Heterogeneous tectonic coal reservoir gas pressure gradient distribution testing device

Abstract

The utility model relates to a heterogeneous tectonic coal reservoir gas pressure gradient distribution testing device, which comprises a sample container, a loading system, a pressure system, a gas pressure sensing system, a liquid pressure sensing system and a solid pressure sensing system, the loading system is used for applying a certain load to the tectonic coal, the pressure system is used for injecting water and gas into the tectonic coal, and the gas pressure sensing system, the liquid pressure sensing system and the solid pressure sensing system are used for monitoring the gas pressure, the liquid pressure and the internal stress of the tectonic coal. The testing device disclosed by the utility model can be used for simulating the dynamic change of air pressure and water pressure in the extraction (drainage) process of gas and coal bed gas of the heterogeneous tectonic coal reservoir, and also can be used for testing the gas pressure and gradient distribution of the gas of the heterogeneous tectonic coal reservoir under different stress states and water-bearing conditions; and accurate extraction or treatment of coal mine gas is guided.

Description

TECHNICAL FIELD

[0001] The utility model belongs to coal mine safety and coal bed gas exploitation technical field, concretely relates to a kind of non-homogeneous structural coal reservoir gas pressure gradient distribution testing device. BACKGROUND

[0002] Coal reservoir experiences multiple structural deformation modification, and layered coal reservoir under original deposition condition is broken to form granular coal reservoir and mylonitic coal reservoir. These coal reservoirs that have experienced late geological modification all have dispersed structure and can be collectively referred to as structural coal reservoir. Different structural coal reservoirs experience different stress states due to different geological processes, and have one-time stress disturbance and multiple stress disturbances. The original pore and fissure structure of coal reservoir is reformed under different stress disturbances, so that methane gas is easily sharply in local area, forming local high-methane-content and high-methane-gas-pressure zone, and forming a high-risk area of coal and gas outburst. In addition, under in-situ geological conditions, the presence of water in coal reservoir often produces water lock effect, which restricts the migration of gas, further causing the differential distribution of gas in different positions of structural coal reservoir, and aggravating the heterogeneity of the reservoir. Especially for local high-gas-pressure area, if the coal body is damaged under the action of gas permeation force, coal and gas outburst accident is more likely to occur. UTILITY MODEL CONTENT

[0003] The utility model aims to provide a kind of non-homogeneous structural coal reservoir gas pressure gradient distribution testing device, to provide experimental support for the basic theoretical research of the pressure heterogeneity distribution of structural coal reservoir under in-situ conditions and related disciplines, so as to further analyze the gas pressure distribution of non-homogeneous structural coal reservoir, facilitate the zoning and accurate management of coal mine gas outburst risk, and provide technical evaluation and guidance for actual engineering.

[0004] To achieve the above-mentioned purpose, the utility model adopts the technical scheme of non-homogeneous structural coal reservoir gas pressure gradient distribution testing device, which includes a sample container for loading dispersed structure of pulverized coal as structural coal to be tested.

[0005] The loading system includes a pressure disc arranged in the sample container and a hydraulic push rod connected to the pressure disc. The hydraulic push rod drives the pressure disc to apply a certain load to the structural coal in the sample container under the drive of the hydraulic pump.

[0006] The pressure system includes a gas pressure system and a liquid pressure system, the gas pressure system is used for gas injection operation on the tectonic coal in the sample container, and the liquid pressure system is used for water injection operation on the tectonic coal in the sample container; the gas pressure system includes a gas cylinder, a gas booster pump and a front-end gas flow meter, the gas cylinder is communicated with the sample container through a gas injection pipe, and the gas injection pipe is connected with the gas booster pump and the front-end gas flow meter; the liquid pressure system includes a water storage tank, a water injection pump and an inlet liquid flow meter, the water storage tank is communicated with the sample container through a water injection pipe, and the water injection pipe is connected with the water injection pump and the inlet liquid flow meter.

[0007] The gas pressure sensing system includes a plurality of gas pressure sensors and is arranged on the side of the sample container and is used for monitoring the gas pressure of the tectonic coal at different positions in the sample container.

[0008] The liquid pressure sensing system includes a plurality of liquid pressure sensors and is arranged on the side of the sample container and is used for monitoring the liquid pressure of the tectonic coal at different positions in the sample container.

[0009] The solid pressure sensing system includes a plurality of solid pressure sensors and is embedded in the tectonic coal and is used for monitoring the stress value at different positions in the tectonic coal.

[0010] Further, the pressure disc is provided with a gas injection through hole and a water injection through hole, the gas injection through hole is used for connecting with the end of the gas injection pipe, and the water injection through hole is used for connecting with the end of the water injection pipe.

[0011] Further, the data acquisition and storage system further includes a computer and a data integration box, the data monitored and acquired by the gas pressure sensing system, the liquid pressure sensing system, the solid pressure sensing system, the front-end gas flow meter, the tail-end gas flow meter, the inlet liquid flow meter and the outlet liquid flow meter are uploaded to the data integration box for storage.

[0012] Further, the rear end of the sample container is further connected with a vacuum pump, and the sample container is vacuumized by the vacuum pump.

[0013] Further, the pressure disc is provided with a displacement meter for measuring the displacement of the pressure disc.

[0014] Further, according to the loading mode of the loading system on the tectonic coal, the number of the solid pressure sensors is determined, when the one-time loading mode is adopted, one solid pressure sensor is arranged; when the hierarchical loading mode is adopted, the number of the solid pressure sensors is consistent with the number of the tectonic coal.

[0015] The utility model discloses a beneficial effect is: utilize the utility model one aspect can to the non -uniform structure coal reservoir gas (coal seam gas) extraction (row extraction) process in the gas pressure and water pressure dynamic change carries out simulation, the other side can be used for the non -uniform structure coal reservoir gas gas pressure and its gradient distribution under different stress state and water content condition test.

[0016] The utility model discloses simple structure, low in cost, easy to process manufacturing can realize to the different loading mode and water injection operation of structure coal, monitor the stress and water content of corresponding position simultaneously, simulate the non -uniform structure coal reservoir under different stress state and water content condition. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will be to the embodiment or prior art description needed to use the drawing of simple introduction, obviously, the following description in the drawing is only some embodiments of the utility model, for the ordinary skilled person in the art comes, under the premise of not paying the creative labor, can also obtain other drawings according to these drawings.

[0018] Figure 1 For the structure schematic drawing of the test device of the utility model when adopting to structure coal once loading;

[0019] Figure 2 For the structure schematic drawing of the test device of the utility model when adopting to structure coal three times loading.

[0020] Marked in the figure: 1, gas cylinder; 2, water storage tank; 3, gas booster pump; 4, water injection pump; 5, hydraulic pump; 6, front end gas flow meter; 7, hydraulic push rod; 8, sample container; 9, tectonic coal; 10, displacement meter; 11, pressure plate; 12, first gas pressure sensor; 13, second gas pressure sensor; 14, third gas pressure sensor; 15, fourth gas pressure sensor; 16, fifth gas pressure sensor; 17, sixth gas pressure sensor; 18, solid pressure sensor; 18-1, first solid pressure sensor; 18-2, second solid pressure sensor; 18-3, third solid pressure sensor; 19, first liquid pressure sensor; 20, second liquid pressure sensor; 21, third liquid pressure sensor; 22, fourth liquid pressure sensor; 23, fifth liquid pressure sensor; 24, sixth liquid pressure sensor; 25, end valve; 26, gas injection inlet valve; 27, water injection inlet valve; 28, gas-water separator; 29, end gas flow meter; 30, outlet liquid flow meter; 31, inlet liquid flow meter; 32, computer; 33, data integration box; 34, vacuum pump; 35, data line. DETAILED DESCRIPTION

[0021] The utility model will be further explained in detail below in combination with the drawings and examples, but not as any limit basis for the utility model.

[0022] Example 1: the testing device of heterogeneous tectonic coal reservoir gas pressure gradient distribution, including pressure system, loading system, gas pressure sensing system, liquid pressure sensing system, solid pressure sensing system, sample container 8 and data acquisition and storage system.

[0023] The sample container 8 is used to fill tectonic coal 9, and the tectonic coal 9 is loaded by the loading system to form a heterogeneous tectonic coal reservoir. The tectonic coal 9 is a powder coal with a bulk structure, and different particle sizes can be used according to research needs. The two ends of the sample container 8 are the container front end and the container rear end, respectively, wherein the container front end is connected with the pressure system, and the container rear end is used to connect with the end valve 25, the gas-water separator 28 and the vacuum pump 34.

[0024] The loading system includes a pressure plate 11 arranged in the sample container 8, and a hydraulic push rod connected to the pressure plate 11. The hydraulic pump 5 outside the sample container 8 drives the hydraulic push rod 7 to control the pressure plate 11 to slide along the inner wall of the sample container 8, apply pressure to the tectonic coal 9 in the sample container 8, and realize the loading of the tectonic coal 9.

[0025] The periphery of the pressure plate 11 and the inner wall of the sample container 8 are in close and smooth contact and can slide relative to each other. The close contact can avoid leakage of gas, moisture and tectonic coal 9 between the pressure plate 11 and the inner wall of the sample container 8, and the smooth contact is used to avoid the loss of hydraulic oil power caused by friction between the pressure plate 11 and the inner wall of the sample container 8, and further avoid distortion of the load applied to the tectonic coal 9.

[0026] The displacement meter 10 is arranged on the side of the pressure plate 11 opposite to the tectonic coal 9, and the two ends of the displacement meter 10 are respectively connected to the pressure plate 11 and the inner side of the front end face of the sample container 8. The displacement meter 10 can be used to test the displacement L2 of the pressure plate 11 during the loading and compaction of the tectonic coal 9 in the sample container 8.

[0027] The initial length of the tectonic coal 9 filled in the sample container 8 is L1, and the length of the tectonic coal 9 after compaction by the pressure plate 11 is L1-L2. When the pressure plate 11 moves to the inner side of the front end of the sample container 8, the initial length of the tectonic coal 9 is the length of the sample container 8 minus the thickness of the pressure plate 11. In actual tests, it is difficult to move to the limit position of the pressure plate 11 adhering to the inner side of the front end of the container because the pressure plate 11 also needs to be connected to the gas injection pipe and the water injection pipe. Therefore, the length of the sample container 8 can be determined by the extension of the hydraulic push rod 7, and the initial length of the tectonic coal 9 filled in the sample container 8 can be obtained.

[0028] The tectonic coal 9 in the sample container 8 and the inner wall of the sample container 8 can be in smooth contact by applying lubricant, cooperating with plastic film and other methods, to ensure that the tectonic coal 9 is not caused by friction between the tectonic coal 9 and the inner wall of the sample container 8 during the loading and compaction of the tectonic coal 9 by the pressure plate 11, and to avoid load loss and further distortion of the load applied to the tectonic coal 9.

[0029] The gas pressure sensing system, liquid pressure sensing system and solid pressure sensing system are arranged on the sample loading container 8 and are connected with the data acquisition and storage system through data lines to upload data to the data acquisition and storage system. The gas pressure sensing system includes a plurality of gas pressure sensors and is arranged on the side of the sample loading container 8 to monitor the gas pressure at different positions of the tectonic coal 9 in the sample loading container 8. The liquid pressure sensing system includes a plurality of liquid pressure sensors and is arranged on the side of the sample loading container 8 to monitor the liquid pressure at different positions of the tectonic coal 9 in the sample loading container 8. The solid pressure sensing system includes at least one solid pressure sensor 18 and is embedded in the tectonic coal 9 to monitor the stress value inside the tectonic coal 9. According to the loading mode of the tectonic coal 9 in the sample loading container 8, the solid pressure sensor 18 is arranged as one or more. When a plurality of solid pressure sensors 18 are arranged, the plurality of solid pressure sensors 18 are arranged at intervals along the length of the tectonic coal 9. Specifically, when the tectonic coal 9 in the sample loading container 8 is loaded to the target load at one time, the tectonic coal 9 in the sample loading container 8 is loaded at one time, and the solid pressure sensor 18 is arranged as one, as shown in FIG. 2; when the tectonic coal 9 in the sample loading container 8 is loaded to the target load for multiple times, the tectonic coal 9 in the sample loading container 8 needs to be loaded for multiple times, and the loading times are equal to the loading times, so that a solid pressure sensor 18 needs to be embedded in the tectonic coal 9 for each loading, for example, three times of loading to the target load, so that three solid pressure sensors 18 need to be embedded in the tectonic coal 9 of the sample loading container 8, as shown in FIG. 3, which are a first solid pressure sensor 18-1, a second solid pressure sensor 18-2 and a third solid pressure sensor 18-3, respectively, for monitoring the stress f1, f2 and f3 borne by the tectonic coal 9 at different positions. Figure 1 Figure 2

[0030] In this embodiment, six gas pressure sensors are arranged, which are a first gas pressure sensor 12, a second gas pressure sensor 13, a third gas pressure sensor 14, a fourth gas pressure sensor 15, a fifth gas pressure sensor 16 and a sixth gas pressure sensor 17. The six gas pressure sensors are uniformly arranged at the corresponding loaded tectonic coal 9 of the sample loading container 8 along the length of the sample loading container 8, and the gas pressures at different positions of the tectonic coal 9 in the sample loading container 8 are P1, P2, P3, P4, P5 and P6, respectively.

[0031] ​​In this embodiment, the liquid pressure sensing system includes six liquid pressure sensors, namely, a first liquid pressure sensor 19, a second liquid pressure sensor 20, a third liquid pressure sensor 21, a fourth liquid pressure sensor 22, a fifth liquid pressure sensor 23 and a sixth liquid pressure sensor 24. The six liquid pressure sensors are uniformly arranged on the sample loading container 8 along the length of the sample loading container 8, and the liquid pressures at different positions of the constructed coal 9 in the sample loading container 8 are w1, w2, w3, w4, w5 and w6, respectively.

[0032] The pressure system is divided into a gas pressure system and a liquid pressure system. The gas pressure system is used for gas injection operation on the constructed coal 9 in the sample loading container 8, and the liquid pressure system is used for water injection operation on the constructed coal 9 in the sample loading container 8.

[0033] Specifically, the gas pressure system includes a gas cylinder 1, a gas booster pump 3 and a front-end gas flow meter 6. The gas cylinder 1 is filled with gas or simulated gas, and the gas cylinder 1 is connected with the sample loading container 8 through a gas injection pipe provided with a gas injection inlet valve 26. The end of the gas injection pipe penetrates through the front end face of the sample loading container 8 and is connected to a gas injection hole on the pressure disc 11. The gas injection pipe is a flexible pipe, and the gas booster pump 3 and the front-end gas flow meter 6 are connected to the gas injection pipe. The gas booster pump 3 is used in cooperation with the gas cylinder 1 to pressurize the gas in the gas cylinder 1, which is used for gas injection on the constructed coal in the sample loading container 8. The front-end gas flow meter 6 is used for monitoring the gas injection amount.

[0034] Specifically, the liquid pressure system includes a water storage tank 2, a water injection pump 4 and an inlet liquid flow meter 31. The water storage tank 2 is connected with the sample loading container 8 through a water injection pipe provided with a water injection inlet valve 27. The end of the water injection pipe penetrates through the front end face of the sample loading container 8 and is connected to a water injection hole on the pressure disc 11. The water injection pipe is a flexible pipe, and the water injection pump 4 and the inlet liquid flow meter 31 are connected to the water injection pipe. The water injection pump 4 is used in cooperation with the water storage tank 2 to pressurize the water in the water storage tank 2, which ensures the smooth water injection. The inlet liquid flow meter 31 is used for monitoring the water injection amount.

[0035] The rear end face of the sample loading container 8 is provided with a water-gas discharge pipe, and the water-gas discharge pipe is provided with a rear-end valve 25 and a gas-water separator 28. The gas discharge pipe of the gas-water separator 28 is provided with a terminal gas flow meter 29, and the liquid discharge pipe of the gas-water separator 28 is provided with an outlet liquid flow meter 30. The rear end face of the sample loading container 8 is also connected with a vacuum pump 34, which is used to vacuumize the sample loading container 8.

[0036] The data collection and storage system comprises a computer 32 and a data integration box 33. The respective gas pressure sensor, liquid pressure sensor, solid pressure sensor, front-end gas flow meter, end gas flow meter, inlet liquid flow meter and outlet liquid flow meter are connected to the data integration box 33 through data lines 35, so as to upload the pressure values measured by the gas pressure sensor, the pressure values measured by the liquid pressure sensor, the pressure values measured by the solid pressure sensor 18, the gas flow values measured by the front-end gas flow meter 6 and the end gas flow meter 29, and the liquid flow values measured by the inlet liquid flow meter 31 and the outlet liquid flow meter 30 into the data integration box 33, and to store the various data in the data integration box 33, which can be viewed through the computer 21.

[0037] It can be understood that the uploading of the above data can also be transmitted to the data integration box 33 through a wireless network.

[0038] Embodiment 2: A test method for gas pressure gradient distribution of a non-homogeneous tectonic coal reservoir, which adopts the test device of embodiment 1 and specifically comprises the following steps:

[0039] Step one: The tectonic coal 9 in the sample loading container 8 is loaded by the pressure disc 11 to achieve a target load, and the length of the tectonic coal 9 after loading is measured as L1-L2.

[0040] In step one, the loading modes include one-time loading, staged equal loading and staged differential loading. The total mass of the tectonic coal 9 in the sample loading container is equal in different loading modes, which is m. Different stress sizes are formed in the coal body under different loading modes of the tectonic coal 9, and the stress is monitored by the solid pressure sensor 18.

[0041] Step two: The tectonic coal in the sample loading container 8 is vacuumized by the vacuum pump 34.

[0042] Step three: After vacuumizing, the water inlet valve 27 is opened, the end valve 25 is kept closed, the water injection pump 4 is started to inject water into the sample loading container 8, the water injection amount is recorded by the inlet liquid flow meter 31, and the first liquid pressure sensor 19, the second liquid pressure sensor 20, the third liquid pressure sensor 21, the fourth liquid pressure sensor 22, the fifth liquid pressure sensor 23 and the sixth liquid pressure sensor 24 are started to monitor the water pressure distribution at each position. The water injection is ended when the water pressure at the corresponding position monitored by each liquid pressure sensor no longer fluctuates.

[0043] By applying target load and water injection in different modes, the heterogeneous tectonic coal reservoirs in different tectonic evolution backgrounds are simulated, which have differences in stress state and water content. The solid pressure sensor arranged therein can monitor the stress state of the heterogeneous tectonic coal reservoir; the liquid pressure sensor can monitor the water content of the heterogeneous tectonic coal reservoir; and then the stress parameters and water content parameters for characterizing the heterogeneous tectonic coal reservoir can be obtained.

[0044] Step four, keep the end valve and the water injection inlet valve closed, open the gas injection inlet valve, and start the gas booster pump to inject gas into the sample container at a gas injection pressure greater than the water injection pressure, carry out the gas drive water simulation, and use the front gas flow meter 6 to record the gas injection amount; at the same time, start the first gas pressure sensor 12, the second gas pressure sensor 13, the third gas pressure sensor 14, the fourth gas pressure sensor 15, the fifth gas pressure sensor 16 and the sixth gas pressure sensor 17 to monitor the gas pressure distribution at each place.

[0045] Step five, when the gas pressure data of each gas pressure sensor no longer fluctuates, continue to inject gas into the sample container 8, open the end valve 25 and start the gas-water separator 28, the water and gas in the tectonic coal 9 flow out from the end valve 25, are separated by the gas-water separator 28, the end gas flow meter 29 can realize the measurement of the outflow gas amount, the outlet liquid flow meter 30 can realize the measurement of the outflow water amount, and the measured data is transmitted to the data integration box.

[0046] Step six, during the gas injection process, if no coal powder appears in the gas-water separator 28, close the rear end valve 25, increase the gas injection pressure, first close the rear end valve when increasing the gas injection pressure, after the gas pressure data displayed by each gas pressure sensor is stable and no longer fluctuates, open the rear end valve 25 again, observe whether there is coal powder in the gas-water separator 28, if not, repeat the gas injection process, and cycle until coal powder appears in the gas-water separator, which indicates that the tectonic coal 9 in the sample container 8 is damaged, the test is ended, and the pressure data of each gas pressure sensor at this time is recorded.

[0047] Step seven, according to the gas pressure data of the tectonic coal at different positions obtained in the above step, combined with the length of the tectonic coal 9 in the sample container 8, the gas pressure gradient when the tectonic coal is damaged to cause coal powder to appear in the gas-water separator 28 is calculated, the gas pressure gradient = the gas pressure difference between the two ends of the tectonic coal at this length ÷ the length of the tectonic coal.

[0048] For example, when the tectonic coal is destructed, the data of the gas pressure sensor is Px, and the gas pressure values measured by the first to sixth gas pressure sensors in the embodiment are P1x, P2x, P3x, P4x, P5x and P6x respectively. For the gas pressure distribution of the tectonic coal at both ends of the first loading, the calculation formula is (P1x-P6x) / (L1-L2 fa ), for the gas pressure distribution of the tectonic coal at both ends of the second loading, the calculation formula is (P1x-P6x) / (L1-L2 fe ), and for the gas pressure distribution of the tectonic coal at both ends of the third loading, the calculation formula is (P1x-P6x) / (L1-L2 fd ). Wherein, L2 fa is the displacement of the pressure disc under the first loading mode, L2 fe is the displacement of the pressure disc under the second loading mode, and L2 fd is the displacement of the pressure disc under the third loading mode.

[0049] The above calculation formula calculates the gas gradient between the front end and the rear end of the tectonic coal 9 during the gas injection process. Similarly, the gas distribution gradient between the front and rear of a certain section of the tectonic coal 9 can also be calculated. For example, the gas distribution gradient of the tectonic coal 9 between the first gas pressure sensor 12 and the third gas pressure sensor 14 can be calculated by using the pressure difference between the two gas pressure sensors and dividing the length of the section of the tectonic coal 9, and the length of the section of the tectonic coal 9 can be approximately equal to the distance between the two gas pressure sensors.

[0050] In addition, the above calculation method can not only calculate the gas pressure distribution when the tectonic coal is destructed, but also calculate the gas pressure distribution of the tectonic coal at any time point during the gas injection. At this time, the gas pressure value used is the reading of the gas pressure sensor corresponding to the time point.

[0051] In the above step process, the gas injection pressure is higher than the water injection pressure, and both the gas injection pressure and the water injection pressure are less than the target load, so that the gas-water two-phase flow can occur in the tectonic coal of the sample loading system.

[0052] In the above method, the number of gas pressure sensors and liquid pressure sensors can be increased or decreased according to the test requirements.

[0053] Through the above method, the critical destruction gas pressure gradient of the heterogeneous tectonic coal reservoir under different target load loading modes, different stress states and different water injection pressure conditions can be determined. According to the laboratory test results, if the actual situation is greater than this value, it is a dangerous area, and if the actual situation is less than this value, it is a safe area, so as to realize the zoning and banding of the gas occurrence of the heterogeneous tectonic coal reservoir, and guide the accurate extraction or treatment of the coal mine gas.

[0054] The three loading modes involved in the above method are operated according to the following method, wherein the solid pressure sensor adopts one or three, and the liquid pressure sensor and the gas pressure sensor are both six.

[0055] (1) One-time loading of target load fa

[0056] First, the construction coal 9 with a total mass of m is loaded into the sample container 8 at one time, and then the solid pressure sensor 18 is buried in the construction coal 9 for monitoring the stress of the construction coal 9, as shown in the figure. Figure 1 According to the simulated stratum burial depth, 100 meters of stratum burial depth is approximately equal to 2.5 MPa, and in this case, 400 meters of stratum burial depth is simulated, i.e. the target load is 10 MPa. Start the hydraulic pump 5 to cooperate with the hydraulic push rod 7 and the pressure plate 11 to apply a load of 10 MPa to the construction coal 9, and make it bear for 2 days under this load to ensure the compaction degree; thus, the one-time loading of the target load fa is completed. Under this loading mode, the displacement of the pressure plate 11 is L2 fa , and the length of the construction coal 9 formed in the sample container 8 is L1-L2 fa .

[0057] (2) Stepwise equal loading of target load fe

[0058] S1, first load 1 / 3 of the construction coal 9 with a total mass of m into the sample container 8, and place the third solid pressure sensor 18-3 in the middle of the construction coal 9 for monitoring the stress at the corresponding position; at the same time, the fifth gas pressure sensor 16 and the sixth gas pressure sensor 17 are used to monitor the gas pressure of the section; start the hydraulic pump 5 to cooperate with the hydraulic push rod 7 and the pressure plate 11 to apply a load of 10 MPa to the construction coal 9, and make it bear for 2 days under this load to complete the first step of loading and loading.

[0059] S2, according to the loading step of the above step S1, load 1 / 3 of the construction coal 9 with a total mass of m into the sample container 8 again, and place the second solid pressure sensor 18-2 in the middle of the construction coal 9 for monitoring the stress at the corresponding position; at the same time, the third gas pressure sensor 14 and the fourth gas pressure sensor 15 are used to monitor the gas pressure of the section; start the hydraulic pump 5 to cooperate with the hydraulic push rod 7 and the pressure plate 11 to apply a load of 10 MPa to the construction coal 9, and make it bear for 2 days under this load to complete the second step of loading and loading.

[0060] S3: according to the sample loading step of the above step S2, the third step of loading and loading the sample is carried out, 1 / 3 of the total mass m of the constructed coal 9 is loaded into the sample container 8 again, and the upper part of the second loading sample container 8 is vertically loaded, and the front end is upward), the first solid pressure sensor 18-1 is centrally placed in the loaded constructed coal 9 for monitoring the stress size at the corresponding position; at the same time, the first gas pressure sensor 12 and the second gas pressure sensor 13 are used to monitor the gas pressure of the segment; the hydraulic pump 5 is started again to cooperate with the hydraulic push rod 7 and the pressure plate 11 to apply a load of 10 MPa to the constructed coal 9, and the load is borne for 2 days under the load, and the third step of loading and loading is completed.

[0061] After the above S1, S2, S3 three steps, the stepwise equal loading fe of the target load is completed, as shown in Figure 2 The displacement L2 generated by the pressure plate 11 is tested by the displacement meter 10 in this loading mode fe , and the length of the constructed coal 9 formed in the sample container 8 is L1-L2 fe .

[0062] The above stepwise equal loading is completed in three times, and in other embodiments, two or more than three times of loading can be used to complete the stepwise equal loading, and the load of each loading is the target load.

[0063] (3) Stepwise difference loading fd of target load

[0064] S1, 1 / 3 of the total mass m of the constructed coal 9 is loaded into the sample container 8, the third solid pressure sensor 18-3 is centrally placed in the constructed coal 9 for monitoring the stress size at the corresponding position; at the same time, the fifth gas pressure sensor 16 and the sixth gas pressure sensor 17 are used to monitor the gas pressure of the segment; the hydraulic pump 5 is started to cooperate with the hydraulic push rod 7 and the pressure plate 11 to apply a load of 6 MPa to the constructed coal 9, and the load is borne for 2 days under the load, and the first step of loading and loading is completed.

[0065] S2, according to the sample loading step of the above step S1, the second step of loading and loading the sample is carried out, 1 / 3 of the total mass m of the constructed coal 9 is loaded into the sample container 8 again, and the upper part of the first loading sample container 8 is vertically loaded, and the front end is upward), the second solid pressure sensor 18-2 is centrally placed in the second loaded constructed coal 9 for monitoring the stress size at the corresponding position; at the same time, the third gas pressure sensor 14 and the fourth gas pressure sensor 15 are used to monitor the gas pressure of the segment; the hydraulic pump 5 is started again to cooperate with the hydraulic push rod 7 and the pressure plate 11 to apply a load of 8 MPa to the constructed coal 9, and the load is borne for 2 days under the load, and the second step of loading and loading is completed.

[0066] S3: according to the sample loading step of step S2, the third step of loading and loading the sample and loading, loading 1 / 3 of the total mass m of the constructed coal 9 into the sample container 8 again, and the second time loading the sample container 8 vertically loaded and the front end upward, the first solid pressure sensor 18-1 is placed in the loaded constructed coal 9 for monitoring the stress size at the corresponding position; At the same time, the first gas pressure sensor 12 and the second gas pressure sensor 13 are used to monitor the gas pressure of the segment; Start the hydraulic pump 5 again to cooperate with the hydraulic push rod 7 and the pressure plate 11 to apply a load of 10 MPa to the constructed coal 9, and load it under this load for 2 days, complete the third step of loading and loading.

[0067] After the above S1, S2, S3 three steps, the target load is completed by the stepwise loading fd. The displacement of the pressure plate 11 is L2 under the loading mode by the displacement meter 10 fd , then the length of the constructed coal 9 formed in the sample container 8 is: L1-L2 fd .

[0068] The above-mentioned three times of loading are completed in the stepwise difference loading, and in other embodiments, two or more than three times of loading can be used to complete the stepwise difference loading, the load of the last loading is greater than the load of the previous loading, and the load of the last loading is the target load.

[0069] The above examples are only used to illustrate the technical scheme of the present application and not to limit it, and those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by the above examples, and any modification or equivalent replacement without departing from the spirit and scope of the present application. The claims within the scope of the application.

Claims

1. A device for testing the distribution of gas pressure gradients in a non-homogeneous tectonic coal reservoir, characterized in that it comprises: The device comprises a sample container for loading the pulverized coal in bulk structure as the structured coal to be tested; the rear end of the sample container is provided with a water vapor discharge pipe, the water vapor discharge pipe is provided with a rear end valve and a gas-water separator, the gas discharge pipe of the gas-water separator is provided with a terminal gas flow meter, and the liquid discharge pipe of the gas-water separator is provided with an outlet liquid flow meter; The loading system comprises a pressure plate arranged in the sample container and a hydraulic push rod connected to the pressure plate, and the hydraulic push rod drives the pressure plate to apply a certain load to the structured coal in the sample container under the drive of a hydraulic pump; The pressure system comprises a gas pressure system and a liquid pressure system, the gas pressure system is used for gas injection operation on the structured coal in the sample container, and the liquid pressure system is used for water injection operation on the structured coal in the sample container; the gas pressure system comprises a gas cylinder, a gas booster pump and a front-end gas flow meter, the gas cylinder is communicated with the sample container through a gas injection pipe, and the gas injection pipe is connected with the gas booster pump and the front-end gas flow meter; the liquid pressure system comprises a water storage tank, a water injection pump and an inlet liquid flow meter, the water storage tank is communicated with the sample container through a water injection pipe, and the water injection pipe is connected with the water injection pump and the inlet liquid flow meter; The gas pressure sensing system comprises a plurality of gas pressure sensors and is arranged on the side of the sample container, and is used for monitoring the gas pressure at different positions of the structured coal in the sample container; The liquid pressure sensing system comprises a plurality of liquid pressure sensors and is arranged on the side of the sample container, and is used for monitoring the liquid pressure at different positions of the structured coal in the sample container; The solid pressure sensing system comprises at least one solid pressure sensor and is embedded in the structured coal, and is used for monitoring the stress value in the structured coal.

2. The apparatus according to claim 1, wherein the apparatus is characterized by: The pressure plate is provided with a gas injection hole and a water injection hole, the gas injection hole is used for connecting with the end of the gas injection pipe, and the water injection hole is used for connecting with the end of the water injection pipe.

3. The apparatus of claim 1, wherein: The data acquisition and storage system comprises a computer and a data integration box, the data monitored and acquired by the gas pressure sensing system, the liquid pressure sensing system, the solid pressure sensing system, the front-end gas flow meter, the terminal gas flow meter, the inlet liquid flow meter and the outlet liquid flow meter are uploaded to the data integration box for storage.

4. The apparatus of claim 1, wherein: The rear end of the sample container is further connected with a vacuum pump, and the sample container is vacuumized by the vacuum pump.

5. The apparatus of claim 1, wherein: The pressure plate is provided with a displacement meter for measuring the displacement of the pressure plate.

6. The apparatus of claim 1, wherein: According to the loading mode of the loading system on the structured coal, the number of the solid pressure sensors is determined, when the one-time loading mode is adopted, one solid pressure sensor is arranged; when the hierarchical loading mode is adopted, the number of the solid pressure sensors is consistent with the number of the structured coal.

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