Wettability testing method, device and equipment

Abstract

The invention relates to the technical field of shale oil and gas reservoir development, in particular to a wettability testing method, device and equipment. The wettability testing method comprises the following steps: acquiring a first adhesive force and a second adhesive force between the tip of a probe and a sampling point on the surface of an organic matter sample; calculating first adhesion work between the tip of the probe and the surface of the organic matter sample according to the first adhesion force, and calculating second adhesion work between the tip of the probe and the surface of the organic matter sample according to the second adhesion force; and determining the wettability of the surface of the organic matter sample according to the first adhesion work and the second adhesion work. According to the embodiment of the invention, the value of the adhesive force between the tip of the probe and the surface of the organic matter sample can be obtained, the wettability of the surface of the organic matter sample under the microphase scale can be simply, conveniently and quickly determined, and then the in-situ wetting characteristics of organic rocks under different reservoir environments can be accurately described; the accuracy of the surface wettability test of the organic matter sample is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of shale oil and gas reservoir development, and specifically to a wettability testing method, device and equipment. Background Art

[0002] Reservoir wettability is a key factor affecting the development of unconventional shale oil and gas resources, controlling the distribution and seepage of fluids in reservoir fractures and pores. However, due to the heterogeneity of organic-rich shale reservoirs, their wettability is affected by the distribution and combination of inorganic and organic matter, making it difficult to fully characterize the wettability of shale reservoirs.

[0003] Existing methods include direct measurement and indirect evaluation. Direct measurement methods usually use experimental methods to directly measure the contact angle of solid surfaces to describe wettability, including sessile droplets, trapped bubbles, μ-CT, and micromodels. Indirect evaluation methods usually collect data related to the contact angle of solid surfaces to evaluate the contact angle to describe wettability, including nuclear magnetic resonance spectroscopy, Amott index method, USBM method, and Lak index method.

[0004] For the above methods, direct measurement is the most commonly used method in oil and gas development, but it is limited in characterizing the wettability of multi-component rocks, and the contact angle measured directly is easily affected by the surface roughness, temperature, pressure and pH of the sample. The indirect evaluation method is also unable to accurately measure the wettability of rocks at the microfacies scale. Therefore, how to establish a simple and fast method for testing the wettability of rock organic matter at the microfacies scale, and then accurately test the wettability of organic-rich rocks in different reservoir environments is a key issue that needs to be solved urgently. Summary of the invention

[0005] The purpose of the embodiments of this specification is to provide a wettability testing method, device and equipment to easily and quickly determine the wettability of the surface of an organic sample at a microphase scale, and to improve the accuracy of the wettability test of the surface of an organic sample.

[0006] On the one hand, an embodiment of the present specification provides a wettability testing method, the method comprising: obtaining a first adhesion force and a second adhesion force between a probe tip and a sampling point on the surface of an organic sample; calculating a first adhesion work between the probe tip and the surface of the organic sample based on the first adhesion force, and calculating a second adhesion work between the probe tip and the surface of the organic sample based on the second adhesion force; and determining the wettability of the surface of the organic sample based on the first adhesion work and the second adhesion work.

[0007] On the other hand, an embodiment of the present specification provides a wettability testing device, which includes: an acquisition module for acquiring a first adhesion force and a second adhesion force between the probe tip and a sampling point on the surface of an organic sample; a calculation module for calculating a first adhesion work between the probe tip and the surface of the organic sample based on the first adhesion force, and calculating a second adhesion work between the probe tip and the surface of the organic sample based on the second adhesion force; and a determination module for determining the wettability of the surface of the organic sample based on the first adhesion work and the second adhesion work.

[0008] In another aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the wettability test method.

[0009] It can be seen from the technical solutions provided in the above embodiments of this specification that the embodiments of this specification obtain the first adhesion force and the second adhesion force between the probe tip and the sampling point on the surface of the organic sample; calculate the first adhesion work between the probe tip and the surface of the organic sample based on the first adhesion force, and calculate the second adhesion work between the probe tip and the surface of the organic sample based on the second adhesion force; determine the wettability of the surface of the organic sample based on the first adhesion work and the second adhesion work. Compared with the existing methods, the embodiments of this specification can obtain the in-situ morphology of the surface of the organic sample and the adhesion force value between the probe tip and the surface of the organic sample, and can easily and quickly determine the wettability of the surface of the organic sample at the microphase scale, and then can accurately describe the in-situ wetting characteristics of organic rocks in different reservoir environments, thereby improving the accuracy of the wettability test of the surface of the organic sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings required for use in the embodiments or the prior art description are briefly introduced below.

[0011] Figure 1 is a flow chart of a wettability testing method provided in an embodiment of this specification;

[0012] Figure 2 It is a plane morphology diagram of the surface research area of ​​the shale organic matter sample under dry conditions provided in the embodiments of this specification;

[0013] Figure 3 It is a three-dimensional morphology map of the surface research area of ​​the shale organic matter sample under dry conditions provided in the embodiments of this specification;

[0014] Figure 4 It is an adhesion image of 16×16 sampling points in a shale organic matter sample study area under dry conditions provided in the embodiments of this specification;

[0015] Figure 5 It is a plane morphology diagram of the research area on the surface of the shale organic matter sample under the wet condition provided in the embodiment of this specification;

[0016] Figure 6 It is a three-dimensional topographic map of the research area on the surface of the shale organic matter sample under the wet condition provided in the embodiment of this specification;

[0017] Figure 7 It is an adhesion image of 16×16 sampling points in the study area of ​​shale organic matter samples under wet conditions provided in the embodiments of this specification;

[0018] Figure 8 It is the contact angle image of the liquid at each sampling point in the study area of ​​the shale organic matter sample under the wetting condition provided in the embodiment of this specification;

[0019] Fig. 9 It is a schematic diagram of the structure of a wettability testing device provided in an embodiment of this specification;

[0020] Fig.10 It is a schematic diagram of the structural composition of a computer device provided in an embodiment of this specification. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this specification.

[0022] Figure 1 The figure is a flow chart of the wettability test method. When implemented, the method includes the following steps:

[0023] S101: Acquire a first adhesion force and a second adhesion force between the probe tip and a sampling point on the surface of the organic sample.

[0024] In some embodiments, before obtaining the first adhesion force and the second adhesion force between the probe tip and the sampling point on the surface of the organic sample, the organic sample can be cut and sampled to produce an organic sample of a size that meets the requirements of the atomic force microscope, and the cut surface of the organic sample can be mechanically milled, subjected to argon ion milling by an ion thinning instrument, and dried in an oven at 60° C. for 24 hours. The organic sample includes a shale organic sample, and the sampling point includes a point on the surface of the organic sample.

[0025] The organic sample can be preliminarily observed using a microscope or the naked eye to determine the area that needs to be cut and mark the cutting line. The shale sample can be fixed on the cutter to ensure stability without shaking. The cutting speed, feed rate and other parameters of the cutter can be adjusted according to the hardness and brittleness of the organic sample, and the cutting can be performed along the marked cutting line, and the cutting surface should be kept flat and vertical. Coarser abrasive sandpaper (such as 120 mesh, 240 mesh) can be used to preliminarily grind the cut surface to remove cutting marks and uneven parts. Finer abrasive sandpaper (such as 400 mesh, 800 mesh, 1200 mesh) can be gradually replaced to further grind the cut surface until the cut surface is relatively smooth. After preliminary mechanical sectioning, an ion thinning instrument can be used for argon ion sectioning. The ion beam energy, beam density, bombardment time and other parameters can be adjusted based on the material of the organic sample to smooth and polish the cut surface. Argon ion profiling is a high-precision sample surface treatment technology. Argon ion profiling uses high-energy argon ion beams to bombard the sample surface, remove surface materials and tiny scratches and defects that may be left by mechanical profiling through physical sputtering, and achieve a polishing effect at the same time. This method can remove tiny scratches and defects left by mechanical profiling, making the sample surface smoother and flatter. The size of the organic sample can be measured using a vernier caliper or microscope micrometer to ensure that it meets the observation requirements of the atomic force microscope. If further adjustment of the size is required, the grinding and argon ion profiling can be repeated until the required size is reached. After determining that the size of the organic sample meets the requirements, the organic sample can be placed in an oven to dry, thereby removing moisture or other volatile substances that may be adsorbed by the organic sample during the argon ion profiling process. The oven temperature of 60°C can be selected to effectively remove moisture without causing thermal damage to most samples. The drying time can be set to 24 hours to ensure that the organic sample is fully dried to avoid problems caused by residual moisture during subsequent observation or analysis.

[0026] Through a series of processing steps including mechanical grinding, argon ion polishing and drying, organic samples with flat, smooth and dry surfaces can be prepared, providing a high-quality sample basis for subsequent microscopic observation and organic wettability analysis.

[0027] In some embodiments, before obtaining the first adhesion force and the second adhesion force between the probe tip and the sampling point on the surface of the organic sample, the processed organic sample may be placed on an atomic force microscope stage and the atomic force microscope probe may be calibrated.

[0028] On the premise of ensuring that the stage of the atomic force microscope is clean and free of impurities, the processed organic sample can be placed on the stage using tweezers or a special sample holding tool. Make sure that the sample surface is parallel to the stage and that the sample position is stable and does not move or tilt during scanning. The probe of the atomic force microscope can be mounted on the probe arm, and make sure that the appropriate distance between the probe tip and the sample surface is maintained. The shape and state of the probe tip can be checked using the imaging system of the atomic force microscope to ensure that the probe tip is not damaged, contaminated or deformed. Based on the option of the atomic force microscope probe calibration, the calibration procedure can be started to make the probe contact the sample surface, measure the contact force, adjust the scanning parameters, etc. A calibration evaluation report for the atomic force microscope or can be obtained to check whether the contact force, scanning speed, scanning range, etc. in the report are as expected, and can be adjusted as needed.

[0029] By placing the processed organic sample on the atomic force microscope stage and performing probe calibration, it can be ensured that the probe can accurately sense the morphology of the organic sample surface and produce reliable measurement results, providing a high-quality measurement basis for subsequent wettability analysis of the organic sample.

[0030] In some embodiments, before obtaining the first adhesion force and the second adhesion force between the probe tip and the sampling point on the surface of the organic sample, a research area on the surface of the organic sample may be determined; the research area includes a plurality of sampling points.

[0031] The surface of the organic sample can be imaged by the tapping mode of the atomic force microscope, and the research area can be determined by comparing the surface of the organic sample with the scanning electron microscope. The tapping mode of the atomic force microscope reduces damage to the sample and improves the imaging resolution by vibrating the probe at a certain frequency and gently tapping the sample surface. The scanning parameters such as the scanning range, scanning speed, probe vibration frequency and amplitude of the atomic force microscope can be adjusted according to the hardness and brittleness of the organic sample. By allowing the probe to perform topographic imaging in the organic area, the small displacement changes when the probe interacts with the surface of the organic sample can be obtained, so that a three-dimensional topographic map of the surface of the organic sample can be constructed. After the three-dimensional topographic map of the surface of the organic sample is generated by the atomic force microscope, a scanning electron microscope can be used to observe a part of the surface of the organic sample according to the three-dimensional topographic map generated by the atomic force microscope or prior knowledge to generate an observation image, and the generated observation image can be a high-resolution observation image. Prior knowledge can be, for example, a relatively smooth area suitable for observation that is pre-marked with a dividing line. Compared with atomic force microscopy, the resolution of scanning electron microscopy can reach the nanometer level, even close to the atomic level. Scanning electron microscopy can provide a wider field of view and deeper information about organic samples, such as surface morphology, chemical composition, and crystal structure. SEM can provide a wider field of view and deeper sample information, such as surface morphology, chemical composition, and crystal structure. The high-resolution observation image generated by the scanning electron microscope can be compared with the three-dimensional morphology map generated by the atomic force microscope. According to the image area with a roughness less than or equal to the set roughness threshold in the high-resolution observation image generated by the electron microscope, the corresponding research area can be further determined in the three-dimensional morphology map generated by the atomic force microscope. Roughness can indicate the degree of undulation of the image area. The roughness of the image area can be obtained by calculating the variance of the image area, or the standard deviation. For example, the high-resolution observation image can be grayed, and the standard deviation in each image area can be calculated to obtain the roughness of each image area, and then the image area with a roughness less than the set roughness threshold can be selected as the research area. Reference Figure 2 and Figure 3 , Figure 2 The plane morphology of the study area on the surface of the shale organic matter sample under dry conditions is shown. Figure 3 The three-dimensional morphology of the study area on the surface of a shale organic matter sample under dry conditions is shown.

[0032] By comparing the high-resolution images produced by the scanning electron microscope with the three-dimensional topography produced by the atomic force microscope, a more appropriate research area as well as the precise location and scope can be determined.

[0033] In some embodiments, a dried organic sample can be obtained; a first adhesion force between the probe tip and a sampling point in a study area of ​​the organic sample under dry conditions can be obtained; a wetted organic sample can be obtained; and a second adhesion force between the probe tip and a sampling point in a study area of ​​the organic sample under wet conditions can be obtained.

[0034] After determining the research area on the surface of the organic matter sample, the organic matter sample can be directly obtained after mechanical grinding, argon ion profiling and drying and placed on the stage of the atomic force microscope for testing in a dry state.

[0035] In some embodiments, the viscoelastic properties of the surface of an organic sample can be evaluated by the interaction force between the probe and the sample surface.

[0036] The surface adhesion test can be performed on all sampling points in the study area of ​​the organic sample under dry conditions by the AFM viscoelastic mapping mode. The AFM works by the interaction force between the probe and the sample surface. In the viscoelastic mapping mode, the AFM not only measures static or dynamic vertical forces, but also evaluates the viscoelastic properties of the sample surface, including adhesion and energy dissipation, through specific loading and unloading processes. The speed at which the probe tip approaches and leaves the sample surface and the force applied when the probe tip contacts the sample surface can be set to control the dynamic process of the test. The first adhesion force between the probe tip and the sampling points in the study area of ​​the organic sample under dry conditions can be obtained in real time from the AFM during the dynamic process. Reference Figure 4 , Figure 4 An adhesion image of 16×16 sampling points of the study area of ​​shale organic matter samples under dry conditions is shown.

[0037] After obtaining the first adhesion force corresponding to all sampling points in the study area of ​​the surface of the organic sample under dry conditions, the dry organic sample can be removed from the stage of the atomic force microscope. The dry organic sample can be placed in an atmosphere with a relative humidity of 97% (20°C, -0.95MPa) provided by a supersaturated potassium sulfate solution to wet the sample. The relative humidity is set to 97%, which means that the water vapor content in the air is very close to the saturated vapor pressure of water at this temperature, so the sample can fully absorb moisture and achieve a good wetting effect. The temperature is set to 20°C to maintain the stability and repeatability of the experimental conditions. By placing the dry organic sample in an environment with a relative humidity of 97% and a temperature of 20°C provided by a supersaturated potassium sulfate solution, the sample can fully absorb moisture and achieve the purpose of wetting. The wetted organic sample can be placed on the stage of the atomic force microscope again, and the appropriate scanning parameters such as scanning speed, scanning range, and resolution can be selected to scan and image the study area of ​​the organic sample. The scanned image can be compared with the previously recorded scanned image of the study area under dry conditions to confirm that the scanned area is indeed the study area. Reference Figure 5 and Figure 6 , Figure 5 The plane morphology of the study area on the surface of the shale organic matter sample under wet conditions is shown. Figure 6 The three-dimensional morphology of the study area on the surface of the shale organic matter sample under wet conditions is shown.

[0038] The surface adhesion force test can be performed on all sampling points in the organic sample study area under wetting conditions by the AFM viscoelastic mapping mode. The speed at which the probe tip approaches and leaves the sample surface and the force applied when the probe tip contacts the sample surface can be set to control the dynamic process of the test. The secondary adhesion force between the probe tip and the sampling points in the organic sample study area under wetting conditions can be obtained in real time from the AFM during the dynamic process. Figure 7 , Figure 7 Adhesion force images of 16×16 sampling points in the study area of ​​shale organic matter samples under wet conditions are shown.

[0039] By obtaining the first adhesion force and the second adhesion force between the probe tip and the sampling point in dry and wet conditions respectively, a measurement foundation is laid for characterizing the adhesion work between the probe tip and the surface of the organic sample in dry and wet conditions based on the adhesive contact theory.

[0040] S102: Calculating a first adhesion work between the probe tip and the surface of the organic sample according to the first adhesion force, and calculating a second adhesion work between the probe tip and the surface of the organic sample according to the second adhesion force.

[0041] In some embodiments, an implicit relationship between the adhesion force and the adhesion work between two solid surfaces can be established based on the JKR adhesive contact theory, as shown in the following formula:

[0042]

[0043] Where: F is the adhesion force between two solid surfaces; r is the effective contact radius of the two solid surfaces; W is the adhesion work between the two solid surfaces. The JKR adhesive contact theory characterizes the existence of an elastic deformation region between two solid surfaces. This deformation region is called the contact region. In the contact region, due to the effect of surface energy, the two solid surfaces will attract each other and generate adhesion force. In the contact region, the conversion relationship between the adhesion force and adhesion work between the two solid surfaces can be calculated by formula (1).

[0044] In some embodiments, the first adhesion work and the second adhesion work may be calculated according to the following formula based on the JKR adhesive contact theory:

[0045]

[0046] Where: is the first adhesion force between the probe tip and the sampling point in the organic sample research area under dry conditions; R is the radius of curvature of the probe tip; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is a second adhesion force between the probe tip and a sampling point in the organic sample study area under a wetted condition; It is the second adhesion work between the probe tip and the surface of the organic sample under wet conditions.

[0047] By calculating the adhesion work corresponding to the dry and wet conditions, a data foundation was laid for the subsequent establishment of the first adhesion model and the determination of the wettability of the surface of organic samples.

[0048] S103: Determine the wettability of the surface of the organic sample according to the first adhesion work and the second adhesion work.

[0049] In some embodiments, a first contact angle of the liquid at the probe tip can be obtained; based on the first contact angle, a third adhesion work between the probe tip and the liquid surface can be calculated; based on the first adhesion work, the second adhesion work and the third adhesion work, the second contact angle of the liquid on the organic sample surface can be calculated; and the wettability of the organic sample surface can be determined based on the second contact angles corresponding to all sampling points in the organic sample research area.

[0050] By calculating the second contact angle of the liquid on the surface of the organic sample through the first adhesion work, the second adhesion work and the third adhesion work, the wettability of the sampling point in the organic sample research area can be determined simply and conveniently, and then the wettability of the organic sample surface can be determined.

[0051] When the surface adhesion test is performed on all sampling points in the surface study area of ​​the organic sample under wetting conditions through the atomic force microscope viscoelastic mapping mode, the atomic force microscope can display the first contact angle of the liquid at the probe tip corresponding to any sampling point position in real time, and then the first contact angle of the liquid at the probe tip corresponding to any sampling point position in the surface study area of ​​the organic sample can be obtained.

[0052] The third adhesion work between the probe tip and the liquid surface can be defined as the surface energy of the probe tip plus the surface energy of the liquid minus the interfacial energy between the probe tip and the liquid surface, as shown in the following formula:

[0053]

[0054] Where: is the third adhesion work between the probe tip and the liquid surface; γ tip is the surface energy of the probe tip; γ water is the surface energy of the liquid; γ tip,water is the interfacial energy between the probe tip and the liquid surface.

[0055] Based on Young's equation, the surface energy of the probe tip can be expressed as the sum of the interfacial energy between the probe tip and the liquid surface and the surface energy of the liquid multiplied by the cosine value of the first contact angle of the liquid at the probe tip, as shown in the following formula:

[0056]

[0057] Where: γ tip is the surface energy of the probe tip; γ tip,water is the interfacial energy between the probe tip and the liquid surface; γ water is the surface energy of the liquid; is the first contact angle of the liquid at the probe tip. Young's equation can be defined as the surface energy of the solid equal to the sum of the interfacial energy between the solid surface and the liquid surface and the surface energy of the liquid multiplied by the cosine of the contact angle of the liquid on the solid surface.

[0058] Formula (5) can be substituted into formula (4) to obtain the following formula:

[0059]

[0060] Where: is the third adhesion work between the probe tip and the liquid surface; γ wateris the surface energy of the liquid; is the second contact angle of the liquid on the probe tip.

[0061] After obtaining the first contact angle of the liquid at the probe tip corresponding to any sampling point in the organic sample surface study area, the third adhesion work between the probe tip and the liquid surface corresponding to any sampling point in the organic sample surface study area can be determined by the above formula (8).

[0062] In some embodiments, when the first adhesion work, the second adhesion work, the third adhesion work and the liquid surface energy are determined, the second contact angle of the liquid on the surface of the organic sample at any sampling point can be calculated.

[0063] The contact angle can be a measure of the degree of wetting of a solid surface by a liquid. The contact angle can be the angle between the liquid-solid interface and the tangent line of the liquid surface when the liquid forms a specific shape on the solid surface. When the contact angle is less than 90 degrees, it means that the solid is wetted by the liquid, and the smaller the angle, the better the wettability. When the contact angle is equal to 0 degrees, it means complete wetting, that is, the liquid spreads freely on the solid surface. When the contact angle is greater than 90 degrees, it means that the liquid does not wet the solid, and the larger the angle, the stronger the non-wettability. When the contact angle is equal to 180 degrees, it means no wetting at all.

[0064] The second contact angle of the liquid on the surface of the organic sample at any sampling point can be calculated according to the following formula:

[0065]

[0066] Where: is the second contact angle of the liquid on the surface of the organic sample; arccos(·) is the inverse cosine function; is the first adhesion work between the probe tip and the sampling point surface; is the second adhesion work between the probe tip and the surface of the organic sample; is the third adhesion work between the probe tip and the liquid surface; is the fourth adhesion work between the organic sample surface and the liquid surface; γ water is the surface energy of the liquid.

[0067] Based on the above formula (9), the second contact angle corresponding to all sampling points in the organic sample research area can be calculated. Figure 8 , Figure 8The contact angle of the liquid on the surface of the organic sample calculated for all sampling points in the shale organic sample study area based on formula (9) is shown. The second contact angles corresponding to all sampling points are fused to obtain a third contact angle that can characterize the wettability of the surface of the organic sample. The fusion can be a simple arithmetic average of the second contact angle data corresponding to all sampling points, or a more complex weighted superposition. For example, the arithmetic average of the second contact angle data corresponding to all sampling points can be taken to generate a third contact angle that can characterize the wettability of the surface of the organic sample, and then the wettability of the surface of the organic sample can be measured. For another example, a weight factor can be assigned to different sampling points based on the three-dimensional morphological characteristics of the area where each sampling point is located. Specifically, the fluctuation variance of the area can be calculated based on the three-dimensional morphological characteristics of the area where each sampling point is located, the inverse of the fluctuation variance is taken, and the fluctuation variance after taking the inverse of all sampling points is normalized, and then the weight factor corresponding to each sampling point can be obtained. The weight factor of each sampling point can also be calculated according to other methods, which will not be repeated here. A weighted average value can be taken according to the second contact angle data corresponding to each sampling point and the weight factor to generate a third contact angle that can characterize the wettability of the surface of the organic sample, and then the wettability of the surface of the organic sample can be determined.

[0068] In some embodiments, a fourth work of adhesion between the surface of the organic sample and the surface of the liquid can be calculated based on the first work of adhesion, the second work of adhesion, and the third work of adhesion; and a second contact angle of the liquid on the surface of the organic sample can be calculated based on the fourth work of adhesion.

[0069] In some embodiments, a first contact angle of the liquid at the probe tip can be obtained; a third adhesion work between the probe tip and the liquid surface can be calculated based on the first contact angle; and a fourth adhesion work between the organic sample surface and the liquid surface can be calculated based on the following formula, provided that the first adhesion work, the second adhesion work, and the third adhesion work are determined:

[0070]

[0071] Where: is the fourth adhesion work between the surface of the organic sample and the surface of the liquid; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is the second adhesion work between the probe tip and the surface of the organic sample in a wet state; is the third adhesion work between the probe tip and the liquid surface; γ water Is a constant quantity representing the surface energy of the liquid.

[0072] The fourth adhesion work between the organic sample surface and the liquid surface is calculated through the first adhesion work, the second adhesion work and the third adhesion work, which lays a data foundation for the subsequent calculation of the second contact angle of the liquid on the organic sample surface.

[0073] The fourth adhesion work between the organic sample surface and the liquid surface can be defined as the surface energy of the organic sample surface plus the surface energy of the liquid minus the interfacial energy between the organic sample surface and the liquid surface, as shown in the following formula:

[0074]

[0075] Where: is the fourth adhesion work between the organic sample surface and the liquid surface; γ sample is the surface energy of the organic sample surface; γ water is the surface energy of the liquid; γ sample,water is the interfacial energy between the organic sample surface and the liquid surface.

[0076] Based on Young's equation, the surface energy of the organic sample surface can be expressed as the sum of the interfacial energy between the organic sample surface and the liquid surface and the surface energy of the liquid multiplied by the cosine value of the second contact angle of the liquid on the organic sample surface, as shown in the following formula:

[0077]

[0078] Where: γ sample is the surface energy of the sampling point; γ sample,water is the interfacial energy between the organic sample surface and the liquid surface; γ water is the surface energy of the liquid; is the second contact angle of the liquid on the surface of the organic sample.

[0079] Formula (12) can be substituted into formula (11) to obtain the following formula:

[0080]

[0081] Where: is the fourth adhesion work between the organic sample surface and the liquid surface; γ water is the surface energy of the liquid; is the second contact angle of the liquid on the surface of the organic sample.

[0082] Based on formula (15), the following formula can be obtained:

[0083]

[0084] Where: is the second contact angle of the liquid on the surface of the organic sample; is the fourth adhesion work between the organic sample surface and the liquid surface; γ water is the surface energy of the liquid.

[0085] In some embodiments, under the premise that the fourth adhesion work between the organic sample surface and the liquid surface in the organic sample research area is determined, the second contact angle of the liquid on the organic sample surface can be determined using formula (16). The second contact angles corresponding to all sampling points in the organic sample research area can be calculated using formula (16), and then the second contact angles corresponding to all sampling points can be merged to determine the wettability of the organic sample surface.

[0086] By directly calculating the second contact angle of the liquid on the surface of the organic sample through the fourth adhesion work, the wettability near the sampling point in the organic sample research area can be simply and conveniently determined, and then the wettability of the organic sample surface can be determined.

[0087] The second adhesion work between the probe tip and the organic sample surface under wetting conditions can be defined as the sum of the interfacial energy between the probe tip and the organic sample surface, the interfacial energy between the probe tip and the liquid surface, and the interfacial energy between the organic sample surface and the liquid surface, as shown in the following formula:

[0088]

[0089] Where: is the second adhesion work between the probe tip and the surface of the organic sample; γ tip,sample is the interfacial energy between the probe tip and the surface of the organic sample; γ tip,water is the interfacial energy between the probe tip and the liquid surface; γ sample,water is the interfacial energy between the organic sample surface and the liquid surface.

[0090] Based on the above formula (4) and formula (11), we can get as well as These two expressions can be substituted into the above formula (17) to obtain the following formula:

[0091]

[0092] Where: is the second adhesion work between the probe tip and the surface of the organic sample; γ tip,sample is the interfacial energy between the probe tip and the surface of the organic sample; γ tip is the surface energy of the probe tip; γ sample is the surface energy of the sampling point; is the third adhesion work between the probe tip and the liquid surface; is the fourth adhesion work between the organic sample surface and the liquid surface; γ water is the surface energy of the liquid.

[0093] The first adhesion work between the probe tip and the organic sample surface under dry conditions can be defined as the sum of the surface energy of the probe tip, the surface energy of the organic sample surface, and the interface energy between the probe tip and the organic sample surface. The specific formula is as follows:

[0094]

[0095] Where: is the first adhesion work between the probe tip and the organic sample surface; γ tip,sample is the interfacial energy between the probe tip and the surface of the organic sample; γ tip is the surface energy of the probe tip; γ sample is the surface energy of the sampling point.

[0096] Formula (20) can be substituted into formula (19) to obtain formula (10). Under the premise that the first adhesion work, the second adhesion work and the third adhesion work are determined, the fourth adhesion work between the surface of the organic sample and the liquid surface can be calculated according to formula (10).

[0097] When the first adhesion work, the second adhesion work, and the third adhesion work are determined, formula (10) and formula (15) can be combined. Specifically, formula (15) can be substituted into formula (10) to obtain the solution formula for the second contact angle, that is, formula (9). Based on formula (9), the second contact angles corresponding to all sampling points in the organic sample research area can be calculated, and then the second contact angles corresponding to all sampling points can be merged to determine the wettability of the organic sample surface.

[0098] It can be seen from the technical solutions provided in the above embodiments of this specification that the embodiments of this specification obtain the first adhesion force and the second adhesion force between the probe tip and the sampling point on the surface of the organic sample; calculate the first adhesion work between the probe tip and the surface of the organic sample based on the first adhesion force, and calculate the second adhesion work between the probe tip and the surface of the organic sample based on the second adhesion force; determine the wettability of the surface of the organic sample based on the first adhesion work and the second adhesion work. Compared with the existing methods, the embodiments of this specification can obtain the adhesion force value between the probe tip and the surface of the organic sample, and can easily and quickly determine the wettability of the surface of the organic sample at the microphase scale, and then can accurately describe the in-situ wetting characteristics of organic rocks in different reservoir environments, thereby improving the accuracy of the wettability test of the surface of the organic sample.

[0099] Based on the above wettability test method, this specification also provides an embodiment of a wettability test device. Fig. 9 As shown, the evaluation device may specifically include the following modules:

[0100] An acquisition module 901 may be used to acquire a first adhesion force and a second adhesion force between the probe tip and a sampling point on the surface of the organic sample;

[0101] A calculation module 902 may be used to calculate a first adhesion work between the probe tip and the surface of the organic sample according to the first adhesion force, and to calculate a second adhesion work between the probe tip and the surface of the organic sample according to the second adhesion force;

[0102] The determination module 903 may be used to determine the wettability of the surface of the organic sample according to the first adhesion work and the second adhesion work.

[0103] In some embodiments, the acquisition module 901 can be specifically used to determine a research area on the surface of an organic sample; the research area includes a plurality of sampling points.

[0104] In some embodiments, the above-mentioned acquisition module 901 can also be used to obtain a dried organic sample; obtain a first adhesion force between the probe tip and a sampling point in the organic sample research area under dry conditions; obtain a wetted organic sample; and obtain a second adhesion force between the probe tip and a sampling point in the organic sample research area under wet conditions.

[0105] In some embodiments, the calculation module 902 may be specifically configured to calculate the first adhesion work and the second adhesion work according to the following formula:

[0106]

[0107] Where: is the first adhesion force between the probe tip and the sampling point in the organic sample research area under dry conditions; R is the radius of curvature of the probe tip; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is a second adhesion force between the probe tip and a sampling point in the organic sample study area under a wetted condition; It is the second adhesion work between the probe tip and the surface of the organic sample under wetted condition.

[0108] In some embodiments, the determination module 903 can be specifically used to obtain a first contact angle of the liquid at the probe tip;

[0109] calculating a third adhesion work between the probe tip and the liquid surface according to the first contact angle;

[0110] Based on the first adhesion work, the second adhesion work and the third adhesion work, the second contact angle of the liquid on the surface of the organic sample is calculated according to the following formula:

[0111]

[0112] Where: is the second contact angle of the liquid on the surface of the organic sample; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is the second adhesion work between the probe tip and the surface of the organic sample in a wet state; is the third adhesion work between the probe tip and the liquid surface; γ water is a constant quantity, representing the surface energy of the liquid;

[0113] The wettability of the surface of the organic sample is determined according to the second contact angle.

[0114] In some embodiments, the above-mentioned determination module 903 can also be specifically used to obtain a first contact angle of the liquid on the probe tip; based on the first contact angle, calculate the third adhesion work between the probe tip and the liquid surface; based on the first adhesion work, the second adhesion work and the third adhesion work, calculate the fourth adhesion work between the organic sample surface and the liquid surface; based on the fourth adhesion work, calculate the second contact angle of the liquid on the organic sample surface.

[0115] In some embodiments, the determination module 903 may be further configured to calculate the fourth adhesion work between the surface of the organic sample and the surface of the liquid according to the following formula:

[0116]

[0117] Where: is the fourth adhesion work between the surface of the organic sample and the surface of the liquid; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is the second adhesion work between the probe tip and the surface of the organic sample in a wet state; is the third adhesion work between the probe tip and the liquid surface; γ water Is a constant quantity representing the surface energy of the liquid.

[0118] In some embodiments, the determination module 903 may also be used to calculate the second contact angle of the liquid on the surface of the organic sample according to the following formula:

[0119]

[0120] Where: is the second contact angle of the liquid on the surface of the organic sample; is the fourth adhesion work between the surface of the organic sample and the surface of the liquid; γ water Is a constant quantity representing the surface energy of the liquid.

[0121] It should be noted that the units, devices or modules described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. For the convenience of description, the above devices are described separately by functions divided into various modules. Of course, when implementing this specification, the functions of each module can be implemented in the same or more software and / or hardware, or the modules that implement the same function can be implemented by a combination of multiple sub-modules or sub-units. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0122] As can be seen from the above, based on the wettability testing device provided in the embodiments of this specification, the in-situ morphology of the surface of the organic sample and the adhesion value between the probe tip and the surface of the organic sample can be obtained, the wettability of the surface of the organic sample at the microphase scale can be determined simply and quickly, and then the in-situ wetting characteristics of organic rocks in different reservoir environments can be accurately described, thereby improving the accuracy of the wettability test of the surface of the organic sample.

[0123] In order to complete the above instructions more accurately, refer to Fig.10 As shown, an embodiment of this specification also provides a computer device based on the wettability testing method, wherein the computer device includes a network communication port 1001, a processor 1002 and a memory 1003, and the above structures are connected through internal cables so that each structure can perform specific data interaction.

[0124] In the embodiments of this specification, the network communication port 1001 can be a virtual port that is bound to different communication protocols to send or receive different data. For example, the network communication port 1001 can be a port responsible for web data communication, or it can also be a port responsible for FTP data communication, or it can also be a port responsible for email data communication. In addition, the network communication port 1001 can be a physical communication interface or communication chip. For example, the network communication port 1001 can be a wireless mobile network communication chip. For example, the network communication port 1001 can be a wireless mobile network communication chip that supports protocols such as GSM and CDMA. The network communication port 1001 can also be a Wifi chip or a Bluetooth chip, etc.

[0125] The processor 1002 can be specifically used to obtain a first adhesion force and a second adhesion force between the probe tip and a sampling point on the surface of the organic sample; calculate a first adhesion work between the probe tip and the surface of the organic sample based on the first adhesion force, and calculate a second adhesion work between the probe tip and the surface of the organic sample based on the second adhesion force; and determine the wettability of the surface of the organic sample based on the first adhesion work and the second adhesion work.

[0126] In the embodiments of this specification, the processor 1002 may be implemented in any appropriate manner. For example, the processor 1002 may take the form of a microprocessor or processor and a computer-readable medium storing a computer-readable program code (such as software or firmware) executable by the (micro)processor, a logic gate, a switch, an application-specific integrated circuit (ASIC), a programmable logic controller, and an embedded microcontroller, etc. This specification does not limit this.

[0127] The memory 1003 is specifically used to store corresponding instruction programs.

[0128] In the embodiments of this specification, the memory 1003 includes volatile memory and non-volatile memory. In digital systems, anything that can store binary data can be a memory; in integrated circuits, a circuit with storage function without a physical form is also called a memory, such as RAM, FIFO, etc.; in computer systems, a storage device with a physical form is also called a memory, such as a memory stick, TF card, etc.

[0129] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0130] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0131] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0132] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0133] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wettability testing method, characterized in that: include: obtaining a first adhesion force and a second adhesion force between the probe tip and a sampling point on the surface of the organic sample; Calculating a first adhesion work between the probe tip and the surface of the organic sample according to the first adhesion force, and calculating a second adhesion work between the probe tip and the surface of the organic sample according to the second adhesion force; The wettability of the surface of the organic sample is determined according to the first adhesion work and the second adhesion work.

2. The method according to claim 1, characterized in that The method further comprises: A study area on the surface of the organic matter sample is determined; the study area includes a plurality of sampling points.

3. The method according to claim 1, characterized in that The method of obtaining the first adhesion force and the second adhesion force between the probe tip and the sampling point on the surface of the organic sample comprises: Obtaining dried organic matter samples; obtaining a first adhesion force between the probe tip and a sampling point in a research area of ​​the organic sample in a dry state; Obtain wetted organic matter samples; A second adhesion force is obtained between the probe tip and a sampling point in the organic sample research area under a wetting condition.

4. The method according to claim 1, characterized in that: The step of calculating a first adhesion work between the probe tip and the surface of the organic sample according to the first adhesion force, and calculating a second adhesion work between the probe tip and the surface of the organic sample according to the second adhesion force, comprises: The first adhesion work and the second adhesion work are calculated according to the following formula: Where: is the first adhesion force between the probe tip and the sampling point in the organic sample research area under dry conditions; R is the radius of curvature of the probe tip; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is a second adhesion force between the probe tip and a sampling point in the organic sample study area under a wetted condition; It is the second adhesion work between the probe tip and the surface of the organic sample under wet conditions.

5. The method according to claim 1, characterized in that Determining the wettability of the surface of the organic sample according to the first adhesion work and the second adhesion work includes: Obtaining a first contact angle of the liquid at the tip of the probe; calculating a third adhesion work between the probe tip and the liquid surface according to the first contact angle; Based on the first adhesion work, the second adhesion work and the third adhesion work, the second contact angle of the liquid on the surface of the organic sample is calculated according to the following formula: Where: is the second contact angle of the liquid on the surface of the organic sample; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is the second adhesion work between the probe tip and the surface of the organic sample in a wet state; is the third adhesion work between the probe tip and the liquid surface; γ water is a constant quantity, representing the surface energy of the liquid; The wettability of the surface of the organic sample is determined according to the second contact angle.

6. The method according to claim 1, characterized in that Determining the wettability of the surface of the organic sample according to the first adhesion work and the second adhesion work includes: Obtaining a first contact angle of the liquid at the tip of the probe; calculating a third adhesion work between the probe tip and the liquid surface according to the first contact angle; Calculating a fourth adhesion work between the surface of the organic sample and the surface of the liquid according to the first adhesion work, the second adhesion work and the third adhesion work; A second contact angle of the liquid on the surface of the organic sample is calculated according to the fourth adhesion work.

7. The method according to claim 6, characterized in that The calculating, based on the first adhesion work, the second adhesion work and the third adhesion work, a fourth adhesion work between the surface of the organic sample and the surface of the liquid comprises: The fourth adhesion work between the organic sample surface and the liquid surface is calculated according to the following formula: Where: is the fourth adhesion work between the surface of the organic sample and the surface of the liquid; is the first adhesion work between the probe tip and the surface of the organic sample in a dry state; is the second adhesion work between the probe tip and the surface of the organic sample in a wet state; is the third adhesion work between the probe tip and the liquid surface; γ water Is a constant quantity representing the surface energy of the liquid.

8. The method according to claim 6, characterized in that Calculating a second contact angle of the liquid on the surface of the organic sample according to the fourth adhesion work includes: The second contact angle of the liquid on the surface of the organic sample is calculated according to the following formula: Where: is the second contact angle of the liquid on the surface of the organic sample; is the fourth adhesion work between the surface of the organic sample and the surface of the liquid; γ water Is a constant quantity representing the surface energy of the liquid.

9. A wettability testing device, characterized in that: The device comprises: An acquisition module, used for acquiring a first adhesion force and a second adhesion force between the probe tip and a sampling point on the surface of the organic sample; a calculation module, configured to calculate a first adhesion work between the probe tip and the surface of the organic sample according to the first adhesion force, and to calculate a second adhesion work between the probe tip and the surface of the organic sample according to the second adhesion force; The determination module is used to determine the wettability of the surface of the organic sample according to the first adhesion work and the second adhesion work.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

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