Fracture wave and range evaluation method and system for indoor fracture temporary plugging acid fracturing

Abstract

The invention provides a crack wave and range evaluation method and system for indoor crack temporary plugging acid fracturing. The method comprises the steps that a rock sample is placed in a true triaxial fracturing device, triaxial stress is applied to the rock sample, and after confining pressure is stable, gelled acid liquid is injected into the rock sample till the pressure suddenly drops; injecting a temporary plugging agent into the rock sample, suddenly reducing the pressure again after the pressure building is successful, and ending the temporary plugging acid fracturing; injecting a tracer agent into the rock sample; and splitting the rock sample along the crack of the rock sample, scanning by using a 3D scanner, and evaluating the crack sweep range through three-dimensional modeling according to the volume of holes directly communicated with the crack and the volume of holes indirectly communicated with the tracer agent. The system comprises a true triaxial fracturing device, a multi-pump parallel injection device and a 3D scanner. According to the method and the system, the problems that the fibers cannot enter the pipeline in the temporary plugging process of the seam and the temporary plugging acid fracturing effect of the seam cannot be accurately evaluated are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploitation, and in particular relates to a method and system for evaluating the crack spread range for indoor crack temporary plugging and acid fracturing. Background Art

[0002] Carbonate reservoirs are one of the key and hot areas in the current oil and gas exploration and development, and the acid fracturing transformation process is one of the leading technologies for increasing production and stabilizing the development of carbonate oil and gas reservoirs, and is a key technology for the exploration and development of carbonate oil and gas reservoirs. Conventional acid fracturing refers to the acid injection into the formation under the condition that the bottom hole construction pressure is greater than the fracture pressure of the formation rock. The formation cracks to form artificial fractures. The acid always flows in the open fractures and reacts with the fracture wall, and finally forms fractures with a certain length and a certain acid erosion conductivity to improve the permeability of the reservoir. On the basis of conventional acid fracturing, many scholars in this field have found through experimental research and field practice that temporary plugging and diverting acid fracturing is a more effective process technology to improve the effect of horizontal well transformation in carbonate reservoirs. Temporary plugging and diverting fracturing technology has been successfully applied to tight sandstone and carbonate reservoirs, but there are mainly the following problems in the process of temporary plugging and acid fracturing reservoir transformation in carbonate reservoirs with developed natural fractures:

[0003] (1) High-concentration fiber temporary plugging agents are difficult to enter the construction pipeline and form temporary plugging of the seams inside the carbonate rock, making it difficult to form a three-dimensional seam network;

[0004] (2) After the temporary plugging and acid fracturing experiment is completed, the temporary plugging and acid fracturing effect cannot be accurately evaluated. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a method and system for evaluating the crack spread range of indoor joint temporary plugging and acid fracturing.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for evaluating the crack spread range of indoor crack temporary plugging and acid fracturing, which comprises the following steps:

[0007] (1) Preparation of rock samples;

[0008] (2) placing the rock sample on a test stand of a true triaxial fracturing device, starting the true triaxial fracturing device, applying triaxial stress to the rock sample, and after the confining pressure is stabilized, injecting gelled acid into the rock sample until a sudden pressure drop occurs;

[0009] (3) injecting a temporary plugging agent into the rock sample, and after the pressure is successfully held, a sudden pressure drop occurs again, and the temporary plugging acid fracturing is completed;

[0010] (4) continuously injecting a tracer into the rock sample for a period of time;

[0011] (5) The rock sample is cut open along the cracks of the rock sample, and the crack surface of the rock sample is scanned using a 3D scanner. Through three-dimensional modeling, the crack-affected range is evaluated based on the volume of pores directly communicated by the cracks and the volume of pores indirectly communicated by the tracer.

[0012] In the above method, preferably, in step (1), the rock sample is prepared by the following steps: drilling a wellbore at the center of the rock sample, filling and compacting the soluble material and the degradable fiber material at the pre-set open hole section; then injecting cementing glue, before the cementing glue is bonded, installing the simulated wellhead into the wellbore, and setting the wellbore seal of the simulated wellhead; standing for the cementing glue to bond, opening the seal of the simulated wellhead, and injecting water into the wellbore until the soluble material is completely dissolved to obtain the rock sample. More preferably, the rock sample is a carbonate rock sample. The size of the open hole section can be routinely adjusted by a person skilled in the art.

[0013] In some specific embodiments of the present invention, in step (1), the soluble material includes NaCl or the like.

[0014] In some specific embodiments of the present invention, in step (1), the particle size of the degradable fiber material is 3-4 mm. The degradable fiber material can be conventional in the art, and the present invention does not specifically limit it.

[0015] In some specific embodiments of the present invention, in step (1), the cementing glue may be conventional cementing glue in the art, and the present invention does not specifically limit it.

[0016] In the above method, preferably, in step (2), the injection rate of the gelled acid solution is 20 to 40 ml / min.

[0017] In some specific embodiments of the present invention, in step (3), the gelled acid solution may be an acid solution in the prior art, and the present invention does not impose any particular limitation on its specific composition.

[0018] In the above method, preferably, in step (3), the injection rate of the temporary plugging agent is 20 to 40 ml / min.

[0019] In some specific embodiments of the present invention, in step (3), the temporary plugging agent includes a granular and / or powdered temporary plugging agent, and also includes water and / or guar gum, etc. The present invention does not specifically limit its specific composition, and it can be routinely adjusted by those skilled in the art.

[0020] According to a specific embodiment of the present invention, preferably, the method further comprises: alternately injecting gelled acid solution and a temporary plugging agent into the rock sample, and each time the gelled acid solution is injected until a sudden pressure drop occurs, and then the temporary plugging agent is injected, and each time the temporary plugging agent is injected, the pressure is successfully held back before another sudden pressure drop occurs, completing one temporary plugging acid pressure test, and alternately injecting the gelled acid solution and the temporary plugging agent to complete multiple temporary plugging acid pressure tests.

[0021] In the above method, preferably, in step (4), the tracer is mixed with the gelled acid solution and then injected into the rock sample. The mixing ratio of the tracer and the gelled acid solution can be conventionally adjusted by a person skilled in the art.

[0022] In the above method, preferably, in step (4), the injection speed of the tracer after mixing with the gelled acid solution is 20 to 40 ml / min.

[0023] In the above method, preferably, in step (4), the tracer comprises fluorescent powder.

[0024] In the above method, preferably, in step (4), the time for continuously injecting the tracer into the rock sample is the same as the time for injecting the gelled acid solution in step (2).

[0025] In the above method, preferably, in step (5), the three-dimensional modeling includes pore structure modeling and fracture morphology modeling inside the rock sample. The pore structure modeling can be performed after the rock sample is prepared in step (1), or it can be completed together with the fracture morphology modeling in step (4).

[0026] In the above method, preferably, in step (5), the crack spread range is evaluated by the following formula:

[0027]

[0028] Wherein, V is the volume of the rock sample (i.e., the volume of the original rock sample without the preparation of the rock sample in step (1)), V1 is the volume of the pores directly communicated by the fracture, V2 is the volume of the pores indirectly communicated by the tracer, and K is the fracture sweep coefficient:

[0029] If K≥0.5, the crack affects a wider range; if K<0.5, the crack affects a smaller range.

[0030] Those skilled in the art can understand that, in the above formula for evaluating the crack propagation range, when calculating the crack propagation coefficient K, the units of V, V1 and V2 should remain the same.

[0031] The second aspect of the present invention provides a fracture range evaluation system for temporary plugging of indoor fracture openings and acid fracturing, the system is used to implement the above-mentioned fracture range evaluation method for temporary plugging of indoor fracture openings and acid fracturing, the system comprises: a true triaxial fracturing device, a multi-pump parallel injection device and a 3D scanner;

[0032] The true triaxial fracturing device comprises an experimental frame for placing rock samples, the experimental frame is provided with a guide groove, and the guide groove is used to receive the gelled acid solution, temporary plugging agent and tracer injected into the rock sample;

[0033] The multi-pump parallel injection device comprises a plurality of parallel injection pipelines, and the plurality of parallel injection pipelines are respectively used to inject gelled acid solution, temporary plugging agent and tracer into the rock sample;

[0034] The 3D scanner is used to scan the fracture surface of the rock sample.

[0035] In the above system, preferably, the multi-pump parallel injection device further includes a gelled acid liquid storage tank and a temporary plugging agent storage tank, and the gelled acid liquid storage tank and the temporary plugging agent storage tank are respectively connected to the injection pipeline; the gelled acid liquid storage tank is used to store the gelled acid liquid and the tracer, and the temporary plugging agent storage tank is used to store the temporary plugging agent.

[0036] In the above system, preferably, the true triaxial fracturing device comprises a true triaxial pressure chamber and a hydraulic pressure stabilizing source; the experimental frame is located in the true triaxial pressure chamber; and the hydraulic pressure stabilizing source is used to apply triaxial stress to the rock sample.

[0037] According to a specific embodiment of the present invention, preferably, the above system further comprises: an MTS servo booster, an MTS controller, an MTS hydraulic source, an air compressor and a data monitoring and control device; the MTS servo booster is connected to the multi-pump parallel injection device to control the injection of gelled acid, temporary plugging agent and tracer into the rock sample; the MTS hydraulic source and the air compressor are respectively connected to the MTS servo booster to supply liquid and gas to the MTS servo booster respectively; the MTS servo booster is connected to the data monitoring and control device through the MTS controller. More preferably, the data monitoring and control device may include a computer.

[0038] At present, ensuring that the acid does not leak in the natural fractures is the key to the success of acid fracturing; "effective plugging" and "successful steering" are the key to ensure the success of temporary plugging of the fractures. The current true triaxial fracture temporary plugging acid fracturing physical simulation experiment has the problem of acid leakage during the acid fracturing process, and the problem that the fiber cannot enter the rock sample along the pipeline to form a temporary plugging at the fracture during the temporary plugging process.

[0039] The present invention provides a method and system for evaluating the crack spread range of indoor temporary seam plugging and acid fracturing, which solves the problems in the prior art that fibers cannot enter the pipeline during the temporary seam plugging process and the effect of temporary seam plugging and acid fracturing cannot be accurately evaluated.

[0040] The rock sample prepared by the present invention includes an open hole structure, and adopts a special completion method, that is, pre-placed fibers in the wellbore during the open hole completion, that is, pre-placed fibers at the seam before the experiment. In addition, during the experiment, the present invention can inject gelled acid and temporary plugging agents into the rock sample in an alternating manner to achieve the effect of reducing acid leakage, plugging old seams and starting new seams. At the same time, the present invention also adopts a special injection method, that is, after the temporary plugging acid pressure is completed, the tracer is injected under high pressure and maintained for a period of time. Since the oil and gas in the carbonate reservoir are distributed in the rock matrix and the pore structure, it is possible that some artificial fractures are not directly connected to the pores, but the oil and gas resources inside the pores can still be obtained through seepage. Based on the migration of the tracer, the present invention can divide the fracture transformation effect into direct communication and indirect communication, comprehensively evaluate the fracture transformation effect, and estimate information such as oil and gas production. Specifically, after the experiment is completed, the present invention cuts open the rock sample, uses a 3D scanner to scan the fracture surface of the rock sample, and performs three-dimensional modeling. According to the range of holes directly connected by the fractures, the reservoir production of direct communication by temporary plugging and acid fracturing can be calculated. According to the range of holes indirectly connected by tracers, the reservoir production of indirect communication by temporary plugging and acid fracturing can be calculated. Based on the range of holes directly connected and indirectly connected, the scope of fracture affected by temporary plugging and acid fracturing is evaluated as a whole, and the transformation production can be estimated.

[0041] The technical solution of the present invention has at least the following beneficial effects:

[0042] (1) Using a multi-pump parallel injection device can increase the injection rate;

[0043] (2) The problem that the fiber is too large to enter the pipeline and temporarily plug the seam is solved. The present invention directly adds the fiber to the seam to form a bridge between the seam and the particles and / or powder in the temporary plugging agent, thereby achieving the effect of temporary plugging the seam.

[0044] (3) After temporary plugging and acid fracturing, tracers are injected. Based on the 3D fracture surface reconstruction and the use of three-dimensional modeling, the range of holes directly connected to the fractures formed by temporary plugging and acid fracturing and the range of holes indirectly connected to the tracers can be accurately identified, and the fracture transformation effect can be comprehensively evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the structure of the crack spread assessment system for indoor crack temporary plugging and acid fracturing provided in Example 1.

[0046] Figure 2This is a diagram showing the effect of the rock sample after being loaded with the degradable fiber material in Example 2.

[0047] Figure 3 This is a three-dimensional modeling of the rock samples before and after the experiment in Example 2.

[0048] Figure 4 This is a diagram of the expansion morphology of the temporary plugging acid fracturing fracture in Example 2.

[0049] Description of Figure Numbers:

[0050] 1-True triaxial fracturing device; 2-Multi-pump parallel injection device; 3-3D scanner; 4-MTS servo booster; 5-MTS controller; 6-MTS hydraulic source; 7-Air compressor; 8-Data monitoring and control device;

[0051] 101-true triaxial pressure chamber; 102-hydraulic pressure stabilizing source; 103-experimental frame, 104-guiding trough;

[0052] 201-gelled acid liquid storage tank; 202-temporary plugging agent storage tank. DETAILED DESCRIPTION

[0053] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0054] Example 1

[0055] This embodiment provides a crack spread range evaluation system for indoor crack temporary plugging and acid fracturing, and its structure is as follows: Figure 1 shown.

[0056] It should be noted that Figure 1 A rock sample is also shown.

[0057] The system includes: a true triaxial fracturing device 1, a multi-pump parallel injection device 2, a 3D scanner 3, an MTS servo booster 4, an MTS controller 5, an MTS hydraulic source 6, an air compressor 7, and a data monitoring and control device 8;

[0058] The true triaxial fracturing device 1 comprises a true triaxial pressure chamber 101, a hydraulic pressure stabilizing source 102 and an experimental frame 103; the experimental frame 103 is located in the true triaxial pressure chamber 101, and is used to place rock samples; a guide groove 104 is provided on the experimental frame 103, and the guide groove 104 is used to receive gelled acid solution, temporary plugging agent and tracer injected into the rock sample; the hydraulic pressure stabilizing source 102 is used to apply triaxial stress to the rock sample;

[0059] The multi-pump parallel injection device 2 comprises a gelled acid liquid storage tank 201, a temporary plugging agent storage tank 202 and two parallel injection pipelines. The gelled acid liquid storage tank 201 and the temporary plugging agent storage tank 202 are respectively connected to two injection pipelines. The gelled acid liquid storage tank 201 and the injection pipelines connected thereto are used to inject a mixture of gelled acid liquid, a tracer and gelled acid liquid into a rock sample. The temporary plugging agent storage tank 202 and the injection pipelines connected thereto are used to inject the temporary plugging agent into the rock sample.

[0060] The 3D scanner 3 is used to scan the fracture surface of the rock sample;

[0061] The MTS servo booster 4 is connected to the multi-pump parallel injection device 2, and is used to control the injection of a mixture of gelled acid solution, temporary plugging agent, tracer and gelled acid solution into the rock sample; the MTS hydraulic source 6 and the air compressor 7 are respectively connected to the MTS servo booster 4, and are respectively used to supply liquid and air to the MTS servo booster 4; the MTS servo booster 4 is communicatively connected to the data monitoring and control device 8 through the MTS controller 5; the data monitoring and control device 8 can be a computer.

[0062] Example 2

[0063] This embodiment provides a method for evaluating the scope of cracks affected by temporary plugging and acid fracturing of indoor seams, and the method adopts the system provided in Example 1.

[0064] The method comprises the following steps:

[0065] (1) Preparation of rock samples: a wellbore is drilled at the center of the rock sample, the wellbore having a diameter of 50 mm and a length of 120 mm, and the soluble material and the degradable fiber material are loaded and compacted at a pre-set open hole section. The size of the open hole section can be adjusted routinely by a person skilled in the art. Figure 2 The figure is a rendering of a rock sample after being filled with degradable fiber material, wherein the length of the open hole section is 40 mm; then cementing glue is added, and before the cementing glue is bonded, a simulated wellhead is installed into the wellbore, and a wellbore sealing setting of the simulated wellhead is set; after standing for the cementing glue to bond, the seal of the simulated wellhead is opened, and water is injected into the wellbore until the soluble material is completely dissolved to obtain a rock sample; wherein, the rock sample is a carbonate outcrop, and its size is 300 mm×300 mm×300 mm; three-dimensional modeling is performed on the prepared rock sample to obtain a pore structure modeling inside the rock sample before the experiment, such as Figure 3 As shown in Figure a;

[0066] (2) placing the rock sample on the experimental stand 103 of the true triaxial fracturing device 1, starting the true triaxial fracturing device 1, applying triaxial stress to the rock sample. The triaxial stresses applied in this embodiment are set to 25 MPa, 15 MPa, and 18 MPa, respectively, and the horizontal stress difference is 10 MPa. After the confining pressure is stabilized, a multi-pump parallel injection device 2 is used to inject gelled acid into the rock sample through the simulated wellhead. The injection rate of the gelled acid is 30 ml / min until a sudden pressure drop occurs.

[0067] (3) Then, a temporary plugging agent is injected into the rock sample through the simulated wellhead using a multi-pump parallel injection device 2. The injection rate of the temporary plugging agent is 30 ml / min. After the pressure is successfully held, a sudden pressure drop occurs again, and the temporary plugging acid fracturing is completed;

[0068] (4) Then, a tracer is added to the gelled acid liquid storage tank 201. The amount of the tracer added can be conventionally adjusted by a person skilled in the art. A mixture of the tracer and the gelled acid liquid is continuously injected into the rock sample through the simulated wellhead using a multi-pump parallel injection device 2. The injection rate is 30 ml / min. The continuous injection time is the same as the time for injecting the gelled acid liquid in step (2);

[0069] (5) After the experiment, the rock sample is cut along the crack of the rock sample, and the crack surface of the rock sample is scanned by using a 3D scanner 3, and then three-dimensional modeling is performed to obtain the hole structure modeling of the rock sample after the experiment (the hole structure modeling is the same as that before the experiment) and the crack morphology modeling, as shown in FIG. Figure 3 As shown in Figure b, Figure 3 The volume of pores directly connected to the cracks and the volume of pores indirectly connected to the tracers can be obtained. Based on the volume of pores directly connected to the cracks and the volume of pores indirectly connected to the tracers, the scope of the cracks can be evaluated.

[0070] The crack impact range is evaluated by the following formula:

[0071]

[0072] Wherein, V is the volume of the rock sample (i.e., the volume of the original rock sample without preparing the rock sample in step (1)); V1 is the volume of the pores directly communicated by the fractures, which can be determined by the roughness of the pores, that is, the volume of the pores that react with the gelled acid solution; V2 is the volume of the pores indirectly communicated by the tracer, which can be determined by three-dimensional modeling; K is the fracture sweep coefficient;

[0073] The K calculated in this embodiment is 0.5, so the crack affects a wider range.

[0074] Figure 4This is a diagram of the expansion morphology of the temporary plugging acid fracturing fracture in this embodiment. Figure 4 It can be seen that the particles and powder in the temporary plugging agent did not migrate into the seam, and formed a temporary plugging at the seam opening with the pre-placed fiber material.

[0075] In this embodiment, in step (1), the soluble material is NaCl. The degradable fiber material is a fiber material with a particle size of 3 to 4 mm (produced by China National Petroleum Corporation Southwest Oil and Gas Field). The cementing glue can be conventional cementing glue in the art. The cementing glue used in this embodiment is industrial AB glue.

[0076] In this embodiment, in step (2), the composition of the gelled acid solution is, in terms of mass percentage, 20% hydrochloric acid + 1% iron ion stabilizer (HJZ-803, produced by Hengju Technology) + water as the balance, and the viscosity of the gelled acid solution is 30 mPa.s.

[0077] In this embodiment, in step (3), the temporary plugging agent is composed of: 1% 40 mesh granular temporary plugging agent (produced by PetroChina Southwest Oil and Gas Field Company) + 1% 100 mesh powder temporary plugging agent (produced by PetroChina Southwest Oil and Gas Field Company) + the remainder of guar gum and water, in terms of mass percentage.

[0078] In this embodiment, in step (4), the tracer is fluorescent powder.

[0079] Steps (2) and (3) in the method of this embodiment may also include: alternately injecting gelled acid solution and a temporary plugging agent into the rock sample, and each time the gelled acid solution is injected until a sudden pressure drop occurs, then injecting the temporary plugging agent, and each time the temporary plugging agent is injected, the pressure is successfully held until another sudden pressure drop occurs, completing one temporary plugging acid pressure test, and alternately injecting the gelled acid solution and the temporary plugging agent to complete multiple temporary plugging acid pressure tests.

Claims

1. A method for evaluating the crack spread range of indoor crack temporary plugging and acid fracturing, comprising the following steps: (1) Preparation of rock samples; (2) placing the rock sample on a test stand of a true triaxial fracturing device, starting the true triaxial fracturing device, applying triaxial stress to the rock sample, and after the confining pressure is stabilized, injecting gelled acid into the rock sample until a sudden pressure drop occurs; (3) injecting a temporary plugging agent into the rock sample, and after the pressure is successfully held, a sudden pressure drop occurs again, and the temporary plugging acid fracturing is completed; (4) continuously injecting a tracer into the rock sample for a period of time; (5) The rock sample is cut open along the cracks of the rock sample, and the crack surface of the rock sample is scanned using a 3D scanner. Through three-dimensional modeling, the crack-affected range is evaluated based on the volume of pores directly communicated by the cracks and the volume of pores indirectly communicated by the tracer.

2. The method according to claim 1, wherein: In step (1), the rock sample is prepared by the following steps: drilling a wellbore at the center of the rock sample, filling and compacting a soluble material and a degradable fiber material at a pre-set open hole section; then injecting cementing glue, and before the cementing glue is bonded, installing a simulated wellhead into the wellbore, and setting a wellbore seal of the simulated wellhead; standing the wellbore until the cementing glue is bonded, opening the seal of the simulated wellhead, and injecting water into the wellbore until the soluble material is completely dissolved, thereby obtaining a rock sample; Preferably, the rock sample is a carbonate rock sample.

3. The method according to claim 2, wherein: In step (1), the soluble material includes NaCl; and the particle size of the degradable fiber material is 3 to 4 mm.

4. The method according to claim 1, wherein: The method further comprises: injecting gelled acid solution and temporary plugging agent alternately into the rock sample, and each time the gelled acid solution is injected until a sudden pressure drop occurs, and then injecting the temporary plugging agent, and each time the temporary plugging agent is injected, the pressure is successfully held back until another sudden pressure drop occurs, completing one temporary plugging acid pressure test, and alternately injecting the gelled acid solution and the temporary plugging agent to complete multiple temporary plugging acid pressure tests.

5. The method according to claim 1, wherein: In step (4), the tracer is mixed with the gelled acid solution and then injected into the rock sample; Preferably, the tracer comprises fluorescent powder.

6. The method according to claim 1 or 5, wherein: In step (4), the time for continuously injecting the tracer into the rock sample is the same as the time for injecting the gelled acid solution in step (2).

7. The method according to claim 1, wherein: In step (5), the three-dimensional modeling includes pore structure modeling and crack morphology modeling inside the rock sample.

8. The method according to claim 1, wherein: In step (5), the crack impact range is evaluated by the following formula: Where V is the volume of the rock sample, V1 is the volume of the pores directly communicated by the fracture, V2 is the volume of the pores indirectly communicated by the tracer, and K is the fracture sweep coefficient: If K≥0.5, the crack affects a wider range; if K<0.5, the crack affects a smaller range.

9. A system for evaluating the scope of cracks affected by temporary plugging and acidizing of indoor seams, the system being used to implement the method for evaluating the scope of cracks affected by temporary plugging and acidizing of indoor seams as claimed in any one of claims 1 to 8, the system comprising: True triaxial fracturing device, multi-pump parallel injection device and 3D scanner; The true triaxial fracturing device comprises an experimental frame for placing rock samples, the experimental frame is provided with a guide groove, and the guide groove is used to receive the gelled acid solution, temporary plugging agent and tracer injected into the rock sample; The multi-pump parallel injection device comprises a plurality of parallel injection pipelines, and the plurality of parallel injection pipelines are respectively used to inject gelled acid solution, temporary plugging agent and tracer into the rock sample; The 3D scanner is used to scan the fracture surface of the rock sample.

10. The system according to claim 9, wherein: The multi-pump parallel injection device further comprises a gelled acid liquid storage tank and a temporary plugging agent storage tank, and the gelled acid liquid storage tank and the temporary plugging agent storage tank are respectively connected to the injection pipeline; the gelled acid liquid storage tank is used to store the gelled acid liquid and the tracer, and the temporary plugging agent storage tank is used to store the temporary plugging agent.

11. The system according to claim 9, wherein: The true triaxial fracturing device comprises a true triaxial pressure chamber and a hydraulic pressure stabilizing source; the experimental frame is located in the true triaxial pressure chamber; the hydraulic pressure stabilizing source is used to apply triaxial stress to the rock sample.

12. The system according to claim 9, wherein: The system further includes: an MTS servo booster, an MTS controller, an MTS hydraulic source, an air compressor and a data monitoring and control device; the MTS servo booster is connected to the multi-pump parallel injection device to control the injection of gelled acid, temporary plugging agent and tracer into the rock sample; the MTS hydraulic source and the air compressor are respectively connected to the MTS servo booster to supply liquid and air to the MTS servo booster respectively; the MTS servo booster is connected to the data monitoring and control device through the MTS controller for communication.

Images