Acid-etched fracture conductivity testing device and testing method thereof

Abstract

The invention discloses an acid-etched fracture conductivity testing device and a testing method thereof, the acid-etched fracture conductivity testing device comprises an acid liquid storage tank and a diversion chamber, and an acid storage chamber and a driving chamber are arranged in the acid liquid storage tank; the acid storage chamber is connected with a liquid supplementing container through a pipeline, a gas cavity and a liquid cavity are formed in the liquid supplementing container, the gas cavity is connected with a high-pressure nitrogen gas source, acid liquid is arranged in the liquid cavity, and the liquid cavity is connected with the acid storage chamber; the bottom end of the driving chamber is connected with a constant-flux pump through a pipeline, and the input end of the constant-flux pump is connected with a driving liquid pool; ports at two ends of the flow guide chamber are respectively connected with an output port of a preheater and a discharge pipeline; an input port of the preheater is connected with an acid storage chamber, and an input end pipeline of the preheater is connected with a gas cleaning pipeline; the gas cleaning pipeline comprises a gas cylinder, a buffer tank and a one-way valve; a pressure regulating valve is arranged at the output end of the gas cylinder, a one-way valve and a buffer tank are sequentially arranged at the output end of the gas cylinder in series, and the output end of the buffer tank is connected with the input end of the preheater.

Description

Technical Field

[0001] This invention relates to the field of acid-etched crack conductivity testing technology, specifically to an acid-etched crack conductivity testing device and its testing method. Background Technology

[0002] Fracturing is one of the main methods for enhancing the production of low-permeability reservoirs in oilfields. The production enhancement effect of fracturing is closely related to the conductivity of the propped fractures, which depends on the fracture width and the permeability of the proppant after fracture closure. Therefore, only by selecting and controlling the quality of proppants from different sources before fracturing operations can optimal construction design be guaranteed. The acid-etched fracture conductivity tester provides a scientific and effective experimental evaluation method and platform for evaluating proppant performance, further understanding the variation patterns of different proppants, different displacement rates, different temperatures, and different closure pressures, and for selecting the best proppant. This provides a more scientific, accurate, and reliable basis for related research and production.

[0003] In the prior art, invention patent CN202310283150.7 discloses a method and system for evaluating the dynamic changes in the conductivity of fractures in shale gas wells. This method uses an improved pressure deconvolution algorithm to normalize production dynamic data, transforming pressure data measured in engineering under variable flow rates into pressure data under constant flow rates, thus maintaining consistency with the internal boundary conditions of the seepage mathematical model. Furthermore, using the pressure deconvolution algorithm to normalize production dynamic data reduces errors and improves the fitting effect of the double logarithmic characteristic curve, enabling more accurate interpretation of fracture conductivity during the long-term production stage and the fracturing fluid flowback stage.

[0004] The aforementioned patent describes a method and system for evaluating the dynamic changes in the conductivity of fractures in shale gas wells. It establishes a trilinear seepage physical model for multi-stage fractured horizontal wells in shale gas reservoirs, and separately establishes unsteady seepage mathematical models for gas during the long-term production stage and unsteady seepage mathematical models for liquid during the fracturing fluid flowback stage. However, this method cannot meet the requirements of flow experiments and flowback experiments of different media in fractures, and its limited testing function makes it impossible to perform a variety of experimental operations. Summary of the Invention

[0005] The purpose of this invention is to provide an acid-etched crack conductivity testing device and its testing method, aiming to improve the existing acid-etched crack conductivity testing devices, which have limited testing functions, cannot perform multiple experimental operations with a single experimental device, and cannot meet the requirements of experiments on the flow of different media in cracks and backflow experiments.

[0006] This invention is implemented as follows: A device for testing the conductivity of acid-etched cracks includes an acid storage tank and a flow guiding chamber. The acid storage tank contains an acid storage chamber and a drive chamber. The acid storage chamber is connected to a replenishment container via a pipe. The replenishment container contains a gas chamber and a liquid chamber. The gas chamber is connected to a high-pressure nitrogen source. The liquid chamber contains acid and is connected to the acid storage chamber. The bottom of the drive chamber is connected to a horizontal flow pump via a pipe. The input end of the horizontal flow pump is connected to a drive liquid pool. The two ends of the flow guiding chamber are respectively connected to the output port of a preheater and a discharge pipe. The input port of the preheater is connected to the acid storage chamber, and a gas purging pipeline is connected to the input pipeline of the preheater. The gas purging pipeline includes a gas cylinder, a buffer tank, and a one-way valve. The output end of the gas cylinder is equipped with a pressure regulating valve, and a one-way valve and a buffer tank are connected in series at the output end. The output end of the buffer tank is connected to the input end of the preheater.

[0007] Preferably, the acid storage tank includes a piston and a displacement sensor, and the interior of the acid storage tank is divided into an acid storage chamber and a driving chamber by the piston; the displacement sensor is installed on the acid storage tank.

[0008] Preferably, the system further includes a hydraulic press, which is connected to the flow guide chamber and applies pressure to the flow guide chamber via the hydraulic press. The flow guide chamber includes a fixed base plate, an upper pressure plate, and a clamping piston. The upper pressure plate, the clamping piston, and the fixed base plate are arranged sequentially from top to bottom. A pair of clamping pistons are provided and are respectively connected to the upper end face of the fixed base plate and the lower end face of the upper pressure plate. A cavity for accommodating the rock mold is formed between the pair of clamping pistons and is connected to the ports on both sides of the flow guide chamber. A heating rod is provided inside the clamping piston.

[0009] Preferably, the discharge pipeline includes a waste liquid tank, a vacuum pump, a weighing balance, and a separator; the waste liquid tank, vacuum pump, and weighing balance are arranged in parallel in sequence, and a separator is provided on the weighing balance; a back pressure module is connected between the vacuum pump and the weighing balance, and the back pressure module includes a back pressure pump, a back pressure buffer tank, and a back pressure valve, and the back pressure pump and the back pressure buffer tank are arranged in series on the back pressure valve.

[0010] Preferably, the replenishment container includes a movable plug, and the movable plug is disposed inside the replenishment container, dividing the replenishment container into an air chamber and a liquid chamber.

[0011] According to a second aspect of the present invention, a test method for an acid-etched crack conductivity testing device is provided, the specific steps of which are as follows:

[0012] S100, empty sample calibration of the flow chamber;

[0013] Preparation of S200 and diversion chamber;

[0014] S300, evacuate saturated water;

[0015] S400, flow guidance capability test.

[0016] Preferably, step S100 refers to installing a pair of pistons, sealing rings, and metal plates into the guide chamber without adding proppant; placing the installed guide chamber between the two plates of the hydraulic press; turning on the oil pump switch to increase the pressure to a pressure lower than the first closing pressure and then stopping the pump, and closing the oil pump shut-off valve; turning on the automatic switch to turn on the power supply of the compensation pump, which automatically increases the pressure to the first closing pressure and then stops the pump; adjusting the displacement sensor so that the displacement display is 0; measuring the distance from the upper pressure plate of the guide chamber to the upper surface of the guide chamber with calipers; the compensation pump loading sequentially to each closing pressure according to the set program, and the computer automatically collects the displacement at each closing pressure as the basis value for measuring the proppant filling thickness.

[0017] Preferably, step S200 refers to: placing a stainless steel filter screen at the liquid inlet, outlet, and each pressure testing hole; placing the bottom piston with a sealing ring into the flow guide chamber; placing a metal plate on top of the bottom piston; adding proppant into the flow guide chamber; leveling the proppant for testing with a leveling tool; placing another metal plate on top of the leveled proppant; placing the piston with the upper clamping clamp into the flow guide chamber; placing the installed flow guide chamber between the two plates of the hydraulic press; turning on the oil pump switch to increase the pressure to below the first closing pressure, stopping the pump, and closing the oil pump shut-off valve; turning on the automatic switch, turning on the power supply of the compensation pump, and the compensation pump automatically increasing the pressure to the first closing pressure and stopping the pump; measuring the distance from the upper pressure plate of the flow guide chamber to the upper surface of the flow guide chamber with a vernier caliper.

[0018] Preferably, step S300 refers to closing the valve on the damper, applying control pressure to the back pressure valve, opening the pressure testing valve of the guide chamber and the vacuum pump valve; turning on the vacuum pump to evacuate the guide chamber; evacuating for 30 minutes, opening the liquid inlet valve on the damper and turning on the horizontal flow pump to inject the test medium into the guide chamber, continuing to evacuate, and when the test medium is seen flowing out of the vacuum buffer container, turning off the vacuum pump and the vacuum valve, and continuing to saturate with water; releasing the control pressure of the back pressure valve until the test medium flows out of the outlet of the back pressure valve and the flow rate is constant, at which point the saturation with water ends.

[0019] Preferably, step S400 refers to inputting experimental parameters, including various closing pressures, test flow rates, and pressure-bearing time, into the computer; connecting the power supply to the horizontal flow pump, displacement gauge, balance, and compensating pump; turning the automatic / manual switch to the automatic position; pressing the test start button, and the instrument sequentially measuring the conductivity and permeability at each closing pressure according to the pre-set program; turning on the heating switch, setting the required temperature on the temperature controller, and the temperature controller automatically controlling the flow chamber to heat to the required temperature. A preheater is designed to preheat the medium driven into the flow chamber, and the temperature of the preheater is also set and controlled by the temperature controller; there is a temperature sensor at the inlet and outlet of the flow chamber to measure the inlet and outlet temperatures, which are used in the calculation of conductivity and permeability.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. This invention can meet the testing requirements for proppant conductivity under high temperature and high pressure, including gas conductivity and liquid conductivity; it can meet the requirements for simulating acid flow and flowback experiments in fractures; it can meet the requirements for simulating the flow and flowback experiments of different media such as fracturing fluid and gas-liquid two-phase flow in fractures; it can meet the requirements for evaluating rock acid filtration and fracturing fluid filtration; it can meet the requirements for proppant embedding and flowback experiments; it has multiple functions and can perform a variety of test operations, realizing multiple uses of one instrument.

[0022] 2. By setting up a replenishment container, the acid storage tank can be replenished in a timely manner, avoiding insufficient solution in the acid storage tank during the experiment, and saving manpower, time and effort. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the experimental apparatus of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the acid storage tank of the present invention;

[0025] Figure 3 This is a schematic diagram of the flow guiding chamber of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the fluid replenishment container of the present invention;

[0027] Figure 5 This is the electrical control diagram of the test apparatus of the present invention.

[0028] In the diagram: 1. Acid storage tank; 101. Piston; 102. Acid storage chamber; 103. Drive chamber; 104. Displacement sensor; 2. Preheater; 3. Flow guide chamber; 31. Fixed base plate; 32. Upper pressure plate; 33. Clamping piston; 4. Hydraulic press; 5. Flow pump; 6. Discharge pipe; 61. Waste liquid tank; 62. Vacuum pump; 63. Weighing balance; 64. Separator; 65. Back pressure pump; 66. Back pressure buffer tank; 67. Back pressure valve; 7. Liquid replenishment container; 71. Moving plug; 72. Liquid chamber; 73. Gas chamber; 8. High-pressure nitrogen source; 9. Gas cleaning pipeline; 91. Gas cylinder; 92. Buffer tank; 93. Check valve. Detailed Implementation

[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details:

[0031] Example 1

[0032] like Figure 1 , Figure 2 and Figure 4 As shown, an acid etching crack conductivity testing device includes an acid storage tank 1 and a flow guiding chamber 3. The acid storage tank 1 contains an acid storage chamber 102 and a driving chamber 103. The acid storage tank 1 includes a piston 101 and a displacement sensor 104. The piston 101 divides the acid storage tank 1 into the acid storage chamber 102 and the driving chamber 103. The displacement sensor 104 is mounted on the acid storage tank 1. The acid storage chamber 102 is connected to a replenishment container 7 via a pipe. The replenishment container 7 contains a gas chamber 73 and a liquid chamber 72. The replenishment container 7 includes a movable plug 71, which divides the replenishment container into the gas chamber 73 and the liquid chamber 72. The gas chamber 73 is connected to a high-pressure nitrogen source 8. The liquid chamber 7... The preheater 2 is equipped with acid solution and is connected to the acid storage chamber 102. The bottom of the drive chamber 103 is connected to the horizontal flow pump 5 through a pipe, and the input end of the horizontal flow pump 5 is connected to the drive liquid pool. The two ends of the guide chamber 3 are respectively connected to the output port of the preheater 2 and the discharge pipe 6. The discharge pipe 6 includes a waste liquid tank 61, a vacuum pump 62, a weighing balance 63, and a separator 64. The waste liquid tank 61, the vacuum pump 62, and the weighing balance 63 are arranged in parallel in sequence, and the separator 64 is installed on the weighing balance 63. A back pressure module is connected between the vacuum pump 62 and the weighing balance 63. The back pressure module includes a back pressure pump 65, a back pressure buffer tank 66, and a back pressure valve 67. The back pressure pump 65 and the back pressure buffer tank 66 are connected in series on the back pressure valve 67.

[0033] like Figure 1 and Figure 3As shown, it also includes a hydraulic press 4, which is connected to the flow chamber and applies pressure to the flow chamber 3 through the hydraulic press 4; the flow chamber 3 includes a fixed base plate 31, an upper pressure plate 32, and a clamping piston 33; the upper pressure plate 32, the clamping piston 33, and the fixed base plate 31 are arranged sequentially from top to bottom; a pair of clamping pistons 33 are provided, and are respectively connected to the upper end face of the fixed base plate 31 and the lower end face of the upper pressure plate 32, forming a shape to accommodate the rock mold between the pair of clamping pistons 33. The preheater 2 has a cavity and is connected to the ports on both sides of the flow guide chamber 3; a heating rod is installed inside the clamping piston 33; the inlet of the preheater 2 is connected to the acid storage chamber 102, and a gas cleaning pipeline 9 is connected to the inlet pipeline of the preheater 2; the gas cleaning pipeline 9 includes a gas cylinder 91, a buffer tank 92 and a one-way valve 93; a pressure regulating valve is installed at the outlet of the gas cylinder 91, and a one-way valve 93 and a buffer tank 92 are connected in series at the outlet, and the outlet of the buffer tank 92 is connected to the inlet of the preheater 2.

[0034] The working principle of this invention is as follows: When the device is needed, the horizontal flow pump 5 sends the driving fluid into the drive chamber 103 through the pipeline, and drives the piston 101 in the acid storage tank 1 to work. Then, the liquid in the acid storage chamber 102 is heated by the preheater 2 and sent into the guide chamber 3. At the same time, the movement distance can be detected by the displacement sensor 104 on the acid storage tank 1. A gas cleaning pipeline 9 is also provided on the input pipeline of the preheater 2. The gas in the pipeline can be cleaned by setting up a gas cylinder 91, a buffer tank 92 and a one-way valve 93. At the same time, the replenishment container 7 can be driven by the high-pressure nitrogen gas source 8 to replenish the acid storage chamber 102. Meanwhile, the sample is placed in the guide chamber 3, and the hydraulic press 4 applies pressure to the guide chamber 3 to provide a certain pressure. Then, the liquid in the acid storage tank 1 enters the guide chamber 3 for experimentation. At the same time, the liquid will be discharged through the guide chamber 3 and the discharge pipe 6.

[0035] Example 2

[0036] like Figure 1 and Figure 5 As shown, a test method for an acid-etched crack conductivity testing device is provided in Example 1. The specific steps of this test method are as follows:

[0037] S100, Calibration of the empty sample of the guide chamber; Step S100 refers to installing a pair of pistons, sealing rings, and metal plates into the guide chamber without adding proppant; placing the installed guide chamber between the two plates of the hydraulic press; turning on the oil pump switch to increase the pressure to a pressure lower than the first closing pressure and then stopping the pump, and closing the oil pump shut-off valve; turning on the automatic switch and turning on the power supply of the compensation pump, which automatically increases the pressure to the first closing pressure and then stops the pump; adjusting the displacement sensor so that the displacement display is 0; measuring the distance from the upper pressure plate of the guide chamber to the upper surface of the guide chamber with calipers; the compensation pump loading to each closing pressure in sequence according to the set program, and the computer automatically collects the displacement at each closing pressure as the basis value for measuring the proppant filling thickness.

[0038] S200, Preparation of the flow guide chamber; S200 refers to placing a stainless steel filter screen at the liquid inlet, outlet, and each pressure testing hole; placing the bottom piston with a sealing ring into the flow guide chamber; placing a metal plate on top of the bottom piston; adding proppant into the flow guide chamber; leveling the proppant for the test with a leveling tool; placing another metal plate on top of the leveled proppant; placing the piston with the upper clamping ring into the flow guide chamber; placing the installed flow guide chamber between the two plates of the hydraulic press; turning on the oil pump switch to increase the pressure to below the first closing pressure, stopping the pump and closing the oil pump shut-off valve; turning on the automatic switch, turning on the power supply of the compensation pump, the compensation pump automatically increases the pressure to the first closing pressure and stops the pump; measuring the distance from the upper pressure plate of the flow guide chamber to the upper surface of the flow guide chamber with a vernier caliper.

[0039] S300, Evacuate the saturated water; S300 refers to closing the valve on the damper, applying control pressure to the back pressure valve, opening the pressure test valve of the guide chamber, and opening the vacuum pump valve; turning on the vacuum pump to evacuate the guide chamber; evacuating for 30 minutes, opening the liquid inlet valve on the damper, and turning on the horizontal flow pump to inject the test medium into the guide chamber, continuing to evacuate, and when the test medium is seen flowing out of the vacuum buffer container, turning off the vacuum pump and the vacuum valve, and continuing to saturate the water; releasing the control pressure of the back pressure valve until the test medium flows out of the outlet of the back pressure valve and the flow rate is constant, at which point the saturation water operation ends.

[0040] S400, Flow capacity test; S400 refers to inputting experimental parameters, including various closing pressures, test flow rates, and pressure-bearing time, into the computer; connecting the power supply to the horizontal flow pump, displacement gauge, balance, and compensating pump; turning the automatic / manual switch to the automatic position; pressing the test start button; the instrument sequentially measuring the flow capacity and permeability under each closing pressure according to the pre-set program; turning on the heating switch; setting the required temperature on the temperature controller; the temperature controller automatically controls the flow chamber to heat to the required temperature; a preheater is designed to preheat the medium driven into the flow chamber; the temperature of the preheater is also set and controlled by the temperature controller; there is a temperature sensor at the inlet and outlet of the flow chamber to measure the inlet and outlet temperatures, which are used in the calculation of flow capacity and permeability.

[0041] In summary, this invention can meet the testing requirements for proppant conductivity under high temperature and high pressure, including gas conductivity and liquid conductivity; it meets the requirements for simulating acid flow in fractures and flowback experiments; it meets the requirements for simulating the flow of different media such as fracturing fluid and gas-liquid two-phase flow in fractures and flowback experiments; it meets the requirements for evaluating rock acid filtration and fracturing fluid filtration; it meets the requirements for proppant embedding and flowback experiments; it has multiple functions and can perform various experimental operations, realizing multiple uses of one instrument; by setting up a replenishment container 7, this invention can replenish the acid storage tank 1 in a timely manner, avoiding insufficient solution in the acid storage tank 1 during the experiment, and saving manpower, time and effort.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for testing the conductivity of acid-etched cracks, comprising an acid storage tank (1) and a flow guiding chamber (3), characterized in that, The acid storage tank (1) is equipped with an acid storage chamber (102) and a drive chamber (103) inside; the acid storage chamber (102) is connected to a replenishment container (7) through a pipe, the replenishment container (7) is equipped with a gas chamber (73) and a liquid chamber (72), the gas chamber (73) is connected to a high-pressure nitrogen gas source (8), the liquid chamber (72) is equipped with acid liquid and is connected to the acid storage chamber (102); the bottom end of the drive chamber (103) is connected to a horizontal flow pump (5) through a pipe, the input end of the horizontal flow pump (5) is connected to a drive liquid pool; the guide chamber (3) The two ends of the preheater (2) are connected to the output port and the discharge pipe (6) respectively; the input port of the preheater (2) is connected to the acid storage chamber (102), and the input end pipeline of the preheater (2) is connected to the gas cleaning pipeline (9); the gas cleaning pipeline (9) includes a gas cylinder (91), a buffer tank (92) and a one-way valve (93); the output end of the gas cylinder (91) is equipped with a pressure regulating valve, and the output end is connected in series with the one-way valve (93) and the buffer tank (92), and the output end of the buffer tank (92) is connected to the input end of the preheater (2).

2. The acid etching crack conductivity testing device according to claim 1, characterized in that, The acid storage tank (1) includes a piston (101) and a displacement sensor (104). The inside of the acid storage tank (1) is divided into an acid storage chamber (102) and a drive chamber (103) by the piston (101). The displacement sensor (104) is installed on the acid storage tank (1).

3. The acid etching crack conductivity testing device according to claim 1, characterized in that, It also includes a hydraulic press (4), which is connected to the flow chamber and applies pressure to the flow chamber (3) through the hydraulic press (4); the flow chamber (3) includes a fixed base plate (31), an upper pressure plate (32) and a clamping piston (33); the upper pressure plate (32), the clamping piston (33) and the fixed base plate (31) are arranged sequentially from top to bottom; a pair of clamping pistons (33) are provided and are respectively connected to the upper end face of the fixed base plate (31) and the lower end face of the upper pressure plate (32), and a cavity for accommodating the rock mold is formed between the pair of clamping pistons (33), and they are connected to the ports on both sides of the flow chamber (3); a heating rod is provided inside the clamping piston (33).

4. The acid etching crack conductivity testing device according to claim 1, characterized in that, The discharge pipe (6) includes a waste liquid tank (61), a vacuum pump (62), a weighing balance (63), and a separator (64); the waste liquid tank (61), the vacuum pump (62), and the weighing balance (63) are arranged in parallel in sequence, and the weighing balance (63) is equipped with a separator (64); a back pressure module is connected between the vacuum pump (62) and the weighing balance (63), and the back pressure module includes a back pressure pump (65), a back pressure buffer tank (66), and a back pressure valve (67), and the back pressure pump (65) and the back pressure buffer tank (66) are arranged in series on the back pressure valve (67).

5. The acid etching crack conductivity testing device according to claim 1, characterized in that, The replenishment container (7) includes a movable plug (71), which is provided inside the replenishment container (7) and divides the replenishment container into an air chamber (73) and a liquid chamber (72).

6. A test method for an acid-etched crack conductivity testing device, using the acid-etched crack conductivity testing device as described in claim 1, characterized in that, The specific steps of this monitoring method are as follows: S100, empty sample calibration of the flow chamber; Preparation of S200 and diversion chamber; S300, evacuate saturated water; S400, flow guidance capability test.

7. The test method for the acid etching crack conductivity testing device according to claim 6, characterized in that, Step S100 refers to installing a pair of pistons, sealing rings, and metal plates into the guide chamber without adding proppant; placing the installed guide chamber between the two plates of the hydraulic press; turning on the oil pump switch to increase the pressure to a level below the first closing pressure and then stopping the pump, and closing the oil pump shut-off valve; turning on the automatic switch and the power supply to the compensation pump, which automatically increases the pressure to the first closing pressure and then stops; adjusting the displacement sensor to make the displacement display show 0; measuring the distance from the upper pressure plate of the guide chamber to the upper surface of the guide chamber with calipers; the compensation pump loading sequentially to each closing pressure according to the set program, and the computer automatically collecting the displacement at each closing pressure as the basis value for measuring the proppant filling thickness.

8. The test method for the acid etching crack conductivity testing device according to claim 6, characterized in that, Step S200 refers to: placing a stainless steel filter screen at the liquid inlet, outlet, and each pressure testing hole; placing a bottom piston with a sealing ring into the flow guide chamber; placing a metal plate on top of the bottom piston; adding proppant into the flow guide chamber; leveling the proppant for the test with a leveling tool; placing another metal plate on top of the leveled proppant; placing a piston with an upper clamping clamp into the flow guide chamber; placing the installed flow guide chamber between the two plates of the hydraulic press; turning on the oil pump switch to increase the pressure to below the first closing pressure, stopping the pump, and closing the oil pump shut-off valve; turning on the automatic switch, turning on the power to the compensation pump, and the compensation pump automatically increasing the pressure to the first closing pressure and stopping the pump; measuring the distance from the upper pressure plate of the flow guide chamber to the upper surface of the flow guide chamber with a vernier caliper.

9. The test method for the acid etching crack conductivity testing device according to claim 6, characterized in that, Step S300 refers to closing the valve on the damper, applying control pressure to the back pressure valve, opening the pressure testing valve of the guide chamber and the vacuum pump valve; turning on the vacuum pump to evacuate the guide chamber; evacuating for 30 minutes, opening the liquid inlet valve on the damper and turning on the horizontal flow pump to inject the test medium into the guide chamber, continuing to evacuate, and when the test medium is seen flowing out of the vacuum buffer container, turning off the vacuum pump and the vacuum valve, and continuing to saturate with water; releasing the control pressure of the back pressure valve until the test medium flows out of the outlet of the back pressure valve and the flow rate is constant, at which point the saturation with water is finished.

10. The test method for the acid etching crack conductivity testing device according to claim 6, characterized in that, Step S400 refers to inputting experimental parameters, including various closing pressures, test flow rates, and pressure-bearing time, into the computer; connecting the power supply to the flow pump, displacement gauge, balance, and compensating pump; turning the automatic / manual switch to the automatic position; pressing the test start button, and the instrument sequentially measuring the flow capacity and permeability under each closing pressure according to the pre-set program; turning on the heating switch, setting the required temperature on the temperature controller, and the temperature controller automatically controlling the flow chamber to heat to the required temperature. A preheater is designed to preheat the medium driven into the flow chamber, and the temperature of the preheater is also set and controlled by the temperature controller; there is a temperature sensor at the inlet and outlet of the flow chamber to measure the inlet and outlet temperatures, which are used in the calculation of flow capacity and permeability.

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