阅读说明：本技术 一种可视化页岩吸附变形试验装置及其使用方法 (Visual shale adsorption deformation test device and use method thereof ) 是由 王阳 陈尚斌 向杰 曹庆舜 张彤 于 2021-07-30 设计创作，主要内容包括：本发明涉及页岩气体吸附变形试验领域,公开一种可视化页岩吸附变形试验装置,包括压力控制系统、吸附检测系统、温度控制部和数据采集分析部；压力控制系统能够向吸附检测系统中注入或抽出气体,吸附检测系统能够记录CO-(2)吸附导致页岩变形过程,温度控制部用以调整压力控制系统和吸附检测系统内气体温度,数据采集分析部用以对试验数据进行收集与分析。此外还提出了一种基于上述试验装置的使用方法,本发明利用显微镜实时检测不同温度不同压力状态下CO-(2)吸附导致页岩变形过程,基于数据、图像处理分析获得各个方向上的平面应变,进而计算出精确的体积应变。(The invention relates to the field of shale gas adsorption deformation tests and discloses a visual shale adsorption deformation test device which comprises a pressure control system, an adsorption detection system, a temperature control part and a data acquisition and analysis part, wherein the pressure control system is connected with the adsorption detection system through a pipeline; the pressure control system can inject or extract gas into or out of the adsorption detection system, and the adsorption detection system can record CO 2 The shale deformation process is caused by adsorption, the temperature control part is used for adjusting the gas temperature in the pressure control system and the adsorption detection system, and the data acquisition and analysis part is used for collecting and analyzing test data. In addition, the invention also provides a use method based on the test device, and the invention uses a microscope to detect CO in real time under different temperature and pressure states 2 And in the shale deformation process caused by adsorption, plane strain in each direction is obtained based on data and image processing analysis, and then accurate volume strain is calculated.)

1. The utility model provides a visual shale adsorption deformation test device which characterized in that: comprises a pressure control system and an adsorption detection system; the pressure control system comprises a pressure control part and a gas reference groove (9), the pressure control part is communicated with the gas reference groove (9) through a fifth pipeline, a first temperature sensor (11) is arranged in the gas reference groove (9), the adsorption detection system comprises an adsorption tank communicated with the gas reference groove (9), the pressure control part is used for filling or extracting gas into or from the gas reference groove (9) and the adsorption tank, an objective table (30) and a second temperature sensor (33) are arranged in the adsorption tank, a microscope (18) is arranged on the outer side of the adsorption tank, an acquisition camera (16) is fixedly connected with the microscope (18), and an objective lens of the microscope (18) is arranged opposite to the objective table (30); first temperature sensor (11), second temperature sensor (33) and collection camera (16) all with data acquisition analysis portion electric connection, gaseous reference groove (9) week side with the adsorption tank lower extreme is provided with temperature control portion.

2. The visual shale adsorption deformation test device of claim 1, characterized in that: the adsorption tank further comprises a base (27), a wall body (22), a reinforcing connecting piece (26) and a tank cover (28), the base (27) is fixedly connected with the wall body (22), the upper surface of the base (27) is provided with the reinforcing connecting piece (26), the base (27) and the wall body (22) are fixedly connected with the reinforcing connecting piece (26), the wall body (22) and the reinforcing connecting piece (26) are provided with a gas inlet (15) in a penetrating way, the side wall of the reinforcing connecting piece (26) is fixedly connected with a sample base (25), the sample base (25) is provided with a gas channel in a penetrating way, the upper end of the sample base (25) is fixedly connected with a telescopic structure, the upper end of the telescopic structure is fixedly connected with the lower end surface of the objective table (30), the wall body (22) is fixedly connected with the tank cover (28), and the wall body (22) and the tank cover (28) are provided with an observation window (29), the objective lens, the observation window (29) and the objective table (30) of the microscope (18) are arranged on the same straight line, a sample placing opening (32) is detachably connected to the wall body (22), and the sample placing opening (32) and the objective table (30) are arranged oppositely.

3. The visual shale adsorption deformation test device of claim 2, wherein: extending structure includes flexible support column (23) and bolt (24), flexible support column (23) includes stiff end and expansion end, the stiff end lower extreme is fixed to be set up sample base (25) upper end, the upper end fixed connection of expansion end the lower terminal surface of objective table (30), be provided with a plurality of first through-holes on the stiff end, be provided with the second through-hole on the expansion end, stiff end and expansion end sliding connection, first through-hole and second through-hole all with bolt (24) looks adaptation.

4. The visual shale adsorption deformation test device of claim 1, characterized in that: the microscope (18) and the collection camera (16) are three, the microscope (18) and the collection camera (16) are arranged in a one-to-one correspondence mode, and the three microscopes (18) are arranged perpendicularly to each other.

5. The visual shale adsorption deformation test device of claim 4, wherein: adsorption tank week side is provided with stainless steel base (34), the lower extreme of the terminal surface fixedly connected with microscope stand body of rod (20) on stainless steel base (34), the one end of the upper end of the microscope stand body of rod (20) through short fixed rubber pad (21) fixedly connected with connecting rod (19), the other end of connecting rod (19) can be dismantled through rectangular fixed rubber pad (17) and be connected with microscope (18), connecting rod (19) are three, connecting rod (19) and microscope (18) one-to-one setting.

6. The visual shale adsorption deformation test device of claim 2, wherein: the pressure control part comprises a gas injection unit, a pressurizing unit and a vacuumizing unit, one end of the gas injection unit is communicated with one end of the pressurizing unit, and the other end of the pressurizing unit and one end of the vacuumizing unit are both communicated with the gas reference groove (9).

7. The visual shale adsorption deformation test device of claim 6, wherein: the gas injection unit is a gas storage bottle (1), the pressurizing unit is a plunger booster pump (3), the vacuumizing unit is a vacuum pump (6), the gas storage bottle (1) is communicated with one end of the plunger booster pump (3) through a first pipeline, a first valve (2) is arranged on the first pipeline, the other end of the plunger booster pump (3) is communicated with the reference groove gas through an inlet (10) through a second pipeline and a fourth pipeline in sequence, a second valve (4) is arranged on the second pipeline, a fourth valve (7) is arranged on the fourth pipeline, the second pipeline is communicated with the fourth pipeline, the vacuum pump (6) is communicated with the reference groove gas through an inlet (10) through a third pipeline and a fourth pipeline in sequence, the second pipeline and the third pipeline are arranged in parallel, a third valve (5) is arranged on the third pipeline, and the reference groove gas outlet (12) is communicated with a gas inlet (15) of the adsorption tank through a fifth pipeline, and a gas pressure sensor (13) and a fifth valve (14) are arranged on the fifth pipeline.

8. The visual shale adsorption deformation test device of any one of claims 1-7, wherein: the microscope (18) is a high-resolution telecentric microscope, the temperature control part is a constant-temperature water bath (8), and the data acquisition and analysis part is a computer (35).

9. A test method based on the visual shale adsorption deformation test device of any one of claims 1 to 8, characterized in that: the method comprises the following steps:

preparing a shale sample (31), testing the mass of the shale sample (31), and calculating the volume parameter of the shale sample (31);

performing airtightness inspection on the pressure control part, the gas reference tank (9) and the adsorption tank;

fixing the shale sample (31) on the upper surface of the object stage (30);

the microscope (18) shoots the shale sample (31) by adopting the same multiplying power;

the pressure control part carries out vacuum pumping treatment on the gas reference groove (9) and the adsorption tank;

the temperature control part adjusts the gas temperature in the gas reference tank (9) and the adsorption tank to the formation temperature, test gas is introduced into the gas reference tank (9) through the gas injection unit and the pressurization unit and stands still, and the test temperature is recorded;

injecting a test gas into the canister through the gas reference tank (9), the pressurizing unit gradually increasing the gas pressure up to a set equilibrium pressure position;

collecting test data, analyzing the test data, and processing and analyzing the image data in real time to obtain real-time plane strain and volume strain;

reducing the gas pressure in the gas reference tank (9) and the adsorption tank to a standard atmospheric pressure by the pressure control section;

a shale sample (31) is removed.

10. The test method of the visual shale adsorption deformation test device according to claim 9, wherein: the calculation formula of the plane strain quantity is as follows:

in the formula, epsilon_xThe plane strain is delta s is the area increased by the plane of the shale sample (31), and s is the initial plane area of the plane of the shale sample (31);

the calculation formula of the area increased by the shale sample (31) plane is as follows:

in the formula, delta s is the area increased by the plane of the shale sample (31), s is the initial plane area of the plane of the shale sample (31), N is the number of pixel points on the plane, and delta N is the number of increased pixel points;

the calculation formula of the volume strain amount is as follows:

in the formula, epsilon_vIn terms of volume strain, Δ x is the added length of the shale sample (31), Δ y is the added width of the shale sample (31), and Δ z is the added height of the shale sample (31); x is the initial length of the shale sample (31), y is the initial width of the shale sample (31), and z is the initial height of the shale sample (31);

the calculation formula of the increased side length of the shale sample (31) is as follows:

in the formula, Δ l is the increased side length of the sample, l is the initial side length of the sample, n is the number of pixel points on the side length, and Δ n is the increased number of pixel points.

Technical Field

The invention relates to the field of shale gas adsorption deformation tests, in particular to a visual shale adsorption deformation test device and a using method thereof.

Background

Shale reservoirs have the characteristics of low porosity and low permeability, can be commercially developed only by manual fracturing modification, have huge water demand in a common hydraulic fracturing mode, are difficult to meet the development of shale gas in partial areas, and have more and more attention on efficient shale gas fracturing development technology. Carbon dioxide (CO)₂) Is one of the most important gases causing the greenhouse effect, and a great deal of research shows that CO₂The product can be used as an effective displacement agent in shale gas development engineering, and the shale gas recovery rate is greatly improved. Utilization of CO in shale gas development process₂To methane (CH) in an adsorbed state₄) The Shale Gas which is mainly used is desorbed and displaced, so that not only can the Recovery ratio of the Shale Gas be improved (Enhanced Shale Gas Recovery), but also CO can be recovered in the Shale reservoir₂Effective geological sequestration is performed. However shale reservoirs adsorb CO₂When the molecular weight is in the molecule, the deformation and expansion of a reservoir stratum can be caused, the permeability of the reservoir stratum is reduced, and a gas migration channel is blocked, so that the molecular weight becomes one of important factors for restricting the development of the technology. Therefore, the CO of the shale reservoir under different geological temperature and pressure conditions is obtained through physical test simulation₂The adsorption and deformation characteristics have very important significance.

Disclosure of Invention

The invention aims to provide a visual shale adsorption deformation test device and a using method thereof, which can be used for obtaining CO of shale reservoirs under different geological temperature and pressure conditions through physical test simulation₂Adsorption and deformation characteristics.

In order to achieve the purpose, the invention provides the following scheme: the invention provides a visual shale adsorption deformation test device which comprises a pressure control system and an adsorption detection system, wherein the pressure control system comprises a pressure sensor, a pressure sensor and a pressure sensor; the pressure control system comprises a pressure control part and a gas reference groove, the pressure control part is communicated with the gas reference groove through a fifth pipeline, a first temperature sensor is arranged in the gas reference groove, the adsorption detection system comprises an adsorption tank communicated with the gas reference groove, the pressure control part is used for filling or extracting gas into or from the gas reference groove and the adsorption tank, an objective table and a second temperature sensor are arranged in the adsorption tank, a microscope and an acquisition camera fixedly connected with the microscope are arranged on the outer side of the adsorption tank, and an objective lens of the microscope is arranged opposite to the objective table; first temperature sensor, second temperature sensor and collection camera all with data acquisition analysis portion electric connection, gaseous reference groove week side with the adsorption tank lower extreme is provided with temperature control portion.

Preferably, the adsorption tank further comprises a base, a wall body, a reinforcing connecting piece and a tank cover, the base is fixedly connected with the wall body, the upper surface of the base is provided with the reinforcing connecting piece, the base and the wall body are fixedly connected with the reinforcing connecting piece, the wall body and the reinforcing connecting piece are provided with a gas inlet in a penetrating way, the side wall of the reinforcing connecting piece is fixedly connected with a sample base, the sample base is provided with a gas channel in a penetrating way, the upper end of the sample base is fixedly connected with a telescopic structure, the upper end of the telescopic structure is fixedly connected with the lower end surface of the objective table, the wall body is fixedly connected with the tank cover, the wall body and the tank cover are both provided with observation windows, the objective lens, the observation windows and the objective table of the microscope are arranged on the same straight line, the wall body is detachably connected with a sample placing opening, and the sample placing opening is opposite to the objective table.

Preferably, extending structure includes flexible support column and bolt, flexible support column includes stiff end and expansion end, the stiff end lower extreme is fixed to be set up sample base upper end, the upper end fixed connection of expansion end the lower terminal surface of objective table, be provided with a plurality of first through-holes on the stiff end, be provided with the second through-hole on the expansion end, stiff end and expansion end sliding connection, first through-hole and second through-hole all with bolt looks adaptation.

Preferably, the number of the microscopes and the number of the collecting cameras are three, the microscopes and the collecting cameras are arranged in a one-to-one correspondence mode, and the three microscopes are arranged perpendicularly to each other.

Preferably, adsorption tank week side is provided with the stainless steel base, the lower extreme of the stainless steel base up end fixedly connected with microscope support body of rod, the one end of short fixing rubber pad fixedly connected with connecting rod is passed through to the upper end of the microscope support body of rod, the other end of connecting rod can be dismantled through rectangular fixing rubber pad and be connected with the microscope, the connecting rod is three, connecting rod and the setting of microscope one-to-one.

Preferably, the pressure control part comprises a gas injection unit, a pressurization unit and a vacuum unit, one end of the gas injection unit is communicated with one end of the pressurization unit, and the other end of the pressurization unit and one end of the vacuum unit are both communicated with the gas reference groove.

Preferably, the gas injection unit is a gas cylinder, the pressurizing unit is a plunger booster pump, the vacuumizing unit is a vacuum pump, the gas cylinder is communicated with one end of the plunger booster pump through a first pipeline, the first pipeline is provided with a first valve, the other end of the plunger booster pump is communicated with the reference tank gas inlet through a second pipeline and a fourth pipeline in sequence, the second pipeline is provided with a second valve, the fourth pipeline is provided with a fourth valve, the second pipeline is communicated with the fourth pipeline, the vacuum pump is communicated with the reference tank gas inlet through a third pipeline and a fourth pipeline in sequence, the second pipeline and the third pipeline are connected in parallel, the third pipeline is provided with a third valve, the reference tank gas inlet is communicated with the gas inlet of the adsorption tank through a fifth pipeline, and a gas pressure sensor and a fifth valve are arranged on the fifth pipeline.

Preferably, the microscope is a high-resolution telecentric microscope, the temperature control part is a constant-temperature water bath, and the data acquisition and analysis part is a computer.

The invention discloses the following technical effects: the method can be used for shooting the shale plane photos in the adsorption process under different temperatures and different pressures in real time through a microscope based on optical image processing, carrying out visual observation and digital processing analysis on the shale adsorption deformation phenomenon, and accurately calculating the plane strain and the volume strain by using the size of the photos and the change of pixel points in unit area. The testing device has the advantages of high accuracy, simple process, reasonable structure, convenient disassembly and high safety factor.

The invention provides a use method of a visual shale adsorption deformation test device, which comprises the following steps:

manufacturing a shale sample, testing to obtain the mass of the shale sample, and calculating the volume parameter of the shale sample;

performing air tightness inspection on the pressure control part, the gas reference groove and the adsorption tank;

fixing the shale sample on the upper surface of the objective table;

the microscope shoots the shale sample by adopting the same multiplying power;

the pressure control part carries out vacuum pumping treatment on the gas reference groove and the adsorption tank;

the temperature control part adjusts the gas temperature in the gas reference tank and the adsorption tank to the formation temperature, test gas is introduced into the gas reference tank through the gas injection unit and the pressurization unit and stands still, and the test temperature is recorded;

injecting a test gas into the adsorption tank through the gas reference tank, and gradually increasing the gas pressure by the pressurization unit until an equilibrium pressure position is set;

collecting test data, analyzing the test data, and processing and analyzing the image data in real time to obtain real-time plane strain and volume strain;

reducing, by the pressure control section, the gas pressure within the gas reference tank and the adsorption tank to a standard atmospheric pressure;

and taking out the shale sample.

Preferably, the calculation formula of the plane strain amount is as follows:

in the formula, epsilon_xThe plane strain is the plane strain, delta s is the area increased by the plane of the shale sample, and s is the initial plane area of the plane of the shale sample;

the calculation formula of the area increased by the shale sample plane is as follows:

in the formula, Δ s is the area increased by the shale sample plane, s is the initial plane area of the shale sample plane, N is the number of pixel points on the plane, and Δ N is the number of increased pixel points;

the calculation formula of the volume strain amount is as follows:

in the formula, epsilon_vIn terms of volume strain, Δ x is the added length of the shale sample, Δ y is the added width of the shale sample, and Δ z is the added height of the shale sample; x is the initial length of the shale sample, y is the initial width of the shale sample, and z is the initial height of the shale sample;

the calculation formula of the increased side length of the shale sample is as follows:

in the formula, Δ l is the increased side length of the sample, l is the initial side length of the sample, n is the number of pixel points on the side length, and Δ n is the increased number of pixel points.

The advantages of the using method and the testing device are the same compared with the prior art, and are not described in detail herein.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic structural diagram of a visual shale adsorption deformation test device according to the invention;

FIG. 2 is a front cross-sectional view of an adsorption detection system;

FIG. 3 is a top cross-sectional view of an adsorption detection system;

reference numerals: 1. a gas cylinder; 2. a first valve; 3. a plunger piston booster pump; 4. a second valve; 5. a third valve; 6. a vacuum pump; 7. a fourth valve; 8. a constant-temperature water bath kettle; 9. a gas reference cell; 10. a reference cell gas inlet; 11. a first temperature sensor; 12. a reference cell gas vent; 13. a gas pressure sensor; 14. a fifth valve; 15. a gas input port; 16. a collection camera; 17. rubber pads are fixed on the long strips; 18. a microscope; 19. a connecting rod; 20. a microscope stand rod body; 21. the short strips fix the rubber pads; 22. a wall body; 23. a telescopic support column; 24. a bolt; 25. a sample base; 26. reinforcing the connecting piece; 27. a base; 28. a can lid; 29. an observation window; 30. an object stage; 31. a shale sample; 32. a sample introduction port; 33. a second temperature sensor; 34. a stainless steel base; 35. and (4) a computer.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Referring to fig. 1-3, in one aspect, the invention provides a visual shale adsorption deformation test device, which includes a pressure control system and an adsorption detection system; the pressure control system comprises a pressure control part and a gas reference tank 9, wherein the gas reference tank 9 is used for temporarily storing gas, the gas temperature in the gas reference groove 9 can be measured through the first temperature sensor 11, the pressure control part is communicated with the gas reference groove 9 through a fifth pipeline, the first temperature sensor 11 is arranged in the gas reference groove 9, a carbon dioxide adsorption test is carried out in the adsorption tank, an object stage 30 and a second temperature sensor 33 are arranged in the adsorption tank, the second temperature sensor 33 is used for measuring the gas temperature in the adsorption tank, the object stage 30 is made of high-strength light-transmitting resin materials, a microscope 18 and a collection camera 16 fixedly connected with the collection camera 16 are arranged on the outer side of the adsorption tank, an objective lens of the microscope 18 is arranged opposite to the object stage 30, a shale sample 31 is placed on the object stage 30, and the microscope 18 and the collection camera 16 can shoot the shale sample 31; first temperature sensor 11, second temperature sensor 33 and collection camera 16 all with data acquisition analysis portion electric connection, gaseous reference groove 9 week side and adsorption tank lower extreme are provided with temperature control portion, and temperature control portion can carry out invariable temperature regulation to gaseous reference groove 9 and adsorption tank.

The method can be based on optical image processing, can take plane photos of the shale sample 31 in the adsorption process under different temperatures and different pressures in real time through the microscope 18, can perform visual observation and digital processing analysis on the shale adsorption deformation phenomenon, and accurately calculates the plane strain and the volume strain by using the size of the photos and the change of pixel points in unit area. The testing device has the advantages of high accuracy, simple process, reasonable structure, convenient disassembly and high safety factor.

Further optimized scheme, the adsorption tank also comprises a base 27, a wall body 22, a reinforcing connecting piece 26 and a tank cover 28, the base 27 is fixedly connected with the wall body 22, the reinforcing connecting piece 26 is arranged on the upper surface of the base 27, the base 27 and the wall body 22 are both fixedly connected with the reinforcing connecting piece 26, the reinforcing connecting piece 26 is mainly used for improving the connection between the base 27 and the wall body 22 and playing a reinforcing role, a gas inlet 15 penetrates through the wall body 22 and the reinforcing connecting piece 26, a sample base 25 is welded on the side wall of the reinforcing connecting piece 26, a gas channel is arranged on the sample base 25 in a penetrating way, detected gas or test gas enters or runs out of the interior of the adsorption tank after passing through the gas inlet, a telescopic structure is welded at the upper end of the sample base 25 and can adopt a hydraulic or pneumatic telescopic rod, an electric telescopic rod and the like, the upper end of the telescopic structure is fixedly connected with the lower end surface of the object stage 30, extending and retracting about the extending structure drives objective table 30 and reciprocates, wall body 22 and cover 28 fixed connection, all be provided with observation window 29 on wall body 22 and the cover 28, observation window 29 is made by high strength printing opacity resin material, microscope 18's objective, observation window 29 and objective table 30 set up on same straight line, microscope 18 can observe shale sample 31 on the objective table 30 through observation window 29, can dismantle on the wall body 22 and be connected with sample and put into mouth 32, sample is put into mouth 32 and is set up with objective table 30 relatively, sample is put into mouth 32 and is circular, and through bolted connection between the wall body 22, it makes things convenient for shale sample 31 to place or take out to be provided with sample and puts into mouth 32.

Further optimize the scheme, extending structure includes flexible support column 23 and bolt 24, and flexible support column 23 includes stiff end and expansion end, and the stiff end lower extreme is fixed to be set up in sample base 25 upper end, and the lower terminal surface of the upper end fixed connection objective table 30 of expansion end is provided with a plurality of first through-holes on the stiff end, is provided with the second through-hole on the expansion end, stiff end and expansion end sliding connection, first through-hole and second through-hole all with 24 looks adaptations of bolt.

Further optimize the scheme, microscope 18 and collection camera 16 are three, and microscope 18 and collection camera 16 one-to-one set up, and three microscope 18 mutually perpendicular's setting, three microscope 18 set up respectively in the left side of objective table, rear and top, can observe the deformation condition of shale sample 31 in three direction.

Further optimize the scheme, adsorption tank week side is provided with stainless steel base 34, and the lower extreme of the stainless steel base 34 up end fixedly connected with microscope support body of rod 20, the one end of the short fixed rubber pad 21 fixedly connected with connecting rod 19 is passed through to the upper end of the microscope support body of rod 20, and the other end of connecting rod 19 passes through rectangular fixed rubber pad 17 and microscope 18 fixed connection, and connecting rod 19 is three, and connecting rod 19 sets up with microscope 18 one-to-one.

According to a further optimized scheme, the pressure control part comprises a gas injection unit, a pressurizing unit and a vacuumizing unit, one end of the gas injection unit is communicated with one end of the pressurizing unit, the other end of the pressurizing unit and one end of the vacuumizing unit are both communicated with a gas reference groove 9, a first temperature sensor 11 is arranged in the gas reference groove 9, the gas injection unit supplies detection gas to realize gas tightness detection of the test device, the gas injection unit supplies test gas to test shale test adsorption, and the pressurizing unit is used for improving gas pressure in the gas reference groove 9 and the adsorption tanks.

In a further optimized scheme, the gas injection unit is a gas storage bottle 1, the pressurizing unit is a plunger booster pump 3, the vacuumizing unit is a vacuum pump 6, the gas storage bottle 1 is communicated with one end of the plunger booster pump 3 through a first pipeline, a first valve 2 is arranged on the first pipeline, the other end of the plunger booster pump 3 is communicated with a reference groove gas inlet 10 through a second pipeline and a fourth pipeline in sequence, a second valve 4 is arranged on the second pipeline, a fourth valve 7 is arranged on the fourth pipeline, the second pipeline is communicated with the fourth pipeline, the vacuum pump 6 is communicated with a reference tank gas inlet 10 sequentially through a third pipeline and the fourth pipeline, the second pipeline and the third pipeline are arranged in parallel, a third valve 5 is arranged on the third pipeline, the reference tank gas inlet 12 is communicated with a gas inlet 15 of the adsorption tank through a fifth pipeline, and a gas pressure sensor 13 and a fifth valve 14 are arranged on the fifth pipeline.

In a further optimized scheme, the microscope 18 is a high-resolution telecentric microscope, the temperature control part is a constant-temperature water bath 8, and the data acquisition and analysis part is a computer 35. The invention further provides a test method based on the visual shale adsorption deformation test device, which comprises the following steps:

making a shale sample 31, selecting a shale block sample without obvious cracks or macroscopic stratification, cutting by using a rock cutting machine, polishing the surface of the shale sample 31 by using a polishing machine to be smooth, making into a sheet of 1mm multiplied by 3mm, referring to national rock test method standard for processing precision, and testing to obtain the quality and volume parameters of the shale sample 31;

carry out gas tightness inspection to pressure control portion, gaseous reference groove 9 and adsorption tanks, specifically do: the device is assembled, related pipelines are connected, the system is electrified, the gas storage tank is replaced by the nitrogen gas storage tank 1, all valves are opened, the whole device is subjected to long-time gas tightness inspection, the fluctuation value of the gas pressure in the testing time cannot exceed the precision of the gas pressure sensor 13, and the gas pressure does not fluctuate or fluctuates by less than 0.006Mpa in the process of actually measuring 8h, so that the gas tightness of the testing device is proved to be good;

fixing the shale sample 31 on the upper surface of the object stage 30, specifically: opening the sample introduction port 32, fixing the shale sample 31 on the upper surface of the stage 30, and then closing the sample introduction port 32;

the microscope 18 takes a picture of the shale sample 31 at the same magnification, specifically: operating the microscope 18 in three directions (left, back and up) so that the microscope 18 can clearly observe the surface of the sample through the transparent observation window 29, adjusting so that the sample plane is located at the center of the field of view, filling the field of view as full as possible, requiring the microscope 18 to adjust to the same multiple and ensuring that the picture is clear;

the temperature control part (namely the constant temperature water bath 8) adjusts the gas temperature in the gas reference tank 9 and the adsorption tank to the test temperature;

the pressure control part carries out vacuum pumping treatment on the gas reference groove 9 and the adsorption tank, and the method specifically comprises the following steps: closing the first valve 2 and the second valve 4, simultaneously opening the third valve 5, the fourth valve 7 and the fifth valve 14, starting the vacuum pump 6, and vacuumizing the gas reference tank 9 and the adsorption tank until the relative vacuum degree of the gas pressure sensor 13 is stabilized at-0.098 Mpa;

the temperature control part adjusts the gas temperature in the gas reference tank 9 and the adsorption tank to the formation temperature, and the test gas is introduced into the gas reference tank 9 through the gas injection unit and the pressurization unit and stands, and the test temperature is recorded, specifically: adjusting the gas temperatures in the gas reference tank 9 and the adsorption tank to the formation temperature by using the constant-temperature water bath 8, opening the first valve 2, the second valve 4 and the fourth valve 7, closing the third valve 5 and the fifth valve 14, replacing the gas storage tank with a carbon dioxide gas storage bottle 1, filling a certain amount of carbon dioxide gas into the gas reference tank 9 through the plunger booster pump 3, standing for 6h to fully heat the shale samples 31 in the gas reference tank 9 and the adsorption tank, and after the values of the first temperature sensor 11 and the second temperature sensor 33 are basically the same within an error and are consistent with the set temperature of the constant-temperature water bath 8, filling test temperatures and data tables in the computer 35, and determining the initial number of the planes and the side lengths of the shale samples 31 at the moment;

injecting test gas into the adsorption tank through a gas reference groove 9, and gradually increasing the gas pressure by a pressurizing unit until a set balance pressure position is reached; the method specifically comprises the following steps: after the value of the gas pressure sensor 13 is stabilized, opening a fifth valve 14 between the gas reference tank 9 and the adsorption tank, starting an isothermal adsorption test until adsorption is balanced, and then increasing the gas pressure until a set balance pressure is reached, wherein the set balance pressure is the pressure condition set in the test;

collecting test data, analyzing the test data, processing and analyzing the image data in real time to obtain real-time plane dependent variable and volume dependent variable, which specifically comprises the following steps: through data and image processing analysis of the gas pressure sensor 13, the change process of the plane strain and the volume strain in the process that carbon dioxide adsorption reaches the set balance pressure can be obtained, relevant data is stored in the computer 35 in a form of table data, and through adjustment of test conditions, namely changes of temperature and pressure conditions, the carbon dioxide adsorption deformation characteristics and influence factors under different temperature and pressure conditions can be obtained.

Reducing the gas pressure in the gas reference tank 9 and the adsorption tank to the standard atmospheric pressure by a vacuumizing unit, specifically closing the first valve 2 and the second valve 4, opening the third valve 5, the fourth valve 7 and the fifth valve 14, and starting the vacuum pump 6 until the gas pressure sensor 13 is stabilized at about 0.10133MPa of the standard atmospheric pressure;

the sample inlet 32 was unscrewed and the shale sample 31 was removed with forceps.

In a further optimization scheme, a calculation formula of the plane strain of the shale sample 31 is as follows:

in the formula, epsilon_xIs strain in planeQuantity, delta s is the area of the plane increase of the shale sample 31, and s is the initial plane area of the plane of the shale sample 31;

the calculation formula of the area increased by the shale sample 31 plane is as follows:

in the formula, Δ s is the area increased by the plane of the shale sample 31, s is the initial plane area of the plane of the shale sample 31, N is the number of pixel points on the plane, and Δ N is the number of increased pixel points;

the calculation formula of the volume strain of the shale sample 31 is as follows:

in the formula, epsilon_vIn terms of volume strain, Δ x is the added length of the shale sample 31, Δ y is the added width of the shale sample 31, and Δ z is the added height of the shale sample 31; x is the initial length of the shale sample 31, y is the initial width of the shale sample 31, and z is the initial height of the shale sample 31;

the calculation formula of the increased edge length of the shale sample 31 is as follows:

in the formula, Δ l is the increased side length of the sample, l is the initial side length of the sample, n is the number of pixel points on the side length, and Δ n is the increased number of pixel points.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.