A wetting test method, apparatus and device

Abstract

The present specification relates to the technical field of shale oil and gas reservoir development, and particularly relates to a wettability testing method, device and equipment. The wettability testing method comprises: obtaining a first adhesion force and a second adhesion force between a probe tip and a sampling point on a surface of an organic matter sample; calculating a first adhesion work between the probe tip and the surface of the organic matter sample according to the first adhesion force, and calculating a second adhesion work between the probe tip 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. The present specification can obtain the adhesion force value between the probe tip and the surface of the organic matter sample, can simply and quickly determine the wettability of the surface of the organic matter sample at the microfacies scale, and can accurately describe the in-situ wettability characteristics of the organic rock under different reservoir environments, thereby improving the accuracy of the wettability testing of the surface of the organic matter sample.

Description

Technical Field

[0001] The embodiments of this invention relate to the field of shale oil and gas reservoir development technology, specifically to a wettability testing method, apparatus, and equipment. Background Technology

[0002] Reservoir wettability is a key factor in 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 shale reservoir wettability.

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

[0004] Of the methods mentioned above, direct measurement is the most commonly used in oil and gas development, but it has limitations in characterizing the wettability of multi-component rocks, and the contact angle measured directly is easily affected by sample surface roughness, temperature, pressure, and pH. Indirect assessment methods also cannot accurately measure wettability at the microphase scale of rocks. Therefore, establishing a simple and rapid method for testing the wettability of organic matter in rocks at the microphase scale, and thus accurately testing the wettability of organic-rich rocks in different reservoir environments, is a crucial problem that urgently needs to be solved. Summary of the Invention

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

[0006] On one hand, embodiments of this specification provide 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 matter sample; calculating a first adhesion work between the probe tip and the surface of the organic matter sample based on the first adhesion force, and calculating a second adhesion work between the probe tip and the surface of the organic matter sample based on the second adhesion force; and determining the wettability of the surface of the organic matter sample based on the first adhesion work and the second adhesion work.

[0007] In another aspect, embodiments of this specification provide a wettability testing device, the device comprising: an acquisition module for acquiring a first adhesion force and a second adhesion force between a probe tip and a sampling point on the surface of an organic matter sample; a calculation module for calculating a first adhesion work between the probe tip and the surface of the organic matter sample based on the first adhesion force, and calculating a second adhesion work between the probe tip and the surface of the organic matter sample based on the second adhesion force; and a determination module for determining the wettability of the surface of the organic matter sample based on the first adhesion work and the second adhesion work.

[0008] In another aspect, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor performs the above-described wettability test method.

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

[0010] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below.

[0011] Figure 1 This is a flowchart of a wettability test method provided in the embodiments of this specification;

[0012] Figure 2 This is a planar topographic diagram of the surface study area of ​​a shale organic matter sample under dry conditions, provided in the embodiments of this specification.

[0013] Figure 3 This is a three-dimensional morphology diagram of the surface study area of ​​a shale organic matter sample under dry conditions, provided in the embodiments of this specification.

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

[0015] Figure 5 This is a planar topographic diagram of the surface study area of ​​a shale organic matter sample under wetted conditions, provided in the embodiments of this specification.

[0016] Figure 6 This is a three-dimensional morphology diagram of the surface study area of ​​the shale organic matter sample under wetted conditions provided in the embodiments of this specification;

[0017] Figure 7 This is an adhesion force image of 16×16 sampling points in the study area of ​​a shale organic matter sample under wettability, provided in the embodiments of this specification.

[0018] Figure 8 These are contact angle images of the liquid under wetting conditions at various sampling points in the shale organic matter sample study area, provided in the embodiments of this specification.

[0019] Figure 9 This is a schematic diagram of the structural composition of a wettability testing device provided in the embodiments of this specification;

[0020] Figure 10 This is a schematic diagram of the structural composition of the computer device provided in the embodiments of this specification. Detailed Implementation

[0021] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0022] Figure 1 This is a flowchart of the wettability test method. In practice, the method includes the following steps:

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

[0024] In some embodiments, before obtaining the first and second adhesion forces between the probe tip and the sampling points on the surface of the organic matter sample, the organic matter sample can be cut to prepare an organic matter sample that meets the size requirements of the atomic force microscope. The cut surfaces of the organic matter sample can be mechanically ground, subjected to argon ion thinning, and dried in an oven at 60°C for 24 hours. The organic matter sample includes shale organic matter samples, and the sampling points include points on the surface of the organic matter sample.

[0025] Organic samples can be initially observed using a microscope or the naked eye to determine the areas requiring cutting and mark the cutting lines. The shale sample should be fixed to the cutting machine to ensure stability and prevent shaking. The cutting speed, feed rate, and other parameters of the cutting machine can be adjusted according to the hardness and brittleness of the organic sample. Cutting should be performed along the marked cutting lines, maintaining a flat and perpendicular cut surface. Coarse abrasive paper (such as 120-grit or 240-grit) can be used for initial grinding of the cut surface to remove cutting marks and uneven areas. Finer abrasive paper (such as 400-grit, 800-grit, or 1200-grit) can be gradually used for further grinding until the cut surface is relatively smooth. After initial mechanical grinding, argon ion sectioning can be performed using an ion thinner. Parameters such as ion beam energy, beam density, and bombardment time can be adjusted based on the material of the organic sample to smooth and polish the cut surface. Argon ion sputtering is a high-precision sample surface treatment technique. It utilizes a high-energy argon ion beam to bombard the sample surface, removing surface materials and minor scratches and defects that may be left by mechanical grinding through physical sputtering, while simultaneously achieving a polishing effect. This method removes minor scratches and defects left by mechanical grinding, making the sample surface smoother and more even. The dimensions of organic samples can be measured using calipers or micrometers to ensure they meet the observation requirements of atomic force microscopy. If further adjustments are needed, grinding and argon ion sputtering can be repeated until the desired dimensions are achieved. After confirming that the organic sample dimensions meet the requirements, it can be dried in an oven to remove any moisture or other volatile substances that may have been adsorbed during argon ion sputtering. An 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 the organic sample is thoroughly dried, avoiding 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 matter samples with smooth, flat, and dry surfaces can be prepared, providing a high-quality sample basis for subsequent microscopic observation and organic matter wettability analysis.

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

[0028] Assuming the atomic force microscope (AFM) stage is clean and free of impurities, the treated organic sample can be placed on the stage using tweezers or a dedicated sample holder. Ensure the sample surface is parallel to the stage and that the sample position is stable, without moving or tilting during scanning. The AFM probe can be mounted onto the probe arm, ensuring an appropriate distance between the probe tip and the sample surface. The shape and condition of the probe tip can be checked using the AFM imaging system to ensure it is undamaged, contaminated, or deformed. A calibration procedure can be initiated using the AFM probe calibration options, allowing the probe to contact the sample surface, measure the contact force, and adjust scanning parameters. A calibration evaluation report for the AFM can be obtained to check if the contact force, scanning speed, and scanning range meet expectations, and adjustments can be made as needed.

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

[0030] In some embodiments, a study area on the surface of the organic matter sample can be determined before acquiring a first adhesion force and a second adhesion force between the probe tip and sampling points on the surface of the organic matter sample; the study area includes multiple sampling points.

[0031] Atomic force microscopy (AFM) can be used in tapping mode to image the morphology of organic sample surfaces, and the study area can be determined by comparing the results with those from scanning electron microscopy (SEM) of organic sample surfaces. AFM tapping mode reduces sample damage and improves imaging resolution by vibrating the probe at a specific frequency and gently tapping the sample surface. Scanning parameters such as the scanning range, scanning speed, probe vibration frequency, and amplitude of the AFM can be adjusted according to the hardness and brittleness of the organic sample. By allowing the probe to image the morphology of the organic region, minute displacement changes during the interaction between the probe and the organic sample surface can be obtained, thus constructing a three-dimensional morphological map of the organic sample surface. After generating the three-dimensional morphological map of the organic sample surface using AFM, a portion of the organic sample surface can be observed using SEM based on the generated 3D morphological map or prior knowledge to generate observation images. These observation images can be high-resolution. Prior knowledge can include, for example, pre-marked, relatively smooth areas suitable for observation. Compared to atomic force microscopy (AFM), scanning electron microscopy (SEM) offers resolution down to the nanometer level, even approaching the atomic level. SEM provides a wider field of view and deeper information on organic samples, such as surface morphology, chemical composition, and crystal structure. SEM can provide even wider fields of view and deeper sample information, including surface morphology, chemical composition, and crystal structure. High-resolution images generated by SEM can be compared with three-dimensional topographic maps generated by AFM. Based on the image regions in the high-resolution SEM image with roughness less than or equal to a set roughness threshold, the corresponding study areas can be further determined in the three-dimensional topographic maps generated by AFM. Roughness represents the degree of undulation in an image region. The roughness of an image region can be obtained by calculating the variance or standard deviation of the image region. For example, the high-resolution image can be grayscaled, and the standard deviation of each image region can be calculated to obtain the roughness of each region. Then, image regions with roughness less than a set roughness threshold can be selected as the study areas. (Refer to...) Figure 2 and Figure 3 , Figure 2 This image shows a planar topography of the study area on the surface of a shale organic matter sample under dry conditions. Figure 3 A three-dimensional topographic map of the study area on the surface of a shale organic matter sample under dry conditions is shown.

[0032] By comparing high-resolution images generated by scanning electron microscopy with three-dimensional topographic maps generated by atomic force microscopy, a more suitable study area and precise location and extent can be determined.

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

[0034] After determining the study area on the surface of the organic matter sample, the organic matter sample, after being mechanically polished, argon-ion polished and dried, can be directly obtained and placed on the stage of an atomic force microscope for testing under dry conditions.

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

[0036] Surface adhesion forces can be tested at all sampling points in the study area of ​​an organic matter sample under dry conditions using the viscoelastic mapping mode of atomic force microscopy (AFM). AFM works through the interaction forces between the probe and the sample surface. In viscoelastic mapping mode, AFM not only measures static or dynamic vertical forces but can also evaluate the viscoelastic properties of the sample surface, including adhesion forces and energy dissipation, through specific loading and unloading processes. The speed at which the probe tip approaches and leaves the sample surface, as well as the force applied when the probe tip contacts the sample surface, can be set to control the dynamic process of the test. The initial adhesion force between the probe tip and the sampling points in the study area of ​​the organic matter sample under dry conditions can be acquired in real time from the AFM. (See reference...) Figure 4 , Figure 4 Adhesion force images of 16×16 sampling points in the study area of ​​shale organic matter sample under dry conditions are shown.

[0037] After obtaining the first adhesion force at all sampling points on the study area of ​​the organic sample surface under dry conditions, the dried organic sample can be removed from the stage of the atomic force microscope. The dried organic sample can then be placed in an atmosphere with a relative humidity of 97% (20°C, -0.95 MPa) provided by a supersaturated potassium sulfate solution to wet the sample. A relative humidity of 97% means that the water vapor content in the air is very close to the saturated vapor pressure of water at that temperature, thus allowing the sample to fully absorb moisture and achieve a good wetting effect. A temperature setting of 20°C maintains the stability and repeatability of the experimental conditions. By placing the dried organic sample in an environment provided by a supersaturated potassium sulfate solution with a relative humidity of 97% and a temperature of 20°C, the sample can fully absorb moisture and achieve the purpose of wetting. The wetted organic sample can then be placed back on the stage of the atomic force microscope, and 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 This image shows a planar topography of the study area on the surface of a shale organic matter sample under wetted conditions. Figure 6 A three-dimensional morphological map of the study area on the surface of a shale organic matter sample under wetted conditions is shown.

[0038] Surface adhesion forces can be tested at all sampling points in the study area of ​​a wetted organic sample using an atomic force microscope (AFM) viscoelastic mapping mode. The dynamic process of the test can be controlled by setting the probe tip's approach and departure velocities and the force applied when the probe tip contacts the sample surface. The secondary adhesion force between the probe tip and the sampling points in the wetted organic sample study area can be acquired in real-time from the AFM. (See reference...) Figure 7 , Figure 7 Adhesion force images of 16×16 sampling points in the study area of ​​shale organic matter samples under wettability are shown.

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

[0040] S102: 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.

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

[0042]

[0043] In the formula: F is the adhesive force between the two solid surfaces; r is the effective contact radius between the two solid surfaces; W is the adhesive work between the two solid surfaces. The JKR adhesive contact theory characterizes the existence of an elastic deformation region between two solid surfaces, which is called the contact region. Within the contact region, due to the effect of surface energy, the two solid surfaces will attract each other and generate adhesive force. Within the contact region, the conversion relationship between the adhesive force and the adhesive 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 can be calculated based on JKR adhesive contact theory according to the following formula:

[0045]

[0046] In the formula: R is the first adhesion force between the probe tip and the sampling point in the organic matter sample study area under dry conditions; R is the radius of curvature of the probe tip; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This refers to the second adhesion force between the probe tip and the sampling point in the organic matter sample study area under wettability; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability.

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

[0048] S103: Determine the wettability of the organic sample surface based on 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, a second contact angle of the liquid on the surface of the organic matter sample can be calculated; and the wettability of the surface of the organic matter sample can be determined based on the second contact angles corresponding to all sampling points in the organic matter sample study area.

[0050] By calculating the second contact angle of the liquid on the surface of the organic matter sample using the first adhesion work, the second adhesion work, and the third adhesion work, the wettability of the sampling point in the study area of ​​the organic matter sample can be determined simply and conveniently, thereby determining the wettability of the surface of the organic matter sample.

[0051] When testing the surface adhesion force of all sampling points in the study area of ​​an organic sample under wet conditions using the viscoelastic mapping mode of atomic force microscopy, the atomic force microscope can display the first contact angle of the liquid at the probe tip corresponding to any sampling point in real time, thereby obtaining the first contact angle of the liquid at the probe tip corresponding to any sampling point in the study area of ​​the organic sample surface.

[0052] The third adhesion work between the probe tip and the liquid surface can be defined as the sum of the surface energy of the probe tip and 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] In the formula: The third adhesion work between the probe tip and the liquid surface; γ tip γ is the surface energy at the probe tip; water γ is the surface energy of the liquid; tip,water This represents 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, the surface energy of the liquid, and the cosine of the first contact angle of the liquid at the probe tip, as shown in the following formula:

[0056]

[0057] In the formula: γ tip γ is the surface energy at the probe tip; tip,water γ is the interfacial energy between the probe tip and the liquid surface; water It is the surface energy of the liquid; Let be the first contact angle of the liquid at the probe tip. Young's equation can be defined as the sum of the surface energy of the solid, the interfacial energy between the solid and liquid surfaces, the surface energy of the liquid, and the cosine of the contact angle of the liquid on the solid surface.

[0058] Substituting formula (5) into formula (4), we can obtain the following formula:

[0059]

[0060] In the formula: The third adhesion work between the probe tip and the liquid surface; γ waterIt is the surface energy of the liquid; This is the second contact angle of the liquid at the probe tip.

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

[0062] In some embodiments, given that 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 location can be calculated.

[0063] The contact angle is a measure of the degree to which a liquid wets a solid surface. It is the angle between the liquid-solid interface and the tangent to the liquid surface when the liquid forms a specific shape on the solid surface. When the contact angle is less than 90 degrees, it indicates that the solid is wetted by the liquid, and the smaller the angle, the better the wettability. When the contact angle is 0 degrees, it indicates complete wetting, meaning the liquid spreads freely on the solid surface. When the contact angle is greater than 90 degrees, it indicates that the liquid does not wet the solid, and the larger the angle, the stronger the non-wetting property. When the contact angle is 180 degrees, it indicates complete non-wetting.

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

[0065]

[0066] In the formula: θ is the second contact angle of the liquid on the surface of the organic sample; arccos(·) is the inverse cosine function; The first adhesion work between the probe tip and the sampling point surface; This is the second adhesion work between the probe tip and the surface of the organic sample; This is the third adhesion work between the probe tip and the liquid surface; The fourth adhesion work between the surface of the organic sample and the surface of the liquid; γ water It represents 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 matter sample study area can be calculated. (Refer to...) Figure 8 , Figure 8The diagram shows the contact angles of the liquid on the surface of the organic matter sample, calculated based on formula (9) for all sampling points in the study area of ​​the shale organic matter sample. The second contact angles corresponding to all sampling points are fused to obtain a third contact angle that characterizes the wettability of the organic matter sample surface. Fusion can be a simple arithmetic mean of the second contact angle data corresponding to all sampling points, or a more complex weighted superposition. For example, the arithmetic mean of the second contact angle data corresponding to all sampling points can be taken to generate a third contact angle that characterizes the wettability of the organic matter sample surface, thus determining the wettability of the organic matter sample surface. Another example is that a weighting 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 variance of the fluctuation in the area can be calculated based on the three-dimensional morphological characteristics of the area where each sampling point is located. The reciprocal of the variance is taken, and the variance of the variance after taking the reciprocal of all sampling points is normalized to obtain the weighting factor corresponding to each sampling point. Other methods can also be used to calculate the weighting factor of each sampling point, which will not be elaborated here. A third contact angle that can characterize the wettability of an organic sample surface can be generated by taking the weighted average of the second contact angle data corresponding to each sampling point and the weighting factor, thereby determining the wettability of the organic sample surface.

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

[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; given that the first, second, and third adhesion works are determined, a fourth adhesion work between the organic sample surface and the liquid surface can be calculated according to the following formula:

[0070]

[0071] In the formula: This is the fourth adhesion work between the surface of the organic sample and the liquid surface; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability; The third adhesion work between the probe tip and the liquid surface; γ water It is a constant representing the surface energy of the liquid.

[0072] The fourth adhesion work between the organic sample surface and the liquid surface was calculated by using the first, second, and third adhesion work, which laid the 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 surface of an organic sample and the surface of a liquid can be defined as the sum of the surface energy of the organic sample surface and 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] In the formula: The fourth adhesion work between the surface of the organic sample and the surface of the liquid; γ sample γ is the surface energy of the organic matter sample surface; water γ is the surface energy of the liquid; sample,water It represents the interfacial energy between the surface of the organic sample and the liquid surface.

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

[0077]

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

[0079] Substituting formula (12) into formula (11), we can obtain the following formula:

[0080]

[0081] In the formula: The fourth adhesion work between the surface of the organic sample and the surface of the liquid; γ water It is the surface energy of the liquid; This 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] In the formula: This is the second contact angle of the liquid on the surface of the organic sample. The fourth adhesion work between the surface of the organic sample and the surface of the liquid; γ water It represents the surface energy of the liquid.

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

[0086] By directly calculating the second contact angle of the liquid on the surface of the organic matter sample using the fourth adhesion work, the wettability near the sampling point in the study area of ​​the organic matter sample can be determined simply and conveniently, thereby determining the wettability of the surface of the organic matter sample.

[0087] The second adhesion work between the probe tip and the organic sample surface under wetted 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] In the formula: The second adhesion work between the probe tip and the surface of the organic sample; γ tip,sample γ is the interfacial energy between the probe tip and the surface of the organic sample; tip,water γ is the interfacial energy between the probe tip and the liquid surface; sample,water It represents the interfacial energy between the surface of the organic sample and the surface of the liquid.

[0090] Based on the above formulas (4) and (11), we can obtain as well as Substituting these two expressions into formula (17) above, we can obtain the following formula:

[0091]

[0092] In the formula: The second adhesion work between the probe tip and the surface of the organic sample; γ tip,sample γ is the interfacial energy between the probe tip and the surface of the organic sample; tip γ is the surface energy at the probe tip; sample The surface energy at the sampling point; This is the third adhesion work between the probe tip and the liquid surface; The fourth adhesion work between the surface of the organic sample and the surface of the liquid; γ water It represents 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 interfacial energy between the probe tip and the organic sample surface. The specific formula is as follows:

[0094]

[0095] In the formula: The first adhesion work between the probe tip and the surface of the organic sample; γ tip,sample γ is the interfacial energy between the probe tip and the surface of the organic sample; tip γ is the surface energy at the probe tip; sample Let be the surface energy at the sampling point.

[0096] Substituting formula (20) into formula (19) yields formula (10). Given 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 surface of the liquid can be calculated according to formula (10).

[0097] Given the first, second, and third adhesion work, formulas (10) and (15) can be combined. Specifically, formula (15) can be substituted into formula (10) to obtain the formula for calculating the second contact angle, namely formula (9). Based on formula (9), the second contact angles corresponding to all sampling points in the organic matter sample study area can be calculated. Then, the second contact angles corresponding to all sampling points can be fused to determine the wettability of the organic matter sample surface.

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

[0099] Based on the above-described wettability testing method, this specification also provides embodiments of a wettability testing apparatus. For example... Figure 9 As shown, the evaluation device may specifically include the following modules:

[0100] The acquisition module 901 can be used to acquire the first adhesion force and the second adhesion force between the probe tip and the sampling point on the surface of the organic sample.

[0101] The calculation module 902 can be used to calculate the first adhesion work between the probe tip and the surface of the organic matter sample based on the first adhesion force, and to calculate the second adhesion work between the probe tip and the surface of the organic matter sample based on the second adhesion force.

[0102] The determination module 903 can be used to determine the wettability of the surface of an organic sample based on the first adhesion work and the second adhesion work.

[0103] In some embodiments, the acquisition module 901 described above can be used to determine the study area on the surface of an organic sample; the study area includes multiple sampling points.

[0104] In some embodiments, the acquisition module 901 can also be used to acquire a dried organic matter sample; acquire the first adhesion force between the probe tip and the sampling point in the study area of ​​the organic matter sample under dry conditions; acquire a wetted organic matter sample; and acquire the second adhesion force between the probe tip and the sampling point in the study area of ​​the organic matter sample under wet conditions.

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

[0106]

[0107] In the formula: R is the first adhesion force between the probe tip and the sampling point in the organic matter sample study area under dry conditions; R is the radius of curvature of the probe tip; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This refers to the second adhesion force between the probe tip and the sampling point in the organic matter sample study area under wettability; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability.

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

[0109] Calculate the third adhesion work between the probe tip and the liquid surface based on 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] In the formula: This is the second contact angle of the liquid on the surface of the organic matter sample; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability; The third adhesion work between the probe tip and the liquid surface; γ water It is a constant representing the surface energy of the liquid;

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

[0114] In some embodiments, the determining module 903 may further be used to obtain a first contact angle of the liquid at the probe tip; calculate a third adhesion work between the probe tip and the liquid surface based on the first contact angle; calculate a fourth adhesion work between the organic sample surface and the liquid surface based on the first adhesion work, the second adhesion work, and the third adhesion work; and calculate a second contact angle of the liquid on the organic sample surface based on the fourth adhesion work.

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

[0116]

[0117] In the formula: This is the fourth adhesion work between the surface of the organic sample and the liquid surface; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability; The third adhesion work between the probe tip and the liquid surface; γ water It is a constant representing the surface energy of the liquid.

[0118] In some embodiments, the determining module 903 described above can 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] In the formula: This is the second contact angle of the liquid on the surface of the organic matter sample; The fourth adhesion work between the surface of the organic sample and the liquid surface; γ water It is a constant 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 physical entities, or by products with certain functions. For ease of description, the above devices are described by dividing them into various modules according to their functions. Of course, in implementing this specification, the functions of each module can be implemented in one or more software and / or hardware, or the module that implements the same function can be implemented by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection between the devices or units shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units 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 organic matter samples and the adhesion force between the probe tip and the surface of organic matter samples can be obtained. The wettability of the surface of organic matter samples at the microphase scale can be determined easily and quickly, thereby accurately describing the in-situ wetting characteristics of organic rocks in different reservoir environments and improving the accuracy of wettability testing of organic matter sample surfaces.

[0123] To execute the above instructions more accurately, please refer to... Figure 10 As shown in the embodiments of this specification, a computer device based on a wettability testing method is also provided. The computer device includes a network communication port 1001, a processor 1002, and a memory 1003. The above structures are connected by 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 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 a port responsible for FTP data communication, or a port responsible for email data communication. Furthermore, 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 supporting protocols such as GSM and CDMA. The network communication port 1001 can also be a Wi-Fi chip or a Bluetooth chip, etc.

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

[0126] In the embodiments described in this specification, the processor 1002 may be implemented in any suitable manner. For example, the processor 1002 may take the form of, for example, a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers, etc. This specification is not limiting.

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

[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 considered memory; in integrated circuits, a circuit with storage function but no physical form is also called memory, such as RAM and FIFO; in computer systems, storage devices with physical form are also called memory, such as memory modules and TF cards.

[0129] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied 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] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0131] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0132] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0133] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are 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 within the scope of protection of the present invention.

Claims

1. A wetting property test method characterized by, include: Acquiring a first adhesion force and a second adhesion force between the probe tip and sampling points on the surface of an organic matter sample, including: acquiring a dried organic matter sample; acquiring the first adhesion force between the probe tip and sampling points in the study area of ​​the dried organic matter sample; acquiring a wetted organic matter sample; and acquiring the second adhesion force between the probe tip and sampling points in the study area of ​​the wetted organic matter sample. The first adhesion work between the probe tip and the surface of the organic matter sample is calculated based on the first adhesion force, and the second adhesion work between the probe tip and the surface of the organic matter sample is calculated based on the second adhesion force. The wettability of the organic sample surface is determined based on the first and second adhesion works, including: obtaining the first contact angle of the liquid at the probe tip; calculating the third adhesion work between the probe tip and the liquid surface based on the first contact angle; the third adhesion work is 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; and calculating the second contact angle of the liquid on the organic sample surface based on the first, second, and third adhesion works using the following formula: In the formula: This is the second contact angle of the liquid on the surface of the organic matter sample; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability; This is the third adhesion work between the probe tip and the liquid surface; The surface energy of the liquid is a constant; the wettability of the organic sample surface is determined based on the second contact angle.

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

3. The method according to claim 1, characterized in that, The calculation of the first adhesion work between the probe tip and the surface of the organic sample based on the first adhesion force, and the calculation of the second adhesion work between the probe tip and the surface of the organic sample based on the second adhesion force, include: The first adhesion work and the second adhesion work are calculated according to the following formulas: In the formula: The first adhesion force between the probe tip and the sampling point in the study area of ​​the organic matter sample under dry conditions; The radius of curvature of the probe tip; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This refers to the second adhesion force between the probe tip and the sampling point in the organic matter sample study area under wettability; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability.

4. The method according to claim 1, characterized in that, Determining the wettability of the organic sample surface based on the first adhesion work and the second adhesion work includes: Obtain the first contact angle of the liquid at the tip of the probe; Calculate the third adhesion work between the probe tip and the liquid surface based on the first contact angle; Based on the first adhesion work, the second adhesion work, and the third adhesion work, calculate the fourth adhesion work between the surface of the organic matter sample and the surface of the liquid. The second contact angle of the liquid on the surface of the organic sample is calculated based on the fourth adhesion work.

5. The method according to claim 4, characterized in that, The calculation of the fourth adhesion work between the organic sample surface and the liquid surface based on the first adhesion work, the second adhesion work, and the third adhesion work includes: The fourth adhesion work between the surface of the organic sample and the liquid surface is calculated using the following formula: In the formula: This is the fourth adhesion work between the surface of the organic sample and the liquid surface; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability; This is the third adhesion work between the probe tip and the liquid surface; It is a constant representing the surface energy of the liquid.

6. The method according to claim 4, characterized in that, The calculation of the second contact angle of the liquid on the surface of the organic sample based on the fourth adhesion work includes: The second contact angle of the liquid on the surface of the organic sample is calculated using the following formula: In the formula: This is the second contact angle of the liquid on the surface of the organic matter sample; This is the fourth adhesion work between the surface of the organic sample and the liquid surface; It is a constant representing the surface energy of the liquid.

7. A wettability testing device, characterized in that, The device includes: The acquisition module is used to acquire a first adhesion force and a second adhesion force between the probe tip and sampling points on the surface of an organic matter sample, including: acquiring a dried organic matter sample; acquiring the first adhesion force between the probe tip and sampling points in the study area of ​​the dried organic matter sample; acquiring a wetted organic matter sample; and acquiring the second adhesion force between the probe tip and sampling points in the study area of ​​the wetted organic matter sample. The calculation module is used to calculate the first adhesion work between the probe tip and the surface of the organic matter sample based on the first adhesion force, and to calculate the second adhesion work between the probe tip and the surface of the organic matter sample based on the second adhesion force. The determination module is used to determine the wettability of the organic sample surface based on the first adhesion work and the second adhesion work, including: obtaining a first contact angle of the liquid at the probe tip; calculating a third adhesion work between the probe tip and the liquid surface based on the first contact angle; the third adhesion work being 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; and calculating the second contact angle of the liquid on the organic sample surface based on the first adhesion work, the second adhesion work, and the third adhesion work according to the following formula: In the formula: This is the second contact angle of the liquid on the surface of the organic matter sample; The first adhesion work between the probe tip and the surface of the organic sample under dry conditions; This is the second adhesion work between the probe tip and the surface of the organic sample under wettability; This is the third adhesion work between the probe tip and the liquid surface; The surface energy of the liquid is a constant; the wettability of the organic sample surface is determined based on the second contact angle.

8. 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, it implements the method as described in any one of claims 1-6.

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