Platform and method for testing multi-angle wettability of coal rock in high-temperature pressure environment

Abstract

The invention discloses a coal rock multi-angle wettability test platform in a high-temperature pressure environment, which comprises a visual detection cabin, a cubic sample placing table is arranged on the inner side of the visual detection cabin, the cubic sample placing table is connected with the visual detection cabin through an angle adjusting system, a heating pipe is arranged at the bottom of the inner side of the visual detection cabin, and the heating pipe is connected with the visual detection cabin through an angle adjusting system. The heating pipe is a part of the temperature control system, a liquid injection system, a gas pressurization system and an optical imaging system are further arranged on the side edge of the visual detection cabin, the liquid injection system can add liquid to a test substance on the cubic sample placing table, and the optical imaging system can shoot test steps in real time. The gas pressurization system can adjust the pressure in the visual detection cabin; the coal rock wettability testing device can meet the requirement for testing the coal rock wettability under the indoor simulation deep in-situ condition, multiple samples of coal rock at different angles can be tested in a single experiment, and the scientific research requirements of multiple wettability tests can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reservoir hydraulic fracturing coal rock wettability, in particular to a coal rock multi-angle wettability test platform and method under high temperature and pressure environment. BACKGROUND

[0002] With the gradual shift of oil and gas development to deep, its temperature, reservoir pressure and gas pressure are rising, and the surface properties of rock minerals change under high pressure, which in turn has a certain impact on oil and gas exploitation. The surface properties of rock minerals are the main factors affecting the solid-liquid wettability, and the wettability determines the migration of gas and water in the reservoir.

[0003] For example, in a method for determining coal rock wettability disclosed in a Chinese patent with publication number CN201410841172.1, the pore water absorption simulation test method cannot show the dynamic evolution process of solid water contact, a basin deep reservoir rock and fluid interaction simulation device and use method disclosed in a Chinese patent with publication number CN201711347121.3 does not design high temperature and high pressure experimental conditions, a CO2-water-coal system coal rock component contact angle test device and method disclosed in a Chinese patent with publication number CN202111650671.9 does not design temperature control, and the test pressure is small, so it is not suitable for real deep oil and gas development conditions. From the above, high temperature and pressure wettability test is an important means to simulate the wettability of reservoir in-situ conditions.

[0004] Because in deep coal rock reservoir hydraulic fracturing, the orientation and angle of contact between fracturing fluid and coal rock body are not the same, which also leads to different wettability and different wettability of fracturing fluid when flowing with coal rock body, ultimately affecting the water lock effect of fracturing fluid in coal rock reservoir, affecting the gas production effect of natural gas. For example, an experimental system for measuring dynamic contact angle under high temperature and high pressure environment and its method disclosed in a Chinese patent with publication number CN201910053526.9, which can only test the dynamic advancing and receding contact angle of coal rock contact angle, and cannot simulate different test orientations by presetting angles. From the above, designing coal rock multi-angle high temperature and pressure wettability test is helpful for deep reservoir scientific research and engineering practice.

[0005] When the high-temperature pressure wetting test is performed, due to the high-pressure gas filled in the closed cabin, in order to ensure the sealing of the cabin and the image recognition outside, the wall of the closed cabin is usually thick and the sealing arrangement is complicated. For example, when the sample test is performed, a multi-point contact angle measuring device disclosed in a Chinese patent with publication number 202320063160.5 has fewer single sample measuring points and is accidental, and when multiple samples are tested, the steps are complicated, the test period is long, and gas pollution and waste are caused. Therefore, designing a coal rock multi-angle wettability test platform under high-temperature pressure environment is an important method to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide a coal rock multi-angle wettability test platform and method under high-temperature pressure environment, aiming to simulate the influence factors of coal rock multi-angle wettability under high-temperature high-pressure in-situ environment of deep oil and gas exploitation.

[0007] The present application is implemented as follows: a coal rock multi-angle wettability test platform under high-temperature pressure environment, comprising a visual detection cabin, a cubic sample placing table is arranged on the inner side of the visual detection cabin, the cubic sample placing table is connected with the visual detection cabin through an angle adjusting system, a heating pipe is arranged at the bottom of the inner side of the visual detection cabin, the heating pipe is part of a temperature control system, a liquid injection system, a gas pressurizing system and an optical imaging system are further arranged on the side of the visual detection cabin, the liquid injection system can add liquid to the test substance on the cubic sample placing table, the optical imaging system can shoot the test steps in real time, and the gas pressurizing system can adjust the pressure in the visual detection cabin.

[0008] Preferably, a visual window is arranged on the side wall of the visual detection cabin, a sapphire glass is arranged at the visual window, and a high-pressure rubber sealing ring is arranged at the contact position of the sapphire glass and the visual window.

[0009] Preferably, two symmetrical sample clamps are arranged on the upper, lower, front and rear sides of the cubic sample placing table, the sample clamps are arranged in an L-shaped structure, and the position of the test substance can be limited.

[0010] Preferably, the angle adjusting system comprises a rotating fixing mechanism, a bearing, a rotating shaft and a rotating rod, the bearing is arranged on the side wall of the visual detection cabin, the rotating shaft penetrates through the bearing and the cubic sample placing table, the rotating fixing mechanism is arranged on the outside of the visual detection cabin and connected with the rotating shaft, and the rotating rod is arranged on the side of the rotating fixing mechanism.

[0011] Preferably, the rotating fixing mechanism comprises a steel chain and two gears of different sizes, a large gear is sleeved on the rotating shaft, a small gear is arranged below the large gear, the large gear and the small gear are connected with the steel chain, and the rotating rod is connected with the small gear.

[0012] Preferably, the liquid injection system comprises a liquid storage bottle, a liquid micro-injection pump and a capillary burette, which are connected in series, and the top of the capillary burette is connected with the top of the visual detection cabin through a high-pressure sealing cover; the inner diameter of the nozzle of the capillary burette is 0.5 mm, and the bottom of the capillary burette is located above the cubic sample table.

[0013] Preferably, the optical imaging system comprises a cold light source and a high-speed camera, which are arranged on the two sides of the visual detection cabin and face the visual window, and the high-speed camera is electrically connected with a computer.

[0014] Preferably, the gas pressurization system comprises a gas storage bottle, a vacuum pump, a booster pump, a gas buffer cylinder, a pressure reducing valve and a four-way valve, the gas storage bottle is connected with the vacuum pump in parallel, the booster pump, the gas buffer cylinder and the pressure reducing valve are connected in series, the outlet of the pressure reducing valve is connected with the four-way valve, and the four-way valve is connected with the gas injection pipe of the visual detection cabin, a pressure sensor and a gas recovery bottle.

[0015] Preferably, the temperature control system further comprises a silica gel heat conduction plate and a temperature sensor, the silica gel heat conduction plate is arranged above the heating pipe, and the temperature sensor is arranged above the silica gel heat conduction plate; the pressure sensor and the temperature sensor are connected with the computer through a data acquisition controller.

[0016] A method for testing multi-angle wettability of coal rock under high-temperature and high-pressure environment, comprising the following steps

[0017] Step one: first polish the top and bottom ends of a standard coal rock sample with a diameter of 38 mm and a thickness of 10 mm to be smooth by using 300-mesh, 600-mesh, 800-mesh and 1200-mesh sandpaper;

[0018] Step two: open the high-pressure sealing cover at the top of the visual detection cabin, fix the four coal rock samples on the sample holder, fill the visual detection cabin with methane gas with the highest pressure required by the experiment, close all valves of the device, and check the sealing property of the device;

[0019] Step three: close all outlet valves, open all communication valves in the experimental device, start the vacuum pump for degassing, and continue to vacuum for 40 min after the pressure sensor is reduced to-0.10 MPa;

[0020] Step four: open the temperature control system and set the temperature to reach the required experimental conditions;

[0021] Step five: open the gas inlet valve, start the booster pump, and increase the pressure in the visual detection cabin to the required experimental pressure;

[0022] Step six: after all conditions are set, the temperature and pressure values are maintained for 6 h;

[0023] Step seven: turn on the cold light source, high-speed camera, computer image recognition processing software;

[0024] Step eight: rotate the rotating fixed mechanism rotating rod, and observe the coal rock sample identification image to reach the preset angle;

[0025] Step nine: turn on the high-speed camera camera function, rotate the liquid micro-injection pump, and drop a drop of test liquid on the surface of the coal rock solid through the capillary titration needle;

[0026] Step ten: after completion, repeat steps eight and nine, and the sample can be replaced or other coal rock samples can be tested at a pre-prepared angle;

[0027] Step eleven: after all the tests are completed, turn off the heating pipe, and open the gas recovery bottle valve 24 to collect the test gas.

[0028] Compared with the prior art, the beneficial effects of the present application are:

[0029] (1) The present application can simulate the change characteristics of coal rock wettability in the fracturing flow process under the deep high temperature and high pressure in-situ environment.

[0030] (2) The present application can adjust the angle of the liquid to be tested in contact with the coal rock during the test, and simulate the wettability effect of the coal rock body under different states of contact with the fracturing fluid.

[0031] (3) The present application can test multiple samples of coal rock in a single experiment, avoiding the randomness caused by single results, and the structure is simple to operate, accurate and safe. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a schematic diagram of a coal rock multi-angle wettability test platform simulating deep high temperature and pressure environment;

[0033] Figure 2 It is a side view of the visual detection cabin;

[0034] Figure 3 It is a plan view of the angle adjusting device.

[0035] In the figure: 1, visual detection cabin; 2, methane storage cylinder; 3, mechanical pressure gauge; 4, needle valve; 5, booster pump; 6, vacuum pump; 7, liquid storage bottle; 8, cold light source; 9, liquid micro-injection pump; 10, bolt; 11, sapphire glass; 12, high-pressure sealing cover; 13, capillary titration needle; 14, computer; 15, high-speed camera; 16, angle adjusting device; 17, rotating rod; 18, data acquisition controller; 19, cubic sample placement table; 20, sample holder; 21, gas recovery bottle; 22, heating tube; 23, silica gel heat-conducting plate; 24, recovery bottle valve; 25, pressure sensor; 26, four-way valve; 27, sealing screw; 28, rotating shaft; 29, bearing; 30, pressure reducing valve; 31, gas buffer cylinder; 32, large gear; 33, steel chain; 34, small gear. DETAILED DESCRIPTION

[0036] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] Further description will be made below in combination with the drawings and specific embodiments:

[0038] The methane storage cylinder 2 and the vacuum pump 6 are connected in parallel, and the booster pump 5, the gas buffer cylinder 31 and the pressure reducing valve 30 are connected in series to form a gas pressurization system. The outlet of the pressure reducing valve 30 is connected to the four-way valve 26, and the four-way valve 26 is connected to the gas injection pipe of the visual detection cabin 1, the pressure sensor 25 and the gas recovery bottle 21 respectively. The mechanical pressure gauge 3 and the needle valve 4 are arranged on the top of the methane storage cylinder 2. Through the working of the gas pressurization system, the pressure in the visual detection cabin 1 can be adjusted, providing support for testing under different pressure environments. The pressure in the visual detection cabin 1 can be transmitted in real time to the computer 14 through the pressure sensor 25, providing a reference for the staff to adjust the visual detection cabin 1.

[0039] The liquid storage bottle 7, the liquid micro-injection pump 9 and the capillary titration needle 13 are connected in series through the connecting pipeline to form a liquid injection system, and the capillary titration needle 13 with an inner diameter of 0.5 mm is located at the top center of the visual detection cabin 1. Through the working of the liquid micro-injection pump 9, the liquid can be moved from the liquid storage bottle 7 to the capillary titration needle 13, and then dropped on the test piece through the capillary titration needle 13, and quantitative micro-addition can be realized.

[0040] The top of the capillary titration needle 13 is connected to the top of the visual detection cabin 1 through the high-pressure sealing cover 12, and the bottom of the capillary titration needle 13 is located at the upper part of 1.5 cm in the horizontal state of the cubic sample placing table 19.

[0041] The heating pipe 22, the silica gel heat-conducting plate 23, the temperature sensor, the data acquisition controller 18 and other components form a temperature and pressure control system; the heating pipe 22 is arranged at the bottom of the visual detection cabin 1, the silica gel heat-conducting plate 23 covers the upper part of the heating pipe 22, the temperature sensor is arranged at the top of the silica gel heat-conducting plate 23, and the pressure sensor 25 is installed at one end of the four-way valve at the bottom of the visual detection cabin, which are all transmitted to the computer through the data acquisition controller 18. Under the action of the temperature control system, the temperature in the visual detection cabin 1 can be adjusted to provide support for testing at different temperature environments. Through the work of the temperature sensor, the temperature in the visual detection cabin 1 can be detected in real time to provide a reference for the staff to adjust the temperature in the visual detection cabin 1.

[0042] The cold light source 8, the high-speed camera 15, the computer 14 and other components form an optical imaging system, the cold light source 8 and the high-speed camera 15 are arranged at opposite positions outside the visual window of the visual detection cabin 1 respectively, and the resolution of the high-speed camera 15 is not less than 120 Hz. Under the work of the high-speed camera 15, the situation in the visual detection cabin 1 can be photographed in real time, and the photographed information can be transmitted to the computer 14 for analysis and judgment to provide support for testing.

[0043] The cubic sample placing table 19, the rotating fixing mechanism 16, the sample holder 20, the bearing 29, the rotating shaft 28, the rotating rod 17 and other components form an angle adjusting system, the bearing 29 is arranged inside the light source side box, the bearing 29 is fixed with the rotating rod 28, the rotating rod 28 supports the cubic sample placing table 19 and penetrates through the other side rotating fixing mechanism 16 outside the box. Under the action of the sample holder 20, the test sample can be stably attached to the cubic sample placing table 19, and the test sample can be conveniently replaced according to the requirements.

[0044] In addition to the rotating rod 28 connecting two sides of the cubic sample placing table 19, the remaining four sides are all installed with the coal rock sample holder 20, and the test sample is a pie-shaped sample with a thickness of 1 cm.

[0045] The sample holder 20 is arranged at the front and rear ends of the cubic sample placing table 19, the compression spring is arranged inside the cubic sample placing table 19, and the bottom of the compression spring is connected with the L-shaped long strip-shaped contraction rod. A magnet that can attract each other can also be arranged on the sample holder 20 and the cubic sample placing table 19, and under the action of the magnet, the sample holder 20 can stably limit the test sample.

[0046] The rotating fixing mechanism 16 is arranged outside the visual detection cabin 1 on the side of the high-speed camera 15, and is composed of two gears and a steel chain 33. One large gear 32 has a diameter of 5 cm and is fixed at the center of the rotating shaft 28. The other small gear 34 has a diameter of 1 cm and is arranged at the lower part of the rotating shaft 28 and connected with the rotating rod 17 at the outside. The two gears are connected through the steel chain 33. By rotating the rotating rod 17, the small gear 34 can be controlled to rotate, thereby driving the large gear 32 to rotate, and at the same time, the rotating shaft 28 is controlled to rotate, so as to realize the rotation of the cubic sample placing table 19.

[0047] The visual detection cabin 1 is provided with a visual window of 100 cm2, and a 3 cm thick sapphire glass 11 is arranged outside the visual window. The sapphire glass 11 is fixed outside the visual detection cabin 1 through the bolt 10, and the sapphire glass 11 and the edge of the stainless steel visual window are clamped with a high-pressure rubber sealing ring.

[0048] By using the above technical method, a test method for simulating the multi-angle wettability of coal rock under high temperature and pressure environment is provided, and the specific test operation steps are as follows:

[0049] 1) First, the standard coal rock sample with a diameter of 38 mm and a thickness of 10 mm is polished smooth at both ends by using 300 mesh, 600 mesh, 800 mesh and 1200 mesh sandpaper;

[0050] 2) Open the high-pressure sealing cover plate 12 at the top of the visual detection cabin 1, fix the four coal rock samples on the clamping device 20, fill the visual detection cabin 1 with methane gas with the highest pressure required by the experiment, close all valves of the device, and check the sealing property of the device;

[0051] 3) Close all outlet valves, open all communication valves in the experimental device, start the vacuum pump 6 for degassing treatment, and continue to vacuum for 40 min after the pressure sensor is reduced to-0.10 MPa;

[0052] 4) Open the temperature control system and set the temperature to reach the required experimental conditions;

[0053] 5) Open the gas inlet valve, start the booster pump 5, and increase the pressure in the visual detection cabin 1 to the required experimental pressure;

[0054] 6) After all the conditions are set, the temperature and pressure values are kept for 6 h;

[0055] 7) Turn on the cold light source 8, the high-speed camera 15 and the computer image recognition processing software;

[0056] 8) Rotate the rotating rod 17 of the rotating fixing mechanism, and observe the coal rock sample identification image to reach the preset angle;

[0057] 9) Turn on the high speed camera 15, and rotate the liquid micro-injection pump 9 to drop one drop of test liquid on the surface of the coal rock solid through the capillary needle 13;

[0058] 10) Repeat the steps 8) and 9) after finishing, and replace the sample or replace other coal rock sample to test at a pre-set angle;

[0059] 11) After all the tests are finished, turn off the heater 22, and open the valve 24 of the gas recovery bottle to collect the test gas.

[0060] The preferred embodiments of the present application have been described above with the preferred embodiments, but the present application is not limited to them and can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-angle wettability testing platform for coal and rock under high temperature and pressure conditions, characterized in that, The system includes a visualization detection chamber (1), on the inner side of which is a cubic sample placement stage (19). The cubic sample placement stage (19) is connected to the visualization detection chamber (1) via an angle adjustment system. A heating tube (22) is provided at the bottom of the inner side of the visualization detection chamber (1). The heating tube (22) is part of the temperature control system. A liquid injection system, a gas pressurization system, and an optical imaging system are also provided on the side of the visualization detection chamber (1). The liquid injection system can add liquid to the test material on the cubic sample placement stage (19). The optical imaging system can capture test steps in real time. The gas pressurization system can adjust the pressure inside the visualization detection chamber (1).

2. The coal and rock multi-angle wettability testing platform under high temperature and pressure environment according to claim 1, characterized in that, A viewing window is provided on the side wall of the visualization detection chamber (1), and a sapphire glass (11) is provided at the viewing window. A high-pressure rubber sealing ring is provided at the contact point between the sapphire glass (11) and the viewing window.

3. The coal and rock multi-angle wettability testing platform and method under high temperature and pressure environment according to claim 2, characterized in that, Two symmetrical sample holders (20) are provided on the upper, lower, front and rear sides of the cubic sample stage (19). The sample holders (20) are configured with an L-shaped structure and can restrict the position of the test substance.

4. The coal and rock multi-angle wettability testing platform under high temperature and pressure environment according to claim 3, characterized in that, The angle adjustment system includes a rotating fixing mechanism, a bearing (29), a rotating shaft (28), and a rotating rod (17). The bearing (29) is installed on the side wall of the visualization inspection chamber (1). The rotating shaft (28) passes through the bearing (29) and the cubic sample stage (19). The rotating fixing mechanism is installed on the outside of the visualization inspection chamber (1) and connected to the rotating shaft (28). The rotating rod (17) is installed on the side of the rotating fixing mechanism.

5. The coal and rock multi-angle wettability testing platform under high temperature and pressure environment according to claim 4, characterized in that, The rotating fixing mechanism includes a steel chain (33) and two gears of different sizes. The large gear (32) is sleeved on the rotating shaft (28), and the small gear (34) is located below the large gear (32). Both the large gear (32) and the small gear (34) are connected to the steel chain (33). The rotating rod (17) is connected to the small gear (34).

6. The coal and rock multi-angle wettability testing platform under high temperature and pressure environment according to claim 2, characterized in that, The liquid injection system includes a storage bottle (7), a liquid micro-injection pump (9), and a capillary titration needle (13). The storage bottle (7), the liquid micro-injection pump (9), and the capillary titration needle (13) are connected in series. The top of the capillary titration needle (13) is connected to the top of the visualization detection chamber (1) through a high-pressure sealing cap (12). The inner diameter of the capillary titration needle (13) is 0.5 mm, and the bottom of the capillary titration needle (13) is located above the cubic sample stage (19).

7. The coal and rock multi-angle wettability testing platform under high temperature and pressure environment according to claim 2, characterized in that, The optical imaging system includes a cold light source (8), a high-speed camera (15), and a computer (14). The cold light source (8) and the high-speed camera (15) are respectively located on both sides of the visualization detection cabin (1) and face the viewing window. The high-speed camera (15) and the computer (14) are electrically connected.

8. The coal and rock multi-angle wettability testing platform under high temperature and pressure environment according to claim 7, characterized in that, The gas pressurization system includes a gas storage cylinder, a vacuum pump (6), a booster pump (5), a gas buffer cylinder (31), a pressure reducing valve (30), and a four-way valve (26). The gas storage cylinder stores methane and is connected in parallel with the vacuum pump (6). The booster pump (5), the gas buffer cylinder (31), and the pressure reducing valve (30) are connected in series. At the same time, the outlet of the pressure reducing valve (30) is connected to the four-way valve (26). The four-way valve (26) is connected to the gas injection pipe, the pressure sensor (25), and the gas recovery bottle (21) of the visualization detection chamber (1), respectively.

9. The coal and rock multi-angle wettability testing platform under high temperature and pressure environment according to claim 8, characterized in that, The temperature control system also includes a silicone heat-conducting plate (23), a temperature sensor and a data acquisition controller (18). The silicone heat-conducting plate (23) is located above the heating tube (22), and the temperature sensor is located above the silicone heat-conducting plate (23). The pressure sensor (25) and the temperature sensor are both connected to the computer (14) through the data acquisition controller (18).

10. A method for testing the multi-angle wettability of coal and rock under high temperature and pressure, used on the platform described in claim 10, characterized in that, Includes the following steps Step 1: First, smooth the top and bottom ends of a standard coal and rock sample with a diameter of 38mm and a thickness of 10mm using 300-grit, 600-grit, 800-grit, and 1200-grit sandpaper, respectively. Step 2: Open the high-pressure sealing cover (12) on the top of the visualization detection chamber (1), fix the four coal and rock samples on the sample holder (20), fill the visualization detection chamber (1) with methane gas at the highest pressure required by the experiment, close all valves of the device, and check the sealing of the device; Step 3: Close all outlet valves, open all connecting valves in the experimental apparatus, turn on the vacuum pump (6) for degassing, and continue evacuating for 40 minutes after the pressure sensor (25) drops to -0.10MPa. Step 4: Turn on the temperature control system and set the temperature to meet the experimental requirements; Step 5: Open the gas inlet valve and start the booster pump (5) to increase the internal pressure of the visualization detection chamber (1) to the required experimental pressure; Step Six: After all conditions are set, maintain the temperature and pressure values ​​for 6 hours; Step 7: Turn on the cold light source (8), high-speed camera (15), computer (14) image recognition processing software; Step 8: Rotate the rotating rod (17) of the rotating fixing mechanism to observe the coal and rock sample identification image to reach the preset angle; Step 9: Turn on the high-speed camera (15) and rotate the liquid micro-injection pump (9) to drip a drop of test liquid onto the coal and rock solid surface through the capillary titration needle (13); Step 10: After completion, repeat steps 8 and 9. You can then replace the next sample or test a different coal and rock sample at a different pre-fabricated angle. Step 11: After all tests are completed, turn off the heating tube (22) and open the valve 24 of the gas recovery bottle (21) to collect the test gas.

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