True triaxial acid fracturing physical simulation and conductivity integrated synchronous test device and method

Abstract

Provided in the present application are a true triaxial acid fracturing physical simulation and conductivity integrated synchronous test device and a method. The device comprises: a clamping module, comprising a clamping holder, an X-axis assembly, a Y-axis assembly, a Z-axis assembly and a perfluoroelastomer sleeve; a seepage module, comprising a simulated wellbore; and a monitoring module, used for monitoring the flow rate of an acid fracturing fluid, the fluid distribution in a core, and the morphology and conductivity of acid-etched fractures or hydraulic fractures. At least one surface of the X-axis assembly, the Y-axis assembly and the Z-axis assembly is in close contact with the inner side of the perfluoroelastomer sleeve, and the clamping module is configured to, under the drive of a servo module, change liquid chambers of the X-axis assembly, the Y-axis assembly and the Z-axis assembly, so as to squeeze a core wrapped in the perfluoroelastomer sleeve. The described configuration can achieve integrated monitoring of the fluid distribution in a core and the morphology and conductivity of acid-etched fractures or hydraulic fractures, and also reduce adverse effects caused by stress concentration, so as to improve the accuracy of tests.

Description

A true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device and method

[0001] The present application claims priority to the Chinese patent application No. 202410869294.5, filed on June 28, 2024, and entitled "A true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device and method", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of oil and gas field development, in particular to a true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device and method. BACKGROUND

[0003] With the gradual expansion of carbonate rock oil and gas exploration and development to the ultra-deep field, the reservoir temperature and stress are super high, the porosity and permeability are low, and the natural fractures are not well developed. Acidizing and fracturing is a key technology to improve single well production. Acid fracturing process simulation acidizing and fracturing effect, evaluation of acid fracturing mold and acid etched fracture conductivity, etc. is an important means to optimize acidizing and fracturing process parameters.

[0004] The true triaxial mold experiment device is an experimental equipment for simulating the stress and seepage behavior of underground rock, which is widely used in the fields of geomechanics, geotechnical engineering and oil and gas exploration. Its structural design aims to simulate the three-dimensional mechanical behavior and seepage characteristics of underground rock, including experimental cabin, stress loading module system, temperature control module system, seepage module system and data acquisition module system.

[0005] However, the existing device cannot realize the integrated monitoring of fluid distribution in the core, acid etched fracture or hydraulic fracture morphology and flow conductivity, and cannot well simulate the real formation environment, and the test result reliability is poor. SUMMARY

[0006] In order to solve at least one problem mentioned in the background art, the present application provides a true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device and method, aiming to solve the technical problem that the device in the related art cannot realize the integrated monitoring of fluid distribution in the core, acid etched fracture or hydraulic fracture morphology and flow conductivity, and cannot well simulate the real formation environment, and the test result reliability is poor.

[0007] In order to achieve the above-mentioned purpose, in a first aspect, the present application provides a true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device, comprising:

[0008] The clamping module comprises a holder, an X-axis assembly, a Y-axis assembly, a Z-axis assembly and a perfluoroether rubber sleeve, the X-axis assembly, the Y-axis assembly and the Z-axis assembly are connected to the holder, the perfluoroether rubber sleeve is used to wrap the core, the X-axis assembly is located on the opposite sides of the perfluoroether rubber sleeve along a first direction, the Y-axis assembly is located on the opposite sides of the perfluoroether rubber sleeve along a second direction, the Z-axis assembly is located on the opposite sides of the perfluoroether rubber sleeve along a third direction, the first direction, the second direction and the third direction are perpendicular to each other; at least one of the X-axis assembly, the Y-axis assembly and the Z-axis assembly is in close contact with the inside of the perfluoroether rubber sleeve, and the X-axis assembly, the Y-axis assembly and the Z-axis assembly all have independent liquid chambers;

[0009] The servo module is connected with the X-axis assembly, the Y-axis assembly and the Z-axis assembly, and is used to change the liquid chambers of the X-axis assembly, the Y-axis assembly and the Z-axis assembly;

[0010] The seepage module comprises a simulated wellbore, one end of the simulated wellbore is used to introduce acidizing and fracturing fluid, and the one end is located in the core;

[0011] The monitoring module is used to monitor the flow of the acidizing and fracturing fluid, the distribution of the acidizing and fracturing fluid in the core, the acid-etched fracture or the hydraulic fracture shape and the conductivity;

[0012] The clamping module is configured to change the liquid chambers of the X-axis assembly, the Y-axis assembly and the Z-axis assembly under the driving of the servo module, so as to extrude the core wrapped by the perfluoroether rubber sleeve.

[0013] In the true triaxial acid fracturing physical model and conductivity integrated synchronous testing device, optionally, one of the X-axis assembly, the Y-axis assembly and the Z-axis assembly comprises a frame, a first liquid chamber is formed between the frame and the perfluoroether rubber sleeve, and the first liquid chamber is in communication with the servo module;

[0014] The first liquid chamber is configured to change under the driving of the servo module, so as to extrude the core wrapped by the perfluoroether rubber sleeve;

[0015] At least one of the other two of the X-axis assembly, the Y-axis assembly and the Z-axis assembly comprises an indirect pressure head and a baffle, the indirect pressure head is close to the perfluoroether rubber sleeve relative to the baffle, and the indirect pressure head and the baffle are spaced apart to form a second liquid chamber;

[0016] The second liquid chamber is configured to change under the driving of the servo module and drive the indirect pressure head to move to extrude the core wrapped by the perfluoroether rubber sleeve.

[0017] In the true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device, the first liquid chamber and the second liquid chamber are isolated by the spacer pressure head, and the pressure of the second liquid chamber is greater than the pressure of the first liquid chamber.

[0018] In the true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device, the X-axis assembly includes the frame, and the Y-axis assembly includes the indirect pressure head and the baffle.

[0019] The Z-axis assembly includes an upper plug and a pressure booster, the upper plug abuts against the top of the perfluoroether rubber sleeve, and the pressure booster is located on the side of the upper plug away from the perfluoroether rubber sleeve; the pressure booster is used to provide pressure and transmit the pressure to the plug, so that the upper plug extrudes the perfluoroether rubber sleeve.

[0020] and / or,

[0021] The Z-axis assembly includes a hydraulic coring tool, the hydraulic coring tool is located at the bottom of the perfluoroether rubber sleeve, and the hydraulic coring tool includes a lower plug used to abut against the perfluoroether rubber sleeve; the hydraulic coring tool is used to drive the lower plug to move close to or away from the perfluoroether rubber sleeve to load or unload the core.

[0022] In the true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device, the clamping module further includes:

[0023] A sealing ring is located between the frame and the perfluoroether rubber sleeve, and between the indirect pressure head and the baffle.

[0024] A temperature sensing element includes a temperature sensing end, the temperature sensing end is close to the perfluoroether rubber sleeve, and the temperature sensing element is used to obtain temperature information of the core wrapped by the perfluoroether rubber sleeve.

[0025] A heating element is electrically connected with the temperature sensing element, the heating element is used to obtain the temperature information obtained by the temperature sensing element and heat the perfluoroether rubber sleeve.

[0026] In the true triaxial acid fracturing mold and flow conductivity integrated synchronous testing device, the servo module includes,

[0027] An X-axis pump group is connected to the first liquid chamber, and the X-axis pump group is used to inject or suck liquid into the first liquid chamber.

[0028] A Y-axis pump group, which is connected to the second liquid chamber, and is used to inject or suck liquid into the second liquid chamber;

[0029] A Z-axis pump group, which is connected to the pressure booster, and is used to inject or suck liquid into the pressure booster to change the pressure of the pressure booster;

[0030] Three regulating assemblies, each of which comprises a pressure gauge and a needle valve connected to the pressure gauge, and each of which corresponds to a pump group, and is used to regulate the pressure and flow of the corresponding pump group.

[0031] In the above-mentioned true triaxial acid fracturing model and flow conductivity integrated synchronous testing device, optionally, the simulated wellbore comprises,

[0032] A tubing;

[0033] A casing, which is sleeved on the outer periphery of the tubing;

[0034] A packer, which is located between the tubing and the casing;

[0035] A fixing resin, which covers the packer and part of the casing, and is used to fix the simulated wellbore in the core;

[0036] And / or,

[0037] The seepage module further comprises,

[0038] A container, which is connected to the simulated wellbore, and is used to store the acid fracturing fluid;

[0039] An acid fracturing pump group, which is connected to the container, and is used to make the acid fracturing fluid in the container flow into the simulated wellbore.

[0040] In the above-mentioned true triaxial acid fracturing model and flow conductivity integrated synchronous testing device, optionally, the monitoring module comprises,

[0041] An acoustic emission probe, which is installed in the perfluoroelastomer rubber sleeve and on the surface of the core, and is used to receive acoustic signals of rock breaking in the core acid fracturing process to detect the morphology of acid-etched cracks or hydraulic fractures;

[0042] A main magnet, an electromagnetic wave transmitting element and a receiving coil, which are all installed on the holder, and are configured to cooperate with each other to monitor the flow of the acid fracturing fluid by nuclear magnetic resonance.

[0043] In the true triaxial acid fracturing mold, the acid fracturing fluid includes one or more of water, a fracturing fluid, an acid liquid, and supercritical CO2.

[0044] In a second aspect, the application also provides a method of a true triaxial acid fracturing mold, a flow conductivity integrated synchronous testing device, which is used in the true triaxial acid fracturing mold, the flow conductivity integrated synchronous testing device, and the method includes:

[0045] The core wrapped by the perfluoroether rubber sleeve is placed on the clamp of the clamping module;

[0046] The servo module is turned on, and the X-axis assembly, the Y-axis assembly, and the Z-axis assembly respectively apply pressure to the perfluoroether rubber sleeve along the first direction, the second direction, and the third direction;

[0047] The monitoring module is turned on;

[0048] The seepage module is turned on, and the acid fracturing fluid is introduced into the simulated wellbore;

[0049] The monitoring module monitors the flow rate of the acid fracturing fluid, the fluid distribution in the core, the acid-etched fracture or hydraulic fracture morphology, and the flow conductivity.

[0050] The true triaxial acid fracturing mold, the flow conductivity integrated synchronous testing device, and the method provided by the application can realize four-sided rigid extrusion and two-sided contact through the liquid chamber, compared with the traditional way of using rigid contact on the six sides of the core to extrude the core, the stress concentration problem caused by the six-sided rigid contact can be reduced; in addition, the seepage module can be used to better simulate the seepage condition inside the core, and the accuracy of the test can be improved. Secondly, the monitoring module can be used to realize the integrated monitoring of the fluid distribution in the core, the acid-etched fracture or hydraulic fracture morphology, and the flow conductivity, while reducing the adverse effects of stress concentration, improving the accuracy of the test, and reducing the cost without the need for step-by-step experiments and tests.

[0051] The structure of the application and its other application purposes and beneficial effects will be more obvious and easy to understand through the description of the preferred embodiments in conjunction with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0053] Fig. 1 is a structural schematic diagram of a true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0054] Fig. 2 is a structural schematic diagram of a clamping module of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0055] Fig. 3 is a structural schematic diagram of a servo module of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0056] Fig. 4 is a structural schematic diagram of a seepage module of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0057] Fig. 5 is a sectional structural schematic diagram of a simulated wellbore of the seepage module of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0058] Fig. 6 is a partial sectional structural schematic diagram of a simulated wellbore and a receiving coil of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0059] Fig. 7 is a top structural schematic diagram of the simulated wellbore and the receiving coil of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0060] Fig. 8 is a partial sectional structural schematic diagram of a simulated wellbore and an acoustic emission probe of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0061] Fig. 9 is a top structural schematic diagram of the simulated wellbore and the acoustic emission probe of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application;

[0062] Fig. 10 is a flow schematic diagram of a method of the true triaxial acid fracturing mold and flow capacity integrated synchronous testing device provided by an embodiment of the present application.

[0063] Explanation of reference signs: 10-true triaxial acid fracturing mold, diversion capacity integrated synchronous testing device; A-core; Y-second direction; Z-third direction; 100-clamping module; 110-clamp; 120-Y axis assembly; 121-indirect pressure head; 122-baffle; 123-second liquid chamber; 130-Z axis assembly; 131-upper plug; 132-pressure booster; 133-hydraulic coring tool; 134-lower plug; 140-perfluoroether rubber sleeve; 150-sealing ring; 160-temperature sensing element; 170-heating element; 180-X axis assembly; 181-frame; 182-first liquid chamber; 200-servo module; 210-X axis pump group; 220-Y axis pump group; 230-Z axis pump group; 240-regulating assembly; 241-pressure gauge; 242-needle valve; 243-three-way valve; 300-seepage module; 310-simulated wellbore; 311-tubing; 312-casing; 313-packer; 314-fixed resin; 315-flowback outlet valve; 316-pressure relief valve; 320-vessel; 330-acid fracturing pump group; 331-pressure regulating valve; 332-flow controller; 333-buffer vessel; 334-gas booster pump; 400-monitoring module; 410-acoustic emission probe; 420-main magnet; 430-electromagnetic wave emitting element; 440-receiving coil; 500-control module.

[0064] The specific embodiments of the present application have been shown and described in the foregoing drawings, which will be described in more detail hereinafter. These drawings and detailed description are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to a person skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0065] Firstly, the current experimental evaluation of acid fracturing process parameter optimization mostly uses rock samples after triaxial compression to carry out diversion capacity, hydraulic fracture or acid etching fracture morphology research, and multiple researches are carried out separately. However, the rock sample will be damaged after compression and then stress loading or unloading in the next experimental process, and the opening of the fracture and the friction coefficient will be greatly affected. When the related device obtains the fracture morphology, diversion capacity and other parameters of the rock sample in real time, the metal frame around the rock sample and the gas-liquid pipeline will interfere, resulting in that the nuclear magnetic scanning cannot rotate fully, so the morphology of the hydraulic fracture or acid etching fracture in the rock sample cannot be collected, and the diversion capacity parameter situation of the formed hydraulic fracture or acid etching fracture cannot be mastered in real time. The device in the prior art cannot better simulate the real formation environment, and the reliability of the test result is poor, and the integrated monitoring of the fluid distribution, acid etching fracture or hydraulic fracture morphology and diversion capacity in the core cannot be realized.

[0066] Secondly, in the related art, in order to simulate the core compression condition of the real formation, a rigid object such as steel or iron is used to extrude the six surfaces of the core, which may cause stress concentration in the contact gap between the rigid object and the core, affect the overall mechanical properties of the rock, and result in unrealistic simulation and unreliable test results.

[0067] In addition, CN106896043B discloses a device for simulating cracking and evaluating crack seepage under true triaxial stress, which includes a core clamping system, a true triaxial stress loading system, an acid liquid and fracturing fluid injection system, and a seepage capacity measurement system. The device uses X-axis, Y-axis and Z-axis three planes to pressurize, and uses a perforated hastelloy alloy through plate to compress a tetrafluoroethylene rubber sealing sleeve. However, the left side of the tetrafluoroethylene rubber sealing sleeve is fully open, and the core is easy to overflow from the left side after fracturing, which cannot reflect the real flow conductivity of the core.

[0068] Based on the above technical problems, the embodiments of the present application provide a true triaxial acid fracturing object and flow conductivity integrated synchronous testing device and method. The device includes a clamping module, which includes a clamp, an X-axis assembly, a Y-axis assembly, a Z-axis assembly and a perfluoroether rubber sleeve. The X-axis assembly, the Y-axis assembly and the Z-axis assembly are connected to the clamp. The perfluoroether rubber sleeve is used to wrap the core. The X-axis assembly is located on the opposite sides of the perfluoroether rubber sleeve along a first direction. The Y-axis assembly is located on the opposite sides of the perfluoroether rubber sleeve along a second direction. The Z-axis assembly is located on the opposite sides of the perfluoroether rubber sleeve along a third direction. The first direction, the second direction and the third direction are perpendicular to each other. At least one side of the X-axis assembly, the Y-axis assembly and the Z-axis assembly is in close contact with the inside of the perfluoroether rubber sleeve. The X-axis assembly, the Y-axis assembly and the Z-axis assembly each have an independent liquid chamber. A servo module is connected to the X-axis assembly, the Y-axis assembly and the Z-axis assembly. The servo module is used to change the liquid chamber of the X-axis assembly, the Y-axis assembly and the Z-axis assembly. A seepage module includes a simulated wellbore. One end of the simulated wellbore is used to introduce acidizing and fracturing fluid, and one end is located in the core. A monitoring module is used to monitor the flow of acidizing and fracturing fluid, the distribution of acidizing and fracturing fluid in the core, the morphology of acid-etched cracks or hydraulic fractures and the flow conductivity. The clamping module is configured to change the liquid chamber of the X-axis assembly, the Y-axis assembly and the Z-axis assembly under the driving of the servo module, so as to extrude the core wrapped by the perfluoroether rubber sleeve.

[0069] The true triaxial acid fracturing mold, flow conductivity integrated synchronous testing device and method provided by the embodiment of the present application can realize four rigid extrusions and contact of two sides through a liquid chamber, compared with the traditional method of rigid contact on the six outer sides of the core to extrude the core, has more uniform stress distribution, and can reduce the stress concentration problem caused by the six rigid contacts. In addition, by setting the seepage module, the seepage condition inside the core can be better simulated, and the accuracy of the test can be improved. Secondly, by setting the monitoring module, the fluid distribution in the core, the acid etching crack or hydraulic fracture morphology and the flow conductivity can be integrated monitored. On the one hand, the experimental results are close to the actual situation, and on the other hand, the cost can be reduced, and the experiment and test do not need to be completed step by step.

[0070] To make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below in combination with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals represent the same or similar structural elements or structural elements with the same or similar functions throughout. The described embodiments are part of the structural embodiments of the present application, not the whole structural embodiments. The embodiments described below in combination with the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below in combination with the drawings.

[0071] Referring to FIG. 1, in a first aspect, the embodiment of the present application provides a true triaxial acid fracturing mold, flow conductivity integrated synchronous testing device 10, which comprises a clamping module 100, a servo module 200, a seepage module 300 and a monitoring module 400.

[0072] Referring to FIG. 2, specifically, the clamping module 100 comprises a clamp 110, an X-axis assembly 180, a Y-axis assembly 120, a Z-axis assembly 130 and a perfluoroether rubber sleeve 140. The clamp 110 can provide a stable support structure to ensure the correct position and movement trajectory of each assembly. The perfluoroether rubber sleeve 140 is used to wrap the core A.

[0073] It can be understood that the perfluoroether rubber (FFKM) has excellent high-temperature resistance, can maintain stable performance in high-temperature environment, is not easy to deform or age, and is suitable for use in high-temperature conditions. In addition, the perfluoroether rubber has excellent chemical corrosion resistance and can resist the corrosion of various chemicals, is not easy to be corroded and damaged, and has a long service life. Furthermore, the perfluoroether rubber has good sealing performance, can effectively prevent the leakage of liquid or gas, and ensure the sealing and stability of the system. The perfluoroether rubber has high wear resistance, can resist friction and wear, maintain smooth surface, and prolong service life. The perfluoroether rubber is an environmentally friendly material, does not contain harmful substances such as freon, meets environmental protection requirements, and is harmless to the human body and the environment.

[0074] By using the perfluoroether rubber sleeve 140 to wrap the core A, the perfluoroether rubber sleeve 140 protects and fixes the core A, preventing the core A from being damaged or moving during clamping. In addition, the perfluoroether rubber sleeve 140 can ensure the sealing of the core A from the external environment, and will not affect the influence of the acidizing and fracturing fluid on the core A, thereby ensuring the reliability of the test and experiment. It should be noted that the core A is wrapped by the perfluoroether rubber sleeve 140 only on four sides, such as the four sides in the X-axis and Y-axis directions.

[0075] The X-axis assembly 180, the Y-axis assembly 120, and the Z-axis assembly 130 are all connected to the clamp 110. The X-axis assembly 180 is located on the opposite sides of the perfluoroether rubber sleeve 140 along the first direction, the Y-axis assembly 120 is located on the opposite sides of the perfluoroether rubber sleeve 140 along the second direction Y, and the Z-axis assembly 130 is located on the opposite sides of the perfluoroether rubber sleeve 140 along the third direction Z. The first direction, the second direction Y, and the third direction Z are perpendicular to each other. In this way, the device 10 can realize multi-axis motion control, accurate positioning, and clamping of the target object.

[0076] It can be understood that the first direction is the X-axis direction, the second direction Y is the Y-axis direction, and the third direction Z is the Z-axis direction.

[0077] In this way, the X-axis assembly 180, the Y-axis assembly 120, and the Z-axis assembly 130 are located on different sides of the perfluoroether rubber sleeve 140, so that the core A can be clamped and fixed in three directions to realize multi-axis clamping and fixing, and improve the stability and precision of clamping.

[0078] Among them, at least one of the X-axis assembly 180, the Y-axis assembly 120, and the Z-axis assembly 130 is in close contact with the inner side of the perfluoroether rubber sleeve 140 to extrude the core wrapped by the perfluoroether rubber sleeve 140.

[0079] The X-axis assembly, the Y-axis assembly and the Z-axis assembly each have an independent liquid chamber, and the liquid chamber is communicated with the perfluoroether rubber sleeve 140; by arranging the liquid chamber, a certain liquid pressure environment can be formed around the perfluoroether rubber sleeve 140, which is beneficial to the uniform distribution and transmission of the liquid and improves the extrusion effect on the core A.

[0080] The servo module 200 is connected with the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130, and the servo module 200 is used to change the liquid chamber of the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130.

[0081] The seepage module 300 includes a simulated wellbore 310, one end of the simulated wellbore 310 is used to introduce acidizing fracturing fluid, and the one end is located in the core A; the simulated wellbore 310 can simulate downhole conditions in a laboratory environment, and can simulate the underground rock structure and fluid seepage in an actual oil field, so that it is possible to study and test the seepage behavior of the acidizing fracturing fluid in the core A.

[0082] The monitoring module 400 is used to monitor the flow of the acidizing fracturing fluid, and is used to monitor the fluid distribution in the core A and the flow conductivity of the core after the acidizing fracturing fluid acts. The monitoring module 400 can monitor the flow of the acidizing fracturing fluid in real time, understand the fluid behavior in the simulated wellbore 310, and monitor the acid-etched cracks or hydraulic fracture morphology in the core A at the same time, thereby providing data support for studying the rock seepage characteristics.

[0083] The clamping module 100 is configured to change the liquid chamber of the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130 under the driving of the servo module 200. If the pressure of the liquid chamber changes, such as increases, the liquid chamber will extrude the core A wrapped by the perfluoroether rubber sleeve 140. Through the movement of the clamping module 100, uniform extrusion of the core A can be realized, the wrapping and compaction effect of the perfluoroether rubber sleeve 140 on the core A is ensured, and the accuracy and reliability of the experiment are improved.

[0084] It can be understood that in the clamping module 100, one of the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130 can directly contact and extrude the perfluoroether rubber sleeve 140; or other structures can be driven by the liquid chamber to extrude the perfluoroether rubber sleeve 140 to realize indirect extrusion.

[0085] By setting the clamping module 100, the liquid chamber has a more uniform stress distribution compared to rigid extrusion, which can reduce the adverse effects of stress concentration. In addition, by setting the seepage module 300, the seepage condition inside the core A can be simulated well, and the accuracy of the test can be improved. Secondly, by setting the monitoring module 400, the fluid distribution inside the core, the acid-etched crack or hydraulic fracture morphology and the integrated monitoring of the flow conductivity can be realized, and the synchronization of the test and the monitoring can be realized. On the one hand, the experimental results are close to the real situation, and on the other hand, the cost can be reduced, and the experiment and the test do not need to be completed step by step.

[0086] As an optional implementation, one of the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130 includes a frame 181, and the frame 181 and the perfluoroether rubber sleeve 140 form a first liquid chamber 182. The first liquid chamber 182 formed by the frame 181 and the perfluoroether rubber sleeve 140 is in communication with the servo module 200, so that the control and transmission of the liquid can be realized, and the uniform distribution and effect of the liquid during the extrusion of the core A can be ensured.

[0087] The first liquid chamber 182 is configured to change under the driving of the frame 181 to extrude the core A wrapped by the perfluoroether rubber sleeve 140. By driving the frame 181, the first liquid chamber 182 changes to realize the extrusion operation of the core A wrapped by the perfluoroether rubber sleeve 140, so as to ensure the processing effect and operation precision of the core A.

[0088] It can be understood that the first liquid chamber 182 can be used in a position where a rigid structure cannot abut, and can directly abut the perfluoroether rubber sleeve 140, that is, the liquid in the first liquid chamber 182 can directly extrude the core A. Compared with the traditional way of using rigid contact on the six sides of the core to extrude the core, the stress concentration problem caused by the six rigid contacts can be reduced.

[0089] At least one of the other two of the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130 includes an indirect pressure head 121 and a baffle 122, the indirect pressure head 121 is close to the perfluoroether rubber sleeve 140 relative to the baffle 122, and the indirect pressure head 121 and the baffle 122 are spaced apart to form a second liquid chamber 123. The second liquid chamber 123 realizes the control and transmission of the liquid, and ensures the uniform distribution and effect of the liquid during the extrusion of the core A.

[0090] The second liquid chamber 123 is configured to change under the driving of the indirect pressure head 121 and drive the indirect pressure head 121 to move to extrude the core A wrapped by the perfluoroether rubber sleeve 140. The second liquid chamber 123 is configured to change under the driving of the servo module 200 and drive the indirect pressure head 121 to move, so as to realize the extrusion operation on the core A and ensure the processing effect and operation accuracy of the core A in the experiment.

[0091] It can be understood that the second liquid chamber 123 indirectly abuts against the perfluoroether rubber sleeve 140 through the indirect pressure head 121, that is, the liquid in the second liquid chamber 123 can indirectly extrude the core A, and the user can adjust the extrusion force of the indirect pressure head 121 on the perfluoroether rubber sleeve 140 by adjusting the liquid pressure in the second liquid chamber 123, which has high adjustment accuracy and is beneficial to realize accurate experiment and test.

[0092] It should be noted that the shapes of the first liquid chamber 182 and the second liquid chamber 123 can be arbitrary. For example, the shapes of the first liquid chamber 182 and the second liquid chamber 123 are the same, both being cuboids or cylinders, etc. For another example, the shapes of the first liquid chamber 182 and the second liquid chamber 123 are different, for example, the first liquid chamber 182 is a cuboid and the second liquid chamber 123 is a cylinder. The specific shapes of the first liquid chamber 182 and the second liquid chamber 123 are not limited in the application embodiment, and are not limited to the above examples.

[0093] As an optional embodiment, the X-axis assembly 180 includes a frame 181, that is, the first liquid chamber 182 is formed between the X-axis assembly 180 and the perfluoroether rubber sleeve 140. Referring to FIG. 2, the Y-axis assembly 120 includes the indirect pressure head 121 and the baffle 122, that is, the second liquid chamber 123 is formed between the indirect pressure head 121 and the baffle 122.

[0094] As an optional embodiment, the first liquid chamber 182 and the second liquid chamber 123 are isolated by the indirect pressure head 121.

[0095] The pressure of the second liquid chamber 123 is greater than that of the first liquid chamber 182, so that the liquid in the second liquid chamber 123 can avoid moving the baffle 122 away from the perfluoroether rubber sleeve 140, and further avoid the pressure of the core A in the first direction and the second direction Y being the same, which does not conform to the stress condition of the real core A and cannot realize more realistic formation simulation.

[0096] As shown in FIG. 2, as an optional embodiment, the Z-axis assembly 130 includes an upper plug 131 abutting a top of the perfluoroether rubber sleeve 140 and a booster 132 located on a side of the upper plug 131 away from the perfluoroether rubber sleeve 140. The booster 132 is configured to provide pressure to the upper plug 131 to press the perfluoroether rubber sleeve 140. The booster 132 can be used to precisely control and adjust the upper plug 131, thereby ensuring accurate control of the pressure and position of the perfluoroether rubber sleeve 140.

[0097] As an optional embodiment, the Z-axis assembly 130 includes a hydraulic coring device 133 located at a bottom of the perfluoroether rubber sleeve 140. The hydraulic coring device 133 includes a lower plug 134 abutting the perfluoroether rubber sleeve 140. The hydraulic coring device 133 is configured to move the lower plug 134 towards or away from the perfluoroether rubber sleeve 140 to load or unload the core.

[0098] It should be noted that the booster 132 and the hydraulic coring device 133 can work independently.

[0099] As shown in FIG. 2, as an optional embodiment, the clamping module 100 further includes a sealing ring 150, a temperature sensing device 160, and a heating device 170.

[0100] Specifically, the sealing ring 150 is located between the frame 181 and the perfluoroether rubber sleeve 140, and between the indirect pressure head 121 and the baffle 122. The sealing ring 150 can effectively prevent liquid or gas leakage, thereby ensuring the sealing and stability during the experiment.

[0101] The temperature sensing device 160 includes a temperature sensing end. The temperature sensing end is close to the perfluoroether rubber sleeve 140, which can more accurately obtain the temperature information of the surface or the inside of the core A, and reduce the influence of thermal resistance between the sensor and the core A. The temperature sensing end is configured to obtain the temperature information of the core A wrapped by the perfluoroether rubber sleeve 140, thereby providing important temperature information for the experiment.

[0102] The heating device 170 is electrically connected to the temperature sensing device 160. The heating device 170 is configured to obtain the temperature information obtained by the temperature sensing device 160, and heat the perfluoroether rubber sleeve 140. In this way, according to the temperature data obtained by the temperature sensing device 160, the working state and power of the heating device 170 are controlled to realize the heating control of the perfluoroether rubber sleeve 140, thereby ensuring the temperature requirement and stability of the experiment.

[0103] It can be understood that by setting the temperature sensing device 160 and the heating device 170, the actual temperature state of the formation can be simulated to simulate the real formation.

[0104] As an alternative embodiment, the servo module 200 includes,

[0105] The X-axis pump group 210 is connected to the first liquid chamber 182, and is used to inject or suck liquid into the first liquid chamber 182. The X-axis pump group 210 can precisely control and adjust the liquid in the first liquid chamber 182, thereby ensuring the accuracy and stability of the experimental operation.

[0106] The Y-axis pump group 220 is connected to the second liquid chamber 123, and is used to inject or suck liquid into the second liquid chamber 123. The Y-axis pump group 220 can precisely control and adjust the liquid in the second liquid chamber 123, thereby ensuring the accuracy and stability of the experimental operation.

[0107] The Z-axis pump group 230 is connected to the pressure booster 132, and is used to inject or suck liquid into the pressure booster 132 to change the pressure of the pressure booster 132. The Z-axis pump group 230 can precisely control and adjust the liquid in the pressure booster 132, thereby ensuring the accuracy and stability of the experimental operation.

[0108] The three regulating assemblies 240 each include a pressure gauge 241 and a needle valve 242. The needle valve 242 is connected to the pressure gauge 241. Each needle valve 242 is connected to a pump group. The regulating assembly 240 is used to regulate the pressure and flow of the corresponding pump group. The pressure is monitored by the pressure gauge 241, thereby achieving precise control and adjustment of the liquid.

[0109] It can be understood that the X-axis pump group 210, the Y-axis pump group 220, and the Z-axis pump group 230 can each be a constant-speed constant-pressure pump group. It should be noted that, in order to ensure the accuracy of the constant-speed constant-pressure pump group, the constant-speed constant-pressure pump group can include two pumps with opposite directions, i.e., the X-axis pump group 210, the Y-axis pump group 220, and the Z-axis pump group 230 each include two pumps with opposite working directions. One pump is used to inject liquid to increase the pressure, and the other pump is used to suck liquid to decrease the pressure.

[0110] It should be noted that the two pumps can be connected by a three-way valve 243, i.e., each regulating assembly 240 further includes a three-way valve 243. In addition, each regulating assembly 240 includes two needle valves 242, i.e., the three ends of the three-way valve 243 are connected to the pressure gauge 241 and the two needle valves 242.

[0111] As an alternative embodiment, the simulated wellbore 310 includes a tubing 311, a casing 312, and a packer 313, as shown in FIG. 5.

[0112] The tubing 311 is used for transmitting the simulated well fluid or other experimental medium, and plays a role of transmission and encapsulation. In the embodiment of the present application, the tubing 311 is used for transmitting the acid fracturing fluid. The casing 312 is sleeved on the outer periphery of the tubing 311, and is used for protecting the tubing 311 and providing additional support and protection to prevent the tubing 311 from being damaged or corroded by the external environment. The casing 312 is usually made of metal or other materials. The packer 313 is located between the tubing 311 and the casing 312, and is used for isolating different parts of the fluid or medium, and plays a role of closing and separating.

[0113] The fixing resin 314 covers the packer 313 and part of the casing 312, and is used for fixing the simulated wellbore 310 in the core A. The fixing resin 314 can provide stable support and fixation, and ensure that the simulated wellbore 310 does not move or deform during the experiment, thereby ensuring the accuracy and reliability of the experimental results.

[0114] Referring to FIG. 2, in some embodiments, the simulated wellbore 310 further includes a flowback outlet valve 315 and a pressure relief valve 316. The flowback outlet valve 315 is connected between the tubing 311 and the casing 312, and is used for annular fluid flowback between the tubing 311 and the casing 312. During the experiment, annular fluid may accumulate between the tubing 311 and the casing 312, affecting fluid circulation and the accuracy of experimental results. By providing the flowback outlet valve 315, the annular fluid can be discharged regularly or as needed to ensure smooth fluid circulation and avoid experimental errors caused by accumulation. It can be understood that the flowback outlet valve 315 can be connected to the annular flowback outlet 3121 of the casing 312.

[0115] The pressure relief valve 316 is connected to the tubing 311. During the experiment, if there is an abnormal pressure or a situation that requires rapid pressure relief, the pressure relief valve 316 can be used to release the pressure, thereby protecting the experimental equipment and the safety of the operator.

[0116] Referring to FIG. 4, as an optional implementation, the seepage module 300 further includes a container 320 and an acid fracturing pump set 330.

[0117] The container 320 is connected to the simulated wellbore 310, and the container 320 is used for storing the acid fracturing fluid. The container 320 can effectively store and manage the acid fracturing fluid, and ensure sufficient supply and control of the fluid during the experiment.

[0118] The acid fracturing pump set 330 is connected to the container 320, and is used for flowing the acid fracturing fluid in the container 320 into the simulated wellbore 310. The acid fracturing pump set 330 is used for providing fluid pressure and flow to deliver the acid fracturing fluid stored in the container 320 to the experimental device 10. The acid fracturing pump set 330 can control the flow rate and pressure of the acid fracturing fluid, and ensure accurate supply and flow of the fluid during the experiment.

[0119] Referring to FIG. 4, in some embodiments, the acid fracturing pump set 330 is also connected with a pressure regulating valve 331 and a flow controller 332.

[0120] Through the setting of the pressure regulating valve 331, the pressure of the fluid can be monitored and adjusted in real time, ensuring that it remains stable within the set range, improving the safety and stability of the experiment or operation.

[0121] The flow controller 332 is used to control the flow size of the fluid. Through the setting of the flow controller 332, the flow size of the fluid can be accurately adjusted, ensuring that the supply amount of the fluid meets the requirements during the experiment or operation, improving the accuracy and controllability of the experiment or operation.

[0122] As an optional implementation, the acid fracturing fluid includes one or more of water, fracturing fluid, acid fluid, and supercritical CO2.

[0123] It can be understood that the acid fracturing fluid can only include water, only fracturing fluid, only acid fluid, or only supercritical CO2. Of course, the acid fracturing fluid can also be a mixture of the above-mentioned fluids. The specific components of the acid fracturing fluid in the embodiments of the present application are not limited, and are not limited to the above-mentioned examples.

[0124] In some embodiments, water is usually used as a base liquid. Water plays a role in dissolving, delivering, and diluting other components during the acid fracturing process. As a basic component of the acid fracturing fluid, water, through mixing and dissolving with other components, forms a fluid with specific properties and concentrations for the experiment or operation process.

[0125] In some embodiments, the fracturing fluid is used to increase the viscosity and fracturing effect of the fluid. The fracturing fluid usually contains additives and adjuvants for improving the properties and effects of the fluid and increasing the permeability of the fluid in the rock.

[0126] In some embodiments, the acid fluid is used to dissolve minerals in the core A and increase the porosity. The acid fluid usually contains acid substances such as hydrochloric acid, mud acid. The addition of acid fluid can promote the dissolution and destruction of rock, increase the porosity and permeability, and improve the effect and success rate of acid fracturing.

[0127] In some embodiments, supercritical CO2 has high permeability and solubility, which improves the permeation effect of the fluid in the rock.

[0128] It is to be noted that the acid fracturing fluid is supercritical CO2, and the gas booster pump 334 and the buffer container 333 are further included, the gas booster pump 334 is provided with a gas cylinder as a gas source, and the gas booster pump 334 can compress the gas to a maximum pressure of 150 MPa, so as to realize the superhigh-pressure gas flow capacity test and the supercritical CO2 preparation. The buffer container 333 is used for storing and heating the gas compressed by the gas booster pump 334, for example, the buffer container 333 is used for storing and heating the CO2 compressed by the gas booster pump 334 to a critical temperature of 31.1°C or above. The buffer container 333 can be a high-pressure buffer container 333.

[0129] As an optional embodiment, the monitoring module 400 includes the acoustic emission probe 410, the main magnet 420, the electromagnetic wave emitter 430 and the receiving coil 440, as shown in FIGS. 1, 6-9.

[0130] The acoustic emission probe 410 is installed in the perfluoroether rubber sleeve 140 and on the surface of the core A, and is used for receiving the acoustic signals of rock breaking in the acid fracturing process of the core A, so as to monitor the acid-etched fracture or the hydraulic fracture morphology and provide important data for the percolation process of the acid fracturing fluid.

[0131] The main magnet 420, the electromagnetic wave emitter 430 and the receiving coil 440 are all installed on the holder 110, and the main magnet 420, the electromagnetic wave emitter 430 and the receiving coil 440 are configured to cooperate with each other to monitor the flow of the acid fracturing fluid by nuclear magnetic resonance.

[0132] The main magnet 420 is used for generating a strong magnetic field, and the atomic nuclei of the fluid in the core A precess in the strong magnetic field and have a certain frequency.

[0133] The electromagnetic wave emitter 430 is used for emitting electromagnetic waves with the same frequency as the precession frequency, i.e., nuclear magnetic resonance. In the resonance process, the atomic nuclei can absorb the energy of the electromagnetic waves.

[0134] The receiving coil 440 is used for receiving and recording the electromagnetic wave signals before and after the resonance, so that the difference between the electromagnetic wave energies before and after the resonance (the atomic nucleus energy absorption curve) can form a nuclear magnetic resonance spectrum, and the spectrum can monitor the flow of the acid fracturing fluid. Through the cooperation of the main magnet 420, the electromagnetic wave emitter 430 and the receiving coil 440, nuclear magnetic resonance can be formed to monitor the flow of the acid fracturing fluid in real time, monitor the distribution of the fluid in the fluid, and infer the composition and distribution of the fluid according to the signal characteristics of the fluid, so as to provide data support for the analysis of the experimental results.

[0135] The receiving coil 440 is used for receiving the electromagnetic wave signals to monitor the flow of the acid fracturing fluid.

[0136] Referring to FIG. 1, as an optional embodiment, the device 10 further comprises a control module 500, which comprises a temperature control module, a processor and a pressure control module. The processor can be electrically connected to the temperature control module and the pressure control module, and control the use of the temperature control module and the pressure control module.

[0137] The temperature control module is electrically connected to the heating rod, and the output power of the heating rod is controlled to realize the heating and temperature control of the core A. Through the electrical connection between the temperature control module and the heating rod, the output power of the heating rod can be accurately controlled to realize the heating and temperature control of the core A, and ensure the stability and accuracy of the experimental conditions.

[0138] The pressure control module is electrically connected to the servo module 200 and the seepage module 300, and is used to control the triaxial stress of the servo module 200 and the fluid pressure.

[0139] The pressure control module is electrically connected to the servo module 200 and the seepage module 300, and is used to control the triaxial stress of the servo module 200 and the fluid pressure. By adjusting the output signal of the control module, the stress and fluid pressure of the servo module 200 can be accurately controlled to provide the required pressure environment for the experiment. In this way, the pressure conditions during the experiment can be ensured to be stable, and the accuracy and reliability of the experimental data can be ensured.

[0140] Referring to FIG. 10, in a second aspect, the embodiments of the present application further provide a method for a true triaxial acid fracturing model and flow conductivity integrated synchronous testing device 10, which is used for the true triaxial acid fracturing model and flow conductivity integrated synchronous testing device 10, and the method comprises:

[0141] S100, placing the core wrapped by the perfluoroether rubber sleeve on the clamp of the clamping module;

[0142] First, the core A is wrapped with the perfluoroether rubber sleeve 140 to ensure that the surface of the core A is smooth and protected. Then, the wrapped core A is placed on the clamp 110 of the clamping module 100, i.e. between the X, Y and Z axis assemblies 130, to ensure the stability and accuracy of the core A during the experiment.

[0143] By wrapping the core A with the perfluoroether rubber sleeve 140, the core A can be effectively isolated from the external environment, and the core A can be protected from external influences. The core A is placed between the X, Y and Z axis assemblies 130 to provide stable support and positioning for subsequent experiments.

[0144] S200, turning on the servo module, so that the X-axis assembly, the Y-axis assembly and the Z-axis assembly respectively exert pressure on the perfluoroether rubber sleeve along the first direction, the second direction and the third direction;

[0145] The servo module 200 is turned on, the pressure of the liquid chamber corresponding to the X, Y and Z axis assemblies 130 is adjusted, the pressure of the liquid chamber of the X axis assembly is increased, and the liquid directly applies pressure to the perfluoroether rubber sleeve 140; the pressures of the liquid chambers of the Y axis assembly and the Z axis assembly are both increased, and the liquid pushes the indirect pressure head 121 and the upper plug 131 to apply pressure to the perfluoroether rubber sleeve 140. Through the precise control of the servo module 200, the pressure environment to which the underground rock is subjected can be simulated, and real conditions are provided for subsequent experiments.

[0146] Through the control of the servo module 200, the X, Y and Z axis assemblies 130 can extrude the core A wrapped by the perfluoroether rubber sleeve 140, simulate the real underground pressure environment, and provide necessary conditions for subsequent experiments.

[0147] S300, turn on the monitoring module;

[0148] The monitoring module 400 is turned on, and various data in the experimental process are monitored in real time through sensors and other devices, including pressure, temperature, flow rate and other parameters, so that the experimental conditions can be adjusted in time and the experimental results can be recorded. The opening of the monitoring module 400 can monitor various parameters and data in the experimental process in real time, ensuring the accuracy and reliability of the experiment.

[0149] S400, turn on the seepage module, and introduce the acidizing and fracturing fluid into the simulated wellbore;

[0150] The seepage module 300 is started, and the pre-prepared acidizing and fracturing fluid is introduced into the simulated wellbore 310, so that the effect of acidizing and fracturing on the underground rock can be simulated. In this way, relevant experimental research can be carried out to understand the properties and reaction of the rock.

[0151] By turning on the seepage module 300, the acidizing and fracturing fluid can be introduced into the simulated wellbore 310 to simulate the environment of acidizing and fracturing on the underground rock, and relevant experimental research can be carried out.

[0152] S500, the monitoring module monitors the flow rate of the acidizing and fracturing fluid, the distribution of the acidizing and fracturing fluid in the core, the morphology and conductivity of the acid-etched fracture or hydraulic fracture.

[0153] The monitoring module 400 monitors the flow rate of the acidizing and fracturing fluid through sensors and other devices, and monitors the fluid distribution in the core A, the morphology and conductivity of the acid-etched fracture or hydraulic fracture in real time, providing data support for the analysis and evaluation of experimental results.

[0154] In some embodiments, before the core A is wrapped with the perfluoroether rubber sleeve 140, the following steps are included:

[0155] S010, cutting the formation core or natural outcrop into a square core column with a size of 100*100*200mm; the square core column is the core A.

[0156] S020, drilling a hole with a diameter of 15 mm and a depth of 75 mm in the center of the prepared core column end face;

[0157] S030, winding tape around the variable diameter below the packer 313; in this way, the fixed resin 314 can avoid plugging the outlet;

[0158] S040, inserting the simulated wellbore 310 into the core A end face hole, and injecting the fixed resin 314 to fix the simulated wellbore 310;

[0159] In some embodiments, the core A is wrapped with the perfluoroether rubber sleeve 140, and the core A wrapped with the perfluoroether rubber sleeve 140 is placed between the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130, including:

[0160] S110, wrapping the core A with the perfluoroether rubber sleeve 140;

[0161] S120, pushing the lower plug 134 with the hydraulic coring tool 133;

[0162] S130, placing the core A wrapped with the perfluoroether rubber sleeve 140 into the clamping module 100, so that the bottom of the perfluoroether rubber sleeve 140 covers the lower plug 134 of the core A holder;

[0163] S140, lowering the lower plug 134 of the core A holder to the bottom with the hydraulic coring tool 133;

[0164] S150, covering the upper plug 131, so that the upper part of the perfluoroether rubber sleeve 140 covers the upper plug 131, and the core A wrapped with the perfluoroether rubber sleeve 140 is placed between the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130.

[0165] In some embodiments, after the core A wrapped with the perfluoroether rubber sleeve 140 is placed between the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130, before the servo module 200 is started, further including:

[0166] S160, starting the temperature control module and setting the target temperature. The target temperature can be heated to a maximum of 300°C.

[0167] S170, calculating the difference between the temperature sensing element 160 test temperature and the target temperature by the processor, and controlling the heating power of the heating element 170.

[0168] In some embodiments, the servo module 200 is started, so that the X-axis assembly 180, the Y-axis assembly 120 and the Z-axis assembly 130 respectively apply pressure to the perfluoroether rubber sleeve 140 along the first direction, the second direction Y and the third direction Z, including:

[0169] S210, turn on the Y-axis pump group 220 to pump liquid into the second liquid chamber 123 to make the Y-axis pressure 1-2 MPa, so that the baffle 122 is tightly attached to the surface of the perfluoroether rubber sleeve 140;

[0170] S220, turn on the X-axis pump group 210 to pump liquid into the first liquid chamber 182 to make the X-axis pressure 0.5 MPa;

[0171] S230, turn on the Z-axis pump group 230 to make the core A bear a certain initial pressure in the third direction Z;

[0172] In this way, the core A is simultaneously pressed in three directions to the actual three-directional stress of the formation, and it is ensured that the Y-axis pressure is always greater than the X-axis pressure during the entire pressurization process, avoiding that the liquid in the second liquid chamber 123 pushes the indirect pressure head 121 back to cause the core A to bear the same pressure in the first direction X and the second direction Y.

[0173] It can be understood that the servo module 200 can make the core A be in the actual pressure environment of the simulated target reservoir, and the highest working pressure of the servo module 200 is 200 MPa.

[0174] In some embodiments, the monitoring module 400 is turned on, including:

[0175] S310, monitor the inlet end seepage pressure and the outlet end fluid flow of the simulated wellbore 310 during the acidizing and fracturing reconstruction of the core A. Among them, the outlet end pressure of the core A is recorded as atmospheric pressure, which reflects the change of the flow conductivity of the core A in real time during the reconstruction process.

[0176] S320, turn on the acoustic emission probe 410 to monitor the acoustic emission intensity change of each part of the core A;

[0177] S330, turn on the main magnet 420, the electromagnetic wave emitting element 430 and the receiving coil 440 to monitor the fluid distribution change in the core A.

[0178] In some embodiments, if the acidizing and fracturing fluid is water, the seepage module 300 is turned on to guide the acidizing and fracturing fluid into the simulated wellbore 310, including:

[0179] S410a, put water into the container 320;

[0180] S420a, turn on the acidizing and fracturing pump group 330 to push the piston of the container 320 to push the water into the simulated wellbore 310 for fracturing;

[0181] In some embodiments, if the acidizing and fracturing fluid is fracturing fluid, the seepage module 300 is turned on to guide the acidizing and fracturing fluid into the simulated wellbore 310, including:

[0182] S410b, put the fracturing fluid into the container 320;

[0183] S420b, open the acid fracturing pump set 330 to push the piston of the container 320 to push the fracturing fluid into the simulated wellbore 310 for fracturing.

[0184] In some embodiments, if the acid fracturing fluid is acid liquid. Open the seepage module 300 to guide the acid fracturing fluid into the simulated wellbore 310, including:

[0185] S410c, put the acid liquid into the container 320;

[0186] S420c, open the acid fracturing pump set 330 to push the piston of the container 320 to push the acid liquid into the simulated wellbore 310 for fracturing.

[0187] In some embodiments, if the acid fracturing fluid is supercritical CO2. Open the seepage module 300 to guide the acid fracturing fluid into the simulated wellbore 310, including:

[0188] S410d, heat the container 320 to 40℃;

[0189] S410d, the gas booster pump 334 takes the CO2 gas cylinder as the gas source, compresses the CO2 to a critical pressure of 7.39 MPa or more, and punches the supercritical CO2 in the buffer container 333 into the container 320.

[0190] S410d, open the acid fracturing pump set 330 to push the piston of the container 320 to push the supercritical CO2 into the simulated wellbore 310 for fracturing.

[0191] In some embodiments, the monitoring module 400 monitors the flow of the acid fracturing fluid, the distribution of the acid fracturing fluid in the core A, the acid-etched fracture or hydraulic fracture morphology and the conductivity of the core A, including:

[0192] S510, the processor automatically collects and calculates the permeability change of the core A during the acid fracturing operation and the gas test process of the core A and forms a data report;

[0193] S520, the processor automatically collects and records the acoustic emission signals of the core A at each part of the core A during the acid fracturing operation of the core A, inverts the fracture development and evolution of the core A, forms the acid-etched fracture or hydraulic fracture morphology graph of the core A at different times, the acid-etched fracture or hydraulic fracture width, and combines the permeability tested in the early stage to calculate the conductivity of the core after the acid fracturing experiment simulation.

[0194] S530, the processor automatically collects and records the fluid distribution change in the core A to invert the migration path of the fluid; forms the fluid distribution graph of the core A at different times.

[0195] In some embodiments, if the target reformation well is a gas well, after the acid fracturing fluid pumping is completed, nitrogen cylinders can be used as a gas source, a gas booster pump 334 is used to compress nitrogen into a buffer container 333, and a permeability test is performed. The pressure at the inlet end of the core A is adjusted using a pressure regulating valve 331, and the gas flow rate change is monitored in real time using a flow controller 332, combined with the monitored acid etching crack or hydraulic fracture width, and then the conductivity is calculated.

[0196] In the description of the embodiments of the present application, it should be understood that, unless specifically defined and limited otherwise, the terms "mount", "connect", "connection" should be interpreted broadly, for example, it can be fixed connection, or indirect connection through an intermediate medium, or the communication of the structure of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0197] The terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0198] The terms "first", "second", "third", "first" and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily describe a particular order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0199] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to the structure or whole structure technical features thereof; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A true triaxial acid fracturing model and a synchronous testing device for conductivity, characterized in that, include: A clamping module includes a clamp, an X-axis assembly, a Y-axis assembly, a Z-axis assembly, and a perfluoroether rubber sleeve. The X-axis assembly, Y-axis assembly, and Z-axis assembly are all connected to the clamp. The perfluoroether rubber sleeve is used to wrap the core sample. The X-axis assembly is located on opposite sides of the perfluoroether rubber sleeve along a first direction, the Y-axis assembly is located on opposite sides of the perfluoroether rubber sleeve along a second direction, and the Z-axis assembly is located on opposite sides of the perfluoroether rubber sleeve along a third direction. The first direction, the second direction, and the third direction are perpendicular to each other. At least one side of each of the X-axis assembly, the Y-axis assembly, and the Z-axis assembly is in close contact with the inner side of the perfluoroether rubber sleeve. Each of the X-axis assembly, the Y-axis assembly, and the Z-axis assembly has an independent liquid chamber. A servo module is connected to the X-axis assembly, the Y-axis assembly, and the Z-axis assembly, and the servo module is used to change the liquid chambers of the X-axis assembly, the Y-axis assembly, and the Z-axis assembly; The seepage module includes a simulated wellbore, one end of which is used to introduce acid fracturing fluid, and the other end is located inside the core. The monitoring module is used to monitor the flow rate of the acid fracturing fluid, the distribution of the acid fracturing fluid in the core, and the morphology and conductivity of the acid-etched fractures or hydraulic fractures. The clamping module is configured to, under the drive of the servo module, cause changes in the liquid chambers of the X-axis assembly, the Y-axis assembly, and the Z-axis assembly to compress the core encased in the perfluoroether rubber sleeve.

2. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to claim 1, characterized in that, One of the X-axis assembly, the Y-axis assembly, and the Z-axis assembly includes a frame, and a first liquid chamber is formed between the frame and the perfluoroether rubber sleeve, the first liquid chamber being in communication with the servo module; The first liquid chamber is configured to change under the drive of the servo module to compress the core encased in the perfluoroether rubber sleeve; At least one of the other two of the X-axis assembly, the Y-axis assembly, and the Z-axis assembly includes an indirect pressure head and a baffle, the indirect pressure head being close to the perfluoroether rubber sleeve relative to the baffle, and the indirect pressure head being spaced apart from the baffle to form a second liquid chamber; The second liquid chamber is configured to change under the drive of the servo module, thereby moving the indirect pressure head to compress the core encased in the perfluoroether rubber sleeve.

3. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to claim 2, characterized in that, The first liquid chamber and the second liquid chamber are isolated by the indirect pressure head, and the pressure in the second liquid chamber is greater than the pressure in the first liquid chamber.

4. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to claim 3, characterized in that, The X-axis assembly includes the frame, and the Y-axis assembly includes the indirect pressure head and the baffle; The Z-axis assembly includes an upper plug and a pressure booster. The upper plug abuts against the top of the perfluoroether rubber sleeve, and the pressure booster is located on the side of the upper plug opposite to the perfluoroether rubber sleeve. The pressure booster is used to provide pressure and transmit it to the plug so that the upper plug squeezes the perfluoroether rubber sleeve. And / or, The Z-axis assembly includes a hydraulic coring component located at the bottom of the perfluoroether rubber sleeve. The hydraulic coring component includes a lower plug for abutting against the perfluoroether rubber sleeve. The hydraulic coring component is used to move the lower plug closer to or away from the perfluoroether rubber sleeve to load and unload the core.

5. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to claim 4, characterized in that, The clamping module also includes: A sealing ring is located between the frame and the perfluoroether rubber sleeve, and between the indirect pressure head and the baffle. A temperature sensing element includes a temperature sensing end, which is close to the perfluoroether rubber sleeve. The temperature sensing element is used to obtain temperature information of the rock core wrapped by the perfluoroether rubber sleeve. A heating element is electrically connected to the temperature sensor. The heating element is used to acquire the temperature information acquired by the temperature sensor and to heat the perfluoroether rubber sleeve.

6. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to claim 4, characterized in that, The servo module includes, An X-axis pump unit is connected to the first liquid chamber, and the X-axis pump unit is used to inject or draw liquid into the first liquid chamber. A Y-axis pump unit is connected to the second liquid chamber, and the Y-axis pump unit is used to inject or draw liquid into the second liquid chamber. A Z-axis pump assembly is connected to the intensifier. The Z-axis pump assembly is used to inject or draw liquid into the intensifier to change the pressure of the intensifier. Three regulating components, each including a pressure gauge and a needle valve, the needle valve being connected to the pressure gauge, each needle valve being connected to a corresponding pump group, the regulating components being used to regulate the pressure and flow rate of the corresponding pump group.

7. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to any one of claims 1-6, characterized in that, The simulated wellbore includes, oil pipe; A casing is fitted around the outer periphery of the oil pipe; A packer is located between the tubing and the casing; A fixing resin is used to cover the packer and part of the casing to fix the simulated wellbore inside the core. And / or, The seepage module also includes, A container connected to the simulated wellbore, the container being used to store the acid fracturing fluid; An acid fracturing pump unit, connected to the container, is used to allow the acid fracturing fluid in the container to flow into the simulated wellbore.

8. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to any one of claims 1-6, characterized in that, The monitoring module includes, An acoustic emission probe is installed inside the perfluoroether rubber sleeve and mounted on the core surface. The acoustic emission probe is used to receive acoustic signals of rock fracturing during the core acid fracturing process in order to monitor the morphology of acid-etched fractures or hydraulic fractures. The main magnet, the electromagnetic wave transmitter, and the receiving coil are all mounted on the holder. The main magnet, the electromagnetic wave transmitter, and the receiving coil are configured to cooperate with each other to monitor the flow of acid fracturing fluid via nuclear magnetic resonance.

9. The true triaxial acid fracturing model and conductivity integrated synchronous testing device according to any one of claims 1-6, characterized in that, The acid fracturing fluid includes one or more of water, fracturing fluid, acid, and supercritical CO2.

10. A method for a true triaxial acid fracturing model and a synchronously integrated testing device for conductivity, characterized in that, The method for the integrated synchronous testing device for true triaxial acid fracturing model and conductivity as described in any one of claims 1-9 includes: The core, which is wrapped in the perfluoroether rubber sleeve, is placed on the clamp of the clamping module; The servo module is activated, and the X-axis assembly, Y-axis assembly, and Z-axis assembly apply pressure to the perfluoroether rubber sleeve along the first direction, the second direction, and the third direction, respectively. Enable monitoring module; Activate the seepage module to introduce acid fracturing fluid into the simulated wellbore; The monitoring module monitors the flow rate of the acid fracturing fluid, the fluid distribution within the core, and the morphology and conductivity of the acid-etched or hydraulic fractures.

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