Method and apparatus for determining the microscopic contact angle of rock strata surface
By using helium ion beam imaging technology and the surface tension balance equation of the contact line to determine the microscopic contact angle of the rock surface, the problems of inaccurate contact angle measurement and cumbersome procedures have been solved, and efficient and accurate contact angle measurement has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-11-25
- Publication Date
- 2026-05-26
AI Technical Summary
In existing technologies, the measurement of contact angle on rock surfaces is inaccurate and the measurement process is cumbersome, which affects the kinetics and efficiency of hydrate decomposition.
Standard sample images of liquid droplets on the surface of rock strata were obtained using helium ion beam imaging technology. The contact angle was determined by utilizing the correspondence between liquid-solid interfacial tension, liquid surface tension, and the surface tension of the rock strata under test, through the surface tension balance equation of the contact line, thus reducing the dependence on macroscopic droplet images.
It improves the accuracy and efficiency of contact angle determination, reduces manpower and equipment downtime, and enhances the precision of rock surface wettability measurement.
Smart Images
Figure CN122084464A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of contact angle measurement technology for rock strata surfaces, specifically to a method for determining the microscopic contact angle of a rock strata surface and an apparatus for doing so. Background Technology
[0002] In oil and gas exploration and development, the wettability of rock surfaces plays a crucial role in enhancing oil recovery. Interfacial wettability is characterized by the contact angle formed at the interface between the gas, liquid, and solid phases, reflecting the strength of the interactions between molecules of different phases in the system at equilibrium. Taking the hydrate decomposition process as an example, differences in interfacial wettability directly alter the spatial distribution and molecular structure of hydrates, thus directly affecting the kinetics of hydrate decomposition and the final decomposition efficiency.
[0003] In existing technologies, the common method is to use nuclear magnetic resonance (NMR) and atomic force imaging (AFM) techniques to capture images of droplets on the surface of rock strata, and then measure the contact angle formed by the interface between the gas, liquid, and solid phases in the images. However, the contact angle determined by existing technologies is a macroscopic contact angle, which is inaccurate, and the contact angle needs to be remeasured every time the liquid is changed, making the contact angle determination process cumbersome. Summary of the Invention
[0004] To address the technical problems of inaccurate contact angle measurement and cumbersome measurement procedures in existing technologies, this invention provides a method and apparatus for determining the microscopic contact angle of rock strata surfaces. This method can improve the accuracy and efficiency of contact angle determination, while reducing the required human resources and equipment usage time.
[0005] To achieve the above objectives, the first aspect of the present invention provides a method for determining the microscopic contact angle of a rock stratum surface. This method includes: acquiring a standard sample image of a droplet formed by a known liquid on the surface of a rock stratum to be tested; determining the known droplet contact angle on the surface of the rock stratum to be tested using the standard sample image; determining a contact angle equation using the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock stratum to be tested, as well as the contact line surface tension balance equation; wherein the contact angle equation represents the correspondence between the contact angle and the droplet surface tension and the surface tension of the rock stratum to be tested; determining the surface tension of the rock stratum to be tested using the contact angle equation, the known droplet contact angle, and the known liquid surface tension; and determining the contact angle of the droplet formed by the liquid on the surface of the rock stratum to be tested based on the contact angle equation, the surface tension of the rock stratum to be tested, and the surface tension of the liquid to be tested.
[0006] Furthermore, the step of acquiring a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested includes: acquiring a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested using helium ion beam imaging technology.
[0007] Furthermore, the known liquid is an ionic liquid that does not volatilize in a vacuum.
[0008] Furthermore, the step of determining the known droplet contact angle of a droplet on the surface of the rock layer to be tested using a standard sample image includes: in the standard sample image, taking the intersection point of the known liquid droplet, the rock layer to be tested, and air as the origin, drawing a tangent along the surface of the known liquid; and taking the angle between the tangent and the surface of the rock layer to be tested as the known droplet contact angle.
[0009] Furthermore, the determination of the contact angle equation using the correspondence between liquid-solid interfacial tension, liquid surface tension, and the surface tension of the rock layer to be measured, as well as the contact line surface tension balance equation, includes: ; + -2 ; ) / ; in, For liquid surface tension, For liquid-solid interfacial tension, The surface tension of the rock stratum to be measured. It represents the contact angle.
[0010] A second aspect of the present invention provides a device for determining the microscopic contact angle of a rock stratum surface. The device comprises: an acquisition module for acquiring a standard sample image of a droplet formed by a known liquid on the surface of a rock stratum to be tested; a known droplet contact angle determination module for determining the known droplet contact angle on the surface of the rock stratum to be tested using the standard sample image; a contact angle equation determination module for determining a contact angle equation using the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock stratum to be tested, as well as the contact line surface tension balance equation; wherein the contact angle equation represents the correspondence between the contact angle, the droplet surface tension, and the surface tension of the rock stratum to be tested; a rock stratum surface tension determination module for determining the surface tension of the rock stratum to be tested using the contact angle equation, the known droplet contact angle, and the surface tension of the known liquid; and a droplet contact angle determination module for determining the droplet contact angle formed by the liquid to be tested on the surface of the rock stratum to be tested based on the contact angle equation, the surface tension of the rock stratum to be tested, and the surface tension of the liquid to be tested.
[0011] Furthermore, the step of acquiring a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested includes: acquiring a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested using helium ion beam imaging technology.
[0012] Furthermore, the known liquid is an ionic liquid that does not volatilize in a vacuum.
[0013] Furthermore, the step of determining the known droplet contact angle of a droplet on the surface of the rock layer to be tested using a standard sample image includes: in the standard sample image, taking the intersection point of the known liquid droplet, the rock layer to be tested, and air as the origin, drawing a tangent along the surface of the known liquid; and taking the angle between the tangent and the surface of the rock layer to be tested as the known droplet contact angle.
[0014] Furthermore, the determination of the contact angle equation using the correspondence between liquid-solid interfacial tension, liquid surface tension, and the surface tension of the rock layer to be measured, as well as the contact line surface tension balance equation, includes: ; + -2 ; ) / ; in, For liquid surface tension, For liquid-solid interfacial tension, The surface tension of the rock stratum to be measured. It represents the contact angle.
[0015] The present invention has at least the following technical effects through the technical solution provided by the present invention: The method for determining the microscopic contact angle of rock strata surfaces according to the present invention first acquires a standard sample image of a known liquid forming droplets on the surface of the rock stratum to be tested, and uses the standard sample image to determine the contact angle of the known droplets. Then, it uses the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock stratum to be tested, as well as the surface tension balance equation of the contact line, to determine the contact angle equation. Using the contact angle equation, the known droplet contact angle, and the known surface tension of the liquid, the surface tension of the rock stratum to be tested is calculated. Based on the contact angle equation, the surface tension of the rock stratum to be tested, and the surface tension of the liquid to be tested, the contact angle of the droplets formed by the liquid to be tested on the surface of the rock stratum to be tested is determined. The method for determining the microscopic contact angle of rock strata surfaces provided by the present invention does not require acquiring macroscopic droplet images for different liquids to be tested, which can improve the accuracy of the contact angle, improve the efficiency of contact angle determination, and reduce the required human resources and equipment usage time.
[0016] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description
[0017] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 A flowchart of a method for determining the microscopic contact angle of rock strata surface provided in an embodiment of the present invention; Figure 2 The image of the contact angle of the ionic liquid on the silicon wafer surface, obtained by helium ion beam imaging technology, in the method for determining the microscopic contact angle of rock strata surface provided in the embodiments of the present invention. Figure 3 This is a schematic diagram of a device for determining the microscopic contact angle of rock strata surface provided in an embodiment of the present invention. Detailed Implementation
[0018] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.
[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.
[0020] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions.
[0021] As described in the background section, existing semiconductor structures have poor performance. This will be explained in detail below with reference to the accompanying drawings.
[0022] Please refer to Figure 1The first aspect of this invention provides a method for determining the microscopic contact angle of a rock layer surface. The method includes: S101: acquiring a standard sample image of a droplet formed by a known liquid on the surface of a rock layer to be tested; S102: determining the known droplet contact angle on the surface of the rock layer to be tested using the standard sample image; S103: determining a contact angle equation using the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock layer to be tested, as well as the contact line surface tension balance equation; wherein the contact angle equation represents the correspondence between the contact angle and the droplet surface tension and the surface tension of the rock layer to be tested; S104: determining the surface tension of the rock layer to be tested using the contact angle equation, the known droplet contact angle, and the known liquid surface tension; S105: determining the contact angle of the droplet formed by the liquid on the surface of the rock layer to be tested based on the contact angle equation, the surface tension of the rock layer to be tested, and the surface tension of the liquid to be tested.
[0023] Specifically, in this embodiment of the invention, the surface of the rock layer to be tested is first cleaned to prevent surface-adsorbed impurities from interfering with the imaging results. The rock layer sample is ultrasonically cleaned in acetone solution, then transferred to deionized water for further cleaning, and finally dried in a vacuum drying oven to remove surface moisture. Then, a known liquid is used to form a droplet on the surface of the rock layer to be tested, and a standard sample image is acquired. The known droplet contact angle on the surface of the rock layer to be tested is determined using the standard sample image. Next, the contact angle equation is determined using the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock layer to be tested, as well as the contact line surface tension balance equation. The contact angle equation represents the correspondence between the contact angle and the droplet surface tension and the surface tension of the rock layer to be tested. The contact angle equation only includes the contact angle, droplet surface tension, and surface tension of the rock layer to be tested; therefore, it is not necessary to obtain the liquid-solid interfacial tension between the liquid and the surface of the rock layer to be tested, reducing complex determination steps. Next, the surface tension of the rock layer to be tested is determined by using the contact angle equation, the known droplet contact angle, and the known surface tension of the liquid. Then, the surface tension of the liquid to be tested and the determined surface tension of the liquid to be tested are substituted into the contact angle equation to determine the contact angle of the droplet formed by the liquid to be tested on the surface of the rock layer to be tested.
[0024] The contact angle is the angle formed between the liquid-solid interface and the liquid-gas interface, with the origin at the confluence of the three-phase interface of the liquid, the surface of the rock layer, and air. To obtain the contact angle, it is necessary to first determine the interfacial tension between the liquid and the rock layer, the surface tension of the liquid, and the surface tension of the rock layer. The surface tension of the liquid can be obtained from literature after determining its composition. The interfacial tension can be expressed as the surface tension of the solid and the liquid. Therefore, to quickly and accurately calculate the microscopic contact angle, the surface tension of the rock layer must be determined. In this application, a known liquid forms a droplet on the surface of the rock layer, and the microscopic contact angle is obtained using ion microscopy imaging, which is then used to calculate the surface tension of the rock layer. Based on the calculated surface tension, the microscopic contact angle of any liquid on the solid surface of this rock layer can be quickly obtained.
[0025] The method for determining the microscopic contact angle of rock strata provided by the present invention eliminates the need to acquire macroscopic droplet images for each different test liquid, thereby improving the accuracy and efficiency of contact angle determination and reducing the required human resources and equipment usage time.
[0026] Furthermore, the step of acquiring a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested includes: acquiring a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested using helium ion beam imaging technology.
[0027] Specifically, in this embodiment of the invention, a known liquid is dropped onto the surface of the rock layer to be tested using a syringe, and then transferred to the imaging cavity of an ion microscope. The instrument parameters are adjusted, and the microscopic contact angle formed by the known liquid droplet on the surface of the rock layer to be tested is imaged based on the interaction principle between helium ion beam imaging and the sample. The magnification is adjusted according to the required nanoscale. The imaging parameters used are a beam current of 0.6 pA and a scanning dwell time of 5 µs.
[0028] The method for determining the microscopic contact angle of rock strata provided by the present invention can obtain standard sample images at the nanoscale, improve the accuracy of subsequent contact angle determination, accurately reflect the wettability of rock strata surface, and improve the recovery rate.
[0029] Furthermore, the known liquid is an ionic liquid that does not volatilize in a vacuum.
[0030] Specifically, in this embodiment of the invention, the known liquid is an ionic liquid that remains stable and non-volatile under vacuum. In this embodiment, 1-butyl-3-methylimidazolium tetrafluoroborate (C8H) is used. 15 N2BF4 is a known liquid with a viscosity of 140 cP (25°C) and a density of 1.26 g / cm³. 3 The surface tension is 44.7 mN / m (25℃).
[0031] The method for determining the microscopic contact angle of rock strata provided by the present invention can use a stable ionic liquid in the imaging cavity of an ion microscope as a known liquid, ensuring the stability of the droplet, improving the measurement accuracy of the contact angle, and helping to obtain accurate surface tension of the rock strata to be measured in the later stage.
[0032] Furthermore, the step of determining the known droplet contact angle of a droplet on the surface of the rock layer to be tested using a standard sample image includes: in the standard sample image, taking the intersection point of the known liquid droplet, the rock layer to be tested, and air as the origin, drawing a tangent along the surface of the known liquid; and taking the angle between the tangent and the surface of the rock layer to be tested as the known droplet contact angle.
[0033] Specifically, in this embodiment of the invention, after acquiring the standard sample image, as follows: Figure 2 As shown, in the standard sample image, the origin is taken as the intersection point of the known liquid droplet, the rock layer to be tested, and air. A tangent is drawn along the surface of the known liquid, and the angle between the tangent and the surface of the rock layer to be tested is taken as the contact angle of the known liquid droplet. .
[0034] Furthermore, the determination of the contact angle equation using the correspondence between liquid-solid interfacial tension, liquid surface tension, and the surface tension of the rock layer to be measured, as well as the contact line surface tension balance equation, includes: ; + -2 ; ) / ; in, For liquid surface tension, For liquid-solid interfacial tension, The surface tension of the rock stratum to be measured. It represents the contact angle.
[0035] Specifically, in this embodiment of the invention, the surface tension balance equation of the contact line is: ,in, For liquid surface tension, For liquid-solid interfacial tension, The surface tension of the rock stratum to be measured. The contact angle will be utilized. The liquid-solid interfacial tension will be used. With liquid surface tension and the surface tension of the rock strata to be tested Substituting the correspondence between them into the equation, we obtain the contact angle equation. ) / .
[0036] Given the droplet contact angle and the surface tension of a known liquid Substituting into the contact angle equation, we get ) / The surface tension of the rock layer to be tested can be obtained through calculation. .
[0037] For the contact angle of the droplet formed by the liquid to be tested on the surface of the rock layer to be tested, the corresponding contact angle equation is: ) / ,in, The contact angle of the test droplet formed by the test liquid on the surface of the test rock layer is the contact angle of the test droplet. The surface tension of the liquid to be measured. and the surface tension of the rock strata to be tested Substituting into the contact angle equation, the contact angle of the droplet formed by the liquid to be tested on the surface of the rock layer to be tested can be obtained by calculation. .
[0038] Example 1 First, the silicon wafer sample was cleaned to prevent surface-adsorbed impurities from interfering with the imaging results. The silicon wafer was ultrasonically cleaned in acetone solution for 2 minutes, then transferred to deionized water for 5 minutes, and finally the surface moisture was removed in a vacuum drying oven. The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (C8H) was then injected using a syringe. 15 N2BF4 was dropped onto the surface of the silicon wafer to be tested and then transferred to the imaging chamber of an ion microscope. The instrument parameters were adjusted, and the microscopic contact angle formed by the known liquid droplet on the surface of the silicon wafer was imaged based on the principle of interaction between helium ion beam imaging and the sample. The magnification was adjusted according to the required nanoscale. The imaging parameters used were a beam current of 0.6 pA and a scanning dwell time of 5 µs.
[0039] In the standard sample image, the origin is taken as the intersection point of the known liquid droplet, the silicon wafer under test, and air. A tangent is drawn along the surface of the known liquid, and the angle between the tangent and the surface of the silicon wafer under test is taken as the contact angle of the known liquid droplet. In this embodiment, 42°.
[0040] Given the droplet contact angle (42°) and the known surface tension of the liquid Substituting (44.7 mN / m) into the contact angle equation ) / The surface tension of the rock stratum under test can be obtained through calculation. mN / m.
[0041] For the contact angle of the droplet formed by the liquid to be tested on the surface of the rock layer to be tested, the corresponding contact angle equation is: ) / In this embodiment, the contact angle of the droplets formed by the oil-removing agent ABI-5 on the surface of the silicon wafer under test is to be determined. Surface tension of oil-removing agent ABI-5 It is 38.75 mN / m, therefore, ) / ) / Calculations yielded The contact angle of the droplets formed by the oil-removing agent ABI-5 on the surface of the silicon wafer under test was 29.3°.
[0042] Please refer to Figure 3 The second aspect of the present invention provides a device for determining the microscopic contact angle of a rock stratum surface. The device includes: an acquisition module for acquiring a standard sample image of a droplet formed by a known liquid on the surface of a rock stratum to be tested; a known droplet contact angle determination module for determining the known droplet contact angle on the surface of the rock stratum to be tested using the standard sample image; a contact angle equation determination module for determining a contact angle equation using the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock stratum to be tested, as well as the contact line surface tension balance equation; wherein the contact angle equation represents the correspondence between the contact angle, the droplet surface tension, and the surface tension of the rock stratum to be tested; a rock stratum surface tension determination module for determining the surface tension of the rock stratum to be tested using the contact angle equation, the known droplet contact angle, and the surface tension of the known liquid; and a droplet contact angle determination module for determining the droplet contact angle of the droplet formed by the liquid to be tested on the surface of the rock stratum to be tested based on the contact angle equation, the surface tension of the rock stratum to be tested, and the surface tension of the liquid to be tested.
[0043] Furthermore, the acquisition of a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested includes: acquiring a standard sample image of a known liquid forming droplets on the surface of the rock layer to be tested using helium ion beam imaging technology.
[0044] Furthermore, the known liquid is an ionic liquid that does not volatilize in a vacuum.
[0045] Furthermore, the step of determining the known droplet contact angle of a droplet on the surface of the rock layer to be tested using a standard sample image includes: in the standard sample image, taking the intersection point of the known liquid droplet, the rock layer to be tested, and air as the origin, drawing a tangent along the surface of the known liquid; and taking the angle between the tangent and the surface of the rock layer to be tested as the known droplet contact angle.
[0046] Furthermore, the determination of the contact angle equation using the correspondence between liquid-solid interfacial tension, liquid surface tension, and the surface tension of the rock layer to be measured, as well as the contact line surface tension balance equation, includes: ; + -2 ; ) / ; in, For liquid surface tension, For liquid-solid interfacial tension, The surface tension of the rock stratum to be measured. It represents the contact angle.
[0047] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.
[0048] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.
[0049] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.
Claims
1. A method for determining the microscopic contact angle of a rock stratum surface, characterized in that, The method for determining the microscopic contact angle of the rock stratum surface includes: Acquire standard sample images of droplets formed by a known liquid on the surface of the rock stratum to be tested; The known droplet contact angle on the surface of the rock layer to be tested is determined using standard sample images; The contact angle equation is determined by utilizing the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock layer to be measured, as well as the contact line surface tension balance equation; wherein, the contact angle equation is used to represent the correspondence between the contact angle and the surface tension of the droplet and the surface tension of the rock layer to be measured; The surface tension of the rock layer to be tested is determined using the contact angle equation, the known droplet contact angle, and the known surface tension of the liquid. The contact angle of the droplet formed by the liquid to be tested on the surface of the rock layer is determined based on the contact angle equation, the surface tension of the rock layer to be tested, and the surface tension of the liquid to be tested.
2. The method for determining the microscopic contact angle of rock strata surface according to claim 1, characterized in that, The acquisition of standard sample images of droplets formed by known liquids on the surface of the rock stratum under test includes: Helium ion beam imaging technology was used to obtain standard sample images of droplets formed by known liquids on the surface of the rock layer under test.
3. The method for determining the microscopic contact angle of rock strata surface according to claim 1, characterized in that, The known liquid is an ionic liquid that does not volatilize in a vacuum.
4. The method for determining the microscopic contact angle of rock strata surface according to claim 1, characterized in that, The process of determining the known microscopic contact angle of a droplet on the surface of the rock layer under test using a standard sample image includes: In the standard sample image, the origin is the intersection of the known liquid droplet, the rock layer to be tested, and air, and a tangent is drawn along the surface of the known liquid. The angle between the tangent and the surface of the rock layer to be tested is taken as the known droplet micro-contact angle.
5. The method for determining the microscopic contact angle of rock strata surface according to claim 1, characterized in that, The method of determining the contact angle equation by utilizing the correspondence between liquid-solid interfacial tension, liquid surface tension, and the surface tension of the rock layer under test, as well as the contact line surface tension balance equation, includes: ； + -2 ； ) / ； in, For liquid surface tension, For liquid-solid interfacial tension, The surface tension of the rock stratum to be measured. It represents the contact angle.
6. A device for determining the microscopic contact angle of a rock stratum surface, characterized in that, The device for determining the microscopic contact angle of the rock stratum surface includes: The acquisition module is used to acquire standard sample images of droplets formed by known liquids on the surface of the rock layer to be tested; The known droplet contact angle determination module is used to determine the known droplet contact angle on the surface of the rock layer to be tested using a standard sample image; The contact angle equation determination module is used to determine the contact angle equation by utilizing the correspondence between the liquid-solid interfacial tension, the liquid surface tension, and the surface tension of the rock layer to be measured, as well as the contact line surface tension balance equation; wherein, the contact angle equation is used to represent the correspondence between the contact angle and the droplet surface tension and the surface tension of the rock layer to be measured; The module for determining the surface tension of the rock layer under test is used to determine the surface tension of the rock layer under test using the contact angle equation, the known droplet contact angle, and the known surface tension of the liquid. The test droplet contact angle determination module is used to determine the test droplet contact angle of the droplet formed on the surface of the test rock layer by the test liquid based on the contact angle equation, the surface tension of the test rock layer and the surface tension of the test liquid.
7. The device for determining the microscopic contact angle of rock strata surface according to claim 6, characterized in that, The acquisition of standard sample images of droplets formed by known liquids on the surface of the rock stratum under test includes: Helium ion beam imaging technology was used to obtain standard sample images of droplets formed by known liquids on the surface of the rock layer under test.
8. The device for determining the microscopic contact angle of rock strata surface according to claim 6, characterized in that, The known liquid is an ionic liquid that does not volatilize in a vacuum.
9. The device for determining the microscopic contact angle of rock strata surface according to claim 6, characterized in that, The method of determining the known droplet contact angle on the surface of the rock layer to be tested using a standard sample image includes: In the standard sample image, the origin is the intersection of the known liquid droplet, the rock layer to be tested, and air, and a tangent is drawn along the surface of the known liquid. The angle between the tangent and the surface of the rock layer to be tested is taken as the known droplet contact angle.
10. The device for determining the microscopic contact angle of rock strata surface according to claim 6, characterized in that, The method of determining the contact angle equation by utilizing the correspondence between liquid-solid interfacial tension, liquid surface tension, and the surface tension of the rock layer under test, as well as the contact line surface tension balance equation, includes: ； + -2 ； ) / ； in, For liquid surface tension, For liquid-solid interfacial tension, The surface tension of the rock stratum to be measured. It represents the contact angle.