CN214952906U

CN214952906U - Crack conductivity testing system

Info

Publication number: CN214952906U
Application number: CN202121152190.0U
Authority: CN
Inventors: 张健; 赵文韬; 刘练波; 尹玉龙; 张国祥
Original assignee: Huaneng Clean Energy Research Institute
Current assignee: Huaneng Clean Energy Research Institute
Priority date: 2021-05-26
Filing date: 2021-05-26
Publication date: 2021-11-30
Anticipated expiration: 2031-05-26

Abstract

The utility model discloses a crack conductivity test system has the crack conductivity test method to following multiple model: the test of the diversion capacity of the layered fracture, the test of the diversion capacity of the single-layer zigzag fracture, the test of the diversion capacity of the fracture network fracture and the test of the diversion capacity of the full-diameter core with the fracture or the micro fracture can be flexibly selected and used according to the requirement. The utility model designs two sets of piston containers to alternately supply liquid, thereby realizing long-time uninterrupted liquid supply; in addition, a back pressure pump and a back pressure valve are designed, so that the migration resistance of the medium in the crack under the real condition can be accurately simulated.

Description

Crack conductivity testing system

Technical Field

The utility model relates to an oil gas development field, concretely relates to crack conductivity test system.

Background

In recent years, the amount of low-permeability oil and gas resources in China is huge, and especially in the development of unconventional oil and gas resources such as coal bed gas, shale gas and the like, a fracturing technology plays an extremely important role and becomes the most main technical means for realizing economic and efficient development and yield increase of low-permeability oil and gas resources. The main purpose of hydraulic fracturing is to create artificial fractures of a certain scale in oil and gas reservoirs through fracturing construction, as oil and gas seepage channels, and the artificial fractures generally need stable and high fracture conductivity. Therefore, the method is particularly important for testing and researching the flow conductivity of the fractured fractures.

With the further research on the conductivity of the fractured fractures, many experimental systems and methods for testing the conductivity of the fractures are researched, for example, a multi-angle acid-etched fracture conductivity testing system and the like. However, the prior art has some disadvantages: (1) the diversion chamber of most experimental systems only has a single model and cannot simulate and test the diversion capacity of complex cracks such as multilayer cracks, reticular cracks and the like; (2) the existing similar equipment is concentrated on the influence of fracturing fluid and propping agent on the flow conductivity of the fracture, and the influence of a fracture model on the flow conductivity test effect of the fracture is neglected; (3) most of crack conductivity test equipment have simple internal structures and low applicability and operability, can not accurately simulate and test the real conductivity of underground complex cracks under the condition of underground temperature and pressure, and can not simulate the influence of the conductivity of micro cracks of a rock sample.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a crack conductivity test system to overcome the problem that exists among the prior art, the utility model discloses the design has the crack conductivity test method to following four kinds of models: the method comprises the steps of testing the diversion capacity of a layered fracture, testing the diversion capacity of a single-layer zigzag fracture, testing the diversion capacity of a fracture network fracture, and testing the diversion capacity of a full-diameter core with a fracture or a micro-fracture. The four models can be flexibly selected and used according to experimental research needs.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a crack conductivity testing system comprises a gas and liquid combined supply device capable of supplying gas or liquid independently, wherein the outlet end of the gas and liquid combined supply device is connected with a testing device for conductivity testing, a vacuumizing device is connected to the gas and liquid combined supply device, and the testing device is a first testing device for layered conductivity testing, a second testing device for crack network crack conductivity testing and single-layer zigzag crack conductivity testing, or a third testing device for full-diameter core conductivity testing with cracks or micro cracks; the outlet ends of the first testing device, the second testing device and the third testing device are respectively connected to the first metering device, the second metering device and the third metering device;

the first testing device comprises a first diversion chamber and a second diversion chamber which are connected to the outlet end of the gas and liquid combined supply device, the inlet end of the first diversion chamber is connected with the outlet end of the gas and liquid combined supply device, and the outlet end of the first diversion chamber is connected to the metering device; the inlet end of the second diversion chamber is connected with the outlet end of the combined gas and liquid supply device through an eighteenth valve, the outlet end of the second diversion chamber is connected to a twentieth valve through two metering branches, and the outlet end of the twentieth valve is connected to the first metering device through a second thermometer; the first flow guide chamber and the second flow guide chamber are respectively connected with a first closing pressure applying device and a second closing pressure applying device, and a first pressure difference sensing device is arranged between the inlet end and the outlet end of the first flow guide chamber;

the second testing device comprises a third diversion chamber, the inlet end of the third diversion chamber is connected with the outlet end of the gas and liquid combined supply device through a twenty-fourth valve, a twenty-fifth valve and a twenty-sixth valve which are arranged in parallel, the outlet end of the third diversion chamber is connected to a second metering device through a twenty-seventh valve, a twenty-eighth valve and a twenty-ninth valve which are arranged in parallel, a third closing pressure applying device is connected onto the third diversion chamber, and a second differential pressure sensing device is arranged between the inlet end and the outlet end of the third diversion chamber;

the third testing device comprises a fourth flow guide chamber, the inlet end of the fourth flow guide chamber is connected with the outlet end of the gas and liquid combined supply device, the outlet end of the fourth flow guide chamber is connected to a third metering device, the fourth flow guide chamber is connected with a fourth closing pressure applying device, a third pressure difference sensing device is arranged between the inlet end and the outlet end of the fourth flow guide chamber, and the outlet end of the fourth flow guide chamber is further connected to the axial pressure pump through an eighth pressure gauge.

Further, the combined gas and liquid supply device comprises a gas supply device and a liquid supply device, the gas supply device comprises a gas cylinder, the outlet end of the gas cylinder is sequentially connected with a first valve, a filter, a second valve, a first flowmeter, a preheater, a first thermometer, a first pressure gauge and a third valve, and the outlet end of the third valve is connected to the inlet end of the first diversion chamber and the inlet end of the second diversion chamber, or the inlet end of the third diversion chamber, or the inlet end of the fourth diversion chamber.

Furthermore, the liquid supply device comprises a first water container, the outlet end of the first water container is connected with a water pump, the outlet of the water pump is divided into two branches, one branch is sequentially connected with a sixth valve, a first piston container and a seventh valve, the other branch is sequentially connected with an eighth valve, a second piston container and a ninth valve, and the outlets of the seventh valve and the ninth valve are connected to the inlet of the preheater;

the liquid supplementing device comprises a liquid supplementing container, an inlet at the top of the liquid supplementing container is connected between the filter and the second valve through a fourth valve, an outlet pipeline of the liquid supplementing container is connected to an inlet of the preheater through a fifth valve, and the fourth valve is connected to the top of the liquid supplementing container through a pipeline; and a pipeline connecting the fifth valve and the fluid infusion container is inserted at the bottom of the fluid infusion container.

Further, be provided with alarm device when reaching minimum liquid level on the fluid infusion container, still be provided with safety device on the fluid infusion container, when causing pressure to rise to the protective pressure because of the maloperation, safety device can open automatically and make the automatic overflow of liquid.

Further, evacuating device includes the buffer tank, the design of buffer tank bottom has the tenth valve that the unloading was used, and the top of buffer tank has connected gradually vacuum pump and twelfth valve, and buffer tank top entry connection has the eleventh valve, and when testing arrangement adopted first testing arrangement or second testing arrangement, the entry end of eleventh valve was connected between preheater and first thermometer, and when testing arrangement adopted the third testing arrangement, the exit end at the third valve was connected to the entry end of eleventh valve.

Further, the first closing pressure applying device comprises a second pressure gauge, a tenth valve and a first closing pressure pump which are connected in sequence;

the second closing pressure applying device comprises a fourth pressure gauge, a seventeenth valve and a second closing pressure pump which are sequentially connected;

the third closing pressure applying device comprises a fifth pressure gauge, a thirtieth valve and a third closing pressure pump which are sequentially connected;

the fourth closing pressure applying device comprises a seventh pressure gauge, a thirty-fourth valve and a fourth closing pressure pump which are connected in sequence;

the first closing pressure pump, the second closing pressure pump, the third closing pressure pump and the fourth closing pressure pump are provided with an attached closing pressure automatic compensation device for keeping the closing pressure constant.

Further, the first differential pressure sensing device comprises a fifteenth valve, a first differential pressure sensor and a sixteenth valve which are connected in sequence;

the second differential pressure sensing device comprises a thirtieth valve, a second differential pressure sensor and a thirtieth valve which are sequentially connected;

the third differential pressure sensing device comprises a third seventeen valve, a third differential pressure sensor and a thirty-eighth valve which are sequentially connected.

Further, the first metering device comprises a fourteenth valve, a first back-pressure valve and a second water container which are sequentially connected, the second water container is arranged on the first balance, and the side surface of the first back-pressure valve is connected to the first back-pressure pump through a third pressure gauge;

the second metering device comprises a thirty-one valve, a second back pressure valve and a third water container which are connected in sequence, the third water container is arranged on a second balance, and the side surface of the second back pressure valve is connected to a second back pressure pump through a sixth pressure gauge;

the third metering device comprises a fifteenth valve, a third back pressure valve and a fourth water container which are sequentially connected, the fourth water container is arranged on a third balance, and the side surface of the third back pressure valve is connected to a third back pressure pump through a ninth pressure gauge and a thirty-sixth valve.

Further, first water conservancy diversion room, second water conservancy diversion room and third water conservancy diversion room are provided with the temperature regulation apparatus that can heat the rock specimen to the target temperature that the experiment needs, the fourth water conservancy diversion room is provided with electric heater unit, and the fourth water conservancy diversion outdoor side is provided with the insulation cover for different cover pressure conditions of simulation.

Furthermore, one of the two metering branches at the outlet end of the second diversion chamber is sequentially connected with a nineteenth valve, a second flow meter and a twentieth valve, and the other metering branch is sequentially connected with a twenty-first valve, a third flow meter and a twentieth valve.

Compared with the prior art, the utility model discloses following profitable technological effect has:

the utility model discloses the design has the crack conductivity testing method to following multiple model: the test of the diversion capacity of the layered fracture, the test of the diversion capacity of the single-layer zigzag fracture, the test of the diversion capacity of the fracture network fracture and the test of the diversion capacity of the full-diameter core with the fracture or the micro fracture can be flexibly selected and used according to the requirement.

Specifically, the utility model has the following characteristics: the system and the method can test the flow conductivity of the four conditions of a layering crack, a zigzag crack, a crack network crack, a full-diameter core with cracks or microcracks; the experiment system optimizes the inlet and outlet lines of the fracturing medium of the flow guide chamber in the flow guide of the slotted net so as to simulate the effect of multipoint injection and multipoint fracturing; the system and the method also design a fourth diversion chamber (a full-diameter triaxial core holder) and a method for testing the fracture diversion capability of the full-diameter core with cracks or microcracks; the system and the method design the axial pressure pump and the closed pressure pressurization function in the diversion capability test of the full-diameter core, and meet the requirement of testing the diversion capability of the formation fracture under the condition of simulating the formation; the system and the method design 2 sets of piston containers to alternately supply liquid, thereby realizing long-time uninterrupted liquid supply; sixthly, the system and the method design a back pressure pump and a back pressure valve so as to accurately simulate the migration resistance of the medium in the crack under the real condition.

Furthermore, the fluid infusion container is mainly used for infusion of the piston container, and when the fluid infusion container reaches the lowest liquid level, an automatic alarm can be given to remind a user of filling fluid. The liquid supplementing container is provided with a safety device, and when the pressure rises to the protection pressure due to misoperation, the safety device can be automatically opened to enable the liquid to automatically overflow.

Further, in the required heating test, in order to ensure that the test is performed at the required temperature, the preheater is required to preheat the fluid, so as to ensure that the temperature of the injected fluid is consistent with that of the diversion chamber.

Furthermore, three diversion inlets and three diversion outlets are designed in the third diversion chamber, so that the slotted net diversion is simulated more truly, and the situation that the difference between the test result and the actual situation is large due to one diversion inlet and one diversion outlet is avoided.

Furthermore, the first diversion chamber, the second diversion chamber and the third diversion chamber are provided with temperature adjusting devices capable of heating the rock sample to target pressure required by an experiment, so that the formation temperature condition can be better simulated, the fourth diversion chamber is provided with an electric heating device, and the outer side of the fourth diversion chamber is provided with a heat insulation sleeve for simulating different pressure covering conditions.

Drawings

FIG. 1 is a schematic view of the layered flow conductivity testing system of the present invention;

FIG. 2 is a schematic view of the system for testing the crack conductivity of the slotted net and the conductivity of the single-layer zigzag crack of the present invention;

fig. 3 is a schematic view of the full-diameter core conductivity testing system with cracks or microcracks of the present invention.

Wherein, 1 gas cylinder, 2 first valve, 3 filter, 4 second valve, 5 first flowmeter, 6 preheater, 7 first thermometer, 8 first pressure gauge, 9 third valve, 10 fourth valve, 11 fluid infusion container, 12 fifth valve, 13 first water container, 14 suction pump, 15 sixth valve, 16 first piston container, 17 seventh valve, 18 eighth valve, 19 second piston container, 20 ninth valve, 21 tenth valve, 22 buffer tank, 23 eleventh valve, 24 vacuum pump, 25 tenth valve, 26 first diversion chamber, 27 first closed pressure pump, 28 tenth valve, 29 second pressure gauge, 30 third pressure pump, 31 fourteenth valve, 32 third pressure gauge, 33 first back pressure valve, 34 first balance, 35 second water container, 36 first differential pressure sensor, 37 fifteenth valve, 38 sixteenth valve, 39 second diversion chamber, 40 second closed pressure pump, 41 seventeenth valve, a fourth pressure gauge 42, an eighteenth valve 43, a nineteenth valve 44, a second flow meter 45, a twentieth valve 46, a twenty-first valve 47, a third flow meter 48, a twentieth valve 49, a twentieth valve 50, a second thermometer 51, a twenty-fourth valve 52, a twenty-fifth valve 53, a twenty-sixth valve 54, a third diversion chamber 55, a twenty-seventh valve 56, a twenty-eighth valve 57, a twenty-ninth valve 58, a third closed pressure pump 59, a thirtieth valve 60, a fifth pressure gauge 61, a second back pressure pump 62, a thirty-first valve 63, a sixth pressure gauge 64, a second back pressure gauge 65, a second balance 66, a third water container 67, a second differential pressure sensor 68, a thirtieth valve 69, and a thirtieth valve 70; 71 a fourth diversion chamber, 72 a fourth closing pressure pump, 73 a thirty-fourth valve, 74 a seventh pressure meter, 75 axial pressure pump, 76 a thirty-fifth valve, 77 an eighth pressure meter, 78 a third back pressure pump, 79 a thirty-sixth valve, 80 a third back pressure valve, 81 a third balance, 82 a fourth water container, 83 a third differential pressure sensor, 84 a thirty-seventh valve, 85 a thirty-eighth valve and 86 a ninth pressure meter.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

As shown in fig. 1, in the system, a gas cylinder 1 is connected with a first valve 2, a filter 3, a second valve 4, a first flowmeter 5, a preheater 6, a first thermometer 7, a first pressure gauge 8 and a third valve 9 in sequence, and then divided into two branches: one branch is connected with the inlet of the first diversion chamber 26 in sequence, and the other branch is connected with the inlet of the second diversion chamber 39 in sequence through an eighteenth valve 43;

the first water container 13 is connected with a water pump 14, and an outlet of the water pump 14 is divided into two branches: an inlet connecting the sixth valve 15, the first piston reservoir 16, the seventh valve 17 and the preheater 6; the other branch connects the eighth valve 18, the second piston reservoir 19, the ninth valve 20 and the inlet of the preheater 6.

A branch is divided between the filter 3 and the second valve 4, and the fourth valve 10, the fluid infusion container 11, the fifth valve 12 and the inlet of the preheater 6 are connected in sequence through pipelines. Wherein, the fourth valve 10 is connected with a pipeline at the top of the liquid supplementing container 11; a line connecting the fifth valve 12 and the fluid replacement container 11 is inserted into the bottom of the fluid replacement container 11.

A tenth valve 21 for emptying is designed at the bottom of the buffer tank 22; the top of the buffer tank 22 is connected with a vacuum pump 24 and a tenth valve 25 in sequence; a branch is arranged between the preheater 6 and the first thermometer 7, and an eleventh valve 23 is connected with the top of the buffer tank 22 in turn through a pipeline.

The side surface of the first diversion chamber 26 is provided with a second pressure gauge 29, a thirteenth valve 28 and a first closing pressure pump 27 which are connected in sequence; the fifteenth valve 37, the first differential pressure sensor 36 and the sixteenth valve 38 are connected in sequence by pipelines between the inlet end and the outlet end of the first diversion chamber.

An outlet of the first diversion chamber 26 connects the fourteenth valve 31, the first back pressure valve 33, and the second water container 35 in sequence through a pipeline, and the second water container 35 is placed on the first level 34. The first back-pressure valve 33 is connected in series on its side to the third pressure gauge 32 and to the first back-pressure pump 30 via a line.

The side surface of the second diversion chamber 39 is connected with a fourth pressure gauge 42, a seventeenth valve 41 and a second closed pressure pump 40 in sequence through pipelines; the outlet of the second diversion chamber is divided into two branches, one branch connects the inlets of a nineteenth valve 44, a second flow meter 45, a twentieth valve 46 and a twentieth valve 50 in sequence, and the other branch connects the inlets of a twenty-first valve 47, a third flow meter 48, a twentieth valve 49 and a twentieth valve 50 in sequence; the outlet of the twentieth valve 50 is connected with the inlet of the fourteenth valve 31 and the second thermometer 51 in sequence.

The first diversion chamber 26 and the second diversion chamber 39 can adjust the temperature to heat the rock sample to the target temperature required by the experiment, so as to better simulate the formation temperature condition.

The preheater 6 can heat the liquid and the gas flowing through, so that the liquid and the gas reach the target temperature, and the accuracy of the simulated experiment effect is ensured.

By adjusting the first back-pressure pump 30, the back pressure required by the experiment can be set to the experiment target pressure for the first diversion chamber 26 and the second diversion chamber 55 respectively, so that the accuracy of the simulated experiment effect is ensured.

As shown in fig. 2, in the system, a gas cylinder 1 is connected with a first valve 2, a filter 3, a second valve 4, a first flowmeter 5, a preheater 6, a first thermometer 7, a first pressure gauge 8 and a third valve 9 in sequence;

The outlet of the third valve 9 is divided into three branches, and one valve is arranged on each branch, namely a twenty-fourth valve 52, a twenty-fifth valve 53 and a twenty-sixth valve 54. The three branches are then connected to a third baffle compartment 55. The outlet of the third diversion chamber 55 is also divided into three branches, each branch is provided with a valve which is a twenty-seventh valve 56, a twenty-eighth valve 57 and a twenty-ninth valve 58, the three branches are connected with a thirty-first valve 63, a second back pressure valve 65 and a third water container 67 after being converged, and the third water container 67 is placed on a second balance 66. The second back-pressure valve 65 is connected to the sixth pressure gauge 64 and the second back-pressure pump 62 in this order from the side.

The third diversion chamber 55 is provided with a fifth pressure gauge 61, a thirtieth valve 60 and a third closing pressure pump 59 which are connected in sequence on the side surface. The inlet end and the outlet end of the third guide flow chamber 55 are connected to a second differential pressure sensor 68 and a thirty-third valve 70 through a thirty-third valve 69.

The third diversion chamber 55 can adjust the temperature, heat the rock sample to the target pressure required by the experiment, and better simulate different formation temperature conditions.

By adjusting the second back pressure pump 62, the back pressure required by the experiment can be set to reach the experiment target pressure, and the accuracy of the simulated experiment effect is ensured.

As shown in fig. 3, in the system, a gas cylinder 1 is connected with a first valve 2, a filter 3, a second valve 4, a first flowmeter 5, a preheater 6, a thermometer 7, a first pressure gauge 8 and a third valve 9 in sequence;

A tenth valve 21 for emptying is designed at the bottom of the buffer tank 22; the top of the buffer tank 22 is connected with a vacuum pump 24 and a tenth valve 25 in sequence; the top of the buffer tank 22 connects the eleventh valve 23 to the outlet of the third valve 9 in this order.

The outlet of the third valve 9 is connected to a fourth flow guiding chamber 71. A seventh pressure gauge 74, a fourteenth valve 73 and a fourth closing pressure pump 72 are arranged on the side surface of the fourth diversion chamber 71 and are connected in sequence; the inlet end and the outlet end of the fourth diversion chamber 71 are connected in sequence through a seventeenth valve 84, a third differential pressure sensor 83 and a thirty eighth valve 85.

An outlet of the fourth diversion chamber 71 is sequentially connected with a thirty-fifth valve 76, a third back pressure valve 80 and a fourth water container 82, and the fourth water container 82 is placed on a third balance 81. The third back pressure valve 80 is connected in turn at its side to a ninth pressure gauge 86, a thirty-sixth valve 79 and a third back pressure pump 78. The outlet of the fourth guide flow chamber 71 is connected to an eighth pressure gauge 77 and an axial pressure pump 75 in this order.

The fourth diversion chamber 71 can adjust the temperature, heat the rock sample to the target pressure required by the experiment, and better simulate the formation temperature condition.

By adjusting the third back pressure pump 78, the back pressure required by the experiment can be set to reach the experiment target pressure, and the accuracy of the simulated experiment effect is ensured.

The utility model discloses divide into four kinds of circumstances of full diameter rock core crack conductivity test introduction of layering crack conductivity test, the tortuous crack conductivity test of individual layer, seam net crack conductivity test, area crack or micro-fracture. The principle of the test is the same as that of a general crack flow guide instrument in the industry, and the product of the permeability K and the crack width W is known in the industry after the permeability K is measured and solved according to Darcy's law:

the specific implementation mode is described in three cases as follows:

1) if the layered conductivity test is performed, selecting the connection relation as shown in fig. 1, wherein the implementation method is as follows:

checking airtightness: and connecting the equipment, checking the air tightness of the system, closing all valves and preparing for an experiment.

Sample preparation experiment: the first and second flow-guiding chambers 26 and 39 are filled with samples and prepared for the gas and liquid required for the experiment.

Vacuumizing: the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, the tenth valve 21, the fourteenth valve 31 are closed. And opening the twelfth valve 25 and the eleventh valve 23, starting the vacuum pump 24, and vacuumizing the whole pipeline in the system.

Adding closing pressure and back pressure: and when the system is vacuumized, closing the eleventh valve 23 and the tenth valve 25, and simultaneously closing the vacuum pump 24. Opening the first closing pressure pump 27, the thirteenth valve 28, and adjusting the pressure of the first closing pressure pump 27 according to the indication of the second pressure gauge 29; opening the fourteenth valve 31, the first back-pressure pump 30, and adjusting the pressure of the first back-pressure pump 30 according to the third pressure gauge 32; opening the nineteenth, twentieth, twenty-first, twenty-second valves 44, 46; opening the seventeenth valve 41, closing the second pressure pump 40, and adjusting the pressure of the second pressure pump 40 according to the reading of the fourth pressure gauge 42;

the first closing pressure pump 27 and the second closing pressure pump 40 are provided with automatic closing pressure compensation devices, and when closing pressure is applied to the rock sample to deform, the closing pressure is kept constant.

Measuring the flow conductivity by gas: if the injected gas tests the fracture conductivity, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, the twenty-first valve 47, the twenty-second valve 49 are closed, and the first valve 2 and the second valve 4 are opened. Gas in the gas cylinder 1 is filtered by the filter 3, the gas flow is measured by the first gas flowmeter 5, and then the gas passes through the preheater 6, and the third valve 9 is opened when the temperature and the pressure meet the test requirements.

The first flow meter 5 can measure the gas flow rate and meter the gas flow rate flowing through the system for a certain time. The second flow meter 45 may measure the flow of gas through the second baffle compartment 39 over time. In a heating test, the preheater 6 needs to preheat fluid to ensure that the temperature of the injected fluid is consistent with that of the diversion chamber in order to ensure that the test is carried out at a required temperature.

The gas enters the first diversion chamber 26 and the second diversion chamber 39, the fifteenth valve 37 and the sixteenth valve 38 are opened, and the pressure at the two ends of the first diversion chamber 26 and the second diversion chamber 39 is measured by the first differential pressure sensor 36; and after the differential pressure of the differential pressure sensor, the gas flow, the length, the sectional area and other dimensions of the rock sample of the diversion chamber are recorded, and the fluid viscosity is measured, the total diversion capacity of the stratified cracks under the experimental condition and the diversion capacity of each single-layer crack can be calculated according to the differential pressure shown by the first differential pressure sensor 36 and the flow shown by the first flowmeter 5 and the second flowmeter 45.

The second flow meter 45 may measure the flow of gas through the second baffle compartment 39 over time.

Sixthly, measuring the flow conductivity: if the injected liquid tests the fracture conductivity, the second valve 4, the nineteenth valve 44 and the twentieth valve 46 are closed, and the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20 are opened. The liquid in the liquid replenishing container is used for replenishing the liquid for the piston container due to the driving of the liquid. After the liquid is supplied, the first valve 2, the fourth valve 10 and the fifth valve 12 are closed, the water pump 14, the sixth valve 15, the seventh valve 17, the eighth valve 18 and the ninth valve 20 are opened, and the first piston container 16 and the second piston container 19 are started. Then the liquid passes through the preheater 6, and when the temperature and the pressure reach the test requirements, the third valve 9 is opened.

In a heating test, the preheater 6 needs to preheat fluid to ensure that the temperature of the injected fluid is consistent with that of the diversion chamber in order to ensure that the test is carried out at a required temperature.

The third flow meter 48 may measure the liquid flow rate from the second diversion chamber 39 in real time.

The pump 14 or the first balance 34 can measure the flow of liquid flowing through in real time.

The liquid enters a first diversion chamber 26 and a second diversion chamber 39, a fifteenth valve 37 and a sixteenth valve 38 are opened, the pressure at two ends of the first diversion chamber 26 and the second diversion chamber 39 is measured by a first differential pressure sensor 36, finally the liquid flows to a second water container 35, and the liquid quality can be measured by a first balance 34; after the differential pressure sensor differential pressure, the liquid flow rate, the length of the rock sample in the diversion chamber, the sectional area and other dimensions are recorded, and after the fluid viscosity is measured, when the first balance 34 and the water suction pump 14 measure equal flow rates and the flow rates meet the experimental requirements, the total fracture diversion capacity of the layered fracture and the diversion capacity of each single-layer fracture under the experimental conditions can be calculated according to the differential pressure shown by the first differential pressure sensor 36 and the flow rates recorded by the first balance 34, the water suction pump 14 and the third flow meter 48.

The cleaning equipment comprises: after the test is finished, the instrument is disassembled, all containers and pipelines are cleaned, and the equipment is kept clean.

The key parts of the system are described in detail as follows:

a: in order to ensure the long guide function, the liquid can be supplied uninterruptedly for a long time, so that the first piston container 16 and the second piston container 19 of 2 sets of piston containers are designed, the liquid can be supplied alternately, and the operation and the use are convenient.

B: the liquid supplementing container 11 is mainly used for supplementing liquid for a piston container, and when the liquid supplementing container 11 reaches the lowest liquid level, an automatic alarm can be given to remind of requiring liquid adding. The liquid supplementing container 11 is provided with a safety device, and when the pressure rises to the protection pressure due to misoperation, the safety device can be automatically opened to enable the liquid to automatically overflow, so that the protection effect is achieved.

C: the first flow meter 5 can measure the gas flow for metering the gas flow flowing through the experimental system for a certain time.

D: in the required heating test, in order to ensure that the test is carried out at the required temperature, the preheater 6 is required to preheat the fluid, so as to ensure that the temperature of the injected fluid is consistent with that of the diversion chamber.

E: the first diversion chamber 26 and the second diversion chamber 39 are both made of high-strength stainless steel materials and have certain corrosion resistance and pressure resistance. The size is large, and the flow conductivity test of most rock samples can be met.

And F, when the outlet pressure of the diversion chamber reaches the control pressure of the top of the first back-pressure valve 33, the first back-pressure valve is automatically opened to release pressure, so that the outlet pressure is ensured to be constant, and the migration resistance of the medium in the crack is simulated.

After the flow of liquid and gas and the pressure difference between two ends of the diversion chamber are measured, the general principle of diversion capability can be tested in the industry: according to the obtained pressure difference delta P, the liquid flow Q or the gas flow Q, the rock sample length L, the cross-sectional area and other dimensions A of the diversion chamber, the fluid viscosity mu and the like obtained by the above tests, through a formula:

and calculating to obtain the conductivity parameter of the crack under the experimental condition.

H: the first diversion chamber 26 and the second diversion chamber 39 can adjust the temperature, heat the rock sample to the target pressure required by the experiment, and better simulate the formation temperature condition.

I: the pressures of the first closing pressure pump 27, the second closing pressure pump 40, and the first back-pressure pump 30 can be adjusted by themselves for experimental purposes.

2) If the fracture network fracture conductivity test and the single-layer zigzag fracture conductivity test are carried out, the connection relation shown in the figure 2 is selected, and the implementation mode is as follows:

Sample preparation experiment: according to the experimental protocol, a rock sample is loaded in the third diversion chamber 55.

Vacuumizing: the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, the thirty-first valve 63 are closed. And opening the twelfth valve 25 and the eleventh valve 23, starting the vacuum pump 24, and vacuumizing the whole pipeline in the system.

Adding closing pressure and back pressure: and when the system is vacuumized, closing the eleventh valve 23 and the tenth valve 25, and simultaneously closing the vacuum pump 24. Opening the third closing pressure pump 59, the thirtieth valve 60, and adjusting the pressure of the third closing pressure pump 59 according to the indication of the fifth pressure gauge 61; the thirty-first valve 63 and the second back-pressure pump 62 are opened, and the pressure of the second back-pressure pump 62 is adjusted according to a sixth pressure gauge 64.

The third closing pressure pump 59 is provided with an automatic closing pressure compensating device for keeping the closing pressure constant when the rock sample is deformed by applying the closing pressure.

Measuring the flow conductivity by gas: if the injected gas tests the flow conductivity of the fracture network, the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20 are closed, and the first valve 2 and the second valve 4 are opened. Gas in the gas cylinder 1 is filtered by the filter 3, the gas flow is measured by the first gas flowmeter 5, and then the gas passes through the preheater 6, and the third valve 9 is opened when the temperature and the pressure meet the test requirements.

The first flow meter 5 can measure the gas flow rate and meter the gas flow rate flowing through the system for a certain time.

The twenty-fourth 52, twenty-fifth 53, twenty-sixth 53, twenty-seventh 56, twenty-eighth 57, and twenty-ninth 58 valves are opened and the gas flows through the third diversion chamber 55. The thirtieth and

thirtieth valves

69 and 70 are opened, and the pressure across the third guide flow chamber 55 is measured by the second differential pressure sensor 68. The pressure difference of the pressure difference sensor, the gas flow, the length of the rock sample in the flow guide chamber, the sectional area and other dimensions are recorded, after the fluid viscosity is measured and the test process is stable, the fracture flow guide capacity under the experimental condition can be calculated according to the pressure difference shown by the second pressure difference sensor 68 and the flow shown by the first flowmeter 5.

Sixthly, measuring the flow conductivity: if the injected liquid tests the fracture conductivity, the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20 are opened, and the liquid in the liquid supplementing container supplies liquid for the piston container due to the driving of the gas. After the liquid is supplied, the first valve 2, the fourth valve 10 and the fifth valve 12 are closed, the water pump 14, the sixth valve 15, the seventh valve 17, the eighth valve 18 and the ninth valve 20 are opened, and the first piston container 16 and the second piston container 19 are started. Then the liquid passes through the preheater 6, and when the temperature and the pressure reach the test requirements, the third valve 9 is opened.

The pump 14 or the second balance 66 can measure the flow of liquid flowing through in real time.

The twenty-fourth 52, twenty-fifth 53, twenty-sixth 53, twenty-seventh 56, twenty-eighth 57, and twenty-ninth 58 valves are opened and the liquid flows through the third guiding chamber 55. Opening thirtieth and

thirtieth valves

69 and 70, and measuring the pressure across the third guide flow chamber 55 with the second differential pressure sensor 68; eventually the liquid will flow to the third water container 67 and the mass of the liquid can be measured with the second balance 66. After the differential pressure of the differential pressure sensor, the liquid flow rate, the length of the rock sample in the diversion chamber, the sectional area and other dimensions are recorded, and after the fluid viscosity is measured, when the flow rates measured by the second balance 66 and the water pump 14 are equal and the flow rates meet the experimental requirements, the fracture diversion capacity under the experimental condition can be calculated according to the differential pressure shown by the second differential pressure sensor 68 and the flow rates shown by the water pump 14 and the second balance 66.

Testing the flow conductivity of the single-layer zigzag crack: and if the single-layer zigzag crack conductivity is tested, performing the crack conductivity tests with different corners and different crack distances by the method similar to the gas measurement and liquid measurement conductivity test.

The key parts of the system are described in detail as follows:

a: first piston reservoir 16 and second piston reservoir 19: in order to ensure the long guide function, the liquid must be supplied uninterruptedly for a long time, so 2 sets of piston containers are designed for facilitating alternate liquid supply and convenient operation

B: the liquid supplementing container 11 is mainly used for supplementing liquid for a piston container, and when the liquid supplementing container reaches the lowest liquid level, an automatic alarm can be given to remind a user of requiring liquid adding. The liquid supplementing container is provided with a safety device, and when the pressure rises to the protection pressure due to misoperation, the safety device can be automatically opened to enable the liquid to automatically overflow.

E: three diversion inlets and three diversion outlets are designed in the third diversion chamber 55, so that the slotted net diversion is simulated more truly, and the situation that the difference between the test result and the actual situation is larger due to one diversion inlet and one diversion outlet is avoided.

F: when the outlet pressure of the third diversion chamber 55 reaches the control pressure at the top of the third back-pressure valve 63, the third back-pressure valve 63 is automatically opened to release the pressure, so that the outlet pressure is ensured to be constant, and the migration resistance of the medium in the crack is simulated.

After the liquid and gas flow and the pressure difference between the two ends of the third diversion chamber 55 are measured, the general principle of diversion capability can be tested according to the industry: according to the obtained pressure difference delta P, the liquid flow Q or the gas flow Q, the rock sample length L, the rock sample cross-sectional area and other dimensions A, the fluid viscosity mu and the like of the diversion chamber, which are obtained through the tests, the method comprises the following steps:

H: the third diversion chamber 55 can adjust the temperature to heat the rock sample to the target pressure required by the experiment, so as to better simulate the formation temperature condition.

I: the pressures of the third closing pressure pump 59 and the second back pressure pump 62 can be adjusted by themselves for experimental purposes.

3) If the full-diameter core conductivity test with cracks or microcracks is carried out, selecting the connection relation shown in the figure 3, wherein the implementation mode is as follows:

Sample preparation experiment: according to the experimental protocol, a rock sample is loaded in the fourth flow guiding chamber 71.

Vacuumizing: the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, the thirty-fifth valve 76 are closed. And opening the twelfth valve 25 and the eleventh valve 23, starting the vacuum pump 24, and vacuumizing the whole pipeline in the system.

Adding closing pressure, back pressure and axial pressure: and when the system is vacuumized, closing the eleventh valve 23 and the tenth valve 25, and simultaneously closing the vacuum pump 24. Opening the fourth closing pressure pump 72, the thirty-fourth valve 73, and adjusting the pressure of the fourth closing pressure pump 72 according to the reading of the seventh pressure gauge 74; opening the thirty-fifth valve 76, the thirty-sixth valve 79, the third back-pressure pump 78, regulating the pressure of the third back-pressure pump 78 according to the ninth pressure gauge 86; the axial pressure pump 75 is turned on, and the pressure of the axial pressure pump 75 is adjusted by the eighth pressure gauge 77. The fourth closing pressure pump 72 is provided with an automatic closing pressure compensating device for keeping the closing pressure constant when the rock sample is deformed by applying the closing pressure.

Measuring the flow conductivity by gas: if the injected gas tests the fracture conductivity, the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20 are closed, and the first valve 2 and the second valve 4 are opened. Gas in the gas cylinder 1 is filtered by the filter 3, the gas flow is measured by the first gas flowmeter 5, and then the gas passes through the preheater 6, and the third valve 9 is opened when the temperature and the pressure meet the test requirements.

The thirty-fifth valve 76 is opened and gas flows through the fourth baffle compartment 71. The third seventeen valve 84 and the third eighteen valve 85 are opened, and the pressure across the fourth guide flow chamber 71 is measured by the third differential pressure sensor 83. The differential pressure of the differential pressure sensor, the gas flow, the length of the rock sample of the diversion chamber, the sectional area and other dimensions are recorded, and after the fluid viscosity is recorded, the diversion capacity can be calculated according to the differential pressure shown by the third differential pressure sensor 83 and the flow shown by the first flowmeter 5.

Sixthly, measuring the flow conductivity: if the injected liquid is used for testing the flow conductivity of the crack, the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20 are opened, and the liquid in the liquid supplementing container is used for supplementing the liquid for the piston container due to the driving of the gas. After the liquid is supplied, the first valve 2, the fourth valve 10 and the fifth valve 12 are closed, the water pump 14, the sixth valve 15, the seventh valve 17, the eighth valve 18 and the ninth valve 20 are opened, and the first piston container 16 and the second piston container 19 are started. Then the liquid passes through the preheater 6, and when the temperature and the pressure reach the test requirements, the third valve 9 is opened.

The water pump 14 or the third balance 81 can measure the liquid flow rate flowing through in real time.

The thirty-fifth valve 76 is opened and the liquid flows through the fourth baffle chamber 71. The seventeenth valve 84 and the eighteenth valve 85 are opened, and the pressure at both ends of the fourth diversion chamber 71 is measured by the third differential pressure sensor 83; eventually, the liquid will flow to the fourth water container 82, and the liquid quality can be measured on the third day 81. And after the pressure difference of the pressure difference sensor, the liquid flow, the length of the rock sample in the diversion chamber, the sectional area and other dimensions are recorded, and after the fluid viscosity is measured, when the flow measured by the third pressure difference sensor 81 is equal to the flow measured by the water suction pump 14 on the third day and the flow meets the experimental requirements, the diversion capacity of the full-diameter rock core with cracks or microcracks can be calculated according to the pressure difference shown by the third pressure difference sensor 83 and the flow shown by the water suction pump 14 and the third pressure difference 81 on the third day.

The key parts of the system are described in detail as follows:

E: full-diameter triaxial core fourth diversion chamber 71: the electric heating mode with the additional heat preservation sleeve is designed for simulating different covering pressure conditions.

F, when the outlet pressure of the diversion chamber reaches the control pressure of the top of the back pressure valve 80, the back pressure valve automatically opens to release pressure, so that the outlet pressure is ensured to be constant, and the migration resistance of the medium in the crack is simulated.

And G, applying axial pressure to the fourth diversion chamber 71 of the full-diameter triaxial core by the axial pressure pump 75, and more truly simulating the requirement of the field diversion capability test.

After the liquid and gas flow and the pressure difference between the two ends of the fourth diversion chamber 71 are measured, the general principle of diversion capability can be tested according to the industry: according to the obtained pressure difference delta P, the liquid flow Q or the gas flow Q, the rock sample length L, the rock sample cross-sectional area and other dimensions A, the fluid viscosity mu and the like of the diversion chamber, which are obtained through the tests, the method comprises the following steps:

and calculating to obtain the conductivity parameter of the crack.

The test method specifically comprises the following steps:

the utility model discloses divide into four kinds of circumstances of full diameter rock core conductivity test introduction of layering crack conductivity test, the tortuous crack conductivity test of individual layer, seam net crack conductivity test, area crack or micro fracture:

(1) if the layered conductivity test is performed, the connection relationship shown in fig. 1 is selected.

Firstly, equipment is connected, the air tightness of the system is checked, and all valves are closed to prepare for experiments.

Secondly, according to the experimental scheme, rock samples are filled in the first diversion chamber 26 and the second diversion chamber 39.

Vacuumizing: and starting the vacuum pump 24 to vacuumize the whole pipeline in the system.

Adding closing pressure and back pressure: after the system is vacuumized, adjusting the pressure of the first closing pressure pump 27; adjusting the pressure of the first back-pressure pump 30; the pressure of the second closing pressure pump 40 is adjusted.

The closing pressure and the back pressure are flexibly set according to experimental purposes, and the first closing pressure pump 27 and the second closing pressure pump 40 are provided with automatic closing pressure compensation devices for keeping the closing pressure constant.

Measuring the flow conductivity by gas: if the injected gas is used for testing the flow conductivity of the crack, the gas flow is measured by the first gas flow meter 5, and then the gas passes through the preheater 6, and the third valve 9 is opened when the temperature and the pressure meet the test requirements.

The gas enters the first flow guide chamber 26 and the second flow guide chamber 39, the pressure difference and the gas flow of the differential pressure sensor, the length and the sectional area of the rock sample of the flow guide chamber and other dimensions are recorded, and after the fluid viscosity is recorded, the total flow guide capacity of the stratified cracks under the experimental condition and the flow guide capacity of each single-layer crack can be calculated according to the pressure difference shown by the first differential pressure sensor 36 and the flow shown by the first flowmeter 5 and the second flowmeter 45.

Sixthly, measuring the flow conductivity: if the injected liquid is used for testing the flow conductivity of the crack, the liquid in the liquid supplementing container is used for supplementing the liquid for the piston container due to the driving of the gas. The liquid supply is completed and the suction pump 14 is turned on, starting the first piston reservoir 16 and the second piston reservoir 19. Then the liquid passes through the preheater 6, and when the temperature and the pressure reach the test requirements, the third valve 9 is opened.

Liquid enters the first flow guide chamber 26 and the second flow guide chamber 39, the differential pressure of the differential pressure sensor, the liquid flow rate, the length of a rock sample of the flow guide chamber, the sectional area and other dimensions are recorded, after the fluid viscosity is tested and stabilized, the total fracture flow guide capacity of the stratified fractures and the flow guide capacity of each single-layer fracture under the experimental condition can be calculated according to the differential pressure shown by the first differential pressure sensor 36 and the flow rate recorded by the first balance 34, the water suction pump 14 and the third flow meter 48.

(2) If the fracture network fracture conductivity test and the single-layer zigzag fracture conductivity test are carried out, the connection relation shown in the figure 2 is selected.

Secondly, according to the experimental scheme, a rock sample is loaded in the third diversion chamber 55.

Adding closing pressure and back pressure: after the system is vacuumized, the pressure of the third closing pressure pump 59 is adjusted; the pressure of the second back-pressure pump 62 is regulated. The third closing pressure pump 59 is provided with a closing pressure automatic compensating means for keeping the closing pressure constant.

Measuring the flow conductivity by gas: if the injected gas is used for testing the crack flow conductivity, the gas in the gas cylinder 1 is filtered by the filter 3, the gas flow is measured by the first gas flow meter 5, and then the gas passes through the preheater 6, and the third valve 9 is opened when the temperature and the pressure meet the test requirements.

And after the differential pressure of the differential pressure sensor, the gas flow, the length, the sectional area and other dimensions of the rock sample of the diversion chamber are recorded, and after the fluid viscosity and the testing process are stable, the diversion capacity of the fracture network fracture under the experimental condition can be calculated according to the differential pressure shown by the second differential pressure sensor 68 and the flow shown by the first flowmeter 5.

Eventually the liquid will flow to the third water container 67 and the mass of the liquid can be measured with the second balance 66. After the differential pressure of the differential pressure sensor, the liquid flow rate, the length of the rock sample, the sectional area of the diversion chamber and other dimensions are recorded, and after the fluid viscosity is stabilized and the testing process is stable, the diversion capacity of the fracture network fracture under the experimental condition can be calculated according to the differential pressure shown by the second differential pressure sensor 68 and the flow rates shown by the water suction pump 14 and the second balance 66.

If the single-layer zigzag crack flow conductivity test is carried out, the operation is similar to the gas measurement and liquid measurement flow conductivity method, and the crack flow conductivity test with different corners and different crack distances is carried out.

(3) And if the full-diameter core conductivity test with cracks or microcracks is carried out, selecting the connection relation shown in the figure 3.

Secondly, according to the experimental scheme, a rock sample is filled in the fourth diversion chamber 71.

Adding closing pressure, back pressure and axial pressure: after the system is vacuumized, adjusting the pressure of a fourth closing pressure pump 72; adjusting the pressure of the third back pressure pump 78; the pressure of the axial pressure pump 75 is adjusted. Said fourth closing pressure pump 72 is provided with closing pressure automatic compensation means for keeping the closing pressure constant.

The gas flows through the fourth baffle compartment 71 and the pressure across the fourth baffle compartment 71 is measured by the third differential pressure sensor 83. And after the differential pressure of the differential pressure sensor, the gas flow, the length, the sectional area and other dimensions of the rock sample of the diversion chamber are recorded, and the fluid viscosity is measured, the diversion capacity of the full-diameter rock core with cracks or microcracks can be calculated according to the differential pressure shown by the third differential pressure sensor 83 and the flow shown by the first flowmeter 5. .

Sixthly, measuring the flow conductivity: if the injected liquid is used for testing the flow conductivity of the crack, the liquid in the liquid supplementing container is used for supplementing the liquid for the piston container due to the driving of the liquid. The liquid supply is completed and the first piston reservoir 16 and the second piston reservoir 19 are activated simultaneously. Then the liquid passes through the preheater 6, and when the temperature and the pressure reach the test requirements, the third valve 9 is opened.

Measuring the pressure across the fourth diversion chamber 71 with the third differential pressure sensor 83; eventually, the liquid will flow to the fourth water container 82, and the liquid quality can be measured on the third day 81. And after the fluid viscosity is recorded and the stability is to be tested, the flow conductivity of the full-diameter core with cracks or microcracks can be calculated according to the pressure difference shown by the third pressure difference sensor 83 and the flow rates shown by the water suction pump 14 and the third average 81.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be considered as the protection scope of the present invention.

Claims

1. A crack conductivity testing system is characterized by comprising a gas and liquid combined supply device capable of supplying gas or liquid independently, wherein the outlet end of the gas and liquid combined supply device is connected with a testing device for testing conductivity, the gas and liquid combined supply device is connected with a vacuumizing device, and the testing device is a first testing device for testing layered conductivity, a second testing device for testing crack conductivity of a fracture network and conductivity of a single-layer zigzag crack or a third testing device for testing conductivity of a full-diameter rock core with cracks or micro cracks; the outlet ends of the first testing device, the second testing device and the third testing device are respectively connected to the first metering device, the second metering device and the third metering device;

the first testing device comprises a first diversion chamber (26) and a second diversion chamber (39) which are connected to the outlet end of the combined gas and liquid supply device, the inlet end of the first diversion chamber (26) is connected with the outlet end of the combined gas and liquid supply device, and the outlet end of the first diversion chamber (26) is connected to the metering device; the inlet end of the second diversion chamber (39) is connected with the outlet end of the combined gas and liquid supply device through an eighteenth valve (43), the outlet end of the second diversion chamber (39) is connected to a twentieth three valve (50) through two metering branches, and the outlet end of the twentieth three valve (50) is connected to the first metering device through a second thermometer (51); the first flow guide chamber (26) and the second flow guide chamber (39) are respectively connected with a first closing pressure applying device and a second closing pressure applying device, and a first pressure difference sensing device is arranged between the inlet end and the outlet end of the first flow guide chamber (26);

the second testing device comprises a third diversion chamber (55), the inlet end of the third diversion chamber (55) is connected with the outlet end of the gas and liquid combined supply device through a fourteenth valve (52), a twenty-fifth valve (53) and a twenty-sixth valve (54) which are arranged in parallel, the outlet end of the third diversion chamber (55) is connected to a second metering device through a twenty-seventh valve (56), a twenty-eighth valve (57) and a twenty-ninth valve (58) which are arranged in parallel, a third closing pressure applying device is connected to the third diversion chamber (55), and a second differential pressure sensing device is arranged between the inlet end and the outlet end of the third diversion chamber (55);

the third testing device comprises a fourth flow guide chamber (71), the inlet end of the fourth flow guide chamber (71) is connected with the outlet end of the gas and liquid combined supply device, the outlet end of the fourth flow guide chamber (71) is connected to a third metering device, a fourth closing pressure applying device is connected to the fourth flow guide chamber (71), a third pressure difference sensing device is arranged between the inlet end and the outlet end of the fourth flow guide chamber (71), and the outlet end of the fourth flow guide chamber (71) is further connected to the axial pressure pump (75) through an eighth pressure gauge (77).

2. A fracture conductivity testing system according to claim 1, wherein the combined gas and liquid supply device comprises a gas supply device and a liquid supply device, the gas supply device comprises a gas cylinder (1), the outlet end of the gas cylinder (1) is connected with a first valve (2), a filter (3), a second valve (4), a first flowmeter (5), a preheater (6), a first thermometer (7), a first pressure gauge (8) and a third valve (9) in sequence, and the outlet end of the third valve (9) is connected to the inlet end of the first conductivity cell (26) and the inlet end of the second conductivity cell (39), or the inlet end of the third conductivity cell (55), or the inlet end of the fourth conductivity cell (71).

3. A crack conductivity testing system according to claim 2, wherein the liquid supply device comprises a first water container (13), a water pump (14) is connected to the outlet end of the first water container (13), the outlet of the water pump (14) is divided into two branches, one branch is connected with a sixth valve (15), a first piston container (16) and a seventh valve (17) in sequence, the other branch is connected with an eighth valve (18), a second piston container (19) and a ninth valve (20) in sequence, and the outlets of the seventh valve (17) and the ninth valve (20) are connected to the inlet of the preheater (6);

the liquid supplementing device comprises a liquid supplementing container (11), wherein the top inlet of the liquid supplementing container (11) is connected between the filter (3) and the second valve (4) through a fourth valve (10), the outlet pipeline of the liquid supplementing container (11) is connected to the inlet of the preheater (6) through a fifth valve (12), and the fourth valve (10) is connected to the top of the liquid supplementing container (11) through a pipeline; a pipeline connecting the fifth valve (12) and the fluid infusion container (11) is inserted at the bottom of the fluid infusion container (11).

4. A crack conductivity testing system according to claim 3, characterized in that the fluid infusion container (11) is provided with an alarm device when the lowest fluid level is reached, and the fluid infusion container (11) is further provided with a safety device, when the pressure rises to the protection pressure due to misoperation, the safety device can be automatically opened to enable the fluid to automatically overflow.

5. A crack conductivity testing system according to claim 2, wherein the vacuum pumping device comprises a buffer tank (22), a tenth valve (21) for emptying is designed at the bottom of the buffer tank (22), a vacuum pump (24) and a tenth valve (25) are sequentially connected to the top of the buffer tank (22), an inlet at the top of the buffer tank (22) is connected with an eleventh valve (23), when the testing device adopts a first testing device or a second testing device, an inlet end of the eleventh valve (23) is connected between the preheater (6) and the first thermometer (7), and when the testing device adopts a third testing device, an inlet end of the eleventh valve (23) is connected to an outlet end of the third valve (9).

6. A fracture conductivity testing system according to claim 1, wherein the first closing pressure applying device comprises a second pressure gauge (29), a tenth valve (28) and a first closing pressure pump (27) which are connected in sequence;

the second closing pressure applying device comprises a fourth pressure gauge (42), a seventeenth valve (41) and a second closing pressure pump (40) which are connected in sequence;

the third closing pressure applying device comprises a fifth pressure gauge (61), a thirtieth valve (60) and a third closing pressure pump (59) which are connected in sequence;

the fourth closing pressure applying device comprises a seventh pressure gauge (74), a thirty-four valve (73) and a fourth closing pressure pump (72) which are connected in sequence;

the first closing pressure pump (27), the second closing pressure pump (40), the third closing pressure pump (59) and the fourth closing pressure pump (72) are provided with an additional closing pressure automatic compensation device for keeping the closing pressure constant.

7. A fracture conductivity testing system according to claim 1, wherein the first differential pressure sensing device comprises a fifteenth valve (37), a first differential pressure sensor (36) and a sixteenth valve (38) which are connected in sequence;

the second differential pressure sensing device comprises a thirtieth valve (69), a second differential pressure sensor (68) and a thirtieth valve (70) which are connected in sequence;

the third differential pressure sensing device comprises a third seventeen valve (84), a third differential pressure sensor (83) and a third eighteen valve (85) which are connected in sequence.

8. A crack conductivity testing system according to claim 1, wherein the first metering device comprises a fourteenth valve (31), a first back pressure valve (33) and a second water container (35) which are connected in sequence, the second water container (35) is placed on a first balance (34), and the side surface of the first back pressure valve (33) is connected to the first back pressure pump (30) through a third pressure gauge (32);

the second metering device comprises a thirty-one valve (63), a second back pressure valve (65) and a third water container (67) which are sequentially connected, the third water container (67) is arranged on a second balance (66), and the side surface of the second back pressure valve (65) is connected to a second back pressure pump (62) through a sixth pressure gauge (64);

the third metering device comprises a fifteenth valve (76), a third back pressure valve (80) and a fourth water container (82) which are sequentially connected, the fourth water container (82) is arranged on a third balance (81), and the side surface of the third back pressure valve (80) is connected to a third back pressure pump (78) through a ninth pressure gauge (86) and a sixteenth valve (79).

9. A fracture conductivity testing system according to claim 1, wherein the first conductivity chamber (26), the second conductivity chamber (39) and the third conductivity chamber (55) are provided with temperature adjusting devices capable of heating the rock sample to a target temperature required by the experiment, the fourth conductivity chamber (71) is provided with an electric heating device, and the outside of the fourth conductivity chamber (71) is provided with a thermal insulation sleeve for simulating different overbalance pressure conditions.

10. A fracture conductivity testing system according to claim 1, wherein one of the two metering branches at the outlet end of the second flow guiding chamber (39) is connected with a nineteenth valve (44), a second flow meter (45) and a twentieth valve (46) in sequence, and the other metering branch is connected with a twenty-first valve (47), a third flow meter (48) and a twentieth valve (49) in sequence.