A multi-channel device and method for measuring the permeability coefficient of pyrolytic oil shale.

Abstract

This invention discloses a multi-channel pyrolytic oil shale permeability measurement device and method, belonging to the field of core permeability measurement technology. The device includes: multiple sets of annular and back pressure control systems, multiple sets of axial pressure control systems, multiple sets of core holder systems, a mass acquisition system, a pressure measurement system, and a computer data acquisition and processing system. The multiple sets of annular and back pressure control systems are controlled by a main pressure source, and each axial pressure control system is controlled by an independent axial pressure pump; the pressure control systems do not interfere with each other. The core holder is used to hold the test sample assembly and connects to the pressure control system and the mass acquisition system. This invention also discloses a multi-channel pyrolytic oil shale permeability measurement method. The technical solution of this invention can simultaneously test the permeability of multiple sets of oil shale specimens with different pressure levels and flow requirements, and has the characteristics of simple operation, high efficiency, and good testing results, making it suitable for widespread application.

Description

Technical Field

[0001] This invention relates to the field of core permeability measurement technology, and in particular to a device and method for measuring the permeability of multi-channel pyrolytic oil shale. Background Technology

[0002] The permeability coefficient refers to the ability of rock to allow fluid to pass through under a certain pressure difference; it is a parameter characterizing the rock's ability to conduct liquids. The magnitude of the permeability coefficient plays a crucial role in the migration pathways, forward migration rates, and degree of pollution impact of pollutants in groundwater. In the groundwater environmental impact assessment of in-situ oil shale mining projects, the permeability coefficient is essential for determining the initial assessment level, understanding the regional and project site's environmental hydrogeological conditions, comprehending the hydraulic connections between aquifers, predicting groundwater pollution impacts, and proposing practical environmental protection measures to address the project's potential pollution impacts on groundwater.

[0003] In the field of geology and ecology, permeability measuring devices are frequently used to determine the permeability of rocks to understand their permeability. However, existing permeability measuring devices have certain drawbacks. Traditional devices are complex in structure, difficult to operate, and challenging to measure, and are generally single-channel, resulting in low testing efficiency and high time and labor costs. Furthermore, existing methods for measuring rock permeability mostly use gas as a medium, which cannot accurately simulate the permeation of groundwater in rocks for the geology and ecology field. There is a technological gap in domestic and international patent literature regarding multi-channel, high-efficiency permeability measuring devices for pyrolysis oil shale using water as a medium.

[0004] There is an urgent need in the existing technology for a multi-channel pyrolysis oil shale permeability measurement device and method. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects in the prior art. This invention provides a multi-channel pyrolysis oil shale permeability coefficient measuring device and method. This technical solution can improve testing efficiency, is easy to operate, and can realistically simulate the seepage of groundwater in rocks.

[0006] The embodiments of the present invention are implemented as follows:

[0007] On one hand, embodiments of the present invention provide a multi-channel pyrolytic oil shale permeability measurement device, including a pressure control system, a core holder system, a high-precision mass acquisition system, a pressure measurement system, and a computer data acquisition and processing system. The pressure control system includes annular pressure, back pressure control systems, and axial pressure control systems.

[0008] The annular pressure and back pressure control system includes a main pressure source, and a safety valve, a main pressure sensor, a main accumulator, and an adjusting valve are sequentially connected to the main pressure source pipeline. The main pressure source provides annular pressure and back pressure to multiple sets of core holders, and a sub-accumulator, a solenoid valve, a pressure sensor, and a flow regulating valve are sequentially connected to the annular pressure and back pressure pressure pipelines.

[0009] The axial pressure control system includes an axial pressure control pump, and an inlet flow acquisition device, a solenoid valve, and a pressure sensor are connected in sequence on the axial pressure control pipeline.

[0010] The axial pressure control system is controlled by a separate pressure source axial pressure control pump, which is an air-driven booster pump to ensure the purity of the medium water entering the core specimen; the axial pressure control system monitors the pressure in real time through a pressure sensor; and the axial pressure control system controls the flow rate of the medium water entering the core specimen through an inlet flow acquisition device.

[0011] The multi-channel core holder system comprises multiple independent core holders and a constant temperature chamber shell. The front and rear surfaces of the constant temperature chamber shell are fitted with high-temperature resistant, heat-insulating glass, and the lower part of the shell includes a temperature controller and a temperature sensor. The core holder system is connected to the pressure control system via a high-pressure hose.

[0012] The high-precision quality acquisition system includes a high-precision electronic balance, which can automatically measure the outlet flow rate, achieving automation, and is connected to the computer data acquisition system.

[0013] The pressure measurement system includes a pressure sensor and a pressure and secondary instrument. Pressure data is displayed on the control panel via the instrument, and the pressure sensor data is automatically collected by the computer software system.

[0014] The computer data acquisition and processing system runs in a Windows environment. The instrument's workflow is displayed on the interface, enabling human-computer interaction. After the operator sets the parameters, unattended operation is possible, and the computer can automatically collect all pressure, temperature, and flow data. Preferably, the core holder includes annular pressure port, vent port, and exhaust port, arranged at 90 degrees. This allows for the venting, emptying, and pressurization of the annular pressure chamber without rotating the holder. The core holder employs a novel structure; removing the small pressure cap on the right side and the core chamber allows for quick installation and removal of the core with a slight tilt, avoiding the need to remove the piston and rubber sleeve. A tapered sleeve structure is also used to prevent leakage of the annular pressure fluid during core installation and removal.

[0015] Preferably, the core holder outlet is connected to a high-precision electronic balance, which has software communication functionality.

[0016] Preferably, in the ring pressure and back pressure control system, the main pressure source uses a plunger pump to provide water to the main accumulator for pressure output, and the pressure source provided by the sub-accumulator provides precise pressure control to multiple ring pressure branches and back pressure branches through solenoid valves and flow regulating valves. Each ring pressure and back pressure branch can be pressure controlled independently, and a failure in any one branch will not affect the normal operation of other branches.

[0017] Preferably, the axial pressure control system is controlled by a separate pressure source axial pressure control pump, which is an air-driven booster pump to ensure the purity of the medium water entering the core specimen; the axial pressure control system monitors the pressure in real time through a pressure sensor; and the axial pressure control system controls the flow rate of the medium water entering the core specimen through an inlet flow acquisition device.

[0018] Preferably, the pressure control system is connected to a computer via a communication interface, and the computer can control the flow rate and pressure of the injected seepage medium.

[0019] Preferably, the outer shell of the constant temperature chamber is connected to a computer, and the computer controls the constant temperature heating temperature.

[0020] Preferably, the computer data acquisition system can acquire values ​​from various pressure measuring points, temperature sensors, electronic balances, and gas flow meters in real time;

[0021] Preferably, the computer data acquisition system can acquire the injection rate, cumulative injection volume, and injection pressure of the liquid mass flow controller in real time;

[0022] Preferably, the computer data acquisition system can acquire the pressure difference between the injection pressure of the ring pressure pump and the axial pressure pump and the pore pressure in real time.

[0023] On the other hand, embodiments of the present invention provide an operating method for a multi-channel pyrolysis oil shale permeability coefficient measuring device, comprising the following steps:

[0024] Step 1: Prepare cylindrical specimens of oil shale with a diameter of 50 mm and a height of 100 mm (the maximum diameter can reach 300 mm and the maximum length can reach 1000 mm). After pyrolysis, cool the specimens to room temperature and then place them in a core holder. Seal the experimental device and maintain a certain temperature in the experimental chamber by controlling the heating power of the heating element.

[0025] Step 2: Using a computer data acquisition system, a constant annular pressure and inlet axial pressure are provided by the medium water. The computer also controls a separate channel to provide axial back pressure at the outlet, so as to set the inlet and outlet pore pressure difference.

[0026] Step 3: Using a high-precision mass acquisition system, the flow rate of water seeping into the specimen is measured in real time. The permeability coefficient K of the oil shale specimen is calculated using the following formula:

[0027]

[0028] K: Permeability coefficient

[0029] Q: The volume of water passing through the rock mass per unit time, in meters (m) 3 / s

[0030] L: Length of the rock mass, in meters

[0031] γ w : Specific weight of water, kN / m 3

[0032] P: Pressure difference between the two ends of the rock mass, kPa

[0033] A: Cross-sectional area of ​​the rock mass, m 2

[0034] Step 4: Observe the trend of the permeability coefficient in the computer window over time. The reading shown after it stabilizes is the permeability coefficient of the oil shale specimen under the set pressure conditions.

[0035] Step 5: After the test, shut down the pressure control system in a stepped manner, turn off the heating element, and remove the oil shale specimen.

[0036] Compared with the prior art, the beneficial effects of the embodiments of the present invention are:

[0037] This invention provides a multi-channel device and method for measuring the permeability coefficient of pyrolytic oil shale. It features simple operation, flexibility, and high efficiency. The device and method use water as the medium to measure the permeability coefficient of pyrolytic oil shale. By controlling multiple sets of annular pressure, back pressure, and multiple sets of independently controlled axial pressure through a main pressure source, the device can simultaneously test the permeability coefficient of multiple oil shale specimens with different pressure levels and flow requirements. Furthermore, it uses water as the medium to realistically simulate the seepage behavior of groundwater in pyrolytic oil shale.

[0038] This invention provides a novel approach to determining the permeability coefficient of oil shale. Each core holder system and pressure control system are independent of each other. By adjusting the size of the core holder, the permeability coefficient of oil shale specimens of different sizes can be measured simultaneously.

[0039] This device can measure the permeability coefficient of a single oil shale specimen individually, or simultaneously measure the permeability coefficient of multiple oil shale specimens of different sizes. The measurement channels for multiple oil shale specimens can be independently controlled without time constraints. It is simple to operate, highly efficient, and produces good test results, filling a technological gap in domestic patent literature regarding multi-channel, high-efficiency pyrolysis oil shale permeability coefficient measuring devices. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the multi-channel pyrolysis oil shale permeability measurement device of the present invention;

[0042] Figure 2 This is a schematic diagram of the multi-channel pyrolysis oil shale permeability measuring device in Embodiment 1 of the present invention;

[0043] Figure 3 This is a schematic diagram illustrating the variation of the groundwater permeability coefficient of pyrolytic oil shale with temperature under different annular pressures in an embodiment of the present invention.

[0044] In the diagram, 1-Main pressure source, 2-Safety valve, 3-Main accumulator, 4-Adjusting valve, 5-Main pressure sensor, 6-Sub-accumulator, 7-Flow regulating valve, 8-Pressure sensor, 9-Inlet flow acquisition device, 10-Axial pressure control pump, 11-Solenoid valve, 12-Axial pressure inlet, 13-Annular pressure inlet, 14-Constant temperature chamber, 15-Outlet pressure controller, 16-High-precision quality acquisition, 17-Core holder, 18-Computer data acquisition terminal, 19-Constant temperature chamber insulation layer, 20-Heating element, 21-Infrared temperature sensor. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0046] Please refer to Figures 1 to 2This invention provides a multi-channel pyrolysis oil shale permeability measurement device. The device includes a pressure control system, a core holder system, a high-precision mass acquisition system, a pressure measurement system, and a computer data acquisition and processing system. The pressure control system includes annular pressure, back pressure control, and axial pressure control systems. It comprises: a main pressure source 1, a safety valve 2, a main accumulator 3, an adjusting valve 4, a main pressure sensor 5, a branch accumulator 6, a flow regulating valve 7, a pressure sensor 8, an inlet flow acquisition device 9, an axial pressure control pump 10, a solenoid valve 11, an axial pressure inlet 12, an annular pressure inlet 13, a constant temperature chamber 14, an outlet pressure controller 15, a high-precision mass acquisition device 16, a core holder 17, and a computer data acquisition terminal 18.

[0047] The annular pressure and back pressure control system includes a main pressure source 1, with a safety valve 2, a main pressure sensor 5, a main accumulator 3, and an adjusting valve 4 connected sequentially on the main pressure source pipeline. The main pressure source provides annular pressure and back pressure to multiple sets of core holders. A secondary accumulator 6, a solenoid valve 11, a pressure sensor 8, and a flow regulating valve 11 are connected sequentially on the annular pressure and back pressure pressure pipelines. The axial pressure control system includes an axial pressure control pump 10, with an inlet flow acquisition device 9, a solenoid valve 11, and a pressure sensor 8 connected sequentially on the axial pressure control pipeline.

[0048] The annular pressure, back pressure control system, and axial pressure control system are connected to the core holder system via the annular pressure inlet 13, the outlet pressure controller 15, and the axial pressure inlet 12, respectively. They are connected to the computer data acquisition terminal 18 via the main pressure sensor 5 and the pressure sensor 8, and the inlet axial pressure, annular pressure, and back pressure can be adjusted by the computer. The inlet flow acquisition device 9 is connected to the computer data acquisition terminal 18 to control the flow rate of the medium water entering the core specimen.

[0049] The core holder system includes a core holder 17 and a constant temperature chamber 14. The constant temperature chamber has a refractory fiber insulation layer, which is arranged within the metal frame of the chamber. The heating element is an electric heating element, fixed to the inner side of the insulation layer 4. An infrared temperature sensor 21 is arranged inside the constant temperature chamber and connected to a computer data acquisition terminal.

[0050] The high-precision quality acquisition system 16 includes a high-precision electronic balance, which can automatically measure the outlet flow rate, achieve automation, and connect to a computer data acquisition system.

[0051] The pressure measurement system includes a main pressure sensor 5, a pressure sensor 8, an inlet flow acquisition device 9, an outlet pressure controller 15, and secondary instruments. Pressure data is displayed on the computer control panel via the instruments, and the computer software system automatically acquires pressure sensor data.

[0052] The computer data acquisition and processing system 18 runs in a Windows environment. The instrument's workflow is displayed on the interface, enabling human-machine interaction. After the operator sets the parameters, unattended operation is possible, and the computer can automatically acquire all pressure, temperature, and flow data. The measurement method of this device includes the following specific implementation process:

[0053] Step 1: Prepare the oil shale into cylindrical specimens with a diameter of 50 mm and a height of 100 mm (the maximum diameter can reach 300 mm and the maximum length can reach 1000 mm). After pyrolysis, cool the specimens to room temperature and then place them in the core holder 14. Seal the experimental device and maintain a certain temperature in the experimental chamber by controlling the heating power of the heating element 20.

[0054] Step 2: Using the computer data acquisition system 18, a constant annular pressure and inlet axial pressure are provided by the medium water. At the same time, the computer controls a separate channel to provide axial back pressure at the outlet, so as to achieve the setting of the inlet and outlet pore pressure difference.

[0055] Step 3: Using a high-precision mass acquisition system 16, the flow rate of water seeping into the specimen is measured in real time. The permeability coefficient K of the oil shale specimen is calculated using the following formula:

[0056]

[0057] K: Permeability coefficient

[0058] Q: The volume of water passing through the rock mass per unit time, in meters (m) 3 / s

[0059] L: Length of the rock mass, in meters

[0060] γ w : Specific weight of water, kN / m 3

[0061] P: Pressure difference between the two ends of the rock mass, kPa

[0062] A: Cross-sectional area of ​​the rock mass, m 2

[0063] Step 4: Observe the trend of the permeability coefficient in the computer window over time. The reading shown after it stabilizes is the permeability coefficient of the oil shale specimen under the set pressure conditions.

[0064] Step 5: After the test, shut down the pressure control system in a stepwise manner, turn off the heating element 20, and remove the oil shale specimen.

[0065] Example

[0066] The variation of groundwater permeability coefficient with temperature in pyrolytic oil shale under different annular pressures is as follows: Figure 3As shown: On the one hand, in the pyrolysis temperature range of 100℃ to 300℃, the groundwater permeability coefficient gradually decreases to a minimum; in the range of 300℃ to 500℃, the change in groundwater permeability coefficient is more complex, influenced by temperature, pressure, and the hydrophysical properties of the rock. On the other hand, under low annular pressure, the groundwater permeability coefficient first increases and then decreases; under high annular pressure, the water absorption capacity of oil shale is limited, and the groundwater permeability coefficient at this point is mainly affected by temperature.

[0067] Coal ore with a diameter of 50 mm and a height of 100 mm was pyrolyzed at 500℃. After cooling to room temperature, it was placed in a device for seepage experiments. The ring pressure, inlet water pressure, and outlet water pressure were set to 3 MPa, 1.5 MPa, and 0.5 MPa, respectively. Distilled water was used as the liquid seepage medium. The mass and volume of the seepage liquid were measured daily using an electronic balance and a graduated cylinder. The average permeability coefficient change was calculated according to the formula.

[0068]

[0069] K: Permeability coefficient

[0070] Q: The volume of water passing through the rock mass per unit time, in meters (m) 3 / s

[0071] L: Length of the rock mass, in meters

[0072] γ w : Specific weight of water, kN / m 3

[0073] P: Pressure difference between the two ends of the rock mass, kPa

[0074] A: Cross-sectional area of ​​the rock mass, m 2

[0075] The specific experimental data are shown in Table 1. Solenoid valves were used to precisely control the pressure throughout the experiment, and data recording began once the pressure reached the set target value.

[0076] Table 1

[0077]

[0078] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A device for measuring the permeability coefficient of multi-channel pyrolytic oil shale, characterized in that, It includes a pressure control system, a core holder system, a pressure measurement system, a mass acquisition system, and a computer data acquisition and processing system. The pressure control system, the core holder system, and the pressure measurement system are connected in sequence. The mass acquisition system is connected to the core holder system. The pressure measurement system and the mass acquisition system are respectively connected to the computer data acquisition and processing system. The pressure control system includes a ring pressure control system, a back pressure control system, and an axial pressure control system. The annular pressure and back pressure control system includes a main pressure source (1), and a safety valve (2), a main pressure sensor (5), a main accumulator (3), and an adjusting valve (4) are connected in sequence on the main pressure source (1) pipeline; the main pressure source (1) provides annular pressure and back pressure to multiple sets of core holders (17), and a solenoid valve (11), a pressure sensor (8), a flow regulating valve (7), a branch accumulator (6), and a back pressure controller (15) are connected in sequence on the annular pressure and back pressure pressure pipeline; The axial pressure control system includes an axial pressure control pump (10), which mainly provides axial pressure for the core holder. The axial pressure control pipeline is connected in sequence to an inlet flow acquisition device (9), a solenoid valve (11), and a pressure sensor (8). The core holder system includes a core holder (17) and a constant temperature chamber (14). The core holder (17) is fixed inside the constant temperature chamber (14). The core holder (17) is sealed to the axial pressure inlet (12), the annular pressure inlet (13), the back pressure controller (15), and the mass acquisition system (16). The constant temperature chamber (14) includes an insulation layer (19) made of refractory fiber and arranged inside the metal frame of the constant temperature chamber. The heating element is an electric heating plate fixed on the inner side of the insulation layer (19). An infrared temperature sensor (21) is arranged inside the constant temperature chamber (14) and connected to the computer data acquisition and processing system (18). The quality acquisition system (16) includes a high-precision electronic balance for automatic measurement of outlet flow, achieving automation, and is connected to a computer data acquisition and processing system (18). The pressure measurement system includes a main pressure sensor (5), a pressure sensor (8), an inlet flow acquisition device (9), a back pressure controller (15), and secondary instruments. Pressure data is displayed on the computer control panel through the instruments, and pressure sensor data is automatically acquired by the computer data acquisition system. The computer data acquisition and processing system (18) runs in the Windows environment. The instrument workflow is displayed on the interface, enabling human-computer interaction. After the operator sets the parameters, the system can be unattended, and the computer automatically collects all pressure, temperature and flow data.

2. The measuring device for the permeability coefficient of multi-channel pyrolytic oil shale according to claim 1, characterized in that: The main pressure source (1) pressurization medium is water and N2 gas.

3. The measuring device for the permeability coefficient of multi-channel pyrolytic oil shale according to claim 1, characterized in that: The main pressure source (1) uses a plunger pump to supply water to the main accumulator (3) for pressure output. Through the solenoid valve (11) and the flow regulating valve (7), it provides precise pressure control to the ring pressure branch and the back pressure branch.

4. The measuring device for the permeability coefficient of multi-channel pyrolysis oil shale according to claim 1, characterized in that: The ring pressure and back pressure control system monitors the pressure in real time through the accumulator (6), pressure sensor (8), solenoid valve (11) and flow regulating valve (7), and replenishes or releases pressure according to the pressure change.

5. The measuring device for the permeability coefficient of multi-channel pyrolysis oil shale according to claim 1, characterized in that: The axial pressure control system is controlled by a separate pressure source axial pressure control pump (10), which is an air-driven booster pump to ensure the purity of the medium water entering the core specimen; the axial pressure control system monitors the pressure in real time through a pressure sensor (8) and a solenoid valve (11); the axial pressure control system controls the flow rate of the medium water entering the core specimen through an inlet flow acquisition device (9).

6. A method for operating the multi-channel pyrolysis oil shale permeability measuring device according to any one of claims 1-5, characterized in that: Includes the following steps: Step 1: Prepare oil shale into cylindrical specimens with a diameter of 50 mm and a height of 100 mm. After pyrolysis, cool the specimens to room temperature and then place them in a core holder (14). Seal the experimental device and maintain a certain temperature in the experimental chamber by controlling the heating power of the heating element (20). Step 2: Using the computer data acquisition and processing system (18), the medium water is used to provide constant ring pressure and inlet axial pressure. The computer also controls a separate channel to provide outlet axial back pressure, so as to set the inlet and outlet pore pressure difference. Step 3: Using a mass acquisition system (16), the flow rate of water seeping into the specimen is measured in real time. The permeability coefficient K of the oil shale specimen is calculated using the following formula: K: Permeability coefficient Q: The volume of water passing through the rock mass per unit time, in meters (m) 3 / s L: Length of the rock mass, in meters γ w : Specific weight of water, kN / m 3 P: Pressure difference between the two ends of the rock mass, kPa A: Cross-sectional area of ​​the rock mass, m 2 Step 4: Observe the trend of the permeability coefficient in the computer window over time. The reading shown after it stabilizes is the permeability coefficient of the oil shale specimen under the set pressure conditions. Step 5: After the test, shut down the pressure control system in a stepwise manner, turn off the heating element (20), and take out the oil shale specimen.

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