A fracture conductivity testing system and method

Abstract

The present invention discloses a fracture conductivity test system and method, which is designed with fracture conductivity test methods for the following multiple models: layered fracture conductivity test, single-layer tortuous fracture conductivity test, fracture network fracture conductivity test, and full-diameter core conductivity test with cracks or microcracks, which can be flexibly selected and used as needed. The present invention designs two sets of piston containers to alternately supply liquid, so as to achieve long-term uninterrupted liquid supply; in addition, a back pressure pump and a back pressure valve are also designed to accurately simulate the migration resistance of the medium in the fracture under real conditions.

Description

Technical Field

[0001] The invention relates to the field of oil and gas development, and in particular to a fracture conductivity testing system and method. Background Art

[0002] In recent years, my country's oil and gas resources have a huge amount of low-permeability oil and gas resources, especially in the development of unconventional oil and gas resources such as coalbed methane and shale gas. Fracturing technology plays an extremely important role and has become the most important technical means to achieve economical and efficient development and increase production of low-permeability oil and gas resources. The main purpose of hydraulic fracturing is to create a certain scale of artificial fractures in the oil and gas reservoir through fracturing construction as oil and gas seepage channels, and artificial fractures generally require stable and high fracture conductivity. Therefore, the testing and research of the conductivity of fracturing fractures is particularly important.

[0003] As people further deepen their research on the conductivity of hydraulic fractures, many experimental systems and methods for testing fracture conductivity have been developed, such as the multi-angle acid-etched fracture conductivity test system. However, there are some shortcomings in the existing technology: (1) The conductivity chamber of most experimental systems has only a single model, which cannot simulate the conductivity of complex fractures such as multi-layer fractures and mesh fractures; (2) Existing similar equipment focuses on the influence of fracturing fluid and proppant on fracture conductivity, ignoring the influence of fracture model on fracture conductivity test results; (3) Most fracture conductivity test equipment has a relatively simple internal structure, and its applicability and operability are not strong. It cannot accurately simulate the actual conductivity of underground complex fractures under underground temperature and pressure conditions, and cannot simulate the influence of micro-cracks in the rock sample itself on the conductivity. Summary of the invention

[0004] The purpose of the present invention is to provide a fracture conductivity test system and method to overcome the problems existing in the prior art. The present invention designs fracture conductivity test methods for the following four models: layered fracture conductivity test, single layer tortuous fracture conductivity test, fracture network fracture conductivity test, and full diameter core conductivity test with fractures or microcracks. These four models can be flexibly selected and used according to the needs of experimental research.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A fracture conductivity testing system, comprising a gas and liquid combined supply device capable of supplying gas alone or liquid alone, wherein the outlet end of the gas and liquid combined supply device is connected to a test device for conducting conductivity testing, and the gas and liquid combined supply device is connected to a vacuum device, wherein the test device is a first test device for conducting layered conductivity testing, a second test device for conducting fracture network fracture conductivity testing and single-layer tortuous fracture conductivity testing, or a third test device for conducting full-diameter core conductivity testing with fractures or microcracks; the outlet ends of the first test device, the second test device and the third test device are connected to a first metering device, a second metering device and a third metering device, respectively;

[0007] The first test device comprises a first flow guide chamber and a second flow guide chamber connected to the outlet end of the gas and liquid combined supply device, the inlet end of the first flow guide chamber is connected to the outlet end of the gas and liquid combined supply device, and the outlet end of the first flow guide chamber is connected to the metering device; the inlet end of the second flow guide chamber is connected to the outlet end of the gas and liquid combined supply device through an eighteenth valve, the outlet end of the second flow guide chamber is connected to the twenty-third valve through two metering branches, and the outlet end of the twenty-third 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 to a first closing pressure applying device and a second closing pressure applying device, and a first pressure difference sensing device is provided between the inlet end and the outlet end of the first flow guide chamber;

[0008] The second test device comprises a third flow guide chamber, the inlet end of the third flow guide chamber is connected to 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 arranged in parallel, the outlet end of the third flow guide chamber is connected to the second metering device through a twenty-seventh valve, a twenty-eighth valve and a twenty-ninth valve arranged in parallel, and the third flow guide chamber is connected to a third closing pressure applying device, and a second pressure difference sensing device is arranged between the inlet end and the outlet end of the third flow guide chamber;

[0009] The third testing device includes a fourth flow guide chamber, the inlet end of the fourth flow guide chamber is connected to the outlet end of the gas and liquid combined supply device, the outlet end of the fourth flow guide chamber is connected to the third metering device, and the fourth flow guide chamber is connected to a fourth closed pressure applying device, a third differential pressure 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 also connected to the axial pressure pump through an eighth pressure gauge.

[0010] Furthermore, the gas and liquid combined supply device includes a gas supply device and a liquid supply device, the gas supply device includes a gas cylinder, the outlet end of the gas cylinder is sequentially connected to a first valve, a filter, a second valve, a first flow meter, a preheater, a first thermometer, a first pressure gauge and a third valve, the outlet end of the third valve is connected to the inlet end of the first guide chamber and the inlet end of the second guide chamber, or the inlet end of the third guide chamber, or the inlet end of the fourth guide chamber.

[0011] Further, the liquid supply device includes a first water container, the outlet end of the first water container is connected to a water pump, the outlet of the water pump is divided into two branches, one branch is connected to the sixth valve, the first piston container and the seventh valve in sequence, and the other branch is connected to the eighth valve, the second piston container and the ninth valve in sequence, and the outlets of the seventh valve and the ninth valve are connected to the inlet of the preheater;

[0012] It also includes a liquid replenishing device, which includes a liquid replenishing container, wherein the top inlet of the liquid replenishing container is connected to between the filter and the second valve through a fourth valve, and the outlet pipeline of the liquid replenishing container is connected to the inlet of the preheater through a fifth valve, wherein the fourth valve is connected to the top of the liquid replenishing container through a pipeline; and the pipeline connecting the fifth valve and the liquid replenishing container is inserted into the bottom of the liquid replenishing container.

[0013] Furthermore, the liquid replenishment container is provided with an alarm device when the minimum liquid level is reached. The liquid replenishment container is also provided with a safety device. When the pressure rises to a protection pressure due to misoperation, the safety device can automatically open to allow the liquid to overflow automatically.

[0014] Furthermore, the vacuum pumping device includes a buffer tank, a tenth valve for venting is designed at the bottom of the buffer tank, a vacuum pump and a twelfth valve are connected to the top of the buffer tank in sequence, and an eleventh valve is connected to the inlet of the top of the buffer tank. When the testing device adopts the first testing device or the second testing device, the inlet end of the eleventh valve is connected between the preheater and the first thermometer, and when the testing device adopts the third testing device, the inlet end of the eleventh valve is connected to the outlet end of the third valve.

[0015] Further, the first closing pressure applying device comprises a second pressure gauge, a thirteenth valve and a first closing pressure pump connected in sequence;

[0016] The second closing pressure applying device comprises a fourth pressure gauge, a seventeenth valve, and a second closing pressure pump connected in sequence;

[0017] The third closing pressure applying device comprises a fifth pressure gauge, a thirtieth valve and a third closing pressure pump connected in sequence;

[0018] The fourth closing pressure applying device comprises a seventh pressure gauge, a thirty-fourth valve and a fourth closing pressure pump connected in sequence;

[0019] 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 accompanying closing pressure automatic compensation device for keeping the closing pressure constant.

[0020] Further, the first differential pressure sensing device comprises a fifteenth valve, a first differential pressure sensor and a sixteenth valve connected in sequence;

[0021] The second differential pressure sensing device comprises a thirty-second valve, a second differential pressure sensor and a thirty-third valve connected in sequence;

[0022] The third differential pressure sensing device includes a thirty-seventh valve, a third differential pressure sensor and a thirty-eighth valve which are connected in sequence.

[0023] Further, the first metering device comprises a fourteenth valve, a first back-pressure valve and a second water container connected in sequence, the second water container is placed on the first level, and the side of the first back-pressure valve is connected to the first back-pressure pump through a third pressure gauge;

[0024] The second metering device comprises a thirty-first valve, a second back-pressure valve and a third water container connected in sequence, the third water container is placed on the second level, and the side of the second back-pressure valve is connected to the second back-pressure pump through a sixth pressure gauge;

[0025] The third metering device includes a thirty-fifth valve, a third back-pressure valve and a fourth water container which are connected in sequence. The fourth water container is placed on a third balance. The side of the third back-pressure valve is connected to a third back-pressure pump via a ninth pressure gauge and a thirty-sixth valve.

[0026] Furthermore, the first flow guide chamber, the second flow guide chamber and the third flow guide chamber are provided with temperature regulating devices capable of heating the rock sample to the target temperature required for the experiment, the fourth flow guide chamber is provided with an electric heating device, and an insulation sleeve is provided outside the fourth flow guide chamber for simulating different covering pressure conditions;

[0027] Of the two metering branches at the outlet end of the second guide chamber, one metering branch is sequentially connected to the nineteenth valve, the second flow meter and the twentieth valve, and the other metering branch is sequentially connected to the twenty-first valve, the third flow meter and the twenty-second valve.

[0028] A fracture conductivity test method, including four conditions: layered fracture conductivity test, single layer tortuous fracture conductivity test, fracture network fracture conductivity test, and full diameter core conductivity test with fractures or microcracks;

[0029] When conducting a delamination fracture conductivity test, the following steps are involved:

[0030] Step 1.1: Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment;

[0031] Step 1.2: According to the experimental plan, the rock samples are filled in the first flow diversion chamber and the second flow diversion chamber;

[0032] Step 1.3: Turn on the vacuum device to vacuum the entire pipeline in the system;

[0033] Step 1.4: After the system is evacuated, adjust the first closing pressure applying device, the second closing pressure applying device and the back pressure device on the first metering device according to the experimental purpose;

[0034] Step 1.5: When the conductivity is tested by gas, the gas and liquid combined supply device supplies gas, and when the temperature and pressure meet the test requirements, the gas enters the first and second flow chambers, and the gas flow rate, the pressure difference of the first pressure difference sensor, and the length and cross-sectional area of ​​the rock sample in the first and second flow chambers, and the fluid viscosity are recorded. Then, according to the gas flow rate entering and flowing out of the rock sample and the pressure difference indicated by the first pressure difference sensor, the total conductivity of the layered fractures under the experimental conditions and the conductivity of each single-layer fracture therein can be calculated;

[0035] Step 1.6: When the conductivity is tested by liquid, liquid is supplied through the gas and liquid combined supply device. When the temperature and pressure meet the test requirements, the liquid enters the first flow diversion chamber and the second flow diversion chamber. The liquid flow rate, the pressure difference of the first pressure difference sensor, and the length and cross-sectional area of ​​the rock sample in the first flow diversion chamber and the second flow diversion chamber, and the fluid viscosity are recorded. Then, according to the liquid flow rate entering and flowing out of the rock sample and the pressure difference indicated by the first pressure difference sensor, the total fracture conductivity of the layered fractures and the conductivity of each single-layer fracture under the experimental conditions can be calculated;

[0036] Step 1.7: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean;

[0037] When testing the fracture conductivity of a seam network, the following steps are included:

[0038] Step 2.1: Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment:

[0039] Step 2.2: According to the experimental plan, the rock sample is filled in the third diversion chamber;

[0040] Step 2.3: Turn on the vacuum device to vacuum the entire pipeline in the system;

[0041] Step 2.4: After the system is evacuated, adjust the third closing pressure applying device and the back pressure device on the second metering device according to the experimental purpose;

[0042] Step 2.5: When the flow conductivity is tested by gas, the gas and liquid combined supply device supplies gas, and when the temperature and pressure meet the test requirements, the gas enters the third flow chamber, and the gas flow rate, the pressure difference of the second pressure difference sensor, and the length and cross-sectional area of ​​the rock sample in the third flow chamber, and the fluid viscosity are recorded. After the test process is stable, the flow conductivity can be calculated based on the intake air flow rate and the pressure difference shown by the second pressure difference sensor;

[0043] Step 2.6: When the conductivity is tested by liquid, liquid is supplied through the gas and liquid combined supply device. When the temperature and pressure meet the test requirements, the liquid enters the third flow diversion chamber, and the liquid flow rate, the pressure difference of the second pressure difference sensor device, and the length and cross-sectional area of ​​the rock sample in the third flow diversion chamber, and the fluid viscosity are recorded. After the test process is stable, the conductivity of the fracture network under this condition can be calculated based on the pressure difference shown by the second pressure difference sensor device and the flow rate of the second metering device;

[0044] Step 2.7: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean;

[0045] When testing the conductivity of a single layer of tortuous cracks, on the basis of testing the conductivity of cracks in a network, similar operations are performed as described above with the gas and liquid testing methods to test the conductivity of cracks with different tortuous crack angles and different crack spacings;

[0046] When conducting a conductivity test on a full diameter core with fractures or microcracks, the following steps are involved:

[0047] Step 3.1: Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment;

[0048] Step 3.2: According to the experimental plan, the rock sample is filled in the fourth flow chamber;

[0049] Step 3.3: Turn on the vacuum device to vacuum the entire pipeline in the system;

[0050] Step 3.4: After the system is evacuated, adjust the fourth closing pressure applying device and the back pressure device on the third metering device according to the experimental purpose, and also adjust the pressure of the axial pressure pump;

[0051] Step 3.5: When the flow conductivity is tested by gas, the gas and liquid combined supply device supplies gas, and when the temperature and pressure meet the test requirements, the gas enters the fourth flow chamber, and the gas flow rate, the pressure difference of the third pressure difference sensor, and the length and cross-sectional area of ​​the rock sample in the fourth flow chamber, and the fluid viscosity are recorded. After the test process is stable, the flow conductivity can be calculated based on the intake air flow rate and the pressure difference shown by the third pressure difference sensor;

[0052] Step 3.6: When the conductivity is tested by liquid, the gas and liquid combined supply device supplies liquid, and when the temperature and pressure meet the test requirements, the liquid enters the fourth flow chamber, and the liquid flow rate, the pressure difference of the third pressure difference sensor device, and the length and cross-sectional area of ​​the rock sample in the fourth flow chamber, and the fluid viscosity are recorded. After the test process is stable, the conductivity of the full-diameter core with cracks or microcracks can be calculated based on the pressure difference shown by the third pressure difference sensor device and the flow rate of the third metering device;

[0053] Step 3.7: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean.

[0054] Compared with the prior art, the present invention has the following beneficial technical effects:

[0055] The present invention is designed with fracture conductivity testing methods for the following multiple models: layered fracture conductivity testing, single-layer tortuous fracture conductivity testing, fracture network fracture conductivity testing, and full-diameter core conductivity testing with fractures or microcracks, which can be flexibly selected and used as needed.

[0056] Specifically, the present invention has the following characteristics: ① The system and method can test the conductivity of four conditions: layered fractures, tortuous fractures, fracture network fractures, and full-diameter cores with fractures or microcracks; ② The experimental system optimizes the inlet and outlet lines of the fracturing medium of the diversion chamber in the fracture network diversion, thereby simulating the effects of multi-point injection and multi-point fracturing; ③ The system and method also design a fourth diversion chamber (full-diameter triaxial core holder), and a test method for the fracture conductivity of full-diameter cores with fractures or microcracks; ④ The system and method design an axial pressure pump and a closing pressure pressurization function in the conductivity test of the full-diameter core, meeting the needs of testing the conductivity of formation fractures under simulated formation conditions; ⑤ The system and method design two sets of piston containers to alternately supply liquid, thereby achieving long-term uninterrupted liquid supply; ⑥ The system and method design a back pressure pump and a back pressure valve, thereby accurately simulating the migration resistance of the medium in the fracture under real conditions.

[0057] Furthermore, the refill container is mainly used to refill the piston container. When the refill container reaches the lowest liquid level, it will automatically alarm to remind you to add liquid. There is a safety device on the refill container. When the pressure rises to the protection pressure due to misoperation, the safety device will automatically open to allow the liquid to overflow.

[0058] Furthermore, in the test requiring heating, in order to ensure that the test is carried out at the required temperature, it is necessary to preheat the fluid using a preheater to ensure that the temperature of the injected fluid is consistent with that of the flow guide chamber.

[0059] Furthermore, the third diversion chamber is designed with three diversion inlets and three diversion outlets to more realistically simulate the seam network diversion and avoid the large gap between the test results and the actual situation caused by one diversion inlet and one diversion outlet.

[0060] Furthermore, the first flow diversion chamber, the second flow diversion chamber and the third flow diversion chamber are provided with temperature regulating devices capable of heating the rock sample to the target pressure required for the experiment, so as to better simulate the formation temperature conditions. The fourth flow diversion chamber is provided with an electric heating device, and an insulation cover is provided on the outside of the fourth flow diversion chamber for simulating different overburden conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a schematic diagram of a layered flow conductivity testing system of the present invention;

[0062] Figure 2 Schematic diagram of the test system for the flow conductivity of seam network cracks and the flow conductivity of single-layer tortuous cracks of the present invention;

[0063] Figure 3 It is a schematic diagram of the full-diameter core conductivity testing system with cracks or micro-cracks of the present invention.

[0064] Among them, 1 gas cylinder, 2 first valve, 3 filter, 4 second valve, 5 first flow meter, 6 preheater, 7 first thermometer, 8 first pressure gauge, 9 third valve, 10 fourth valve, 11 liquid replenishing container, 12 fifth valve, 13 first water container, 14 water 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 twelfth valve, 26 1st diversion chamber, 27 1st closing pressure pump, 28 13th valve, 29 2nd pressure gauge, 30 1st back pressure pump, 31 14th valve, 32 3rd pressure gauge, 33 1st back pressure valve, 34 1st balance, 35 2nd water container, 36 1st differential pressure sensor, 37 15th valve, 38 16th valve, 39 2nd diversion chamber, 40 2nd closing pressure pump, 41 17th valve, 42 4th pressure gauge, 43 18th valve, 44 19th valve, 45 2nd flow meter, 46 20th valve , 47 the 21st valve, 48 the third flow meter, 49 the 22nd valve, 50 the 23rd valve, 51 the second thermometer, 52 the 24th valve, 53 the 25th valve, 54 the 26th valve, 55 the third flow guide chamber, 56 the 27th valve, 57 the 28th valve, 58 the 29th valve, 59 the third closed pressure pump, 60 the 30th valve, 61 the fifth pressure gauge, 62 the second back pressure pump, 63 the 31st valve, 64 the sixth pressure gauge, 65 the second back pressure valve, 66 the second balance, 67 The third water container, 68 the second differential pressure sensor, 69 the thirty-second valve, 70 the thirty-third valve; 71 the fourth diversion chamber, 72 the fourth closed pressure pump, 73 the thirty-fourth valve, 74 the seventh pressure gauge, 75 the axial pressure pump, 76 the thirty-fifth valve, 77 the eighth pressure gauge, 78 the third back pressure pump, 79 the thirty-sixth valve, 80 the third back pressure valve, 81 the third balance, 82 the fourth water container, 83 the third differential pressure sensor, 84 the thirty-seventh valve, 85 the thirty-eighth valve, 86 the ninth pressure gauge. DETAILED DESCRIPTION

[0065] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0066] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0067] like Figure 1 As shown, in the system, the gas cylinder 1 is connected to the first valve 2, the filter 3, the second valve 4, the first flow meter 5, the preheater 6, the first thermometer 7, the first pressure gauge 8, and the third valve 9 in sequence, and then divided into two branches: one branch is connected to the inlet of the first guide chamber 26 in sequence, and the other branch is connected to the inlet of the second guide chamber 39 in sequence through the eighteenth valve 43;

[0068] The first water container 13 is connected to the water pump 14, and the outlet of the water pump 14 is divided into two branches: one branch connects the sixth valve 15, the first piston container 16, the seventh valve 17 and the inlet of the preheater 6; the other branch connects the eighth valve 18, the second piston container 19, the ninth valve 20 and the inlet of the preheater 6.

[0069] A branch is formed between the filter 3 and the second valve 4, and the fourth valve 10, the liquid replenishing container 11, the fifth valve 12 and the inlet of the preheater 6 are sequentially connected through pipelines. Among them, the fourth valve 10 is connected to the pipeline at the top of the liquid replenishing container 11; the pipeline connecting the fifth valve 12 and the liquid replenishing container 11 is inserted into the bottom of the liquid replenishing container 11.

[0070] The bottom of the buffer tank 22 is provided with a tenth valve 21 for venting; the top of the buffer tank 22 is connected to the vacuum pump 24 and the twelfth valve 25 in sequence; a branch is separated between the preheater 6 and the first thermometer 7, and the eleventh valve 23 is connected to the top of the buffer tank 22 in sequence through a pipeline.

[0071] The side of the first guide chamber 26 is designed with a second pressure gauge 29, a thirteenth valve 28, and a first closing pressure pump 27 connected in sequence; the fifteenth valve 37, the first differential pressure sensor 36, and the sixteenth valve 38 are connected in sequence between the inlet and outlet ends of the first guide chamber through pipelines.

[0072] The outlet of the first flow guiding chamber 26 is connected to the fourteenth valve 31, the first back pressure valve 33, and the second water container 35 in sequence through pipelines, and the second water container 35 is placed on the first balance 34. The side of the first back pressure valve 33 is connected to the third pressure gauge 32 and the first back pressure pump 30 in sequence through pipelines.

[0073] The side of the second guide chamber 39 is connected in sequence to the fourth pressure gauge 42, the seventeenth valve 41, and the second closed pressure pump 40 through a pipeline; the outlet of the second guide chamber is divided into two branches, one branch connects the inlet of the nineteenth valve 44, the second flow meter 45, the twentieth valve 46, and the twenty-third valve 50 in sequence, and the other branch connects the inlet of the twenty-first valve 47, the third flow meter 48, the twenty-second valve 49, and the twenty-third valve 50 in sequence; the outlet of the twenty-third valve 50 is connected in sequence to the second thermometer 51 and the inlet of the fourteenth valve 31.

[0074] The first flow guiding chamber 26 and the second flow guiding chamber 39 can adjust the temperature to heat the rock sample to the target temperature required for the experiment, so as to better simulate the formation temperature conditions.

[0075] The preheater 6 can heat the liquid and gas flowing through it to make the liquid and gas reach the target temperature, thereby ensuring the accuracy of the simulated experimental effect.

[0076] By adjusting the first back pressure pump 30 , the back pressure required for the experiment can be set to the experimental target pressure for the first guide chamber 26 and the second guide chamber 55 , respectively, to ensure the accuracy of the simulated experimental effect.

[0077] like Figure 2 As shown, in the system, the gas cylinder 1 is connected with the first valve 2, the filter 3, the second valve 4, the first flow meter 5, the preheater 6, the first thermometer 7, the first pressure gauge 8, and the third valve 9 in sequence;

[0078] The first water container 13 is connected to the water pump 14, and the outlet of the water pump 14 is divided into two branches: one branch connects the sixth valve 15, the first piston container 16, the seventh valve 17 and the inlet of the preheater 6; the other branch connects the eighth valve 18, the second piston container 19, the ninth valve 20 and the inlet of the preheater 6.

[0079] A branch is formed between the filter 3 and the second valve 4, and the fourth valve 10, the liquid replenishing container 11, the fifth valve 12 and the inlet of the preheater 6 are sequentially connected through pipelines. Among them, the fourth valve 10 is connected to the pipeline at the top of the liquid replenishing container 11; the pipeline connecting the fifth valve 12 and the liquid replenishing container 11 is inserted into the bottom of the liquid replenishing container 11.

[0080] The bottom of the buffer tank 22 is provided with a tenth valve 21 for venting; the top of the buffer tank 22 is connected to the vacuum pump 24 and the twelfth valve 25 in sequence; a branch is separated between the preheater 6 and the first thermometer 7, and the eleventh valve 23 is connected to the top of the buffer tank 22 in sequence through a pipeline.

[0081] The outlet of the third valve 9 is divided into three branches, each of which is provided with a valve, namely the twenty-fourth valve 52, the twenty-fifth valve 53, and the twenty-sixth valve 54. After that, the three branches are connected to the third diversion chamber 55. The outlet of the third diversion chamber 55 is also divided into three branches, each of which is provided with a valve, namely the twenty-seventh valve 56, the twenty-eighth valve 57, and the twenty-ninth valve 58. After the three branches are merged, they are connected to the thirty-first valve 63, the second back pressure valve 65, and the third water container 67. The third water container 67 is placed on the second balance 66. The side of the second back pressure valve 65 is connected to the sixth pressure gauge 64 and the second back pressure pump 62 in sequence.

[0082] The side of the third flow guiding chamber 55 is designed with a fifth pressure gauge 61, a 30th valve 60, and a third closing pressure pump 59 connected in sequence. The inlet and outlet ends of the third flow guiding chamber 55 are connected to the second differential pressure sensor 68 and the 33rd valve 70 in sequence through the 32nd valve 69.

[0083] The third flow guiding chamber 55 can adjust the temperature to heat the rock sample to the target pressure required for the experiment, so as to better simulate the temperature conditions of different formations.

[0084] The preheater 6 can heat the liquid and gas flowing through it to make the liquid and gas reach the target temperature, thereby ensuring the accuracy of the simulated experimental effect.

[0085] By adjusting the second back pressure pump 62, the back pressure required for the experiment can be set to achieve the experimental target pressure and ensure the accuracy of the simulated experimental effect.

[0086] like Figure 3 As shown, in the system, the gas cylinder 1 is connected with the first valve 2, the filter 3, the second valve 4, the first flow meter 5, the preheater 6, the thermometer 7, the first pressure gauge 8, and the third valve 9 in sequence;

[0087] The first water container 13 is connected to the water pump 14, and the outlet of the water pump 14 is divided into two branches: one branch connects the sixth valve 15, the first piston container 16, the seventh valve 17 and the inlet of the preheater 6; the other branch connects the eighth valve 18, the second piston container 19, the ninth valve 20 and the inlet of the preheater 6.

[0088] A branch is formed between the filter 3 and the second valve 4, and the fourth valve 10, the liquid replenishing container 11, the fifth valve 12 and the inlet of the preheater 6 are sequentially connected through pipelines. Among them, the fourth valve 10 is connected to the pipeline at the top of the liquid replenishing container 11; the pipeline connecting the fifth valve 12 and the liquid replenishing container 11 is inserted into the bottom of the liquid replenishing container 11.

[0089] The bottom of the buffer tank 22 is designed with a tenth valve 21 for venting; the top of the buffer tank 22 is connected to the vacuum pump 24 and the twelfth valve 25 in sequence; the top of the buffer tank 22 connects the eleventh valve 23 and the outlet of the third valve 9 in sequence.

[0090] The outlet of the third valve 9 is connected to the fourth flow guide chamber 71. The side of the fourth flow guide chamber 71 is designed with a seventh pressure gauge 74, a thirty-fourth valve 73, and a fourth closing pressure pump 72 connected in sequence; the inlet and outlet ends of the fourth flow guide chamber 71 are connected in sequence through the thirty-seventh valve 84, the third pressure difference sensor 83, and the thirty-eighth valve 85.

[0091] The outlet of the fourth flow guide chamber 71 is connected to the 35th valve 76, the third back pressure valve 80, and the fourth water container 82 in sequence, and the fourth water container 82 is placed on the third balance 81. The side of the third back pressure valve 80 is connected to the 9th pressure gauge 86, the 36th valve 79, and the third back pressure pump 78 in sequence. The outlet of the fourth flow guide chamber 71 is connected to the 8th pressure gauge 77 and the axial pressure pump 75 in sequence.

[0092] The fourth flow guide chamber 71 can adjust the temperature to heat the rock sample to the target pressure required for the experiment, so as to better simulate the formation temperature conditions.

[0093] The preheater 6 can heat the liquid and gas flowing through it to make the liquid and gas reach the target temperature, thereby ensuring the accuracy of the simulated experimental effect.

[0094] By adjusting the third back pressure pump 78, the back pressure required for the experiment can be set to achieve the experimental target pressure and ensure the accuracy of the simulated experimental effect.

[0095] The present invention is divided into four situations: layered fracture conductivity test, single layer tortuous fracture conductivity test, fracture network fracture conductivity test, and full diameter core fracture conductivity test with cracks or microcracks. The principle of the test is the same as that of the fracture conductivity meter commonly used in the industry. It is mainly based on Darcy's law to measure the permeability K and then multiply it by the fracture width W, which is well known in the industry:

[0096]

[0097]

[0098] The specific implementation method is divided into three situations as follows:

[0099] 1) If the layered flow capacity test is to be carried out, the following Figure 1 The connection relationship shown is implemented as follows:

[0100] ① Check air tightness: Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment.

[0101] ② Loading samples and preparing for the experiment: Load samples in the first flow chamber 26 and the second flow chamber 39, and prepare the gases and liquids required for the experiment.

[0102] ③ Vacuuming: Close the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, the tenth valve 21, and the fourteenth valve 31. Open the twelfth valve 25 and the eleventh valve 23, start the vacuum pump 24, and evacuate the entire pipeline in the system.

[0103] ④ Add closing pressure and back pressure: After the system is evacuated, close the eleventh valve 23 and the twelfth valve 25, and at the same time, close the vacuum pump 24. Open the first closing pressure pump 27 and the thirteenth valve 28, and adjust the pressure of the first closing pressure pump 27 according to the reading of the second pressure gauge 29; open the fourteenth valve 31 and the first back pressure pump 30, and adjust the pressure of the first back pressure pump 30 according to the third pressure gauge 32; open the nineteenth valve 44, the twentieth valve 46, the twenty-first valve 47, and the twenty-second valve 49; open the seventeenth valve 41 and the second closing pressure pump 40, and adjust the pressure of the second closing pressure pump 40 according to the reading of the fourth pressure gauge 42;

[0104] The first closing pressure pump 27 and the second closing pressure pump 40 are provided with a closing pressure automatic compensation device, which keeps the closing pressure constant when the rock sample is deformed by the closing pressure.

[0105] ⑤ Gas testing conductivity: If gas is injected to test the conductivity of the fracture, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, the twenty-first valve 47, and the twenty-second valve 49 are closed, and the first valve 2 and the second valve 4 are opened. The gas in the gas cylinder 1 is filtered through the filter 3, and the gas flow is measured by the first gas flow meter 5. After passing through the preheater 6, the third valve 9 is opened when the temperature and pressure meet the test requirements.

[0106] The first flowmeter 5 can measure the gas flow rate, and the gas flow rate flowing through the metering system within a certain period of time. The second flowmeter 45 can measure the gas flow rate flowing through the second flow chamber 39 within a certain period of time. In the required heating test, the preheater 6 needs to preheat the fluid to ensure that the test is carried out at the required temperature, and ensure that the injected fluid is kept consistent with the temperature of the flow chamber.

[0107] The gas enters the first flow diversion chamber 26 and the second flow diversion chamber 39, the fifteenth valve 37 and the sixteenth valve 38 are opened, and the pressure at both ends of the first flow diversion chamber 26 and the second flow diversion chamber 39 is measured by the first differential pressure sensor 36; after recording the differential pressure of the differential pressure sensor, the gas flow rate, and the rock sample length, cross-sectional area and other dimensions of the diversion chamber, and the fluid viscosity, the total conductivity of the layered fractures under the experimental conditions and the conductivity of each single-layer fracture therein can be calculated based on the differential pressure indicated by the first differential pressure sensor 36 and the flow rate indicated by the first flowmeter 5 and the second flowmeter 45.

[0108] The second flow meter 45 can measure the gas flow rate flowing through the second flow guide chamber 39 within a certain period of time.

[0109] ⑥ Liquid test of conductivity: If liquid is injected to test the conductivity of the fracture, close the second valve 4, the nineteenth valve 44, and the twentieth valve 46, and open the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17, and the ninth valve 20. Due to the drive of the liquid, the liquid in the liquid replenishment container replenishes the liquid for the piston container. After the liquid replenishment is completed, close the first valve 2, the fourth valve 10, and the fifth valve 12, open the water pump 14, the sixth valve 15, the seventh valve 17, the eighth valve 18, and the ninth valve 20, and start the first piston container 16 and the second piston container 19 at the same time. After that, the liquid passes through the preheater 6, and when the temperature and pressure meet the test requirements, open the third valve 9.

[0110] In the test requiring heating, the preheater 6 needs to preheat the fluid to ensure that the test is carried out at the required temperature, and ensure that the temperature of the injected fluid is consistent with that of the guide chamber.

[0111] The third flow meter 48 can measure the flow rate of the liquid flowing out of the second flow guide chamber 39 in real time.

[0112] The water pump 14 or the first balance 34 can measure the flow rate of the liquid passing through in real time.

[0113] The liquid 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 both ends of the first diversion chamber 26 and the second diversion chamber 39 is measured by the first differential pressure sensor 36. Finally, the liquid will flow to the second water container 35, and the first balance 34 can be used to measure the mass of the liquid. After recording the differential pressure of the differential pressure sensor, the liquid flow rate, and the rock sample length, cross-sectional area and other dimensions of the diversion chamber, and the viscosity of the fluid, when the flow rates measured by the first balance 34 and the water pump 14 are equal, and the flow rates meet the experimental requirements, the total fracture conductivity of the layered fractures and the conductivity of each single-layer fracture under the experimental conditions can be calculated based on the differential pressure shown by the first differential pressure sensor 36 and the flow rates recorded by the first balance 34, the water pump 14 and the third flowmeter 48.

[0114] ⑦ Equipment cleaning: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean.

[0115] The key parts of the system are described as follows:

[0116] A: In order to ensure the long-distance conduction function, it is necessary to be able to supply liquid uninterruptedly for a long time. Therefore, two sets of piston containers are designed, the first piston container 16 and the second piston container 19, which are convenient for alternating liquid supply and convenient operation.

[0117] B: The liquid replenishing container 11 is mainly used to replenish the piston container. When the liquid replenishing container 11 reaches the lowest liquid level, it will automatically alarm to remind you to add liquid. There is a safety device on the liquid replenishing container 11. When the pressure rises to the protection pressure due to misoperation, the safety device will automatically open to allow the liquid to overflow automatically, playing a protective role.

[0118] C: The first flow meter 5 can measure the gas flow rate, and is used to measure the gas flow rate flowing through the experimental system within a certain period of time.

[0119] D: In the test requiring heating, in order to ensure that the test is carried out at the required temperature, it is necessary to preheat the fluid using the preheater 6 to ensure that the injected fluid is kept consistent with the temperature of the guide chamber.

[0120] E: The first flow diversion chamber 26 and the second flow diversion chamber 39 are both made of high-strength stainless steel, which have certain corrosion resistance and pressure resistance. They are large in size and can meet the flow diversion capacity test of most rock samples.

[0121] F: When the outlet pressure of the diversion chamber reaches the control pressure at the top of the first back pressure valve 33, the first back pressure valve automatically opens to release pressure, ensuring that the outlet pressure is constant, simulating the migration resistance of the medium in the fracture.

[0122] G: After measuring the liquid and gas flow and the pressure difference at both ends of the diversion chamber, the general principle of testing diversion capacity in the industry can be used: according to the pressure difference ΔP, liquid flow Q or gas flow Q obtained from the above test, and the rock sample length L, cross-sectional area and other dimensions A of the diversion chamber, fluid viscosity μ, etc., through the formula:

[0123]

[0124]

[0125] Calculations are performed to obtain the conductivity parameters of the crack under the experimental conditions.

[0126] H: The first flow diversion chamber 26 and the second flow diversion chamber 39 can adjust the temperature to heat the rock sample to the target pressure required for the experiment, so as to better simulate the formation temperature conditions.

[0127] 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 according to the purpose of the experiment.

[0128] 2) If the fracture conductivity test of the seam network and the single layer tortuous fracture conductivity test are to be carried out, the following Figure 2 The connection relationship shown is implemented as follows:

[0129] ① Check air tightness: Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment.

[0130] ② Sample loading and preparation experiment: According to the experimental plan, the rock sample is loaded in the third flow guide chamber 55.

[0131] ③ Vacuuming: Close the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, and the thirty-first valve 63. Open the twelfth valve 25 and the eleventh valve 23, start the vacuum pump 24, and evacuate the entire pipeline in the system.

[0132] ④ Add closing pressure and back pressure: After the system is evacuated, close the eleventh valve 23 and the twelfth valve 25, and at the same time, close the vacuum pump 24. Open the third closing pressure pump 59 and the thirtieth valve 60, and adjust the pressure of the third closing pressure pump 59 according to the reading of the fifth pressure gauge 61; open the thirty-first valve 63 and the second back pressure pump 62, and adjust the pressure of the second back pressure pump 62 according to the sixth pressure gauge 64.

[0133] The third closing pressure pump 59 is provided with a closing pressure automatic compensation device, which keeps the closing pressure constant when the rock sample is deformed by the application of closing pressure.

[0134] ⑤ Gas testing of conductivity: If gas is injected to test the conductivity of cracks in the seam 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. The gas in the gas cylinder 1 is filtered through the filter 3, and the gas flow is measured by the first gas flow meter 5. After that, the gas passes through the preheater 6, and the third valve 9 is opened when the temperature and pressure meet the test requirements.

[0135] The first flow meter 5 can measure the gas flow rate, and measure the gas flow rate flowing through the system within a certain period of time.

[0136] In the test requiring heating, the preheater 6 needs to preheat the fluid to ensure that the test is carried out at the required temperature, and ensure that the temperature of the injected fluid is consistent with that of the guide chamber.

[0137] Open the twenty-fourth valve 52, the twenty-fifth valve 53, the twenty-sixth valve 53, the twenty-seventh valve 56, the twenty-eighth valve 57, and the twenty-ninth valve 58, and the gas flows through the third flow diversion chamber 55. Open the thirty-second valve 69 and the thirty-third valve 70, and use the second differential pressure sensor 68 to measure the pressure at both ends of the third flow diversion chamber 55. After recording the differential pressure of the differential pressure sensor, the gas flow rate, and the rock sample length, cross-sectional area and other dimensions of the diversion chamber, and the fluid viscosity, and after the test process is stable, the fracture conductivity under the experimental conditions can be calculated based on the differential pressure shown by the second differential pressure sensor 68 and the flow shown by the first flowmeter 5.

[0138] ⑥ Liquid test of conductivity: If liquid is injected to test the conductivity of the fracture, the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20 are opened. Due to the drive of the gas, the liquid in the liquid replenishment container replenishes the liquid for the piston container. After the liquid replenishment is completed, the first valve 2, the fourth valve 10, 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 at the same time. After that, the liquid passes through the preheater 6, and when the temperature and pressure meet the test requirements, the third valve 9 is opened.

[0139] In the test requiring heating, the preheater 6 needs to preheat the fluid to ensure that the test is carried out at the required temperature, and ensure that the temperature of the injected fluid is consistent with that of the guide chamber.

[0140] The water pump 14 or the second balance 66 can measure the flow rate of the liquid passing through in real time.

[0141] Open the twenty-fourth valve 52, the twenty-fifth valve 53, the twenty-sixth valve 53, the twenty-seventh valve 56, the twenty-eighth valve 57, and the twenty-ninth valve 58, and the liquid flows through the third diversion chamber 55. Open the thirty-second valve 69 and the thirty-third valve 70, and use the second differential pressure sensor 68 to measure the pressure at both ends of the third diversion chamber 55; eventually the liquid will flow to the third water container 67, and the second balance 66 can be used to measure the liquid mass. After recording the differential pressure of the differential pressure sensor, the liquid flow rate, and the rock sample length, cross-sectional area and other dimensions of the diversion chamber, and the viscosity of the fluid, when the second balance 66 and the pump 14 metered flow rate are equal, and the flow rate meets the experimental requirements, the fracture conductivity under the experimental conditions can be calculated based on the differential pressure shown by the second differential pressure sensor 68, the pump 14 and the flow rate shown by the second balance 66.

[0142] ⑦ Equipment cleaning: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean.

[0143] ⑧ Single-layer tortuous crack conductivity test: If a single-layer tortuous crack conductivity test is performed, the operation is similar to the above-mentioned gas measurement and liquid measurement conductivity methods to conduct crack conductivity tests with different angles and different seam distances.

[0144] The key parts of the system are described as follows:

[0145] A: The first piston container 16 and the second piston container 19: In order to ensure the long-term conduction function, it is necessary to be able to supply liquid uninterruptedly for a long time. Therefore, two sets of piston containers are designed to facilitate alternating liquid supply and convenient operation.

[0146] B: The refill container 11 is mainly used to refill the piston container. When the refill container reaches the lowest liquid level, it will automatically alarm to remind you to add liquid. There is a safety device on the refill container. When the pressure rises to the protection pressure due to misoperation, the safety device will automatically open to allow the liquid to overflow.

[0147] C: The first flow meter 5 can measure the gas flow rate, and is used to measure the gas flow rate flowing through the experimental system within a certain period of time.

[0148] D: In the test requiring heating, in order to ensure that the test is carried out at the required temperature, it is necessary to preheat the fluid using the preheater 6 to ensure that the injected fluid is kept consistent with the temperature of the guide chamber.

[0149] E: The third diversion chamber 55 is designed with three diversion inlets and three diversion outlets to more realistically simulate the seam network diversion and avoid the large gap between the test results and the actual situation caused by one diversion inlet and one diversion outlet.

[0150] F: When the outlet pressure of the third flow guiding chamber 55 reaches the top control pressure of the third back pressure valve 63, the third back pressure valve 63 automatically opens to release the pressure, ensuring that the outlet pressure is constant, simulating the migration resistance of the medium in the fracture.

[0151] G: After measuring the liquid and gas flow rates and the pressure difference at both ends of the third flow diversion chamber 55, the general principle of testing diversion capacity in the industry can be used: according to the pressure difference ΔP, liquid flow Q or gas flow Q obtained from the above test, and the rock sample length L of the diversion chamber, the rock sample cross-sectional area and other dimensions A, fluid viscosity μ, etc., through the formula:

[0152]

[0153]

[0154] Calculations were performed to obtain the conductivity parameters of the crack under the experimental conditions.

[0155] H: The third flow guide chamber 55 can adjust the temperature to heat the rock sample to the target pressure required for the experiment, so as to better simulate the formation temperature conditions.

[0156] I: The pressure of the third closing pressure pump 59 and the second back pressure pump 62 can be adjusted according to the experimental purpose.

[0157] 3) If the conductivity of a full-diameter core with cracks or microcracks is to be tested, select Figure 3 The connection relationship shown is implemented as follows:

[0158] ① Check air tightness: Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment.

[0159] ② Sample loading and preparation experiment: According to the experimental plan, the rock sample is loaded in the fourth flow guide chamber 71.

[0160] ③ Vacuuming: Close the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17, the ninth valve 20, and the thirty-fifth valve 76. Open the twelfth valve 25 and the eleventh valve 23, start the vacuum pump 24, and evacuate the entire pipeline in the system.

[0161] ④ Add closing pressure, back pressure, and axial pressure: After the system is evacuated, close the eleventh valve 23 and the twelfth valve 25, and at the same time close the vacuum pump 24. Open the fourth closing pressure pump 72 and the thirty-fourth valve 73, and adjust the pressure of the fourth closing pressure pump 72 according to the reading of the seventh pressure gauge 74; open the thirty-fifth valve 76, the thirty-sixth valve 79, the third back pressure pump 78, and adjust the pressure of the third back pressure pump 78 according to the ninth pressure gauge 86; open the axial pressure pump 75, and adjust the pressure of the axial pressure pump 75 according to the eighth pressure gauge 77. The fourth closing pressure pump 72 is provided with a closing pressure automatic compensation device, which keeps the closing pressure constant when the closing pressure is applied and the rock sample deforms.

[0162] ⑤ Gas testing conductivity: If gas is injected to test the conductivity of the fracture, close the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20, and open the first valve 2 and the second valve 4. The gas in the gas cylinder 1 is filtered by the filter 3, and the gas flow is measured by the first gas flow meter 5. After passing through the preheater 6, when the temperature and pressure meet the test requirements, open the third valve 9.

[0163] The first flow meter 5 can measure the gas flow rate, and measure the gas flow rate flowing through the system within a certain period of time.

[0164] In the test requiring heating, the preheater 6 needs to preheat the fluid to ensure that the test is carried out at the required temperature, and ensure that the temperature of the injected fluid is consistent with that of the guide chamber.

[0165] Open the thirty-fifth valve 76, and the gas flows through the fourth flow diversion chamber 71. Open the thirty-seventh valve 84 and the thirty-eighth valve 85, and use the third differential pressure sensor 83 to measure the pressure at both ends of the fourth flow diversion chamber 71. After recording the differential pressure of the differential pressure sensor, the gas flow rate, and the rock sample length, cross-sectional area and other dimensions of the diversion chamber, and the fluid viscosity, the diversion capacity can be calculated based on the differential pressure shown by the third differential pressure sensor 83 and the flow rate shown by the first flowmeter 5.

[0166] ⑥ Liquid test conductivity: If liquid is injected to test the conductivity of the fracture, open the first valve 2, the fourth valve 10, the fifth valve 12, the seventh valve 17 and the ninth valve 20. Due to the drive of the gas, the liquid in the liquid replenishment container replenishes the liquid for the piston container. After the liquid replenishment is completed, close the first valve 2, the fourth valve 10, the fifth valve 12, open the water pump 14, the sixth valve 15, the seventh valve 17, the eighth valve 18, and the ninth valve 20, and start the first piston container 16 and the second piston container 19 at the same time. After that, the liquid passes through the preheater 6, and when the temperature and pressure meet the test requirements, open the third valve 9.

[0167] In the test requiring heating, the preheater 6 needs to preheat the fluid to ensure that the test is carried out at the required temperature, and ensure that the temperature of the injected fluid is consistent with that of the guide chamber.

[0168] The water pump 14 or the third balance 81 can measure the flow rate of the liquid passing through in real time.

[0169] Open the thirty-fifth valve 76, and the liquid flows through the fourth diversion chamber 71. Open the thirty-seventh valve 84 and the thirty-eighth valve 85, and use the third differential pressure sensor 83 to measure the pressure at both ends of the fourth diversion chamber 71; eventually the liquid will flow to the fourth water container 82, and the third balance 81 can be used to measure the mass of the liquid. After recording the differential pressure of the differential pressure sensor, the liquid flow rate, and the rock sample length, cross-sectional area and other dimensions of the diversion chamber, and the fluid viscosity, when the flow rates measured by the third balance 81 and the pump 14 are equal, and the flow rate meets the experimental requirements, the diversion capacity of the full-diameter core with cracks or microcracks can be calculated based on the differential pressure shown by the third differential pressure sensor 83, the flow rates shown by the pump 14 and the third balance 81.

[0170] ⑦ Equipment cleaning: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean.

[0171] The key parts of the system are described as follows:

[0172] A: The first piston container 16 and the second piston container 19: In order to ensure the long-term conduction function, it is necessary to be able to supply liquid uninterruptedly for a long time. Therefore, two sets of piston containers are designed to facilitate alternating liquid supply and convenient operation.

[0173] B: The refill container 11 is mainly used to refill the piston container. When the refill container reaches the lowest liquid level, it will automatically alarm to remind you to add liquid. There is a safety device on the refill container. When the pressure rises to the protection pressure due to misoperation, the safety device will automatically open to allow the liquid to overflow.

[0174] C: The first flow meter 5 can measure the gas flow rate, and is used to measure the gas flow rate flowing through the experimental system within a certain period of time.

[0175] D: In the test requiring heating, in order to ensure that the test is carried out at the required temperature, it is necessary to preheat the fluid using the preheater 6 to ensure that the injected fluid is kept consistent with the temperature of the guide chamber.

[0176] E: The fourth flow chamber 71 of the full-diameter triaxial core is designed to be heated by electric heating and an insulation jacket to simulate different overburden conditions.

[0177] F: When the outlet pressure of the diversion chamber reaches the top control pressure of the back pressure valve 80, the back pressure valve automatically opens to release the pressure, ensuring that the outlet pressure is constant, simulating the migration resistance of the medium in the crack.

[0178] G: The axial pressure pump 75 applies axial pressure to the fourth flow conduction chamber 71 of the full-diameter triaxial core, which more realistically simulates the needs of on-site flow conduction capacity testing.

[0179] H: After measuring the liquid and gas flow rates and the pressure difference at both ends of the fourth flow guiding chamber 71, the general principle of testing the flow guiding capacity in the industry can be used: according to the pressure difference ΔP, liquid flow Q or gas flow Q obtained from the above test, and the rock sample length L of the flow guiding chamber, the rock sample cross-sectional area and other dimensions A, the fluid viscosity μ, etc., through the formula:

[0180]

[0181]

[0182] Calculations are performed to obtain the conductivity parameters of the cracks.

[0183] The test method is as follows:

[0184] The present invention is divided into four situations: layered fracture conductivity test, single layer tortuous fracture conductivity test, fracture network fracture conductivity test, and full diameter core conductivity test with fractures or microcracks:

[0185] (1) If a layered flow conductivity test is to be performed, the connection relationship shown in Figure A is selected.

[0186] ① Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment.

[0187] ② According to the experimental plan, rock samples are installed in the first flow diversion chamber 26 and the second flow diversion chamber 39.

[0188] ③ Vacuuming: Turn on the vacuum pump 24 to evacuate the entire pipeline in the system.

[0189] ④ Add closing pressure and back pressure: After the system is evacuated, adjust the pressure of the first closing pressure pump 27; adjust the pressure of the first back pressure pump 30; and adjust the pressure of the second closing pressure pump 40.

[0190] The closing pressure and the back pressure are flexibly set according to the experimental purpose. The first closing pressure pump 27 and the second closing pressure pump 40 are provided with a closing pressure automatic compensation device for keeping the closing pressure constant.

[0191] ⑤ Gas testing of conductivity: If gas is injected to test the conductivity of the fracture, the gas flow rate is measured by the first gas flow meter 5, and then the gas flows through the preheater 6. When the temperature and pressure reach the test requirements, the third valve 9 is opened.

[0192] The gas enters the first diversion chamber 26 and the second diversion chamber 39. After recording the pressure difference of the pressure difference sensor, the gas flow rate, the length of the rock sample, the cross-sectional area and other dimensions of the diversion chamber, and the fluid viscosity, the total conductivity of the layered fractures under the experimental conditions and the conductivity of each single-layer fracture therein can be calculated based on the pressure difference shown by the first pressure difference sensor 36 and the flow rate shown by the first flowmeter 5 and the second flowmeter 45.

[0193] ⑥ Liquid test of conductivity: If liquid is injected to test the conductivity of the fracture, the liquid in the liquid replenishment container replenishes the liquid for the piston container due to the drive of the gas. After the liquid replenishment is completed, the water pump 14 is turned on, and the first piston container 16 and the second piston container 19 are started at the same time. After that, the liquid passes through the preheater 6, and when the temperature and pressure meet the test requirements, the third valve 9 is opened.

[0194] The liquid enters the first diversion chamber 26 and the second diversion chamber 39, and the pressure difference of the pressure difference sensor, the liquid flow rate, and the rock sample length, cross-sectional area and other dimensions of the diversion chamber, and the fluid viscosity are recorded. After the test is stable, the total fracture conductivity of the layered fractures and the conductivity of each single-layer fracture under the experimental conditions can be calculated based on the pressure difference shown by the first pressure difference sensor 36 and the flow recorded by the first balance 34, the water pump 14 and the third flowmeter 48.

[0195] ⑦ Equipment cleaning: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean.

[0196] (2) If the fracture conductivity test of the seam network and the single-layer tortuous fracture conductivity test are to be carried out, the connection relationship shown in Figure B shall be selected.

[0197] ① Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment.

[0198] ② According to the experimental plan, the rock sample is loaded into the third flow guide chamber 55.

[0199] ③ Vacuuming: Turn on the vacuum pump 24 to evacuate the entire pipeline in the system.

[0200] ④ Add closing pressure and back pressure: After the system is evacuated, adjust the pressure of the third closing pressure pump 59; adjust the pressure of the second back pressure pump 62. The third closing pressure pump 59 is provided with a closing pressure automatic compensation device to keep the closing pressure constant.

[0201] ⑤ Gas testing of conductivity: If gas is injected to test the conductivity of the crack, the gas in the gas cylinder 1 is filtered through the filter 3, and the gas flow is measured by the first gas flow meter 5. Then the gas passes through the preheater 6, and when the temperature and pressure meet the test requirements, the third valve 9 is opened.

[0202] After recording the pressure difference of the pressure difference sensor, the gas flow rate, the length of the rock sample in the diversion chamber, the cross-sectional area and other dimensions, and the fluid viscosity, and after the test process is stable, the conductivity of the fracture network under the experimental conditions can be calculated based on the pressure difference shown by the second pressure difference sensor 68 and the flow rate shown by the first flow meter 5.

[0203] ⑥ Liquid test of conductivity: If liquid is injected to test the conductivity of the fracture, the liquid in the liquid replenishment container replenishes the liquid for the piston container due to the drive of the gas. After the liquid replenishment is completed, the water pump 14 is turned on, and the first piston container 16 and the second piston container 19 are started at the same time. After that, the liquid passes through the preheater 6, and when the temperature and pressure meet the test requirements, the third valve 9 is opened.

[0204] Finally, the liquid will flow to the third water container 67, and the mass of the liquid can be measured by the second balance 66. After recording the pressure difference of the pressure difference sensor, the liquid flow rate, the length of the rock sample in the diversion chamber, the cross-sectional area and other dimensions, and the fluid viscosity, and after the test process is stable, the fracture conductivity of the fracture network under the experimental conditions can be calculated based on the pressure difference shown by the second pressure difference sensor 68, the flow rate shown by the water pump 14 and the second balance 66.

[0205] ⑦ Equipment cleaning: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean.

[0206] ⑧ If the conductivity test of a single-layer tortuous crack is to be carried out, the operation is similar to the above-mentioned gas measurement and liquid measurement conductivity methods, and the conductivity test of cracks with different angles and different seam distances is carried out.

[0207] (3) If the conductivity of a full-diameter core with cracks or microcracks is to be tested, the connection relationship shown in Figure C is selected.

[0208] ① Connect the equipment, check the air tightness of the system, close all valves, and prepare for the experiment.

[0209] ② According to the experimental plan, the rock sample is loaded into the fourth flow guide chamber 71.

[0210] ③ Vacuuming: Turn on the vacuum pump 24 to evacuate the entire pipeline in the system.

[0211] ④ Add closing pressure, back pressure, and axial pressure: After the system is evacuated, adjust the pressure of the fourth closing pressure pump 72; adjust the pressure of the third back pressure pump 78; and adjust the pressure of the axial pressure pump 75. The fourth closing pressure pump 72 is provided with a closing pressure automatic compensation device to keep the closing pressure constant.

[0212] ⑤ Gas testing of conductivity: If gas is injected to test the conductivity of the crack, the gas in the gas cylinder 1 is filtered through the filter 3, and the gas flow is measured by the first gas flow meter 5. Then the gas passes through the preheater 6, and when the temperature and pressure meet the test requirements, the third valve 9 is opened.

[0213] The gas flows through the fourth flow chamber 71, and the pressure at both ends of the fourth flow chamber 71 is measured by the third pressure difference sensor 83. After recording the pressure difference of the pressure difference sensor, the gas flow rate, the length of the rock sample, the cross-sectional area and other dimensions of the flow chamber, and the fluid viscosity, the flow conductivity of the full-diameter core with cracks or microcracks can be calculated based on the pressure difference shown by the third pressure difference sensor 83 and the flow rate shown by the first flow meter 5.

[0214] ⑥ Liquid testing of conductivity: If liquid is injected to test the conductivity of the fracture, the liquid in the liquid replenishment container replenishes the liquid for the piston container due to the drive of the liquid. After the liquid replenishment is completed, the first piston container 16 and the second piston container 19 are started at the same time. After that, the liquid passes through the preheater 6, and when the temperature and pressure meet the test requirements, the third valve 9 is opened.

[0215] The pressure at both ends of the fourth flow 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 third balance 81 can be used to measure the mass of the liquid. After recording the differential pressure of the differential pressure sensor, the liquid flow rate, the length of the rock sample in the diversion chamber, the cross-sectional area and other dimensions, and the fluid viscosity, the diversion chamber, and the test is stable, and the diversion capacity of the full-diameter core with cracks or microcracks can be calculated based on the differential pressure shown by the third differential pressure sensor 83, the flow rate shown by the water pump 14 and the third balance 81.

[0216] ⑦ Equipment cleaning: After the test, disassemble the instrument and clean all containers and pipelines to keep the equipment clean.

[0217] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fracture conductivity testing system, characterized in that: It comprises a gas and liquid combined supply device capable of supplying gas alone or liquid alone, the outlet end of the gas and liquid combined supply device is connected to a test device for conducting a flow conductivity test, and the gas and liquid combined supply device is connected to a vacuum device, the test device is a first test device for conducting a layered flow conductivity test; the outlet end of the first test device is connected to a first metering device; The first test device comprises a first flow guide chamber (26) and a second flow guide chamber (39) connected to the outlet end of the gas and liquid combined supply device, the inlet end of the first flow guide chamber (26) is connected to the outlet end of the gas and liquid combined supply device, and the outlet end of the first flow guide chamber (26) is connected to the metering device; the inlet end of the second flow guide chamber (39) is connected to the outlet end of the gas and liquid combined supply device through an eighteenth valve (43), the outlet end of the second flow guide chamber (39) is connected to the twenty-third valve (50) through two metering branches, and the outlet end of the twenty-third 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 to a first closing pressure applying device and a second closing pressure applying device, and a first pressure difference sensing device is provided between the inlet end and the outlet end of the first flow guide chamber (26); The gas and liquid combined supply device comprises a gas supply device and a liquid supply device, wherein the gas supply device comprises a gas cylinder (1), wherein the outlet end of the gas cylinder (1) is sequentially connected to a first valve (2), a filter (3), a second valve (4), a first flow meter (5), a preheater (6), a first thermometer (7), a first pressure gauge (8) and a third valve (9), wherein the outlet end of the third valve (9) is connected to an inlet end of a first flow guide chamber (26) and an inlet end of a second flow guide chamber (39); The liquid supply device comprises a first water container (13), the outlet end of the first water container (13) is connected to a water pump (14), the outlet of the water pump (14) is divided into two branches, one branch is connected to a sixth valve (15), a first piston container (16) and a seventh valve (17) in sequence, and the other branch is connected to 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 invention also comprises a liquid replenishing device, the liquid replenishing device comprising a liquid replenishing container (11), the top inlet of the liquid replenishing container (11) being connected to between the filter (3) and the second valve (4) through a fourth valve (10), the outlet pipeline of the liquid replenishing container (11) being connected to the inlet of the preheater (6) through a fifth valve (12), wherein the fourth valve (10) is connected to the top of the liquid replenishing container (11) through a pipeline; and the pipeline connecting the fifth valve (12) and the liquid replenishing container (11) is inserted into the bottom of the liquid replenishing container (11); The first closing pressure applying device comprises a second pressure gauge (29), a thirteenth 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) connected in sequence; The first closing pressure pump (27) and the second closing pressure pump (40) are provided with an accompanying closing pressure automatic compensation device for maintaining the closing pressure constant.

2. A fracture conductivity testing system, characterized in that: It comprises a gas and liquid combined supply device capable of supplying gas alone or liquid alone, the outlet end of the gas and liquid combined supply device is connected to a test device for conducting a conductivity test, and the gas and liquid combined supply device is connected to a vacuum device, the test device is a second test device for conducting a seam network crack conductivity test and a single layer tortuous crack conductivity test; the outlet end of the second test device is connected to a second metering device; The second test device comprises a third flow guide chamber (55), the inlet end of the third flow guide chamber (55) is connected to the outlet end of the gas and liquid combined supply device through a twenty-fourth valve (52), a twenty-fifth valve (53) and a twenty-sixth valve (54) arranged in parallel, the outlet end of the third flow guide chamber (55) is connected to the second metering device through a twenty-seventh valve (56), a twenty-eighth valve (57) and a twenty-ninth valve (58) arranged in parallel, and the third flow guide chamber (55) is connected to a third closing pressure applying device, and a second pressure difference sensing device is arranged between the inlet end and the outlet end of the third flow guide chamber (55); The gas and liquid combined 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 in sequence to a first valve (2), a filter (3), a second valve (4), a first flow meter (5), a preheater (6), a first thermometer (7), a first pressure gauge (8) and a third valve (9), and the inlet end of the third guide chamber (55) of the third valve (9); The liquid supply device comprises a first water container (13), the outlet end of the first water container (13) is connected to a water pump (14), the outlet of the water pump (14) is divided into two branches, one branch is connected to a sixth valve (15), a first piston container (16) and a seventh valve (17) in sequence, and the other branch is connected to 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 invention also comprises a liquid replenishing device, the liquid replenishing device comprising a liquid replenishing container (11), the top inlet of the liquid replenishing container (11) being connected to between the filter (3) and the second valve (4) through a fourth valve (10), the outlet pipeline of the liquid replenishing container (11) being connected to the inlet of the preheater (6) through a fifth valve (12), wherein the fourth valve (10) is connected to the top of the liquid replenishing container (11) through a pipeline; and the pipeline connecting the fifth valve (12) and the liquid replenishing container (11) is inserted into the bottom of the liquid replenishing container (11); The third closing pressure applying device comprises a fifth pressure gauge (61), a thirtieth valve (60) and a third closing pressure pump (59) connected in sequence; The third closing pressure pump (59) is provided with an accompanying closing pressure automatic compensation device for maintaining the closing pressure constant.

3. A fracture conductivity testing system, characterized in that: It comprises a gas and liquid combined supply device capable of supplying gas alone or liquid alone, the outlet end of the gas and liquid combined supply device is connected to a test device for conducting a conductivity test, and the gas and liquid combined supply device is connected to a vacuum device, the test device is a third test device for conducting a conductivity test of a full-diameter core with cracks or microcracks; the outlet end of the third test device is connected to a third metering device; The third testing device comprises a fourth flow guide chamber (71), the inlet end of the fourth flow guide chamber (71) is connected to the outlet end of the gas and liquid combined supply device, the outlet end of the fourth flow guide chamber (71) is connected to the third metering device, and the fourth flow guide chamber (71) is connected to a fourth closed pressure applying device, a third differential pressure 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 also connected to the axial pressure pump (75) via an eighth pressure gauge (77); The gas and liquid combined 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 in sequence to a first valve (2), a filter (3), a second valve (4), a first flow meter (5), a preheater (6), a first thermometer (7), a first pressure gauge (8) and a third valve (9), the outlet end of the third valve (9) is connected to an inlet end of a fourth flow guide chamber (71); The liquid supply device comprises a first water container (13), the outlet end of the first water container (13) is connected to a water pump (14), the outlet of the water pump (14) is divided into two branches, one branch is connected to a sixth valve (15), a first piston container (16) and a seventh valve (17) in sequence, and the other branch is connected to 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 invention also comprises a liquid replenishing device, the liquid replenishing device comprising a liquid replenishing container (11), the top inlet of the liquid replenishing container (11) being connected to between the filter (3) and the second valve (4) through a fourth valve (10), the outlet pipeline of the liquid replenishing container (11) being connected to the inlet of the preheater (6) through a fifth valve (12), wherein the fourth valve (10) is connected to the top of the liquid replenishing container (11) through a pipeline; and the pipeline connecting the fifth valve (12) and the liquid replenishing container (11) is inserted into the bottom of the liquid replenishing container (11); The fourth closing pressure applying device comprises a seventh pressure gauge (74), a thirty-fourth valve (73) and a fourth closing pressure pump (72) connected in sequence; The fourth closing pressure pump (72) is provided with an accompanying closing pressure automatic compensation device for maintaining the closing pressure constant.

4. A fracture conductivity testing system according to any one of claims 1 to 3, characterized in that: The liquid replenishment container (11) is provided with an alarm device for when the minimum liquid level is reached. The liquid replenishment container (11) is also provided with a safety device. When the pressure rises to a protective pressure due to misoperation, the safety device can be automatically opened to allow the liquid to overflow automatically.

5. A fracture conductivity testing system according to any one of claims 1 to 3, characterized in that: The vacuum extraction device comprises a buffer tank (22), the bottom of the buffer tank (22) is provided with a tenth valve (21) for venting, the top of the buffer tank (22) is connected in sequence with a vacuum pump (24) and a twelfth valve (25), and the top inlet of the buffer tank (22) is connected with an eleventh valve (23), when the test device adopts the first test device or the second test device, the inlet end of the eleventh valve (23) is connected between the preheater (6) and the first thermometer (7), and when the test device adopts the third test device, the inlet end of the eleventh valve (23) is connected to the outlet end of the third valve (9).

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