Visual high-temperature pressurized temporary plugging agent solubility experiment device and evaluation method

Abstract

The invention relates to a visual high-temperature pressurized temporary plugging agent solubility experiment device and an evaluation method. The experiment device comprises an injection system, a visual reservoir simulation system, a femtosecond monitoring system, a temperature and pressure control system and a data acquisition control system, the visual reservoir simulation system comprises a visual window, an electric pressure gauge and a reservoir simulation device, and the reservoir simulation device is used for simulating the reservoir pressure and temperature environment and observing the dissolution condition of a temporary plugging agent at any time in the experiment process; the femtosecond monitoring system is located in the visual window and used for capturing and recording changes in the temporary plugging agent dissolving process in real time. And the data acquisition control system comprises a data acquisition card, a signal processor and an industrial personal computer. The whole process of softening, deformation and dissolution of the temporary plugging material in the high-temperature and high-pressure environment can be observed in real time, the dissolution behavior of the temporary plugging agent can be understood more deeply, and scientific guidance is provided for performance improvement of the temporary plugging agent through detailed dissolution process data and pictures.

Description

Technical Field

[0001] The invention relates to the field of temporary plugging agent solubility testing, and more specifically to a temporary plugging agent solubility experimental device and an evaluation method capable of visual high temperature and pressure. Background Art

[0002] With the continuous deepening of my country's oil resource development, fracturing technology has played an increasingly critical role in increasing oil and gas production. Especially in the development of my country's vast oil fields and shale gas reservoirs, fracturing technology has become an indispensable technical means. In fracturing operations, the application of temporary plugging agents is crucial. It can accurately block fluid channels, similar to the "fine needle" in surgery, effectively improving the efficiency of oil and gas collection. Therefore, the solubility evaluation of temporary plugging agents is of decisive significance for the successful implementation of shale gas fracturing technology. By accurately evaluating the solubility of temporary plugging agents, we can predict their stability in the groundwater environment during and after fracturing, ensure that they can play a role at the predetermined time and place, and further optimize the design of temporary plugging agents, including the selection of raw materials and additives and the adjustment of formulations, to enhance their stability and efficiency under specific conditions.

[0003] Chinese patent CN117365463A discloses a reservoir suitability evaluation method for a temporary plugging agent used for temporary plugging and diverting fracturing in shale gas fractures, including determining the solubility performance parameters of the target temporary plugging agent through a temporary plugging agent solubility performance test experiment; evaluating the solubility performance of the temporary plugging agent based on the solubility performance parameters of the target temporary plugging agent, etc. The dissolution rate test method adopted is a mass difference method, and can only determine the dissolution rate of the temporary plugging agent after a fixed time and has a large manual error, and does not have a continuous test function and visibility.

[0004] Chinese patent CN107202866A discloses a temporary plugging performance evaluation experimental device for temporary plugging agents and a working method thereof. The device includes modules for simulating different cracks, and is mainly used to evaluate the plugging performance of temporary plugging agents, and to assess the plugging effectiveness through pressure changes during the experiment.

[0005] Chinese patent CN111965065A discloses a method for testing and evaluating the degradation performance of organic temporary plugging agents used in oil and gas fields. The method uses a TOC analyzer to measure the initial carbon mass m0 of the organic temporary plugging agent to be tested in a fracturing fluid simulant corresponding to the simulated formation fractures, then continuously or intermittently extracts samples during the dissolution of the temporary plugging agent, uses a TOC analyzer to measure the carbon mass mt of the dissolved temporary plugging agent, calculates and plots the mt / m0 values ​​at multiple moments into a curve, and obtains a curve of the degradation rate of the organic temporary plugging agent in the fracturing fluid simulant corresponding to the simulated formation fractures over time, thereby evaluating the degradation performance of the organic temporary plugging agent.

[0006] The existing evaluation equipment and methods are mainly aimed at the plugging performance of temporary plugging agents, and there are few designs for dissolution performance tests. In addition, there are obvious deficiencies in the evaluation technology of temporary plugging agent solubility. The existing evaluation equipment generally lacks visualization functions and cannot intuitively display the dissolution process of temporary plugging agents under high temperature and high pressure conditions. The test method for dissolution rate is very limited. The dissolution rate can only be determined by testing the temporary plugging agent dissolution residue after a fixed time. The operation process is cumbersome and cannot detect the changes in the temporary plugging agent structure during the entire dissolution process, making it difficult for researchers to deeply understand its dissolution mechanism. In addition, these devices often cannot fully simulate the actual environment of the reservoir, and there is a large gap with the actual formation conditions, such as the limited temperature simulation range and the lack of an effective pressure simulation system. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a visual high-temperature and pressurized temporary plugging agent solubility experimental device and evaluation method, which can observe in real time the softening, deformation and dissolution process of the temporary plugging material under a high-temperature and high-pressure environment. This intuitiveness helps to have a deeper understanding of the dissolution behavior of the temporary plugging agent, and through detailed dissolution process data and pictures, it provides scientific guidance for the performance improvement of the temporary plugging agent, and at the same time provides an important basis for material selection and optimization.

[0008] The technical solution adopted by the present invention to solve the technical problem is: constructing a visual high-temperature pressurized temporary plugging agent solubility experimental device, including an injection system, a visual reservoir simulation system, a femtosecond monitoring system, a temperature and pressure control system and a data acquisition and control system;

[0009] The injection system is used to transport fracturing fluid, temporary plugging agent and clean water to the visual reservoir simulation system;

[0010] The visual reservoir simulation system includes a visual window, an electric pressure gauge and a reservoir simulation device, wherein the reservoir simulation device is used to simulate the reservoir pressure and temperature environment, and observe the dissolution of the temporary plugging agent at any time during the experiment;

[0011] The femtosecond monitoring system is located in the visual window and is used to capture and record the changes in the temporary plugging agent dissolution process in real time. The femtosecond monitoring system includes a laser transmitter and a signal detector. The signal detector includes a beam expander, a beam shaper and a probe. The laser transmitter is used to generate laser pulses and focus the laser beam on the object to be measured. The beam expander and the beam shaper are used to transmit the laser beam to the probe. The probe is used to collect reflected or transmitted signals and then transmit them to the data acquisition and processing system. When the laser pulse is irradiated on the material, various signals are generated. These signals carry information about the surface and internal structure of the temporary plugging agent material. At the same time, the signal information fed back is received by the signal detector. By scanning the surface of the material with a femtosecond laser, the changes in the temporary plugging agent dissolution process are captured and recorded in real time, and the smoothness and roughness of the surface and the material dissolution rate are evaluated.

[0012] The temperature and pressure control system is used to control the temperature and pressure of the reservoir simulation device;

[0013] The data acquisition control system includes a data acquisition card, a signal processor and an industrial computer, which can automatically control various operations of the experimental detection instrument. The data acquisition card collects signals generated by sensors or detectors, and converts them into digital signals through the signal processor for storage and analysis, and displays the data in the form of graphics or images. The industrial computer is used to control the operation of the injection system, visual reservoir simulation system, femtosecond monitoring system and temperature and pressure control system.

[0014] According to the above scheme, the injection system includes a fracturing fluid storage tank, a clean water tank and a delivery pump. The delivery pump is used to deliver the fracturing fluid, temporary plugging agent and clean water to the visual reservoir simulation system. The fracturing fluid storage tank and the clean water tank in the injection system are respectively connected to the input end of the delivery pump through pipelines, and the output end of the delivery pump is connected to the input end of the visual reservoir simulation system.

[0015] According to the above scheme, the reservoir simulation device is made of a double-layer high-purity siliceous mineral material. The reservoir simulation device is cylindrical and transparent as a whole. Two transverse partitions are arranged inside the cylinder.

[0016] According to the above scheme, the temperature and pressure control system includes a temperature control probe, an electric heating device and a pressure detection device. The working temperature of the reservoir simulation device is from room temperature to 200°C. The temperature and pressure control system is used to heat, insulate and control the pressure of the reservoir simulation device to simulate the geothermal heat and pressure of the formation. If the fracturing exceeds the set value, the system will automatically start the pressure relief procedure.

[0017] According to the above scheme, it also includes a recovery and processing system. The output end of the visual reservoir simulation system is connected to the input end of the recovery and processing system. The recovery and processing system includes a cleaning device, a filtering device and a waste liquid recovery device. After the temporary plugging agent is dissolved, the delivery pump delivers clean water to the reservoir simulation device to clean the temporary plugging agent residue dissolved in the core, and then passes through the filtering device to separate the solid residue from the waste liquid, and the waste liquid flows to the waste liquid recovery device.

[0018] According to the above solution, a pressure relief valve is provided between the recovery and processing system and the visual reservoir simulation system.

[0019] The present invention also provides a temporary plugging agent solubility evaluation method, using the above-mentioned visual high temperature pressurized temporary plugging agent solubility experimental device, characterized in that it includes the following steps:

[0020] S1. Accurately weigh the temporary plugging agent sample of required mass and evenly fill it into the reservoir simulation device; respectively fill clean water and pre-prepared fracturing fluid into the clean water tank and the fracturing fluid tank;

[0021] S2, start the heating system to heat the reservoir simulation device until the temperature required for the simulated formation is reached, then stop heating and switch to the insulation mode; while heating, start the delivery pump to pump the fracturing fluid into the reservoir simulation system;

[0022] S3, setting the image acquisition and dissolution rate evaluation interval, recording the dissolution state of the temporary plugging agent and evaluating the dissolution rate according to the set frequency;

[0023] S4. During the experiment, the dissolution of the temporary plugging agent under the simulated reservoir temperature and pressure conditions was observed in real time through the visual window. After the experiment, the reaction time was recorded;

[0024] S5. After the experiment, clean water is injected into the reservoir simulation system using a delivery pump to thoroughly clean the reservoir simulation device; the cleaning liquid is collected into the recovery and processing system through the simulated fracture module, and the automatic filtering device effectively isolates the dissolved residue and solid particles in the cleaning liquid;

[0025] S6. The reaction residue after cleaning is taken out and placed in a constant temperature oven for drying. After complete drying, the quality of the residue is accurately tested and the residue rate is calculated.

[0026] According to the above scheme, in step S6, the residue rate is calculated by the following formula:

[0027]

[0028] Where γ is the residue rate, m1 is the initial temporary plugging agent mass, and m2 is the mass of the dissolved residue after drying.

[0029] The present invention provides a visual high temperature pressurized temporary plugging agent solubility test device and evaluation method, which has the following beneficial effects:

[0030] 1. The present invention adopts the design of visual window and femtosecond monitoring system. The device can output the dissolution state of temporary plugging agent and evaluate the dissolution rate in a continuous or intermittent time, allowing researchers to intuitively observe the softening, deformation and dissolution process of temporary plugging material in a high temperature and high pressure environment in real time. This intuitiveness helps to have a deeper understanding of the dissolution behavior of temporary plugging agent. Through detailed dissolution process data and pictures, it provides scientific guidance for the performance improvement of temporary plugging agent and provides important basis for material selection and optimization.

[0031] 2. The device of the present invention is suitable for various materials such as temporary plugging balls for fracturing, granular temporary plugging agents, powder temporary plugging agents, fiber temporary plugging agents, etc., and can fully cover the types of temporary plugging agents commonly used in the current market.

[0032] 3. The device of the present invention can accurately simulate reservoir temperature and pressure conditions, and can set high temperature and high pressure conditions according to the actual temperature and pressure of the reservoir to ensure the authenticity and reliability of the experimental results. The test results are closer to the formation environment encountered in actual engineering construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0034] Figure 1 It is a structural schematic diagram of a temporary plugging agent solubility experimental device under visual high temperature and pressure of the present invention;

[0035] Figure 2 It is a structural schematic diagram of the reservoir simulation device. DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0037] Example 1

[0038] like Figure 1-2 As shown, the visual high-temperature pressurized temporary plugging agent solubility experimental device of the present invention includes an injection system, a visual reservoir simulation system, a femtosecond monitoring system, a temperature and pressure control system, a recovery and processing system, and a data acquisition and control system.

[0039] The injection system consists of a fracturing fluid storage tank, a clean water tank and a delivery pump. The delivery pump is used to deliver fracturing fluid, temporary plugging agent and clean water to the visual reservoir simulation system. As a power system, the large-displacement delivery pump is mainly used to inject fluids with different flow ranges and pressurize the reservoir simulation system. The maximum pressure can be 50MPa. According to the ratio of the experimental equipment to the actual site scale, it can fully meet the needs of the field experiment. The two liquid tanks are used to hold clean water and fracturing fluid respectively.

[0040] The visual reservoir simulation system includes a visual window, an electric pressure gauge and a reservoir simulation device. The visual window is made of high-aluminum glass and is used to collect experimental data and record the experimental process. The reservoir simulation device is made of double-layer high-purity siliceous mineral materials, with a length of 150mm and a diameter of 5mm. It is cylindrical in appearance and transparent as a whole. Two transverse partitions are installed in the cylinder. The maximum temperature resistance is 200℃ and the pressure resistance is 40MPa. It can simulate the reservoir pressure and temperature environment, and observe the dissolution of the temporary plugging agent at any time during the experiment. The electric pressure gauge is used to detect the pressure changes in the simulation system and is connected to the computer system at the same time.

[0041] The femtosecond monitoring system includes a laser transmitter and a signal detector, and the signal detector includes a beam expander, a beam shaper and a probe. The laser transmitter is used to generate femtosecond laser pulses and is the core component of the system. It can focus the laser beam on the object to be measured. The beam expander and beam shaper are used to transmit the laser beam to the probe. The probe is used to collect reflected or transmitted signals and then transmit them to the data acquisition and processing system. It can capture and record the changes in the dissolution process of the temporary plugging agent in real time with an extremely short time resolution (on the order of 10^-15 seconds). When the laser pulse is irradiated on the material, various signals will be generated. These signals carry information about the surface and internal structure of the temporary plugging agent material, and the signal information fed back is received by the signal detector. By scanning the surface of the material with a femtosecond laser, the changes in the dissolution process of the temporary plugging agent can be captured and recorded in real time, and the smoothness, roughness and material dissolution rate of the surface can be evaluated. The collected photos can be further processed for data calculation and the dissolution rate can be output.

[0042] The temperature and pressure control system includes a temperature control probe, an electric heating device and a pressure detection device. The working temperature is from room temperature to 200°C. The temperature and pressure control system comes with a temperature controller and a temperature probe. Through PID adjustment, it has its own communication port and is connected to the computer for heating, heat preservation and pressure control of the simulation system to simulate the geothermal and pressure of the formation. When the fracturing exceeds the set value, the system will automatically start the pressure relief program. The preferred temperature control system heats and insulates the simulation system by electric heating to simulate the geothermal heat of the formation. The entire device is made of heat-resistant and high-pressure resistant stainless steel. The temperature can be set manually through a temperature control box or by a computer.

[0043] The pressure control part is composed of high-precision pressure sensors, pressure regulating valves, and safety pressure relief devices to ensure pressure stability and safety during the experiment. The entire device is made of heat-resistant and high-pressure resistant stainless steel to adapt to extreme experimental conditions. The temperature can be set manually through the temperature control box or accurately set through a computer. In terms of pressure control, the pressure monitoring and control system requires the operator to automatically control the pressure value through a computer according to the experimental requirements to achieve precise pressure control. When the system pressure is detected to deviate from the preset value, the pressure regulating valve will automatically adjust to restore the target pressure.

[0044] The recovery and treatment system includes a cleaning device, a filtering device and a waste liquid recovery device. After the temporary plugging agent is dissolved, the delivery pump delivers clean water to the reservoir simulation module to clean the temporary plugging agent residue dissolved in the core, and then passes through the filtering device to separate the solid residue from the waste liquid. The waste liquid flows to the waste liquid recovery device. The recovery and treatment system is connected to the computer data acquisition and control system, and preferably two pressure transmitters. Pressure measurement is used to measure the outlet pressure of the equipment. All pressures are displayed by the WP-C901-20-12-P pressure digital display, and can also be collected by the computer through the RS232 port on the digital display. The preferred temperature measurement uses a pt100 temperature probe, and the XMT-7512ZX-RZ temperature controller sets, controls, and measures the temperature. The temperature can also be set and collected by the computer. The preferred flow measurement uses a balance weighing method to calculate the liquid flow.

[0045] The computer data acquisition control system consists of a data acquisition card, a signal processor, an industrial computer and acquisition and processing software. It can automatically control various operations of the experimental detection instrument, including sample processing, data acquisition, adjustment of experimental conditions, etc. At the same time, it can accurately collect the signals generated by sensors or detectors, convert them into digital signals for storage and analysis, and display the data in the form of graphics or images.

[0046] The fracturing fluid storage tank and the clean water tank in the injection system are connected to the input end of the delivery pump through pipelines, the output end of the delivery pump is connected to the input end of the visual reservoir simulation system, and the output end of the visual reservoir simulation system is connected to the input end of the recovery and processing system. The pressure relief valve is located at the connection end between the recovery and processing system and the visual reservoir simulation system. It is composed of a valve body, a check valve core, and a pressure relief valve core. The whole is made of Hastelloy and is operated by a computer to release pressure. The pressure gauges are located at the inlet and outlet of the visual reservoir simulation system; the visual reservoir simulation system transfers pressure through the delivery pump to pump the fracturing fluid into the reservoir simulation device, and at the same time observes the dissolution and pressure changes of the temporary plugging agent within a certain pressure and temperature range through the visual window. The femtosecond monitoring system is located in the visual window, which can perform high-precision image monitoring and data analysis online in real time, evaluate the dissolution rate and photos of the transmission material at intervals, and complete the evaluation of the dissolution performance of the temporary plugging agent under different pressure and temperature conditions.

[0047] Example 2

[0048] The present invention also provides a temporary plugging agent evaluation method, comprising the following steps:

[0049] (1) Sample preparation and device connection

[0050] Accurately weigh the required mass of temporary plugging agent sample (recorded as m1) and evenly fill it into the reservoir simulation device. The filling volume should not exceed the maximum temporary plugging agent addition scale line to ensure that the sample is densely filled and evenly distributed. Connect the reservoir simulation device correctly to the reservoir simulation system to ensure that the connection is firm and there is no leakage.

[0051] (2) Liquid preparation and system connection

[0052] Put clean water and pre-prepared fracturing fluid into the clean water tank and fracturing fluid tank respectively to ensure that the liquids are free of contamination and meet the experimental requirements. Connect the injection system, visual reservoir simulation system and recovery and treatment system through the corresponding interfaces, and carefully check each connection to ensure that the system is completely sealed.

[0053] (3) Temperature and pressure settings

[0054] ①Set the temperature and pressure according to the experimental requirements.

[0055] ② Start the heating system to heat the reservoir simulation device until the required temperature of the simulated formation is reached, then stop heating and switch to the insulation mode.

[0056] ③ Start the delivery pump while heating, and pump the fracturing fluid into the reservoir simulation system. Through computer operation, ensure that the fracturing fluid is continuously injected at a stable rate. Stop delivering the fracturing fluid when the reservoir simulation device is filled with the fracturing fluid or the pressure reaches the set peak value. The computer pressure control system will record and adjust the actual pressure of the reservoir simulation system according to the pressure setting, and start timing at the same time.

[0057] (4) Data collection

[0058] Set the image acquisition and dissolution rate evaluation interval (data acquisition frequency 0.5-1200s / time), click to start acquisition, and the computer data processing system will record the dissolution state of the temporary plugging agent and evaluate the dissolution rate according to the set frequency.

[0059] (5) Real-time observation and cleaning

[0060] ① During the experiment, the dissolution of the temporary plugging agent under the simulated reservoir temperature and pressure conditions can be observed in real time through the visual window;

[0061] ②After the experiment, record the reaction time t, open the pressure relief valve through the computer pressure control system, and reduce the pressure to normal pressure.

[0062] ③The pressure relief valve is always open, and the delivery pump is used to inject clean water into the reservoir simulation system to thoroughly clean the reservoir simulation device. The cleaning fluid is collected into the recovery and processing system through the simulated fracture module, and the automatic filtering device effectively isolates the dissolved residue and solid particles in the cleaning fluid.

[0063] (6) Residue treatment and quality testing

[0064] ① Take out the reaction residue after cleaning and put it into a constant temperature oven for drying.

[0065] ② After complete drying, accurately test the mass of the residue (recorded as m2) for subsequent data analysis and evaluation.

[0066] ② Calculation of residue rate:

[0067]

[0068] γ——residue rate, %;

[0069] m1——initial temporary plugging agent mass, g;

[0070] m2——The mass of the dissolved residue after drying, g.

[0071] Example 3

[0072] Fill 10g of 40-80 mesh granular temporary plugging agent sample into the reservoir simulation device and connect it to the visual reservoir simulation system. Then, fill clean water and fracturing fluid into the clean water tank and fracturing fluid tank of the injection system respectively. Set the temperature required for the experiment to 140℃, the pressure to 40MPa, and the dissolution rate evaluation interval to 5min. Start the heating system to heat the reservoir simulation device, and start the delivery pump to pump the fracturing fluid into the reservoir simulation system. When the temperature reaches the set value, the system automatically stops heating and switches to the insulation mode. Through computer operation, ensure that the fracturing fluid is continuously injected at a stable rate. The computer pressure control system will record and adjust the actual pressure of the reservoir simulation system according to the pressure setting, and start timing when the fracturing fluid fills the reservoir simulation device.

[0073] During the experiment, the dissolution of the temporary plugging agent under the simulated reservoir temperature and pressure is observed in real time through the visual window, and the computer will continuously output the dissolution state image and evaluation of the temporary plugging agent according to the time setting. After the experiment, the reaction time t is recorded, and the pressure relief valve is opened through the computer pressure control system to reduce the pressure to normal pressure. Then, the reservoir simulation device is thoroughly cleaned with clean water, and the cleaning liquid is collected into the recycling system. The dissolved residue and the solid particles in the cleaning liquid are effectively isolated by the automatic filtering device. The reaction residue after cleaning is placed in a constant temperature oven for drying, and then the quality of the residue is accurately tested.

[0074] The residue rate was calculated according to the formula.

[0075]

[0076] The dissolution rate data are shown in Table 1.

[0077] Example 4

[0078] 10g of fiber temporary plugging agent sample was filled into the reservoir simulation device and connected to the visual reservoir simulation system. Then, clean water and fracturing fluid were respectively loaded into the clean water tank and fracturing fluid tank of the injection system. The temperature required for the experiment was set to 100°C, the pressure was set to 20MPa, and the dissolution rate evaluation interval was 5min. The evaluation process was carried out according to Example 1.

[0079]

[0080] The dissolution rate data are shown in Table 1.

[0081] Example 5

[0082] Three temporary plugging ball samples with a diameter of 13 mm were loaded into the reservoir simulation device and connected to the visual reservoir simulation system. Then, clean water and fracturing fluid were loaded into the clean water tank and fracturing fluid tank of the injection system respectively. The temperature required for the experiment was set to 200°C, the pressure was set to 40 MPa, and the dissolution rate evaluation interval was 5 minutes.

[0083] The evaluation process was carried out according to Example 1.

[0084]

[0085] The dissolution rate data are shown in Table 1.

[0086] Table 1 Dissolution rate test table

[0087]

[0088] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A visual high temperature and pressurized temporary plugging agent solubility test device, characterized in that: Including injection system, visual reservoir simulation system, femtosecond monitoring system, temperature and pressure control system and data acquisition and control system; The injection system is used to transport fracturing fluid, temporary plugging agent and clean water to the visual reservoir simulation system; The visual reservoir simulation system includes a visual window, an electric pressure gauge and a reservoir simulation device, wherein the reservoir simulation device is used to simulate the reservoir pressure and temperature environment, and observe the dissolution of the temporary plugging agent at any time during the experiment; The femtosecond monitoring system is located in the visual window and is used to capture and record the changes in the temporary plugging agent dissolution process in real time. The femtosecond monitoring system includes a laser transmitter and a signal detector. The signal detector includes a beam expander, a beam shaper and a probe. The laser transmitter is used to generate laser pulses and focus the laser beam on the object to be measured. The beam expander and the beam shaper are used to transmit the laser beam to the probe. The probe is used to collect reflected or transmitted signals and then transmit them to the data acquisition and processing system. When the laser pulse is irradiated on the material, various signals are generated. These signals carry information about the surface and internal structure of the temporary plugging agent material. At the same time, the signal information fed back is received by the signal detector. By scanning the surface of the material with a femtosecond laser, the changes in the temporary plugging agent dissolution process are captured and recorded in real time, and the smoothness and roughness of the surface and the material dissolution rate are evaluated. The temperature and pressure control system is used to control the temperature and pressure of the reservoir simulation device; The data acquisition control system includes a data acquisition card, a signal processor and an industrial computer. The data acquisition card collects signals generated by sensors or detectors, and converts them into digital signals for storage and analysis through the signal processor, and displays the data in the form of graphics or images. The industrial computer is used to control the operation of the injection system, the visual reservoir simulation system, the femtosecond monitoring system and the temperature and pressure control system.

2. The visual high temperature and pressurized temporary plugging agent solubility test device according to claim 1 is characterized in that: The injection system includes a fracturing fluid storage tank, a clean water tank and a delivery pump. The delivery pump is used to deliver fracturing fluid, temporary plugging agent and clean water to the visual reservoir simulation system. The fracturing fluid storage tank and the clean water tank in the injection system are respectively connected to the input end of the delivery pump through pipelines, and the output end of the delivery pump is connected to the input end of the visual reservoir simulation system.

3. The visual high temperature and pressurized temporary plugging agent solubility test device according to claim 1 is characterized in that: The reservoir simulation device is made of a double-layer high-purity siliceous mineral material. The reservoir simulation device is cylindrical and transparent as a whole. Two transverse partitions are arranged in the cylinder.

4. The visual high temperature and pressurized temporary plugging agent solubility test device according to claim 1 is characterized in that: The temperature and pressure control system includes a temperature control probe, an electric heating device and a pressure detection device. The working temperature of the reservoir simulation device is from room temperature to 200°C. The temperature and pressure control system is used to heat, insulate and control the pressure of the reservoir simulation device to simulate the geothermal heat and pressure of the formation. If the fracturing exceeds the set value, the system will automatically start the pressure relief program.

5. The visual high temperature and pressurized temporary plugging agent solubility test device according to claim 2 is characterized in that: It also includes a recovery and processing system. The output end of the visual reservoir simulation system is connected to the input end of the recovery and processing system. The recovery and processing system includes a cleaning device, a filtering device and a waste liquid recovery device. After the temporary plugging agent is dissolved, the delivery pump delivers clean water to the reservoir simulation device to clean the temporary plugging agent residue dissolved in the core, and then passes through the filtering device to separate the solid residue from the waste liquid, and the waste liquid flows to the waste liquid recovery device.

6. The visual high temperature and pressurized temporary plugging agent solubility test device according to claim 5 is characterized in that: A pressure relief valve is provided between the recovery and processing system and the visual reservoir simulation system.

7. A method for evaluating the solubility of a temporary plugging agent, using the visual high-temperature pressurized temporary plugging agent solubility test device according to any one of claims 1 to 6, characterized in that: The steps include: S1. Accurately weigh the temporary plugging agent sample of required mass and evenly fill it into the reservoir simulation device; respectively fill clean water and pre-prepared fracturing fluid into the clean water tank and the fracturing fluid tank; S2, start the heating system to heat the reservoir simulation device until the temperature required for the simulated formation is reached, then stop heating and switch to the insulation mode; while heating, start the delivery pump to pump the fracturing fluid into the reservoir simulation system; S3, setting the image acquisition and dissolution rate evaluation interval, recording the dissolution state of the temporary plugging agent and evaluating the dissolution rate according to the set frequency; S4. During the experiment, the dissolution of the temporary plugging agent under the simulated reservoir temperature and pressure conditions was observed in real time through the visual window. After the experiment, the reaction time was recorded; S5. After the experiment, clean water is injected into the reservoir simulation system using a delivery pump to thoroughly clean the reservoir simulation device; the cleaning liquid is collected into the recovery and processing system through the simulated fracture module, and the automatic filtering device effectively isolates the dissolved residue and solid particles in the cleaning liquid; S6. The reaction residue after cleaning is taken out and placed in a constant temperature oven for drying. After complete drying, the quality of the residue is accurately tested and the residue rate is calculated.

8. The method for evaluating the solubility of a temporary plugging agent according to claim 7, characterized in that: In step S6, the residue rate is calculated by the following formula: Where γ is the residue rate, m1 is the initial temporary plugging agent mass, and m2 is the mass of the dissolved residue after drying.

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