Device and method for measuring and calculating dynamic and static contact angles of in-situ environment of deep reservoir

Abstract

The invention provides a device and a method for measuring and calculating dynamic and static contact angles of an in-situ environment of a deep reservoir. The device comprises a high-temperature and high-pressure visual kettle, a sample clamping electric lifting platform, a liquid dripping needle group, a backlight lamp, a linkage camera, a liquid dripping system, a heating system, a pressurizing system, a high-speed camera and a central control computer, when the dynamic contact angle is measured and calculated, the high-temperature and high-pressure visible kettle rotates along a fixed shaft, the sample clamping electric lifting platform is positioned in the high-temperature and high-pressure visible kettle, the liquid dripping needle group and the linkage camera are fixed on a kettle cover on the inner side of the high-temperature and high-pressure visible kettle, and the backlight lamp irradiates the sample clamping electric lifting platform; the central control computer controls the heating system to heat the high-temperature and high-pressure visual kettle, controls the pressurization system to pressurize the high-temperature and high-pressure visual kettle and controls the liquid dropping system to enable liquid to flow out of the liquid dropping needle set. According to the technical scheme, the problem that in the prior art, the rock wetting characteristics under the reservoir in-situ condition cannot be conveniently, efficiently and accurately expressed is solved.

Description

Technical Field

[0001] The invention relates to the technical field of dynamic and static contact angle calculation on reservoir rock surface, and in particular to a device and method for calculating dynamic and static contact angles in an in-situ environment of a deep reservoir. Background Art

[0002] The reservoir pressure and temperature differences in geological reservoirs, according to general rules, increase with the depth of geological reservoirs, and the temperature and reservoir pressure increase accordingly, which in turn affects the wettability of fluids on the reservoir rock surface. Under the coupling effect of temperature and reservoir pressure, the change in rock wettability is directly reflected in the change in the contact angle formed between the fluid and the rock surface. Wettability is an important factor in determining the migration of unconventional gas, liquid and other fluids. The contact angle is divided into static contact angle and dynamic contact angle. The static contact angle θ that directly reflects the wettability of rocks is generally defined in the range of 0 to 180°. When the static contact angle of the liquid is 0°<θ<90°, the rock behaves as liquid-loving, that is, the liquid can wet the solid and is not easy to migrate on the rock surface; when θ=90°, the rock is neutral; when 90°<θ<180°, the rock behaves as liquid-repelling, that is, the liquid does not wet the solid and is easy to migrate on the rock surface. At the same time, the contact angle of the droplet on the rock surface is also affected by the surface roughness. Under different in-situ conditions, the difference in contact angle is an intuitive representation of rock wettability, which has an important impact on the viscosity, migration and entrapment of fluids in rock fracture media. Therefore, the dynamic and static contact angle test and droplet profile capture method in deep reservoir in-situ environment have become important scientific issues that need to be solved in the analysis of fluid behavior problems in deep geological reservoirs.

[0003] The sessile drop method is used to measure the static contact angle of the rock surface, and the inclined plate method is used to measure the dynamic contact angle. These are the main technical means to study the equilibrium behavior of droplets on the rock surface and observe the size of the contact angle. Affected by reservoir pressure, reservoir temperature and surface roughness, the wettability of the rock will change significantly, which is reflected in the differences in the contact angles obtained in the sessile drop measurement experiment. Therefore, a device and method are needed to realize the contact angle titration experiment and the droplet profile capture method under geological in-situ conditions.

[0004] The prior art involves measuring static contact angles under in-situ conditions of gas and pressure, for example: Chinese patent: CN202210245586.2 discloses a contact angle test device for coal under high-pressure bearing conditions, which realizes the contact angle measurement experiment of the sessile drop method under the conditions of reproducing the in-situ conditions of the main gas environment and the reservoir pressure of the deep reservoir; CN202210245653.0 discloses a contact angle test method for loaded gas-containing coal;

[0005] Experiments on measuring the dynamic contact angle of solid material surfaces under temperature and pressure conditions by the sessile drop method, for example: CN201910053526.9 discloses an experimental device and method for measuring the dynamic contact angle under high temperature and high pressure environment; CN202411001721.4 discloses an automatic detection method for static contact angle: CN201010288857.X discloses an automatic detection method for static contact angle; CN202011245292.7 discloses a method for obtaining the contour curve and forward (backward) contact angle of a droplet on a tilted hydrophilic surface.

[0006] Existing technologies mostly focus on static contact angle measurements using the sessile drop method under conventional in-situ conditions. There are still deficiencies in conducting sessile drop measurement experiments on reservoir rocks under highly replicated in-situ conditions, especially there are relatively few experimental devices and methods for measuring dynamic contact angles under highly replicated in-situ reservoir conditions based on the sessile drop method and the tilted plate method. At the same time, due to differences in the processing methods of coal and rock samples, it is impossible to completely smooth the rock surface. Most of the existing sessile drop measurement experiments do not consider the impact of the actual surface roughness of coal and rock samples on static and dynamic contact angle measurement experiments, and little work has been invested in the relationship between the contact angle and the roughness of the rock surface. Existing devices and technical methods have not made good breakthroughs in important coupled in-situ conditions such as temperature, pressure, rock surface roughness, and in-situ complex gas environment for reproducing static and dynamic contact angle test experiments on rock surfaces under in-situ conditions of deep geological reservoirs, and cannot conveniently, efficiently, and accurately represent the wetting characteristics of rocks under in-situ reservoir conditions.

[0007] Therefore, there is a need for a device and method for measuring the dynamic and static contact angles in a deep reservoir in-situ environment that can conveniently, efficiently and accurately represent the rock wetting characteristics under in-situ reservoir conditions. Summary of the invention

[0008] The main purpose of the present invention is to provide a device and method for measuring dynamic and static contact angles in an in-situ environment of a deep reservoir, so as to solve the problem that the prior art cannot conveniently, efficiently and accurately represent the rock wetting characteristics under in-situ conditions of the reservoir.

[0009] To achieve the above-mentioned purpose, the present invention provides a deep reservoir in-situ environment dynamic and static contact angle measurement device, comprising: a high-temperature and high-pressure visual kettle, a sample clamping electric lifting platform, a liquid drop needle group, a backlight, a linkage camera, a drop system, a heating system, a pressurization system, a high-speed camera and a central control computer;

[0010] When calculating the dynamic contact angle, the high-temperature and high-pressure visual kettle rotates on a fixed axis, the sample clamping electric lifting platform is located in the high-temperature and high-pressure visual kettle, the coal and rock samples are clamped on the sample clamping electric lifting platform, the sample clamping electric lifting platform is adjusted, and load pressure is applied to the coal and rock samples. The liquid drop needle group and the linkage camera are fixed on the kettle cover on the inner side of the high-temperature and high-pressure visual kettle and are located directly above the sample clamping electric lifting platform. The backlight is located on the outer side of the high-temperature and high-pressure visual kettle and irradiates the sample clamping electric lifting platform; the central control computer controls the heating system to heat the high-temperature and high-pressure visual kettle, controls the pressurization system to pressurize the high-temperature and high-pressure visual kettle, and controls the dripping system to make the liquid flow out of the liquid drop needle group; the high-speed camera is located on one side of the high-temperature and high-pressure visual kettle, and is used to shoot the coal and rock samples on the sample clamping electric lifting platform.

[0011] The present invention also provides a method for calculating the dynamic and static contact angles in an in-situ environment of a deep reservoir, and calculating the static contact angle specifically comprises the following steps:

[0012] S1, input image data and perform image preprocessing and noise reduction, the preprocessing includes: grayscale assignment processing and two-dimensional Gaussian blur method.

[0013] S2, using the Sobel algorithm to separate the droplets and coal rock samples, and to identify the contours of the droplets and coal rock samples respectively.

[0014] S3, according to the determined coal rock sample contour, based on the multi-point secant sampling method, determine the intersection point of the characteristic contour line and the vertical secant line, and according to the specified fitting point, perform coal rock sample contour fitting based on the Polynomial function.

[0015] S4, determining the static droplet sample profile, and determining the position function of the fitting point, performing profile fitting based on the ellipse function according to the specified fitting point, and characterizing the static droplet profile fitting function.

[0016] S5, determine the rectangular coordinate system according to the intersection of the coal rock sample contour and the droplet contour and measure the initial contact angle.

[0017] S6, based on the initial contact angle, the influence of gravity micro-pressure difference on the contact angle is eliminated to obtain the corrected true static contact angle of the coal rock sample surface.

[0018] Furthermore, step S1 specifically includes the following steps:

[0019] S1.1, convert the RGB image into 8-bit images with different grayscale values, and assign grayscale values ​​to the image pixels, where the grayscale assignment formula is:

[0020] H = 0.244R + 0.587G + 0.114B;

[0021] Among them, H is the weighted gray value, R is the RGB red pixel parameter, G is the RGB green pixel parameter, and B is the RGB blue pixel parameter.

[0022] S1.2, based on the two-dimensional Gaussian blur method, the two-dimensional Gaussian normal distribution formula is:

[0023]

[0024] Among them, u is the image X-axis parameter, v is the image Y-axis parameter, G is the pixel grayscale information after Gaussian weighted processing, σ is the data variance, and the image preprocessing is completed according to the two-dimensional Gaussian blur formula.

[0025] Furthermore, step S2 specifically includes the following steps:

[0026] S2.1, the third-order matrix formula for contour recognition based on the Sobel algorithm is:

[0027]

[0028] Among them, Q is the eigenvalue, a ij is the pixel gray value.

[0029] S2.2, the grayscale value between 0 and 15 is the background feature domain of the experimental object, the grayscale value between 16 and 240 is the experimental droplet contour feature domain, and the grayscale value between 241 and 255 is the experimental coal and rock sample feature domain. The characteristic contour lines composed of continuous grayscale feature values ​​are selected for contour recognition and segmentation.

[0030] Furthermore, step S3 specifically includes the following steps:

[0031] S3.1, determine the contour of the coal rock sample, and the characteristic line determination function in the grayscale range of grayscale values ​​241 to 255 is:

[0032] F1(x)=Q s ;

[0033] Among them, F1(x) is the line function of the characteristic points of the coal rock sample contour, Q s is the selected continuous eigenvalue.

[0034] S3.2, determine the basic equation of the vertical secant line as:

[0035]

[0036] Among them, x is the horizontal coordinate of the position of the secant line, U is the total length of the image in the X-axis direction, and U i is the X-axis coordinate of the ith secant line, n is the total number of n secants, n j is the number of the j-th secant line, and ∏(x) is the integration function.

[0037] S3.3, the position function of the fitting point to determine the rock surface profile is:

[0038] C i =(x i ,Q s );

[0039] Among them, C i is the position of the image secant line, x i is the X-axis coordinate of the i-th secant line.

[0040] S3.4, according to the fitting points, the coal rock sample contour is fitted based on the Polynomial function:

[0041] F(x)=a1x 5 +b1x 4 +c1x 3 +d1x 2 +e1x+f1;

[0042] Among them, F(x) is the coal rock sample profile fitting function, a1, b1, c1, d1, e1 and f1 are coefficients, and the coefficients in the Polynomial function are determined based on the fitting points.

[0043] Further, according to step S4, the following steps are specifically included:

[0044] S4.1, determine the static droplet sample profile, the characteristic line determination function in the grayscale range of grayscale values ​​241 to 255 is:

[0045] F2(x)=Q s ;

[0046] Among them, F2(x) is the function of connecting the characteristic points of the static droplet sample contour.

[0047] S4.2, determine the position function of the droplet surface profile fitting point as:

[0048] C j =(x j ,Q s );

[0049] Among them, C j is the position of the droplet surface contour fitting point, x j is the X-axis coordinate of the j-th secant line.

[0050] S4.3, the static droplet surface profile fitting function is:

[0051]

[0052] Among them, A, B, D, E and F are coefficients.

[0053] Further, step S5 specifically includes the following steps:

[0054] S5.1, based on F1(x), obtain the static droplet profile tangent function F2(x):

[0055]

[0056] Among them, a, b, c, d ′ , e, f are coefficients;

[0057] Determine the zero point of the rectangular coordinate system:

[0058] F2(x)=F1(x).

[0059] S5.2, calculate the initial static contact angle:

[0060] F1(x)=kx+c;

[0061] arctanθ0=k;

[0062] Where θ0 is the initial static contact angle, k is the derivative slope of the droplet surface contour, and c is the derivative constant of the droplet surface contour.

[0063] Further, according to step S6, the following steps are specifically included:

[0064] S6.1, restore the static contact angle according to the inverse solution process of Young's equation:

[0065]

[0066] Where θ is the static contact angle under ideal conditions; γ SG is the solid-gas interfacial tension, γ SL is the solid-liquid interfacial tension, γ LG is the interfacial tension between liquid and gas.

[0067] S6.2, based on the influence of the droplet's own bulk density on the contact angle measurement, the static contact angle droplet mass is solved:

[0068] G′=γh;

[0069]

[0070] Among them, G ′ is the gravity correction function, γ is the liquid bulk density, and h is the liquid profile height function.

[0071] S6.3, perform the correction calculation:

[0072]

[0073] Where θ0 is the initial static contact angle.

[0074] S6.4, based on Young's equation, the actual measured contact angle of the coal rock sample surface is calculated and obtained:

[0075]

[0076] Among them, θ r is the actual static contact angle of the rock material surface.

[0077] Furthermore, the method for calculating the dynamic contact angle specifically comprises the following steps:

[0078] S7, preprocessing the image, performing contour fitting based on the Polynomial function according to the specified fitting points, and characterizing the dynamic droplet contour.

[0079] S8, correct the momentum effect on the dynamic droplet profile and calculate the actual dynamic contact angle:

[0080] S8.1, in an image within a certain period of time, the method for determining the movement of the base point of a dynamic droplet is as follows:

[0081] Create a data set:

[0082] DCAI1={P1,P2,P3,…,P n};

[0083] Among them, DCAI1 is the initial preprocessed data set; P n is the contact point between the leading edge and the trailing edge and the coal rock surface in the dynamic contact angle recorded at the nth time;

[0084] The total amount of data is counted. If n is an even number, the calculation is normal; if n is an odd number, the (n+1) / 2 items in the middle are removed and rearranged as follows:

[0085] DCAI2={P1,P2,P3,…,P n};

[0086] Among them, DCAI2 is the data set after completing the initial difference check.

[0087] S8.2, supplement for dynamic droplet acceleration:

[0088]

[0089] Among them, v is the base point movement speed; t is time; T is the capture interval time.

[0090] S8.3, solve the definite integral to obtain the instantaneous velocity of the base point of the dynamic droplet:

[0091]

[0092] Among them, V x is the instantaneous velocity of the dynamic droplet base point, T X and T X+1 They are the starting calculation time interval and the ending calculation time interval respectively.

[0093] S8.4, characterize the dynamic droplet momentum P based on the momentum theorem:

[0094] P = FΔT = mΔV;

[0095]

[0096] Among them, F is the modified mechanical operator; m is the droplet mass; ΔV is the velocity gradient, and ΔT is the time gradient.

[0097] S8.5, the Yang-Laplace equation is modified to obtain the initial dynamic contact angle θ 0’ :

[0098]

[0099] S8.6, correcting for momentum effects according to Young's equation:

[0100]

[0101] Among them, θ ′ The actual dynamic contact angle of the coal rock surface after eliminating the influence of momentum.

[0102] Furthermore, it also includes:

[0103] S9, performing rock surface roughness analysis based on the static contact angle and dynamic contact angle obtained by measurement, specifically comprising the following steps:

[0104] S9.1, the images captured by the two linked cameras are stitched together using the Sobel algorithm, and the images are binarized; the grayscale of each pixel in the binarized image and its surrounding nine pixels are counted, and matrix calculation is performed, and the grayscale matrix calculation values ​​of different pixels are weighted and calculated;

[0105] The matrix calculation formula is:

[0106]

[0107] Among them, Q ′ is the corrected grayscale feature value of different pixels in the image; a ij ′ is the gray value of different pixels in the image.

[0108] S9.2, count the contour lines of the same grayscale matrix calculation value of the image, and obtain the grayscale feature lines of the two images, and splice the images according to the grayscale feature lines:

[0109] L1={P 11 , P 12 ,P 13 ,…,P 1n};

[0110] L2={P 21 , P 22 ,P 23 ,…,P 2n};

[0111] L1=L2;

[0112] Among them, L1 is the grayscale feature line in the image taken by the first linked camera; L2 is the grayscale feature line in the image taken by the second linked camera.

[0113] S9.3, use fractal dimension to perform roughness analysis on the spliced ​​image:

[0114]

[0115] Among them, D is the fractal dimension describing the surface roughness of coal rock, N(ε) is the number of surrounding pixels in a certain area, ε is the relative size of a certain area, and log(·) is the logarithmic function.

[0116] S9.4, read the spliced ​​image obtained in S9.2, and convert it into a binary image, and assign grayscale values ​​to the particle geometry images at different heights on the surface of the coal and rock samples, with the value range being between 0 and 255.

[0117] S9.5, perform Gaussian noise reduction on the image, and then process the rock surface roughness based on the island method:

[0118]

[0119] Where, E represents the perimeter of the closed grayscale block; F represents the area of ​​the closed grayscale block; W is a constant;

[0120] According to the Mandel-brot model, there is a formula:

[0121]

[0122] Among them, C is a constant, D r The fractal dimension of the island of the irregular figure boundary line; D r The larger it is, the more complex the pore structure of the rock surface is, and the greater the roughness of the rock surface is.

[0123] The present invention has the following beneficial effects:

[0124] The present invention more comprehensively realizes the reproduction of the in-situ conditions of deep geological reservoir rock samples, and can realize the real reproduction of deep reservoir environment such as the load pressure, temperature, gas atmosphere change, gas pressure and sample surface roughness consideration, and ambient temperature setting of rock samples. It reduces the situation where the rock surface cracks cannot form a stable equilibrium contact angle for the droplet, reduces the error influence of the rock surface roughness on the contact angle measurement, and establishes the relationship between the influence of the rock surface roughness on the contact angle.

[0125] The present invention realizes the contact angle measurement experiment under the condition of highly restored deep reservoir, which not only includes the traditional temperature and pressure environment simulation, but also adds the consideration of complex gas environment, gas reservoir pressure and surface roughness of coal and rock samples. The relationship between contact angle and reservoir temperature, reservoir pressure, rock surface roughness, coal and rock sample load and complex gas environment is established.

[0126] The high-speed camera and the imaging computer work together, that is, the high-speed camera shoots one frame and the imaging computer processes one frame, realizing real-time description and high-speed measurement of droplets on the surface of coal and rock samples, and then realizing dynamic real-time measurement of contact angle.

[0127] The high-speed camera uses a loop shooting function, that is, saving a period of time in the past to overwrite the old video, so as to achieve the purpose of measuring the dynamic contact angle and rolling angle, avoiding the problem of difficulty in artificially predicting the moment when the droplet rolls.

[0128] The sample clamping electric lifting platform can not only adjust the posture of the sample, but also apply load to the coal and rock samples, so that the rock enters the compaction stage, reduces the existing cracks in the coal and rock samples, and reduces the impact of the cracks on the contact angle experiment.

[0129] Different methods of describing the droplet contour are set up for the static and dynamic contact angle experiments. This is because unlike the static droplets which appear as semicircles or semi-ellipses, dynamic droplets will have a wake in the backward direction when they migrate or tend to migrate on the rock surface. Directly using the static droplet measurement method to calculate the dynamic contact angle will result in errors.

[0130] A manual calculation tool is specially set up for droplets on the rock surface to avoid the situation where geotechnical practitioners are unable to manually review the data when they have objections to the measured contact angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0131] In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the specific implementation or the prior art description. Obviously, the drawings described below are some implementations of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0132] Figure 1 The structure diagram of a deep reservoir in-situ environment dynamic and static contact angle measurement device of the present invention is shown.

[0133] Figure 2 The structure diagram of the high-temperature and high-pressure visual kettle and some valves of the present invention is shown.

[0134] Figure 3 Shows Figure 2 Front view of the high temperature and high pressure visual autoclave.

[0135] Figure 4 The diagram shows the arrangement of the liquid drop needle group and the linked camera of the present invention.

[0136] Figure 5 A three-dimensional diagram of a high-temperature and high-pressure visual kettle according to the present invention is shown.

[0137] Figure 6 Schematic diagram showing the droplet profile description for static contact angle experiments.

[0138] Figure 7 A schematic diagram showing the droplet profile description for a dynamic contact angle experiment is shown.

[0139] Figure 8 The graph shows the actual titration experimental results of the static contact angle on the surface of coal rock samples.

[0140] Fig. 9 The figure shows the actual titration experimental results of the dynamic contact angle on the surface of the coal sample.

[0141] Fig.10 The figure shows the relationship between the contact angle and the pressure data established by the central control computer.

[0142] The description of the drawings for the above drawings is as follows:

[0143] 1. Gas sample tank group; 2. Gas booster pump; 3. Boost closing valve; 4. Pressure storage container; 5. Drive pressure indicator; 6. Drive pressure switch valve; 7. Turbine screw mechanism; 8. Autoclave cavity pressure indicator; 9. Sample rotating table; 10. Microwave generator; 11. Autoclave rotating electric transmission device; 12. Solvent tank group; 13. Central control computer; 14. Sobel algorithm processor; 15. Liquid double cylinder pump; 16. Dialysis solute tank group; 17. Injection system exhaust valve; 18. Injection liquid phase valve; 19. Autoclave injection valve; 20. Backlight; 21. Autoclave body rotating gear; 22. Thermal insulation layer; 23. Ceramic semiconductor heating Heat pipe; 24, coal and rock samples; 25, high-pressure autoclave drop needle base; 26, drop needle injection valve group; 27, linked camera; 28, liquid drop needle group; 29, pipeline exhaust valve; 30, autoclave pressure relief valve; 31, sample clamping electric lifting platform; 32, autoclave cover; 33, cover removal device; 34, fastening screw; 35, imaging computer; 36, high-speed camera data acquisition conversion card; 37, high-speed camera; 38, booster pump control valve; 39, gas mixing chamber; 40, mixing chamber control valve; 41, constant flow ratio mixing chamber; 42, electric gas injection valve group; 43, autoclave body; 44, camera optical cable; 100, high-temperature and high-pressure visual autoclave. DETAILED DESCRIPTION

[0144] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0145] Embodiment 1

[0146] like Figure 1-Figure 5 A deep reservoir in-situ environment dynamic and static contact angle measurement device is shown, comprising: a high temperature and high pressure visual kettle 100, a sample clamping electric lifting platform 31, a liquid drop needle group 28, a backlight 20, a linkage camera 27, a drop system, a heating system, a pressurization system, a high-speed camera 37 and a central control computer 13;

[0147] When calculating the dynamic contact angle, the high-temperature and high-pressure visual kettle rotates on a fixed axis, the sample clamping electric lifting platform is located in the high-temperature and high-pressure visual kettle, the coal and rock samples are clamped on the sample clamping electric lifting platform 31, the sample clamping electric lifting platform is adjusted, and load pressure is applied to the coal and rock samples. The liquid drop needle group and the linkage camera are fixed on the kettle cover 32 on the inner side of the high-temperature and high-pressure visual kettle, and are located directly above the sample clamping electric lifting platform. The backlight is located on the outer side of the high-temperature and high-pressure visual kettle and irradiates the sample clamping electric lifting platform; the central control computer controls the heating system to heat the high-temperature and high-pressure visual kettle, controls the pressurization system to pressurize the high-temperature and high-pressure visual kettle, and the central control computer controls the dripping system to make the liquid flow out of the liquid drop needle group; the high-speed camera is located on one side of the high-temperature and high-pressure visual kettle, and is used to shoot the coal and rock samples 24 on the sample clamping electric lifting platform.

[0148] Specifically, the high-temperature and high-pressure visual kettle is in the shape of a hollow cylinder, and a tempered glass window is opened on the end face of the cylinder; the high-temperature and high-pressure visual kettle includes: a high-pressure kettle cover, a high-temperature and high-pressure visual kettle body, a kettle body rotating gear 21 and a microwave generator, and a ceramic semiconductor heating tube 23 is fixedly installed on the inner side of the tempered glass window around the kettle body; the kettle body is made of insulation material, and the outer periphery of the kettle body is covered with a thermal insulation layer 22 made of thermal insulation fiber.

[0149] Specifically, the microwave generator 10 is located at the bottom of the high-temperature and high-pressure visible autoclave. The power of the microwave generator is adjusted by the built-in microwave generator control software in the central control computer, and the ceramic semiconductor heating tube achieves the purpose of heating the autoclave according to the received microwave power.

[0150] The realization of the temperature change function of the high-temperature and high-pressure visual autoclave mainly consists of a microwave generator, a ceramic semiconductor heating tube, a thermal insulation layer and a central control computer. The built-in microwave generator control software in the central control computer is used to adjust the power of the microwave generator, so that the ceramic semiconductor heating tube can receive microwave power adjustment to achieve the purpose of increasing the ambient temperature in the autoclave.

[0151] Specifically, the autoclave rotating electric transmission device 11 is located at the bottom of the high-temperature and high-pressure visual autoclave. The autoclave rotating electric transmission device uses the autoclave rotating electric transmission device to push the rack at a set speed, and the rack drives the autoclave body to rotate the gear, thereby driving the cylindrical modular high-temperature and high-pressure visual autoclave as a whole to rotate at a certain angular velocity. The autoclave rotating electric transmission device realizes the conversion between linear velocity and angular velocity, thereby achieving the purpose of autonomous constant speed rotation of the high-temperature and high-pressure visual autoclave.

[0152] Specifically, the high-speed camera mounting platform adjusts the posture of the high-speed camera by using a three-axis camera posture adjustment device. The three-axis camera posture adjustment device adopts a mechanical screw mechanism to realize movement in the XYZ direction, thereby achieving the purpose of posture adjustment and long-distance focusing of the high-speed camera.

[0153] Specifically, a linkage camera is provided on one side of the two liquid drop needle groups 28. The linkage camera is composed of two sub-cameras equipped with depth of field lenses. The optical signal captured by the linkage camera is transmitted to the central control computer by the communication optical cable embedded in the kettle body 43 of the high-temperature and high-pressure visual kettle. The power supply is provided by the cable embedded in the kettle body. The linkage camera is embedded in the high-pressure kettle drop needle base to achieve linkage rotation. The linkage cameras arranged on both sides of the drop needle can realize depth of field recognition and focus calibration. The joint structure on the surface of the coal and rock sample can be observed from the high-speed camera above. The two lenses of the linkage camera will be automatically aligned with the drop point through the drop needle co-location technology, and automatic focus will be achieved. The images captured by the depth of field lenses of the two linkage cameras are identified and spliced ​​by the Sobel processor using the Sobel algorithm and transmitted to the central control computer.

[0154] Specifically, Figure 1 As shown, the boosting system includes: a gas sample tank group 1, an electric gas sampling valve group 42, a constant flow ratio mixing chamber 41, a mixing chamber control valve 40, a gas mixing chamber 39, a booster pump control valve 38, a gas booster pump 2, a booster closing valve 3, a pressure storage container 4, a drive pressure indicator 5, a drive pressure switch valve 6 and an autoclave chamber pressure indicator 8, which are connected in sequence through pipelines.

[0155] The gas sample tank group stores gases contained in different geological reservoirs. The gas ratio control software installed on the central control computer is used to set the injection gas ratio, control the electric gas injection valve group to open, and control the injection of different gas samples into the gas mixing chamber through the constant current ratio mixing drive device. After the rated pressure of the gas mixing chamber is reached, the constant current ratio mixing drive device automatically stops to obtain the specified ratio of complex gas in the gas mixing chamber.

[0156] The high-temperature and high-pressure visual autoclave is connected to the pressurization system through a pipeline to realize the pressurization of the gas environment in the autoclave chamber, provide a gas pressure environment, and realize the contact angle measurement function of the sessile drop method.

[0157] Specifically, Figure 1 As shown, the dripping system includes: a solvent tank group 12 and a dialysis solute tank group 16 connected to a Sobel algorithm processor 14, the solvent tank group 12 is connected to the dialysis solute tank group 16 through a liquid double-cylinder pump 15, the dripping system also includes: an injection system exhaust valve 17 and an injection liquid phase valve 18 arranged on the dialysis solute tank group 16, a high-temperature and high-pressure visual autoclave is connected to the dialysis solute tank group 16 through a pipeline, a high-pressure autoclave injection valve 19 is arranged on the dialysis solute tank group, and a dripping needle injection valve group 26 is also arranged on the pipeline connecting the high-temperature and high-pressure visual autoclave and the dialysis solute tank group 16, and the dripping needle injection valve group 26 controls the inflow of liquid in the liquid dripping needle group 28.

[0158] The high temperature and high pressure visual autoclave is connected to the liquid double cylinder pump through independent pipelines. The titration system consists of a central control computer, a solvent tank group, a liquid double cylinder pump, a dialysis solute tank group, an exhaust valve of the injection system, an injection liquid phase valve, an autoclave injection valve, an autoclave drop needle base, a drop needle injection valve group, a pipeline exhaust valve and a liquid drop needle group. The liquid pressure or flow rate is adjusted by the built-in double cylinder pump control software of the central control computer, wherein the double cylinder pump control software can realize the switching of the double cylinder pump constant flow mode or the double cylinder pump constant pressure mode. In order to realize the titration of the liquid drop needle group under normal pressure or high pressure environment in the high temperature and high pressure visual kettle, a high pressure kettle drop needle base 25 is set on the top of the liquid drop needle group 28. When there is a huge pressure difference between the high temperature and high pressure visual kettle and the pipeline, the liquid in the liquid drop needle group does not flow back. At the same time, when the pressure is released in the high temperature and high pressure visual kettle, it can prevent the pressure difference caused by the pressure reduction in the autoclave and the unchanged pressure in the pipeline, which in turn causes the uncontrolled outflow of liquid in the pipeline and the drop needle, polluting the surface of the titrated coal rock sample. By adjusting the double cylinder pump setting software in the central control computer, it is determined that the double cylinder pump first adjusts the liquid pressure in the pipeline to be close to the environmental pressure in the autoclave in the constant pressure mode, reduces the pressure difference on both sides of the autoclave drop needle base, and makes the pipeline and the liquid drop needle group enter the titration preparation state. The double cylinder pump is adjusted to the constant flow mode by the central control computer to ensure that the droplets dripped into the liquid drop needle group are small droplets, and titration is performed on the rock surface.

[0159] Specifically, the central control computer 13 is connected to the gas sample tank group 1 , the Sobel algorithm processor 14 and the linkage camera 27 respectively, and the central control computer 13 is connected to the linkage camera 27 via a camera optical cable 44 .

[0160] Specifically, it also includes:

[0161] The sample rotating table 9 is located above the sample clamping electric lifting platform 31, and is driven to rotate by the turbine screw mechanism 7; the high-temperature and high-pressure visual reactor is built-in with the sample clamping electric lifting platform and the sample rotating table. The sample rotating table adopts a mechanical rotating screw mechanism and is an independent unit body. It is driven by the turbine screw mechanism at the bottom to achieve the purpose of position rotation adjustment.

[0162] The heat preservation and insulation layer 22 is wrapped around the outside of the high temperature and high pressure visible kettle;

[0163] The autoclave drop needle base 25 is located on the liquid drop needle group 28;

[0164] The pipeline exhaust valve 29 is located on the pipeline connecting the high temperature and high pressure visual kettle and the dialysis solute tank group 16;

[0165] The autoclave pressure relief valve 30 is used to relieve pressure for the high-temperature and high-pressure visible autoclave. One end of a pipeline extends into the high-temperature and high-pressure visible autoclave, and the other end is located outside the high-temperature and high-pressure visible autoclave. The autoclave pressure relief valve is arranged on this pipeline.

[0166] The imaging computer 35 is connected to the high-speed camera 37 through the high-speed camera data acquisition conversion card 36. The imaging computer has a built-in high-speed camera shooting system to achieve automatic focusing of the camera and control of the high-speed camera.

[0167] The high-speed camera's high-speed capture image mode adopts a cyclic shooting mode. Based on the artificially set tracing time, when the capture demand occurs, click the "trigger" function key in the high-speed camera shooting system to complete the dynamic contact angle capture work completely and continuously. The capture results are as follows: Figure 8-Figure 9 shown.

[0168] Remove the locking screws 34, and use the cover removal device 33 to lift and remove the autoclave cover 32; the cover removal device (steel screw) is a threaded hole drilled on the autoclave cover, while the autoclave body is not provided with a threaded hole. Rotating the longer cover removal device into the bottom throat of the threaded hole will lift and remove the autoclave cover.

[0169] The method of using the system provided by the present invention is:

[0170] (1) Perform a safety check before the experiment to check that all valves in the system pipeline are in the closed state.

[0171] (2) Remove the locking screws that secure the seal on the autoclave cover, and use the cover removal device to lift and remove the autoclave cover.

[0172] (3) Clamp the sample to be tested of the specified size on the sample clamping electric lifting platform in the high temperature and high pressure visual autoclave, and tighten the locking screws on the sample clamping electric lifting platform to fix the sample.

[0173] (4) By adjusting the turbine screw mechanism, the sample clamping electric lifting platform is moved to adjust the height of the sample so that it is close to the needle tip of the liquid drop needle group.

[0174] (5) Close the kettle cover and the kettle body, install the locking screws, and seal the high-temperature and high-pressure visual kettle.

[0175] (6) The power of the microwave generator is adjusted by the built-in microwave generator control software in the central control computer, so that the ceramic semiconductor heating tube receives the microwave and heats up to increase the ambient temperature in the autoclave.

[0176] (7) Load different gases into the gas sample tank group, and operate the central control computer to mix the gases in the target ratio.

[0177] (8) After the booster pump control valve is opened and the mixed in-situ gas in the gas mixing chamber 39 reaches the calibrated pressure in the pressure storage container 4 through the gas booster pump, observe whether the driving pressure indicator reaches the required pressure in the autoclave.

[0178] (9) Close the booster pump control valve and open the pressure switch valve. The gas in the pressure storage container enters the high-temperature and high-pressure visible autoclave under the action of the pressure difference, so that the gas environment in the high-temperature and high-pressure visible autoclave reaches the specified pressure. Close the pressure switch valve to achieve pressurization of the gas environment in the autoclave chamber.

[0179] (10) Turn on the cold light source backlight at the rear of the high-temperature and high-pressure visual autoclave.

[0180] (11) Turn on the built-in high-speed camera shooting system of the display computer and turn on the real-time image presentation function of the high-speed camera.

[0181] (12) The high-speed camera is mounted on the high-speed camera mounting platform, and a three-axis high-speed camera posture adjustment device is used. By correcting the lead screw mechanism, the real-time display computer screen of the high-speed camera is observed at the same time, and the titration plane and the sample in the high-temperature and high-pressure visual reactor are focused, and the appropriate field of view is adjusted.

[0182] (13) Turn on the linked camera and control the central control computer to perform isotropic focusing shooting of the top area.

[0183] (14) Use the Sobel processor to process the images captured by the linkage camera and record the results through the central control computer.

[0184] (15) Open the built-in double-cylinder pump control software of the central control computer and use the specified number of double-cylinder pumps according to the experimental requirements.

[0185] (16) Add solvent into the solvent tank group, and add solute into the dialysis solute tank group.

[0186] (17) Open the dual-cylinder pump control software of the central control computer, open the exhaust valve of the sampling system, adjust the dual-cylinder pump to enter the constant flow mode, and when stable droplets appear on the exhaust valve of the sampling system, close the exhaust valve of the sampling system.

[0187] (18) According to the different liquid samples required, open different liquid phase injection valves, open the autoclave injection valve and pipeline exhaust valve at the same time, and when a stable liquid flow appears from the pipeline exhaust valve, close the pipeline exhaust valve.

[0188] (19) Open the selected valve in the drop-needle injection valve group, adjust the double-cylinder pump mode in the central control computer to the constant pressure mode, and adjust it to a pressure close to that of the gas in the high-temperature and high-pressure visual kettle. When the pressure stabilizes, use the central control computer to adjust the double-cylinder pump mode to the constant flow mode, and start titrating the liquid sample onto the sample surface. When the titration of the titration sample is completed, close the drop-needle injection valve group.

[0189] (20) After the droplet settles on the sample surface, stop the double-cylinder pump. Use a high-speed camera to capture the contact angle of the droplet, calculate the contact angle value according to the built-in contact angle calculation algorithm of the software, and store the image in the corresponding folder on the computer. The static contact angle measurement is completed.

[0190] (21) Use the central control computer to set the speed of the automatic rotating high-temperature and high-pressure visual kettle as needed.

[0191] (22) When the droplet on the sample surface is observed to roll, the high-speed camera shooting system built into the imaging computer is operated, and the trigger function is clicked to save the video of the droplet migration over a certain period of time to obtain the rolling contact angle, advancing contact angle, and receding contact angle of the sample surface.

[0192] (23) The captured images are obtained by the sessile drop method, and the contact angle is calculated by the built-in algorithm of the central control computer to complete the autonomous processing of the image.

[0193] (24) The composition information of the sample and the experimental area, the actual surface roughness, the measured static contact angle and the dynamic contact angle are fitted to establish a relationship, and the original experimental data of the system is saved in a designated folder.

[0194] (25) After the experiment, open the autoclave pressure relief valve, pipeline exhaust valve, and injection system exhaust valve to discharge high-pressure gas and high-pressure liquid, and perform pressure relief treatment and device cleaning.

[0195] (26) Contact angle verification calculation:

[0196] In the computer software, the grayscale analysis method is used to set a specified threshold between 0 and 255 to perform binarization processing on the image.

[0197] Turn on the contact angle measurement function, use the pen function to separate the sample interface from the droplet, and set the interface baseline.

[0198] Use the anchor point tool to evenly select any 5 points on the droplet or bubble contour, run the contact angle measurement function, and obtain the manually measured contact angle.

[0199] Embodiment 2

[0200] A method for calculating dynamic and static contact angles in an in-situ environment of a deep reservoir, wherein the calculation of the static contact angle specifically comprises the following steps:

[0201] S1, input image data and perform image preprocessing and noise reduction, the preprocessing includes: grayscale assignment processing and two-dimensional Gaussian blur method.

[0202] S2, using the Sobel algorithm to separate the droplets and coal rock samples, and to identify the contours of the droplets and coal rock samples respectively.

[0203] S3, according to the determined coal rock sample contour, based on the multi-point secant sampling method, determine the intersection point of the characteristic contour line and the vertical secant line, and according to the specified fitting point, perform coal rock sample contour fitting based on the Polynomial function.

[0204] S4, determining the static droplet sample profile, and determining the position function of the fitting point, performing profile fitting based on the ellipse function according to the specified fitting point, and characterizing the static droplet profile fitting function.

[0205] S5, determine the rectangular coordinate system according to the intersection of the coal rock sample contour and the droplet contour and measure the initial contact angle.

[0206] S6, based on the initial contact angle, the influence of gravity micro-pressure difference on the contact angle is eliminated to obtain the corrected true static contact angle of the coal rock sample surface.

[0207] Specifically, step S1 includes the following steps:

[0208] S1.1, convert the RGB image into 8-bit images with different grayscale values, and assign grayscale values ​​to the image pixels, where the grayscale assignment formula is:

[0209] H = 0.244R + 0.587G + 0.114B;

[0210] Among them, H is the weighted gray value, R is the RGB red pixel parameter, G is the RGB green pixel parameter, and B is the RGB blue pixel parameter.

[0211] S1.2, grayscale weighted mean processing is performed on the pixels within the concentric circle range of the two-dimensional plane to reduce the noise of the image. The noise reduction processing is based on the two-dimensional Gaussian blur method. The two-dimensional Gaussian normal distribution formula is:

[0212]

[0213] Among them, u is the image X-axis parameter, v is the image Y-axis parameter, G is the pixel grayscale information after Gaussian weighted processing, σ is the data variance, and the image preprocessing is completed according to the two-dimensional Gaussian blur formula.

[0214] Specifically, since there is a difference in light transmittance of the photographed liquid sample and the coal rock sample to the backlight, there is a direct difference in the pixel grayscale assignment of the droplet and the sample in the image.

[0215] The Sobel algorithm uses a third-order matrix to calculate the grayscale values ​​of pixels in the image, identifies characteristic value contours in the image, and identifies the droplet contour according to the contours.

[0216] Step S2 specifically includes the following steps:

[0217] S2.1, the third-order matrix formula for contour recognition based on the Sobel algorithm is:

[0218]

[0219] Among them, Q is the eigenvalue, a ij is the pixel gray value.

[0220] S2.2, the recognition principle is that the gray value of the experimental object background is the smallest, the gray value of the experimental droplet is in the middle, and the gray value of the experimental rock sample is the largest. The gray value between 0 and 15 is the characteristic domain of the experimental object background, the gray value between 16 and 240 is the characteristic domain of the experimental droplet contour, and the gray value between 241 and 255 is the characteristic domain of the experimental coal and rock samples. The characteristic contour lines composed of continuous gray characteristic values ​​are selected for contour recognition and segmentation.

[0221] Specifically, step S3 includes the following steps:

[0222] S3.1, determine the contour of the coal rock sample, and the characteristic line determination function in the grayscale range of grayscale values ​​241 to 255 is:

[0223] F1(x)=Q s ;

[0224] Among them, F1(x) is the line function of the characteristic points of the coal rock sample contour, Q s is the selected continuous eigenvalue.

[0225] S3.2, determine the basic equation of the vertical secant line as:

[0226]

[0227] Among them, x is the horizontal coordinate of the position of the secant line, U is the total length of the image in the X-axis direction, and U i is the X-axis coordinate of the ith secant line, n is the total number of n secants, n j is the number of the j-th secant line, and ∏(x) is the integration function.

[0228] S3.3, the position function of the fitting point to determine the rock surface profile is:

[0229] C i =(x i ,Q s );

[0230] Among them, C i is the position of the image secant line, x i is the X-axis coordinate of the i-th secant line.

[0231] S3.4, according to the fitting points, the coal rock sample contour is fitted based on the Polynomial function:

[0232] F(x)=a1x 5 +b1x 4 +c1x 3 +d1x 2 +e1x+f1;

[0233] Among them, F(x) is the coal rock sample profile fitting function, a1, B1, C1, d1, e1 and F1 are coefficients, and the coefficients in the Polynomial function are determined based on the fitting points.

[0234] Specifically, step S4 includes the following steps:

[0235] S4.1, determine the static droplet sample profile, the characteristic line determination function in the grayscale range of grayscale values ​​241 to 255 is:

[0236] F2(x)=Q; s

[0237] Among them, F2(x) is the function of connecting the characteristic points of the static droplet sample contour.

[0238] S4.2, such as Figure 6 As shown, the position function of the fitting point of the droplet surface profile is determined as:

[0239] C j =(x j , Q s );

[0240] Among them, C j is the position of the droplet surface contour fitting point, x j is the X-axis coordinate of the j-th secant line.

[0241] S4.3, the static droplet surface profile fitting function is:

[0242]

[0243] Among them, A, B, D, E and F are coefficients.

[0244] Specifically, step S5 includes the following steps:

[0245] S5.1, based on F1(x), obtain the static droplet profile tangent function F2(x):

[0246]

[0247] Among them, a, b, c, d ′ , e, f are coefficients;

[0248] Determine the zero point of the rectangular coordinate system:

[0249] F2(x)=F1(x)

[0250] S5.2, calculate the initial static contact angle:

[0251] F1(x)=kx+c;

[0252] arctanθ0=k;

[0253] Where θ0 is the initial static contact angle, k is the derivative slope of the droplet surface contour, and c is the derivative constant of the droplet surface contour.

[0254] Specifically, step S6 includes the following steps:

[0255] S6.1, after measuring the initial contact angle, the contact angle needs to be corrected to remove the influence of needle gravity on the contact angle. The static contact angle is restored according to the inverse solution process of Young's equation:

[0256]

[0257] Where θ is the static contact angle under ideal conditions; γ SG is the solid-gas interfacial tension, γ SL is the solid-liquid interfacial tension, γ LG is the interfacial tension between liquid and gas.

[0258] S6.2, based on the influence of the static droplet's own bulk density on the contact angle measurement, the static contact angle droplet mass is solved:

[0259] G′=γh;

[0260]

[0261] Among them, G ′ is the gravity correction function, γ is the liquid bulk density, and h is the liquid profile height function.

[0262] S6.3, perform the correction calculation:

[0263]

[0264] Where θ0 is the initial static contact angle.

[0265] S6.4, based on Young's equation, the actual measured contact angle of the coal rock sample surface is calculated and obtained:

[0266]

[0267] Among them, θ r is the actual static contact angle of the rock material surface. Record θ r The result value is stored.

[0268] Specifically, the autoclave rotating electric transmission device can realize the rotation of the autoclave at a certain angular velocity, realize the inclination of the sample holding electric lifting platform, and then drive the droplets on the surface of the coal rock sample to migrate. The method for calculating the dynamic contact angle specifically includes the following steps:

[0269] S7, preprocessing the image, the preprocessing method is the same as step S1, according to the specified fitting points, the contour fitting is performed based on the Polynomial function to characterize the dynamic droplet contour, such as Figure 7 As shown. The dynamic droplet profile fitting function is:

[0270]

[0271] Among them, a ′ 、b ′ 、c ′ d ′ 、e ′ and f ′ is the coefficient.

[0272] S8, correct the momentum effect on the dynamic droplet profile and calculate the actual dynamic contact angle:

[0273] S8.1, in an image within a certain period of time, the method for determining the movement of the base point of a dynamic droplet is as follows:

[0274] Create a data set:

[0275] DCAI1={P1,P2,P3,…,P n};

[0276] Among them, DCAI1 is the initial preprocessed data set; P n are the contact points between the leading edge and the trailing edge and the coal rock surface in the dynamic contact angle recorded for the nth time; the dynamic contact angle is the tendency of the droplet to move due to the inclination of the rock surface, the direction in which the droplet has a forward trend is the leading edge, and the other end is the trailing edge.

[0277] Since the frame rate of the high-speed camera capturing images is set to a certain value, the advancing contact angle and receding contact angle of the dynamic droplet are calculated based on the principle of successive difference method.

[0278] The total amount of data is counted. If n is an even number, the calculation is normal; if n is an odd number, the (n+1) / 2 items in the middle are removed and rearranged as follows:

[0279] DCAI2={P1,P2,P3,…,P n};

[0280] Among them, DCAI2 is the data set after completing the initial difference check.

[0281] S8.2, supplement for dynamic droplet acceleration:

[0282]

[0283] Among them, v is the base point movement speed; t is time; T is the capture interval time.

[0284] S8.3, solve the definite integral to obtain the instantaneous velocity of the base point of the dynamic droplet:

[0285]

[0286] Among them, V x is the instantaneous velocity of the dynamic droplet base point, T X and T X+1 They are the starting calculation time interval and the ending calculation time interval respectively.

[0287] S8.4, characterize the dynamic droplet momentum P based on the momentum theorem:

[0288] P = FΔT = mΔV;

[0289]

[0290] Among them, F is the modified mechanical operator; m is the droplet mass; ΔV is the velocity gradient, and ΔT is the time gradient.

[0291] S8.5, the Yang-Laplace equation is modified to obtain the initial dynamic contact angle θ 0’ :

[0292]

[0293] S8.6, correcting for momentum effects according to Young's equation:

[0294]

[0295] Among them, θ ′ The actual dynamic contact angle of the coal rock surface after eliminating the influence of momentum.

[0296] Specifically, it also includes:

[0297] S9, stitching the images captured by the two linked cameras into a large image, blocking the wall drop needle, and performing rock surface roughness analysis on the basis of the large image, and performing rock surface roughness analysis based on the static contact angle and dynamic contact angle obtained by measurement, which specifically includes the following steps:

[0298] S9.1, the images captured by the two linked cameras are stitched together using the Sobel algorithm, and the images are binarized; the grayscale of each pixel in the binarized image and its surrounding nine pixels are counted, and matrix calculation is performed, and the grayscale matrix calculation values ​​of different pixels are weighted and calculated;

[0299] The matrix calculation formula is:

[0300]

[0301] Among them, Q ′ is the corrected grayscale feature value of different pixels in the image; a ij ′ is the gray value of different pixels in the image.

[0302] S9.2, count the contour lines of the same grayscale matrix calculation value of the image, and obtain the grayscale feature lines of the two images, and splice the images according to the grayscale feature lines:

[0303] L1={P 11 , P 12 ,P 13 ,…,P 1n};

[0304] L2={P 21 ,P 22 ,P 23 ,…,P 2n};

[0305] L1=L2;

[0306] Among them, L1 is the grayscale feature line in the image taken by the first linked camera; L2 is the grayscale feature line in the image taken by the second linked camera.

[0307] S9.3, use fractal dimension to perform roughness analysis on the spliced ​​image:

[0308]

[0309] Among them, D is the fractal dimension describing the surface roughness of coal rock, N(ε) is the number of surrounding pixels in a certain area, ε is the relative size of a certain area, and log(·) is the logarithmic function.

[0310] S9.4, read the spliced ​​image obtained in S9.2, and convert it into a binary image, and assign grayscale values ​​to the particle geometry images at different heights on the surface of the coal and rock samples, with the value range being between 0 and 255.

[0311] In order to identify the depth map captured by the linkage camera, read and convert it into a binary image, and assign grayscale values ​​to the particle geometry images at different heights on the surface of the coal and rock samples. The value range is between 0 and 255, and the value assignment principle is that the larger the grayscale value, the deeper the pore; the smaller the grayscale value, the more convex the particle.

[0312] S9.5, perform Gaussian noise reduction on the image, and then process the rock surface roughness based on the island method, and characterize the surface roughness through the area and distribution of grayscale values.

[0313] First, the perimeter E and area F of each closed area on each grayscale isosurface are calculated, and then the perimeter and area are taken logarithmically, and the relationship between lnE and lnF is linearly fitted in the coordinates, and the fractal dimension is finally obtained by calculation.

[0314]

[0315] Where, E represents the perimeter of the closed grayscale block; F represents the area of ​​the closed grayscale block; W is a constant;

[0316] According to the Mandel-brot model, there is a formula:

[0317]

[0318] Among them, C is a constant, D r The fractal dimension of the island of the irregular figure boundary line; D r The larger it is, the more complex the pore structure of the rock surface is, and the greater the roughness of the rock surface is.

[0319] According to different fractal dimensions, the classification is carried out, and the relationship between pressure, static contact angle and dynamic contact angle is established, and the causal analysis is performed, such as Fig.10 shown.

[0320] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A deep reservoir in-situ environment dynamic and static contact angle measurement device, characterized in that: include: High temperature and high pressure visual kettle, electric lifting platform for sample clamping, liquid drop needle set, backlight, linkage camera, drop system, heating system, pressurization system, high-speed camera and central control computer; When calculating the dynamic contact angle, the high-temperature and high-pressure visual kettle rotates on a fixed axis, the sample clamping electric lifting platform is located in the high-temperature and high-pressure visual kettle, the coal and rock samples are clamped on the sample clamping electric lifting platform, the sample clamping electric lifting platform is adjusted, and load pressure is applied to the coal and rock samples. The liquid drop needle group and the linkage camera are fixed on the kettle cover on the inner side of the high-temperature and high-pressure visual kettle and are located directly above the sample clamping electric lifting platform. The backlight is located on the outer side of the high-temperature and high-pressure visual kettle and irradiates the sample clamping electric lifting platform; the central control computer controls the heating system to heat the high-temperature and high-pressure visual kettle, controls the pressurization system to pressurize the high-temperature and high-pressure visual kettle, and controls the dripping system to make the liquid flow out of the liquid drop needle group; the high-speed camera is located on one side of the high-temperature and high-pressure visual kettle, and is used to shoot the coal and rock samples on the sample clamping electric lifting platform.

2. A method for measuring dynamic and static contact angles in an in-situ environment of a deep reservoir, using the device described in claim 1, characterized in that: The calculation of static contact angle includes the following steps: S1, input image data and perform image preprocessing and noise reduction, the preprocessing includes: grayscale assignment processing and two-dimensional Gaussian blur method; S2, using the Sobel algorithm to separate the droplets and the coal-rock samples, and to identify the contours of the droplets and the coal-rock samples respectively; S3, according to the determined coal and rock sample contour, based on the multi-point secant sampling method, determine the intersection point of the characteristic contour line and the vertical secant line, and perform coal and rock sample contour fitting based on the Polynomial function according to the specified fitting point; S4, determining the static droplet sample profile, and determining the position function of the fitting point, performing profile fitting based on the ellipse function according to the specified fitting point, and characterizing the static droplet profile fitting function; S5, determining a rectangular coordinate system according to the intersection of the coal rock sample contour and the droplet contour and measuring the initial contact angle; S6, based on the initial contact angle, the influence of gravity micro-pressure difference on the contact angle is eliminated to obtain the corrected true static contact angle of the coal rock sample surface.

3. A method for calculating dynamic and static contact angles in a deep reservoir in-situ environment according to claim 2, characterized in that: Step S1 specifically includes the following steps: S1.1, convert the RGB image into 8-bit images with different grayscale values, and assign grayscale values ​​to the image pixels, where the grayscale assignment formula is: H = 0.244R + 0.587G + 0.114B; Among them, H is the weighted gray value, R is the RGB red pixel parameter, G is the RGB green pixel parameter, and B is the RGB blue pixel parameter; S1.2, based on the two-dimensional Gaussian blur method, the two-dimensional Gaussian normal distribution formula is: Among them, u is the image X-axis parameter, v is the image Y-axis parameter, G is the pixel grayscale information after Gaussian weighted processing, σ is the data variance, and the image preprocessing is completed according to the two-dimensional Gaussian blur formula.

4. A method for calculating dynamic and static contact angles in a deep reservoir in-situ environment according to claim 3, characterized in that: Step S2 specifically includes the following steps: S2.1, the third-order matrix formula for contour recognition based on the Sobel algorithm is: Among them, Q is the eigenvalue, a ij is the pixel gray value; S2.2, the grayscale value between 0 and 15 is the background feature domain of the experimental object, the grayscale value between 16 and 240 is the experimental droplet contour feature domain, and the grayscale value between 241 and 255 is the experimental coal and rock sample feature domain. The characteristic contour lines composed of continuous grayscale feature values ​​are selected for contour recognition and segmentation.

5. A method for calculating dynamic and static contact angles in a deep reservoir in-situ environment according to claim 4, characterized in that: Step S3 specifically includes the following steps: S3.1, determine the contour of the coal rock sample, and the characteristic line determination function in the grayscale range of grayscale values ​​241 to 255 is: F1(x)=Q s ; Among them, F1(x) is the line function of the characteristic points of the coal rock sample contour, Q s For selected continuous eigenvalues; S3.2, determine the basic equation of the vertical secant line as: Among them, x is the horizontal coordinate of the position of the secant line, U is the total length of the image in the X-axis direction, and U x is the X-axis coordinate of the ith secant line, n is the total number of n secants, n j is the number of the j-th secant line, ∏(x) is the integration function; S3.3, the position function of the fitting point to determine the rock surface profile is: C i =(x i ,Q s ); Among them, C i is the position of the image secant line, x i is the X-axis coordinate of the i-th secant line; S3.4, according to the fitting points, the coal rock sample contour is fitted based on the Polynomial function: F(x)=a1x 5 +b1x 4 +c1x 3 +d1x 2 +e1x+f1; Among them, F(x) is the coal rock sample profile fitting function, a1, b1, c1, d1, e1 and f1 are coefficients, and the coefficients in the Polynomial function are determined based on the fitting points.

6. A method for calculating dynamic and static contact angles in a deep reservoir in-situ environment according to claim 5, characterized in that: Step S4 specifically includes the following steps: S4.1, determine the static droplet sample profile, the characteristic line determination function in the grayscale range of grayscale values ​​241 to 255 is: F2(x)=Q s ; Among them, F2(x) is the function of connecting the characteristic points of the static droplet sample contour; S4.2, determine the position function of the droplet profile fitting point as: C j =(x j ,Q s ); Among them, C j is the position of the droplet profile fitting point, x j is the X-axis coordinate of the j-th secant line; S4.3, static droplet profile fitting function is: Among them, A, B, D, E and F are coefficients.

7. A method for calculating dynamic and static contact angles in a deep reservoir in-situ environment according to claim 6, characterized in that: Step S5 specifically includes the following steps: S5.1, based on F1(x), obtain the static droplet profile tangent function F2(x): Among them, a, b, c, d′, e, and f are coefficients; Determine the zero point of the rectangular coordinate system: F2(x)=F1(x); S5.2, calculate the initial static contact angle: F1(x)=kx+c; arctanθ0=k; Where θ0 is the initial static contact angle, k is the derivative slope of the droplet surface contour, and c is the derivative constant of the droplet surface contour.

8. A method for calculating dynamic and static contact angles in a deep reservoir in-situ environment according to claim 7, characterized in that: Step S6 specifically includes the following steps: S6.1, restore the static contact angle according to the inverse solution process of Young's equation: Where θ is the static contact angle under ideal conditions; γ SG is the solid-gas interfacial tension, γ SL is the solid-liquid interfacial tension, γ LG is the interfacial tension between liquid and gas; S6.2, based on the influence of the droplet's own bulk density on the contact angle measurement, the static contact angle droplet mass force is solved: G′=γh; Where G′ is the gravity correction function, γ is the liquid bulk density, and h is the liquid profile height function; S6.3, perform the correction calculation: Where θ0 is the initial static contact angle; S6.4, based on Young's equation, the actual measured contact angle of the coal rock sample surface is calculated and obtained: Among them, θ r is the actual static contact angle of the rock material surface.

9. A method for calculating dynamic and static contact angles in a deep reservoir in-situ environment according to claim 8, characterized in that: The method for calculating the dynamic contact angle specifically includes the following steps: S7, preprocessing the image, performing contour fitting based on the Polynomial function according to the specified fitting points, and characterizing the dynamic droplet contour; S8, correct the momentum effect on the dynamic droplet profile and calculate the actual dynamic contact angle: S8.1, in an image within a certain period of time, the method for determining the movement of the base point of a dynamic droplet is as follows: Create a data set: DCAI1={P1,P2,P3,…,P n }; Among them, DCAI1 is the initial preprocessed data set; P n is the contact point between the leading edge and the trailing edge and the coal rock surface in the dynamic contact angle recorded at the nth time; The total amount of data is counted. If n is an even number, the calculation is normal; if n is an odd number, the (n+1) / 2 items in the middle are removed and rearranged as follows: DCAI2={P1,P2,P3,…,P n }; Among them, DCAI2 is the data set after the initial difference check is completed; S8.2, supplement for dynamic droplet acceleration: Among them, v is the base point moving speed; t is time; T is the capture interval time; S8.3, solve the definite integral to obtain the instantaneous velocity of the base point of the dynamic droplet: Among them, V x is the instantaneous velocity of the dynamic droplet base point, T X and T X+1 They are the starting calculation time interval and the ending calculation time interval respectively; S8.4, characterize the dynamic droplet momentum P based on the momentum theorem: P = FΔT = mΔV; Where F is the modified mechanical operator; m is the droplet mass; ΔV is the velocity gradient, and ΔT is the time gradient; S8.5, the Yang-Laplace equation is modified to obtain the initial dynamic contact angle θ 0′ : S8.6, correcting for momentum effects according to Young's equation: Among them, θ′ is the actual dynamic contact angle of the coal rock surface after eliminating the influence of momentum.

10. A method for measuring dynamic and static contact angles in a deep reservoir in-situ environment according to claim 9, characterized in that: Also includes: S9, performing rock surface roughness analysis based on the static contact angle and dynamic contact angle obtained by measurement, specifically comprising the following steps: S9.1, the images captured by the two linked cameras are stitched together using the Sobel algorithm, and the images are binarized; the grayscale of each pixel in the binarized image and its surrounding nine pixels are counted, and matrix calculation is performed, and the grayscale matrix calculation values ​​of different pixels are weighted and calculated; The matrix calculation formula is: Among them, Q′ is the corrected grayscale feature value of different pixels in the image; a ij ′ is the gray value of different pixels in the image; S9.2, count the contour lines of the same grayscale matrix calculation value of the image, and obtain the grayscale feature lines of the two images, and splice the images according to the grayscale feature lines: L1={P 11 ,P 12 ,P 13 ,…,P 1n }; L2={P 21 ,P 22 ,P 23 ,…,P 2n }; L1=L2; Wherein, L1 is the grayscale feature line in the image captured by the first linkage camera; L2 is the grayscale feature line in the image captured by the second linkage camera; S9.3, use fractal dimension to perform roughness analysis on the spliced ​​image: Among them, D is the fractal dimension describing the roughness of the coal rock surface, N(ε) is the number of surrounding pixels in a certain area, ε is the relative size of a certain area, and log(·) is the logarithmic function; S9.4, reading the spliced ​​image obtained in S9.2 and converting it into a binary image, and assigning grayscale values ​​to the particle geometric images at different heights on the surface of the coal and rock samples, with the value range being between 0 and 255; S9.5, perform Gaussian noise reduction on the image, and then process the rock surface roughness based on the island method: Where, E represents the perimeter of the closed grayscale block; F represents the area of ​​the closed grayscale block; W is a constant; According to the Mandel-brot model, there is a formula: Among them, C is a constant, D r The fractal dimension of the island of the irregular figure boundary line; D r The larger it is, the more complex the pore structure of the rock surface is, and the greater the roughness of the rock surface is.

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