be noted that the pressure loading module 11 includes an axial pressure servo pump 12 and a confining pressure servo pump 13, and the axial pressure servo pump 12 and the confining pressure servo pump 13 apply axial pressure and confining pressure to the basalt sample respectively. It can be understood that the medium of axial pressure and confining pressure are hydraulic oil. A first pressure sensor 1501 is set at the outlet of the axial pressure servo pump 12, and a second pressure sensor 1502 is set between the upper plug 20 and the oil collecting tank 27. The second pressure sensor 1502 is used to monitor the confining pressure data of the fracturing and sealing device, and can monitor the maintenance status of the axial pressure and confining pressure during the whole process of the fracturing and sealing test. It can be understood that the second pressure sensor 1502 can also be set at the outlet of the confining pressure servo pump 13, and the pressure value of the confining pressure can be obtained.

[0136] In a feasible implementation manner, the fracturing and sealing device further includes a metering component, which is in communication with the test main module and includes:

[0137] A gas-liquid separator 32, a back pressure valve 31 is provided between the gas-liquid separator 32 and the test main module, the gas outlet of the gas-liquid separator 32 is connected to the gas flow meter 28, the liquid outlet of the gas-liquid separator 32 is connected to the liquid collecting bottle 33, and an electronic balance 34 is provided under the liquid collecting bottle 33;

[0138] The fracturing and sealing device further comprises a fluid channel 35, and the fluid channel 35 is used to connect the injection module and the test main module.

[0139] Among them, a fifteenth stop valve 0315 is connected in parallel with the back pressure valve 31, and a third pressure sensor 1503 is connected in series with the back pressure valve 31, and the third pressure sensor 1503 is used to obtain the fluid pressure of the seepage medium during seepage. The fluid channel 35 is a universal flexible port, which can be connected to different units in the injection module according to the test plan. The interface of the fluid channel 35 is a multi-purpose interface, and the connection method is a ferrule joint. In other words, the fluid channel 35 can be connected to different components or pipeline systems. The design of this interface allows a flexible connection method so that different devices in the system (such as metering components, injection modules, fluid output devices, etc.) can be easily connected to the fluid channel.

[0140] It should be noted that the back pressure valve 31 is arranged closer to the basalt assembly 25 than the gas-liquid separator 32, and a fifteenth stop valve 0315 is connected in parallel with the back pressure valve 31, and a third pressure sensor 1503 is also connected in series. This arrangement is to better control and monitor the pressure in the fracturing and sealing device, and to flexibly operate through the bypass branch when necessary. Among them, the back pressure valve 31 is used to maintain the upstream pressure of the system to ensure that the pressure in the injection pipeline 22 does not drop below the set value. The fifteenth stop valve 0315 is connected in parallel with the back pressure valve 31, and is a bypass control component. In some cases, the back pressure valve 31 can be closed, and the fifteenth stop valve 0315 of the bypass can be opened, so that the fluid does not pass through the back pressure valve 31, but directly flows to the downstream part of the system through the bypass. For example, when the fracturing and sealing device processes a gas-liquid mixture, the back pressure valve 31 is closed, and the bypass passage is used by opening the fifteenth stop valve 0315 to directly introduce the gas-liquid mixture into the gas-liquid separator 32 for separation. The gas-liquid separator 32 is used to separate the gas and liquid to ensure that the two do not interfere with each other in the subsequent measurement process. The back pressure valve 31 is used to maintain the pressure balance of the system. It should be noted that the back pressure valve 31 is usually not suitable for simultaneously processing a gas-liquid two-phase mixture. The gas flow meter 28 is used to measure the flow rate of the gas and then calculate the permeability. The liquid collection bottle 33 is used to collect the liquid, and the electronic balance 34 measures the weight of the liquid for solution weighing-based sample analysis after the mineralization reaction.

[0141] Figure 6 The figure is a schematic flow chart of the steps of a fracturing sealing method according to an embodiment of the present invention.

[0142] like Figure 6 As shown, another embodiment of the present invention provides a method based on supercritical CO 2 The fracturing and sealing method for injecting basalt utilizes the above-mentioned pressure sealing device, and the fracturing and sealing method comprises the following steps:

[0143] Step 1: Install the test main module;

[0144] Step 2, start the pressure loading module, apply pressure to the test main module, and monitor the pressure change;

[0145] Step 3, according to the requirements of fracturing, seepage and sealing, start the injection module to realize the fracturing, seepage and sealing test of the test main module;

[0146] Step 4: After the sealing test is completed, the basalt sample in the main test module is taken out to observe the surface morphology of the fracture and the distribution of mineral components on the test surface.

[0147] Specifically, a basalt sample 2503 containing a central through hole 2507 is prepared and placed in the triaxial cavity 24 to form a basalt assembly 25. In this embodiment, a cylindrical basalt sample 2503 with a diameter of 50 mm and a height of 10 mm is selected, a central through hole 2507 is drilled in the basalt sample 2503, the hole wall of the central through hole 2507 is cleaned, and the position of the acoustic probe is marked on the outside of the basalt sample 2503, and strain gauges 2514 are glued on the outside of the basalt sample 2503 near the fracturing hole section 2504 at intervals of 90°. Connect the lower packing assembly 2502 with the lower pressure head 26, and place the lower packing assembly 2502 in the central through hole 2507 of the basalt sample 2503, then insert the upper packing assembly 2501 into the central through hole 2507 from the top of the basalt sample 2503, and place the upper pressure head 21 at the upper end of the basalt sample 2503, keeping the central axis of the upper pressure head 21 aligned with the central axis of the basalt sample 2503, so that the axial pressure is more uniform. After applying the acoustic wave coupling agent at the position of the acoustic emission probe 2508 of the basalt sample 2503, slide in the film heat shrink tube 2505 to tighten the basalt sample 2503, and then slide in the acoustic emission probe positioning sleeve 2509, and use the coupling agent to stick the acoustic emission probe 2508 in the space between the acoustic emission probe positioning sleeve 2509 and the film heat shrink tube 2505, and lock and fix the acoustic emission probe 2508 with a spring. Install the radial deformation meter 2515. After the above installation is completed, the basalt assembly 25 required for the fracturing test is formed in the triaxial cavity 24.

[0148] Start the pressure loading module 11, that is, alternately start the axial pressure servo pump 12 and the confining pressure servo pump 13, alternately apply axial pressure and confining pressure to the basalt sample 2503, and monitor the pressure change (monitor the axial pressure through the first pressure sensor 1501, and monitor the confining pressure through the second pressure sensor 1502); start the heating and heat preservation component 30 outside the triaxial cavity 24 to heat the triaxial cavity 24 and the basalt sample 2503; start the supercritical CO 2The air compressor 04 and the booster 05 in the preparation unit prepare CO at a set pressure. 2 , and stored in CO 2 Injection pump 08. Specifically, check whether the basalt assembly 25 for the fracturing test is installed in place. After installation, assemble it with the triaxial cavity 24 to complete the system sealing, and install the heating and heat preservation component 30 on the outside of the triaxial cavity 24 as a whole. Turn on the pressure loading module 11, set the operation mode of the axial pressure servo pump 12 and the confining pressure servo pump 13 respectively, and load the basalt sample 2503 with alternating axial pressure and confining pressure. The pressure loading module 11 synchronously records and saves the loading mode, axial pressure, confining pressure, displacement and other data. Turn on the heating and heat preservation component 30 to heat the entire triaxial cavity 24 and the internal basalt sample 2503. The setting temperature range can be selected from room temperature to 300°C to simulate the temperature conditions of the basalt formation. Turn on CO 2 The gas cylinder 01, the pressure reducing valve 02, the second stop valve 0302, the air compressor 04 and the supercharger 05 are closed. The first stop valve 0301, the third stop valve 0303 and the fourth stop valve 0304 are closed, and the pressure ratio of the supercharger 05 is set to prepare the specified high-pressure CO 2 and stored in CO 2 Injection pump 08. Among them, the axial pressure is calculated by the load force applied by the axial pressure servo pump 12 (obtained by the first pressure sensor 1501) and the force area of ​​the basalt sample 2503 (directly displayed on the data terminal of the pressure loading module 11); the confining pressure servo pump 13 injects hydraulic oil into the confining pressure medium cavity 2506, and the liquid pressure is the confining pressure, which is directly measured by the second pressure sensor 1502. The data obtained by the strain gauge 2514 are the axial and radial strains of the basalt sample 2503 at the position of the strain gauge 2514; the radial deformation meter 2515 measures the radial change of the basalt sample 2503.

[0149] It should be noted that turning on CO 2 The gas cylinder 01, the pressure reducing valve 02 and the first stop valve 0301 are closed, and the air compressor 04, the booster valve, the second stop valve 0302, the third stop valve 0303 and the fourth stop valve 0304 can be supplied to the CO 2 The input of injection pump 08 is slightly lower than CO 2 Cylinder 01 pressure CO 2 Understandably, CO 2 The pump chamber of injection pump 08 is equipped with a constant temperature circulator, which can control the CO 2 The temperature of the fluid inside the injection pump 08 ranges from -20°C to 100°C, and the supercritical CO 2 The preparation unit is not limited to the triaxial chamber 24 for preparing supercritical CO 2 , and can also prepare and store gaseous or liquid CO at a specified temperature and pressure 2.

[0150] After the temperature in the fracturing hole section 2504 reaches the actual test value and stabilizes, the supercritical CO 2 CO in the production unit 2 Injection pump 08, supercritical CO 2 It should be noted that when conducting a fracturing test, the eighth stop valve 0308, the ninth stop valve 0309 and the tenth stop valve 0310 need to be closed to ensure that the supercritical CO 2 It can be directly injected into the fracturing hole section 2504. It is understandable that it is not limited to CO 2 Fracturing can also be carried out by hydraulic fracturing or other solution fracturing, which can be achieved by adjusting the opening and closing states of the fourth stop valve 0304, the eighth stop valve 0308, the ninth stop valve 0309 and the tenth stop valve 0310, which will not be repeated here.

[0151] After the fracturing test is completed, the axial pressure and the confining pressure of the fracturing and sealing device are alternately unloaded through the pressure loading module 11 .

[0152] Slide out the acoustic emission probe positioning sleeve 2509 and the film heat shrink tube 2505 outside the basalt sample 2503, remove the upper isolation assembly 2501 and the lower isolation assembly 2502, and install the upper pressure pad 2511 with the central through hole 2507 and the lower pressure pad 2512 without the central through hole 2507 to form the basalt assembly 25 required for the radial seepage test. Specifically, after completing the unloading of the axial pressure and the confining pressure, ensure that the confining pressure medium (hydraulic oil) in the triaxial cavity 24 has been completely discharged, contact the assembly of the triaxial cavity 24, push away the shrapnel to remove the acoustic emission probe 2508, slide out the acoustic emission probe positioning sleeve 2509 outside the basalt sample 2503, and remove the film heat shrink tube 2505 on the surface of the basalt sample 2503. After removing the upper pressure head 21 and taking out the basalt sample 2503, the upper isolation assembly 2501 and the lower isolation assembly 2502 in the extractor are removed, so that the central through hole 2507 remains hollow. The lower pressure pad 2512 is installed between the lower part of the basalt sample 2503 and the lower pressure head 26, and the upper pressure pad 2511 is installed between the upper end face of the basalt sample 2503 and the upper pressure head 21, forming the basalt assembly 25 required for the seepage test.

[0153] Only the axial pressure servo pump 12 in the pressure loading module 11 is started to ensure that the seepage medium flows out from the central through hole 2507 to the injection pipe 22 of the upper pressure head 21. It should be noted that in order to ensure the correctness of the radial seepage path, it is necessary to apply a certain axial pressure to the basalt sample 2503 with the aid of the axial pressure servo pump 12 to compress the lower pressure pad 2512 and the upper pressure pad 2511. In this embodiment, the axial pressure in the seepage test is selected to be 1MPa.

[0154] Supercritical CO 2 The preparation unit is connected to the confining pressure medium channel 1902 on the lower plug 19, and the CO 2 Injection pump 08, set the constant pressure injection mode to ensure that the radial seepage cavity 2510 is filled with the seepage medium CO 2 After passing through the radial seepage cavity 2510, the seepage medium enters the central through hole 2507 through the pressure fracture, and flows out of the central through hole 2507 to the metering assembly, and then the radial permeability is calculated based on the data monitored by the gas flow meter 28 in the metering assembly. Specifically, the critical CO 2 The confining pressure medium channel 1902 on the preparation unit and the lower plug 19 is connected to the injection pipe 22 in the upper pressure head 21, the seepage medium channel 1903 and the metering component. 2 The gas cylinder 01, the pressure reducing valve 02, the first stop valve 0301 and the fourth stop valve 0304 are closed, the air compressor 04, the supercharger 05, the second stop valve 0302, the third stop valve 0303, the eighth stop valve 0308, the ninth stop valve 0309 and the tenth stop valve 0310 are closed, and the pressure reducing valve 02 is adjusted to reduce the seepage medium CO 2 Fill the entire radial seepage cavity 2510. Set the upstream pressure of the seepage (greater than the atmospheric pressure), close the back pressure valve 31, open the fifteenth stop valve 0315 (i.e., atmospheric pressure), or open the back pressure valve 31 (lower than the upstream pressure), close the fifteenth stop valve 0315, form a seepage pressure difference, and read and record the monitoring data on the gas flow meter 28 to obtain the radial permeability. Among them, after the seepage pressure difference is formed, the seepage medium can flow, and then the data of the seepage medium can be monitored. The gas flow meter 28 is used to monitor the volume flow rate, that is, the flow rate of the seepage medium when passing through the basalt sample 2503. The data for calculating the radial permeability also requires: upstream pressure and downstream pressure (this is the initial parameter that needs to be set for the seepage test), the geometric parameters of the basalt sample 2503 (inner and outer diameters, height), and dynamic viscosity (this is based on the test parameters. Consult the chemical manual). Since the calculation of radial permeability is not the solution protected by this application, but the common knowledge used in the skill, it will not be repeated here.

[0155] After the radial seepage test, turn off the CO 2 Inject pump 08, unload shaft pressure, remove upper pressure pad 2511 and lower pressure pad 2512, install CO2 resistant 2 The sealing rubber tube 2513 forms the Xuanwu element assembly required for the sealing test.

[0156] Disconnect supercritical CO 2 The connection between the preparation unit and the confining pressure medium channel 1902 is made by injecting supercritical CO 2The preparation unit is connected to the mixed solution injection unit, and the mixed solution channel 1904 of the lower plug 19 is integrally plugged, and then connected to the injection pipeline 22 of the upper pressure head 21, and the metering component is moved to the fluid channel 35 interface, so as to realize the injection and extraction of the sealing solution.

[0157] The pressure loading module 11 is started to apply axial pressure and confining pressure to the sealing basalt assembly 25 alternately.

[0158] Start water injection pump 06 and CO 2 Injection pump 08, CO 2 and water to the mixed solution body container. Specifically, close the sixth stop valve 0306, open the fifth stop valve 0305 and the water injection pump 06, set the negative displacement mode, fill the pump chamber of the water injection pump 06 with water, close the fifth stop valve 0305 and the eighth stop valve 0308, open the seventh stop valve 0307, ​​start the water injection pump 06, inject a certain amount of water into the mixed solution displacement container 09, and record the amount of injected liquid. It should be noted that during the above-mentioned water injection process, the ninth stop valve 0309 and the tenth stop valve 0310 are kept closed. The water here refers to deionized water, but is not limited to deionized water, and can also be sodium bicarbonate solution, seawater or salt water. Close the water injection pump 06 and the seventh stop valve 0307, ​​open the fourth stop valve 0304 and the ninth stop valve 0309, and open the CO 2 Injection pump 08 (as long as there is CO in the pump chamber of injection pump 08 2 , the mixed solution displacement container 09 can be directly injected through the injection pump 08), and high-pressure CO can be continuously input into the mixed solution displacement container 09. 2 At the same time, the circulating agitator in the mixed solution displacement vessel 09 is turned on to promote the CO 2 Dissolve until saturation is reached and then turn off CO 2 Injection pump 08 , ninth stop valve 0309 and fourth stop valve 0304 .

[0159] Start the mixed solution displacement pump 10, set the injection mode, inject the sealing solution into the sealing basalt assembly 25, and start the sealing test. During the sealing test, the mineralized solution is measured in time, weighed and ion analyzed. Specifically, open the tenth stop valve 0310 and the eleventh stop valve 0311, start the mixed solution displacement pump 10, set the displacement mode, and inject the sealing solution into the basalt sample 2503 after fracturing. The mineralized solution is the solution left after the sealing test, which can be unreacted CO 2 (If you are using CO 2 Gas for storage) or other gases. Dissolved ions generated by mineralization reactions, such as carbonate ions (CO 3 2- ) and CO 2The metal ions (calcium, magnesium, iron, etc.) generated after the reaction; the carbonate minerals generated may partially precipitate in the solution, and some may also dissolve in deionized water. 2 dissolves in deionized water and reacts with minerals in basalt sample 2503, i.e., the mineralization reaction occurs in CO 2 It occurs during the process of injection and reaction with minerals. As the test progresses, the mineralization reaction will gradually occur and the mineralization products will gradually accumulate. It should be noted that at the beginning of the storage test, the deionized water is pure, but during the mineralization reaction, the CO in the water 2 It reacts with rock minerals (basalt sample 2503) to produce different ions (such as carbonate ions and metal ions such as calcium (Ca 2+ ), magnesium (Mg 2+ ), iron (Fe 2+ ) etc.). Therefore, the mineralized solution will contain dissolved ions generated by the mineralization reaction, reflecting the progress and effect of the mineralization reaction. Therefore, in the experiment, researchers will measure, weigh and sample the mineralized solution samples after the reaction. Ion analysis can be performed by ion chromatography (IC), inductively coupled plasma mass spectrometry (ICP-MS) and other techniques to detect the concentration of different ions in the solution. The progress of the mineralization reaction can be analyzed by measuring the concentration of calcium, magnesium, iron and other ions in the solution, combined with the carbonate ion concentration. By calculating the molar concentration of the ions and the mass of the product, the amount of minerals produced can be determined.

[0160] It should be noted that the injection modes include the following three: slow and continuous injection at a low constant displacement; injection at a constant volume and medium speed to a specified liquid volume; injection of a certain amount of solution in batches, with the interval between batches being several days or months. It can be understood that the sealing experiment includes static system sealing and dynamic system sealing, and the difference between the two lies in the state of the back pressure valve 31 and the fifteenth stop valve 0315 in the metering component. The static sealing system refers to closing the back pressure valve 31 and the fifteenth stop valve 0315. The pressure of the entire sealing system depends on the output pressure of the mixed solution displacement pump 10. The fifteenth stop valve 0315 is opened when the liquid is taken regularly, and the system pressure is replenished after the liquid is taken. The dynamic sealing system refers to closing the fifteenth stop valve 0315, setting the working pressure of the back pressure valve 31 to be constant and lower than the output pressure of the mixed solution displacement pump 10, and the pressure difference is usually set to 0.5MPa, so as to form a micro-dynamic flow state. The output pressure of the mixed solution displacement pump 10 is usually lower than the confining pressure, so that the basalt sample 2503 can be wrapped. Otherwise, when the fluid pressure is high, the outer film heat shrink tube 2505 is easily damaged, and the sealing solution will leak into the confining pressure medium cavity 2506, resulting in test failure. 2The water or mixed solution, as well as the mineralized solution after the reaction, only exist inside the basalt sample 2503 and will not leak outside the thin film heat shrink tube 2505.

[0161] It is understood that the static sealing system means that the sealing medium and the basalt sample 2503 are kept in a static state during the test, and the fluid is not allowed to flow in the fracturing sealing device. The pressure and temperature in the fracturing sealing device can be maintained stable, but there is neither continuous fluid flow nor external flow stimulation. The sealing medium (such as CO 2 After the basalt sample 2503 and the sealing medium are injected into the sealing cavity, the two are in a relatively static state without continuous fluid circulation. Applicable scenarios and experimental schemes: used to study the long-term stability of mineralization reactions, simulate underground sealing environments, and rocks or minerals with low permeability. Characteristics of experimental results: slow reaction speed, suitable for long-term experiments.

[0162] Dynamic storage system refers to a system in which there is continuous fluid flow during the test, usually through external pressure or flow control, so that the storage medium (such as mineralization solution, CO 2 Gas, etc.) continuously circulates through the basalt sample 2503. Stable pressure and fluid flow rate are maintained in the fracturing and sealing device to simulate the fluid movement in a real underground environment. The fluid circulates continuously in the fracturing and sealing device, and the transfer of reactants is strengthened by the flow of the fluid, thereby enhancing the rate of the sealing reaction. Applicable scenarios and experimental plans: used to study the mineralization rate under flow conditions, simulate actual underground fluid conditions, and highly permeable rocks (such as sandstone, basalt, etc.). Characteristics of the experimental results: fast reaction speed, suitable for short-term experiments. The fracturing and sealing device of the present application can meet the requirements of both static tests and dynamic tests, thereby improving the scope of application of the fracturing and sealing device.

[0163] After the sealing test, the axial pressure and confining pressure were unloaded alternately, and the basalt sample 2503 was taken out to observe the surface morphology of the fracture and the distribution of mineral components on the test surface.

[0164] In the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0165] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The description and examples are to be considered exemplary only.

[0166] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fracturing storage device based on supercritical CO2 injection into basalt, characterized in that: The fracturing and sealing device comprises: The test body module includes a basalt assembly, and the basalt assembly includes a basalt sample; An injection module is used to inject the required gas, liquid or gas-liquid mixture into the test main module; A pressure loading module, connected to the test body, applying axial pressure and / or confining pressure to the test body module; The injection module and the pressure loading module are configured to achieve the fracturing of the basalt sample, the radial permeability of the basalt sample after fracturing, and the storage of CO2 by the basalt sample after fracturing.

2. The fracturing and sealing device based on supercritical CO2 injection into basalt according to claim 1 is characterized in that: The injection module includes a supercritical CO2 preparation unit, a water injection unit and a mixed solution injection unit; the supercritical CO2 preparation unit is configured to achieve the fracturing of the basalt sample and the radial permeability of the basalt sample after fracturing; the supercritical CO2 preparation unit, the water injection unit and the mixed solution injection unit are configured to achieve the sealing of CO2 by the basalt sample after fracturing; wherein, the supercritical CO2 preparation unit, the water injection unit and the mixed solution injection unit are connected in parallel and communicated with the test main module.

3. The fracturing and sealing device based on supercritical CO2 injection into basalt according to claim 1 is characterized in that: The test subject module also includes: Three-axle load-bearing frame; A three-axis loading frame base, located in the three-axis loading frame; A basalt assembly is arranged in a triaxial cavity, a heating and heat preservation component is arranged outside the triaxial cavity, the triaxial cavity is located on the triaxial loading frame base, and the heating and heat preservation component is located in the triaxial loading frame; An axial top cylinder, comprising a piston and an oil chamber, wherein the axial top cylinder is arranged below the base of the three-axis loading frame; The ball-correcting force-transmitting top is arranged above the three-axis cavity, and the ball-correcting force-transmitting top abuts against the upper side of the basalt assembly through a force-transmitting column.

4. The fracturing and sealing device based on supercritical CO2 injection into basalt according to claim 3 is characterized in that: The basalt assembly further comprises: a central through hole provided on the basalt sample, an upper packing assembly and a lower packing assembly located in the central through hole, and a fracturing hole section formed by the central through hole, the upper packing assembly and the lower packing assembly, wherein a high pressure resistant pipe is provided in the lower packing assembly, and the high pressure resistant pipe is used to connect the injection module and the pressure hole section; A thin film heat shrink tube is jacketed on the outside of the basalt sample, an acoustic emission probe positioning sleeve is jacketed on the thin film heat shrink tube, and an acoustic emission probe is arranged between the thin film heat shrink tube and the acoustic emission probe positioning sleeve; A radial deformation meter, comprising a test probe, the test probe abutting against the outer wall of the basalt sample through the film heat shrink tube, the test probe penetrating the acoustic emission probe positioning sleeve, a plurality of radial deformation meters evenly arranged in the circumferential direction at the same height of the basalt sample, the radial deformation meter and the acoustic emission probe being staggered; A strain gauge is arranged on the basalt sample; Wherein, the triaxial cavity and the basalt assembly enclose a confining pressure medium cavity.

5. The fracturing and sealing device based on supercritical CO2 injection into basalt according to claim 3 is characterized in that: The basalt assembly further comprises: a central through hole disposed on the basalt sample; and An upper pressure pad is arranged above the basalt sample, and a central through hole is provided on the upper pressure pad; A lower pressure pad is arranged below the basalt sample; Wherein, the triaxial cavity and the basalt assembly enclose a radial seepage cavity.

6. The fracturing and sealing device based on supercritical CO2 injection into basalt according to claim 3 is characterized in that: The basalt assembly further comprises: a central through hole disposed on the basalt sample; and A CO2-resistant sealing rubber tube is sleeved outside the basalt sample, and the CO2-resistant sealing rubber tube and the triaxial cavity enclose a confined pressure medium cavity.

7. The fracturing and sealing device based on supercritical CO2 injection into basalt according to any one of claims 4 to 6, characterized in that: The basalt assembly also includes: An upper plug is arranged above the triaxial cavity, and an outlet is arranged on the upper plug, and the outlet is communicated with the confining pressure medium cavity, and the confining pressure medium cavity is communicated with the oil collecting tank through a pipeline; An upper pressure head is arranged between the upper plug and the basalt sample, a seepage groove is arranged inside the upper pressure head, a liquid injection pipe is arranged on the upper pressure head, and the liquid injection pipe is communicated with the seepage groove; A lower plug is arranged below the triaxial cavity, and a data line terminal, a confining pressure medium channel, a seepage medium channel and a mixed solution channel are arranged on the lower plug, the wiring terminal is connected to the data integration box, and the confining pressure medium channel, the seepage medium channel and the mixed solution channel are connected to the injection module; The lower pressure head is arranged between the basalt sample and the lower plug.

8. The fracturing storage device based on supercritical CO2 injection into basalt according to any one of claims 3 to 6, characterized in that: The pressure loading module comprises: An axial pressure servo pump is connected to the oil chamber of the axial top cylinder, and the axial pressure servo pump provides axial pressure for the basalt assembly; A confining pressure servo pump is connected to the basalt assembly, and the confining pressure servo pump provides confining pressure for the basalt assembly.

9. The fracturing and sealing device based on supercritical CO2 injection into basalt according to claim 1, characterized in that: The fracturing and sealing device further includes a metering component, which is in communication with the test main module and includes: A gas-liquid separator, a back pressure valve is provided between the gas-liquid separator and the test main body module, the gas outlet of the gas-liquid separator is connected to a gas flow meter, the liquid outlet of the gas-liquid separator is connected to a liquid collecting bottle, and an electronic balance is provided under the liquid collecting bottle; The fracturing and sealing device further comprises a fluid channel, and the fluid channel is used to connect the injection module and the test main module.

10. A fracturing and sealing method based on supercritical CO2 injection into basalt, using the fracturing and sealing device according to any one of claims 1 to 9, characterized in that: The fracturing sealing method comprises the following steps: Install the test main module; Starting the pressure loading module to apply pressure to the test main module and monitoring the change of the pressure; According to the requirements of fracturing, seepage and sealing, the injection module is started to realize the fracturing, seepage and sealing tests on the main test module; After the sealing test is completed, the basalt sample in the test main module is taken out to observe the surface morphology of the fracture and the distribution of mineral components on the test surface.

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