Method and device for characterizing rock wetting heterogeneity based on imbibition wetting angle distribution

Abstract

The present invention provides a method and device for characterizing rock wetting heterogeneity based on the distribution of imbibition wetting angles, the method comprising: immersing a rock saturated with a first fluid in a second fluid; measuring the wetting angle of the first fluid on the rock surface under imbibition; immersing a rock saturated with the second fluid in the first fluid; measuring the wetting angle of the second fluid on the rock surface under imbibition, wherein the first fluid and the second fluid are immiscible. The method and device for characterizing rock wetting heterogeneity based on the distribution of imbibition wetting angles provided by the present invention eliminate the error in wetting angle measurement caused by insufficient contact between a droplet and a core surface; and provide a new idea for measuring and characterizing wetting heterogeneity; and according to the probability distribution of the wetting angle, provide a basis for the study of the displacement mechanism of two-phase fluids in porous media and numerical simulation studies.

Description

Technical Field

[0001] The invention relates to the field of petroleum exploration and development, in particular to a core parameter measurement technology, and specifically to a rock wetting heterogeneity characterization method and device based on imbibition wetting angle distribution. Background Art

[0002] Wettability is an important parameter to describe the physical properties of oil and gas reservoirs. It has a significant impact on multiphase seepage in reservoir rocks. Therefore, both migration and accumulation research and development mechanism research pay great attention to the wettability of reservoir rocks. The commonly used methods for determining wettability in the prior art include the Amott method, the USBM method and the wetting angle method. Among them, the Amott method and the USBM method derive the wettability index based on two-phase displacement and use the wettability index to characterize the wettability of the rock. The wettability measurement process of these two methods is cumbersome and time-consuming, and the obtained wettability index cannot be directly linked to the capillary force of concern in oil and gas exploration and development; for the wetting angle method, when measuring the wetting angle of reservoir rock, a droplet is usually dropped on the core surface, the shape of the droplet is photographed with a camera, and the wetting angle is measured after the droplet shape is analyzed. The defect of this method is that the core surface is rough at the microscopic level and is distributed with many microscopic pits. Therefore, the dropped droplet does not directly contact the rock surface at the pit, but contacts with another phase of fluid retained in the pit, which is bound to bring a large error to the measurement of the wetting angle.

[0003] In addition, due to the influence of factors such as the electrical properties of rock particles themselves and the distribution of oil and water in rock pores, reservoir rocks show non-uniform distribution characteristics in wettability. Although methods such as nuclear magnetic resonance and pigment adsorption have made certain explorations in measuring wettability heterogeneity, these methods are often limited to measuring the ratio of the surface area of ​​oil-wet and water-wet particles, and cannot measure the degree of oil-wet and water-wet. Summary of the invention

[0004] The present invention relates to, but is not limited to, the technical field of laboratory evaluation of core parameters in oil and gas exploration and development research. The embodiments of the present invention provide a method and device for characterizing rock wettability heterogeneity based on imbibition wetting angle distribution, which overcomes the wetting angle calculation error caused by the roughness of the core surface in the prior art, and can more accurately measure and describe the wettability of reservoir rocks.

[0005] On the one hand, an embodiment of the present invention provides a method for characterizing rock wetting heterogeneity based on imbibition wetting angle distribution, comprising:

[0006] immersing the rock saturated with the first fluid in a second fluid;

[0007] measuring a wetting angle of the first fluid on the rock surface under imbibition;

[0008] immersing the rock saturated with the second fluid in the first fluid;

[0009] The wetting angle of the second fluid on the rock surface under imbibition is measured, wherein the first fluid is immiscible with the second fluid.

[0010] In one embodiment, the measuring of the wetting angle of the first fluid on the rock surface under the action of imbibition comprises:

[0011] Taking a picture of the droplets of the first fluid flowing out on the rock surface under the imbibition effect to generate a first picture;

[0012] The wetting angle of the first fluid is calculated based on the first photograph.

[0013] In one embodiment, before immersing the rock saturated with the second fluid in the first fluid, the method further comprises:

[0014] The rocks are dried until they are of a stable weight.

[0015] In one embodiment, the measuring of the wetting angle of the second fluid on the rock surface under the action of imbibition comprises:

[0016] Taking a picture of the droplets of the second fluid flowing out on the rock surface under the imbibition effect to generate a second picture;

[0017] The wetting angle of the second fluid is calculated based on the second photograph.

[0018] In one embodiment, a method of saturating rock includes:

[0019] The rock is saturated with the first fluid or the second fluid by using a vacuum and pressurization method.

[0020] In one embodiment, the rock wetting heterogeneity characterization method based on imbibition wetting angle distribution further includes:

[0021] The rock wetting heterogeneity is characterized according to the wetting angle of the first fluid and the wetting angle of the second fluid.

[0022] On the other hand, an embodiment of the present invention provides a rock wetting heterogeneity characterization device based on imbibition wetting angle distribution, comprising:

[0023] a first soaking module for soaking the rock saturated with the first fluid in a second fluid;

[0024] A first measuring module, used to measure the wetting angle of the first fluid on the rock surface under the action of imbibition;

[0025] a second soaking module, for soaking the rock saturated with the second fluid in the first fluid;

[0026] The second measurement module is used to measure the wetting angle of the second fluid on the rock surface under the action of imbibition, wherein the first fluid is immiscible with the second fluid.

[0027] In one embodiment, the first measurement module includes:

[0028] A first photographing unit, used to photograph the droplets of the first fluid flowing out on the rock surface under the action of the imbibition, so as to generate a first photograph;

[0029] The first wetting angle calculation unit is used to calculate the wetting angle of the first fluid according to the first photo.

[0030] In one embodiment, the rock wetting heterogeneity characterization device based on imbibition wetting angle distribution further includes:

[0031] Rock drying module, used to dry the rock until the weight is stable.

[0032] In one embodiment, the second measurement module includes:

[0033] a second photographing unit, for photographing the droplets of the second fluid flowing out on the rock surface under the action of the imbibition, so as to generate a second photograph;

[0034] The second wetting angle calculation unit is used to calculate the wetting angle of the second fluid according to the second photo.

[0035] In one embodiment, the rock wetting heterogeneity characterization device based on imbibition wetting angle distribution further includes:

[0036] A rock saturation module, used for saturating rock, comprising:

[0037] The vacuum unit is used to saturate the rock with the first fluid or the second fluid by using a vacuum pressurization method.

[0038] In one embodiment, the rock wetting heterogeneity characterization device based on imbibition wetting angle distribution further includes:

[0039] The heterogeneity characterization module is used to characterize the rock wetting heterogeneity according to the wetting angle of the first fluid and the wetting angle of the second fluid.

[0040] In a third aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the processor implements the steps of a method for characterizing rock wetting heterogeneity based on imbibition wetting angle distribution.

[0041] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for characterizing rock wettability heterogeneity based on imbibition wetting angle distribution.

[0042] From the above description, it can be seen that the embodiment of the present invention provides a method and device for characterizing rock wetting heterogeneity based on the distribution of imbibition wetting angles. First, the rock saturated with the first fluid is immersed in the second fluid; then, the wetting angle of the first fluid on the rock surface under the action of imbibition is measured; the rock saturated with the second fluid is immersed in the first fluid; finally, the wetting angle of the second fluid on the rock surface under the action of imbibition is measured, wherein the first fluid and the second fluid are immiscible. The present invention has the following beneficial effects:

[0043] 1. Eliminate the error in wetting angle measurement caused by insufficient contact between the droplet and the rock surface;

[0044] 2. Provides a new method for measuring and characterizing wetting heterogeneity;

[0045] 3. According to the probability distribution of rock wetting angle, it provides a basis for the study of two-phase fluid displacement mechanism and numerical simulation in porous media. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A schematic diagram of a rock wetting heterogeneity characterization method based on imbibition wetting angle distribution provided in an embodiment of the present invention Figure 1 ;

[0048] Figure 2 is a flow chart of step 200 in an embodiment of the present invention;

[0049] Figure 3 Schematic diagram of wetting angle (acute angle) in an embodiment of the present invention;

[0050] Figure 4 Schematic diagram of wetting angle (obtuse angle) in an embodiment of the present invention;

[0051] Figure 5 Schematic diagram of a method for calculating a wetting angle in an embodiment of the present invention;

[0052] Figure 6A schematic diagram of a rock wetting heterogeneity characterization method based on imbibition wetting angle distribution provided in an embodiment of the present invention Figure 2 ;

[0053] Figure 7 is a flow chart of step 400 in an embodiment of the present invention;

[0054] Figure 8 A schematic diagram of a rock wetting heterogeneity characterization method based on imbibition wetting angle distribution provided in an embodiment of the present invention Figure 3 ;

[0055] Fig. 9 It is a schematic diagram of a process of a rock wetting heterogeneity characterization method based on imbibition wetting angle distribution in a specific embodiment of the present invention;

[0056] Fig.10 This is a wetting angle distribution diagram of oil droplets in a D227 core in a specific embodiment of the present invention;

[0057] Fig.11 This is a block of a rock wetting heterogeneity characterization device based on imbibition wetting angle distribution in an embodiment of the present invention. Figure 1 ;

[0058] Fig.12 is a block diagram of the first measurement module 20 in an embodiment of the present invention;

[0059] Fig.13 This is a block of a rock wetting heterogeneity characterization device based on imbibition wetting angle distribution in an embodiment of the present invention. Figure 2 ;

[0060] Fig.14 is a block diagram of the second measurement module 40 in an embodiment of the present invention;

[0061] Fig.15 This is a block of a rock wetting heterogeneity characterization device based on imbibition wetting angle distribution in an embodiment of the present invention. Figure 3 ;

[0062] Fig.16 is a block diagram of a rock saturation module 60 in an embodiment of the present invention;

[0063] Fig.17 This is a block of a rock wetting heterogeneity characterization device based on imbibition wetting angle distribution in an embodiment of the present invention. Figure 4 ;

[0064] Fig.18 It is a schematic diagram of the structure of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0066] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0067] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0068] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0069] In view of the problems and defects in measuring reservoir rock wettability in the prior art, the present invention provides a specific implementation method of a rock wettability heterogeneity characterization method based on imbibition wetting angle distribution, see Figure 1 , the method specifically includes the following contents:

[0070] Step 100: Soaking the rock saturated with the first fluid in a second fluid;

[0071] It is understandable that the rock needs to be saturated with the first fluid in advance. Preferably, a spontaneous imbibition method can be used to form drops on the rock surface (spontaneous imbibition refers to the process in which a wetting fluid in the rock pores spontaneously replaces another non-wetting fluid under the action of capillary force, which is an important mechanism affecting the fracturing transformation of low-permeability reservoirs). It is understandable that the use of the spontaneous imbibition method can avoid the error caused by the droplet not fully contacting the rock to avoid the measurement of the wetting angle. Then the rock is immersed in the second fluid, wherein the first fluid and the second fluid are immiscible.

[0072] Specifically, the rock saturated with the first fluid is immersed in the second fluid. Under the action of capillary force, the second fluid spontaneously infiltrates into the rock, while the first fluid is discharged from the rock and forms droplets on the rock surface.

[0073] Step 200: Measuring the wetting angle of the first fluid on the rock surface under the action of imbibition.

[0074] Affected by the rock wetting heterogeneity and under the action of spontaneous imbibition, the first fluid forms droplets on the rock wall and flows out from the inside of the rock. Then, the droplets are photographed and the wetting angle is calculated. Since the first fluid flows out from the inside of the rock and fills the microscopic pits on the rock surface, the error in measuring the wetting angle caused by the inability of the droplets to fill the pits is avoided.

[0075] Step 300: Soaking the rock saturated with the second fluid in the first fluid;

[0076] It is understandable that the rock needs to be dried until its weight remains unchanged before step 300. The rock saturated with the second fluid is immersed in the first fluid, and under the action of capillary force, the first fluid is spontaneously absorbed into the rock, while the second fluid is discharged from the rock and forms droplets on the surface of the rock.

[0077] Step 400: Measuring the wetting angle of the second fluid on the rock surface under the action of imbibition, wherein the first fluid is immiscible with the second fluid.

[0078] In step 300 and step 400, the wetting angle of the second fluid droplet formed by spontaneous imbibition is also measured and statistically analyzed, the second fluid wetting angle is converted into the first fluid wetting angle, and the statistical results are combined to obtain the comprehensive wetting angle statistical parameters corresponding to the rock surface wetting heterogeneity.

[0079] From the above description, it can be seen that an embodiment of the present invention provides a method for characterizing rock wetting heterogeneity based on the distribution of wetting angles of imbibition. In order to avoid the error in measuring the wetting angle of reservoir rock caused by the inability of droplets to directly contact the rock at the microscopic pits, a spontaneous deep imbibition method is used to form droplets on the rock surface, that is, the rock is saturated with a first fluid, and then the saturated rock is immersed in a second immiscible fluid. Affected by the wetting heterogeneity, under the action of spontaneous imbibition, the first fluid forms droplets on the rock wall. Since the first fluid flows out from the inside of the rock and fills the microscopic pits on the rock surface, the error in measuring the wetting angle caused by the inability of the droplets to fill the pits is avoided. The droplets are photographed and the wetting angle is calculated. Next, in order to measure and characterize the wetting heterogeneity of the rock, the wetting angles of all imbibed droplets were measured and statistically analyzed. The rock was dried and saturated with the second fluid again and then immersed in the first fluid. The wetting angles of the second fluid droplets formed by spontaneous imbibition were also measured and statistically analyzed. The wetting angle of the second fluid was converted into the wetting angle of the first fluid, and the results were combined to obtain the comprehensive wetting angle statistical parameters corresponding to the rock surface wetting heterogeneity.

[0080] In one embodiment, see Figure 2 , step 200 further comprises:

[0081] Step 201: taking a photo of the droplets of the first fluid flowing out on the rock surface under the imbibition effect to generate a first photo;

[0082] Step 202: Calculate the wetting angle of the first fluid according to the first photo.

[0083] Take a picture of the first fluid droplet on the rock surface and measure the wetting angle α corresponding to different droplets i The measurement results are statistically analyzed.

[0084] The wetting angle refers to the angle between the liquid-solid interface and the tangent line of the liquid surface at the contact point between the liquid and the solid phase. When the angle is less than 90°, it indicates wetting. Figure 3 , greater than 90° indicates non-wetting, see Figure 4 . See Figure 5 When step 202 is implemented, it can be performed according to the following formula:

[0085]

[0086] In the above formula: θ is the wetting angle, °; h is the droplet height, mm; D is the chord length of the contact between the droplet and the rock surface, mm.

[0087] In one embodiment, see Figure 6 The rock wetting heterogeneity characterization method based on imbibition wetting angle distribution further includes, before step 300:

[0088] Step 500: Dry the rock until the weight is stable.

[0089] Preferably, the rock is dried at a temperature between 60°C and 110°C until the weight of the rock no longer changes.

[0090] In one embodiment, see Figure 7 , step 400 comprises:

[0091] Step 401: taking a photo of the droplets of the second fluid flowing out on the rock surface under the imbibition effect to generate a second photo;

[0092] Step 402: Calculate the wetting angle of the second fluid according to the second photo.

[0093] Take a picture of the second fluid droplet on the rock surface and measure the wetting angle β corresponding to different droplets j , and the measurement results are statistically analyzed; the wetting angle corresponding to the second fluid droplet is converted into the wetting angle of the first fluid: α j =180°-β j ;

[0094] In one embodiment, the method for saturating the rock is to saturate the rock with the first fluid or the second fluid by using a vacuum pressurization method.

[0095] In one embodiment, see Figure 8 , rock wetting heterogeneity characterization methods based on imbibition wetting angle distribution also include:

[0096] Step 600: Characterize rock wetting heterogeneity according to the wetting angle of the first fluid and the wetting angle of the second fluid.

[0097] Specifically, the wetting angle of the first fluid and the wetting angle of the second fluid are combined to obtain the wettability distribution law of the rock in the first fluid and the second fluid system, thereby characterizing the wetting heterogeneity of the rock.

[0098] In a specific embodiment, the present invention takes the measurement of low permeability rock wetting heterogeneity as an example to provide a specific embodiment of a rock wetting heterogeneity characterization method based on imbibition wetting angle distribution, see Fig. 9 , specifically including the following contents.

[0099] The core number of the tested core is D227 (the core is columnar, but it is also applicable to block and sheet shapes). Its basic parameters are shown in Table 1.

[0100] Table 1D227 core physical parameters

[0101] Core number Diameter(mm) Length(mm) Gas permeability (mD) Porosity(%) D227 25.32 41.44 0.05 7.69

[0102] S1: Place the D227 core in an oven, set the oven temperature to 105°C, and dry until the quality no longer changes;

[0103] S2: Place the dried core in an intermediate container, evacuate for 72 hours, saturate with dyed kerosene, pressurize the well to 25 MPa and maintain for 24 hours, then release the pressure and wait for the kerosene pressure inside and outside the core to balance.

[0104] The purpose of dyeing kerosene red with oil red is to facilitate photographing the oil droplets on the surface of the core;

[0105] S3: Formation water is added to a square glass tank, and the D227 core saturated with kerosene is vertically immersed in the formation water. The formation water enters the D227 core under the action of capillary force, and at the same time, kerosene is discharged from the D227 core and forms red oil droplets on its surface.

[0106] S4: Take photos of the red oil droplets on the core surface at different times, select the spherical crown oil droplets at the same position on the core surface to measure, and measure the wetting angle α corresponding to the oil droplets at different positions i And the measurement results were statistically analyzed (Table 2);

[0107] Table 2 Oil drop wetting angle distribution

[0108]

[0109] S5: Place the D227 core in an oven, set the oven temperature to 105°C, and dry again until the quality does not change;

[0110] S6: Place the dried core in an intermediate container, evacuate the core for 72 hours and saturate it with formation water, pressurize the well to 25 MPa for 24 hours, then release the pressure and wait for the formation water pressure inside and outside the core to balance;

[0111] S7: Add kerosene into a square glass tank, and immerse the D227 core saturated with formation water vertically in the kerosene. The kerosene enters the D227 core under the action of capillary force, while the formation water is discharged from the D227 core and forms water droplets on its surface.

[0112] S8: Take photos of the water droplets on the core surface at different times, select the spherical crown-shaped water droplets at the same position on the surface of the D227 core for measurement, and measure the wetting angle β corresponding to the water droplets at different positions j And the measurement results were statistically analyzed (Table 3);

[0113] Table 3 Water drop wetting angle distribution

[0114]

[0115] S9: converting the wetting angle corresponding to the water droplet into the wetting angle of the oil droplet;

[0116] Step S9 can be implemented by the following formula:

[0117] α j =180°-β j ;

[0118] S10: Comprehensive α i and α j The wettability distribution law of kerosene phase in the core-formation water-kerosene system was obtained.

[0119] See also Fig.10 ,From the figure, we can see that the wettability of the core is weakly hydrophilic as a whole, but there are a small number of pores that are oil-wet.

[0120] From the above description, it can be seen that the embodiment of the present invention provides a rock wetting heterogeneity characterization method based on the distribution of imbibition wetting angles, firstly immersing the rock saturated with the first fluid in the second fluid; then measuring the wetting angle of the first fluid on the rock surface under the action of imbibition; immersing the rock saturated with the second fluid in the first fluid; finally measuring the wetting angle of the second fluid on the rock surface under the action of imbibition, wherein the first fluid and the second fluid are immiscible. The present invention has the following beneficial effects:

[0121] 1. Eliminate the error in wetting angle measurement caused by insufficient contact between the droplet and the rock surface;

[0122] 2. Provides a new method for measuring and characterizing wetting heterogeneity;

[0123] 3. According to the probability distribution of rock wetting angle, it provides a basis for the study of two-phase fluid displacement mechanism and numerical simulation in porous media.

[0124] Based on the same inventive concept, the embodiments of the present application also provide a rock wetting heterogeneity characterization device based on the distribution of imbibition wetting angles, which can be used to implement the methods described in the above embodiments, such as the following embodiments. Since the principle of solving the problem by a rock wetting heterogeneity characterization device based on the distribution of imbibition wetting angles is similar to that of a rock wetting heterogeneity characterization method based on the distribution of imbibition wetting angles, the implementation of a rock wetting heterogeneity characterization device based on the distribution of imbibition wetting angles can refer to the implementation of a rock wetting heterogeneity characterization method based on the distribution of imbibition wetting angles, and the repetitions will not be repeated. As used below, the terms "unit" or "module" can be a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0125] The embodiment of the present invention provides a specific implementation of a rock wetting heterogeneity characterization device based on imbibition wetting angle distribution, which can realize a rock wetting heterogeneity characterization method based on imbibition wetting angle distribution. Fig.11 The rock wetting heterogeneity characterization device based on the imbibition wetting angle distribution specifically includes the following contents:

[0126] A first soaking module 10, for soaking the rock saturated with the first fluid in a second fluid;

[0127] A first measuring module 20, for measuring the wetting angle of the first fluid on the rock surface under the action of imbibition;

[0128] A second soaking module 30, for soaking the rock saturated with the second fluid in the first fluid;

[0129] The second measurement module 40 is used to measure the wetting angle of the second fluid on the rock surface under the action of imbibition, wherein the first fluid is immiscible with the second fluid.

[0130] In one embodiment, see Fig.12 , the first measurement module 20 includes:

[0131] A first photographing unit 201 is used to photograph the droplets of the first fluid flowing out on the rock surface under the action of the imbibition to generate a first photograph;

[0132] The first wetting angle calculation unit 202 is used to calculate the wetting angle of the first fluid according to the first photo.

[0133] In one embodiment, see Fig.13 The rock wetting heterogeneity characterization device based on the imbibition wetting angle distribution also includes:

[0134] The rock drying module 50 is used to dry the rock until the weight is stable.

[0135] In one embodiment, see Fig.14 , the second measurement module 40 includes:

[0136] A second photographing unit 401 is used to take a photograph of the droplets of the second fluid flowing out on the rock surface under the action of the imbibition to generate a second photograph;

[0137] The second wetting angle calculation unit 402 is used to calculate the wetting angle of the second fluid according to the second photo.

[0138] In one embodiment, see Fig.15 The rock wetting heterogeneity characterization device based on the imbibition wetting angle distribution also includes:

[0139] Rock Saturation Module 60, for saturating rock, see Fig.16 , the rock saturation module 60 comprises:

[0140] The vacuum unit 601 is used to saturate the rock with the first fluid or the second fluid by using a vacuum pressurization method.

[0141] In one embodiment, see Fig.17 The rock wetting heterogeneity characterization device based on the imbibition wetting angle distribution also includes:

[0142] The heterogeneity characterization module 70 is used to characterize the rock wetting heterogeneity according to the wetting angle of the first fluid and the wetting angle of the second fluid.

[0143] From the above description, it can be seen that the embodiment of the present invention provides a rock wetting heterogeneity characterization device based on the distribution of imbibition wetting angles, firstly immersing the rock saturated with the first fluid in the second fluid; then measuring the wetting angle of the first fluid on the rock surface under the action of imbibition; immersing the rock saturated with the second fluid in the first fluid; finally measuring the wetting angle of the second fluid on the rock surface under the action of imbibition, wherein the first fluid and the second fluid are immiscible. The present invention has the following beneficial effects:

[0144] 1. Eliminate the error in wetting angle measurement caused by insufficient contact between the droplet and the rock surface;

[0145] 2. Provides a new method for measuring and characterizing wetting heterogeneity;

[0146] 3. According to the probability distribution of rock wetting angle, it provides a basis for the study of two-phase fluid displacement mechanism and numerical simulation in porous media.

[0147] The embodiments of the present application also provide a specific implementation of an electronic device capable of implementing all steps in a rock wetting heterogeneity characterization method based on imbibition wetting angle distribution in the above embodiment, see Fig.18 , electronic equipment specifically includes the following:

[0148] Processor (processor) 1201, memory (memory) 1202, communication interface (CommunicationsInterface) 1203 and bus 1204;

[0149] The processor 1201, the memory 1202, and the communication interface 1203 communicate with each other through the bus 1204; the communication interface 1203 is used to realize information transmission between the server device and the client device and other related devices;

[0150] The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, all the steps in the rock wetting heterogeneity characterization method based on the imbibition wetting angle distribution in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0151] Step 100: Soaking the rock saturated with the first fluid in a second fluid;

[0152] Step 200: measuring the wetting angle of the first fluid on the rock surface under the action of imbibition;

[0153] Step 300: Soaking the rock saturated with the second fluid in the first fluid;

[0154] Step 400: Measuring the wetting angle of the second fluid on the rock surface under the action of imbibition, wherein the first fluid is immiscible with the second fluid.

[0155] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all the steps in a method for characterizing rock wetting heterogeneity based on imbibition wetting angle distribution in the above embodiment. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, all the steps in a method for characterizing rock wetting heterogeneity based on imbibition wetting angle distribution in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0156] Step 100: Soaking the rock saturated with the first fluid in a second fluid;

[0157] Step 200: measuring the wetting angle of the first fluid on the rock surface under the action of imbibition;

[0158] Step 300: Soaking the rock saturated with the second fluid in the first fluid;

[0159] Step 400: Measuring the wetting angle of the second fluid on the rock surface under the action of imbibition, wherein the first fluid is immiscible with the second fluid.

[0160] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the hardware + program embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0161] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0162] Although the present application provides method operation steps such as embodiments or flow charts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in the embodiments is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order of the method shown in the embodiments or the drawings or in parallel (for example, in a parallel processor or multi-threaded processing environment).

[0163] For the convenience of description, the above devices are described in various modules according to their functions. Of course, when implementing the embodiments of this specification, the functions of each module can be implemented in the same or more software and / or hardware, or the module implementing the same function can be implemented by a combination of multiple sub-modules or sub-units. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0164] Those skilled in the art also know that, in addition to implementing the controller in a purely computer-readable program code, the controller can be made to implement the same function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, such a controller can be considered as a hardware component, and the devices for implementing various functions included therein can also be considered as structures within the hardware component. Or even, the devices for implementing various functions can be considered as both software modules for implementing the method and structures within the hardware component.

[0165] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0166] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0167] The present specification embodiments may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present specification embodiments may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0168] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of contradiction, a person skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0169] The above is only an example of the embodiment of the present specification and is not intended to limit the embodiment of the present specification. For those skilled in the art, the embodiment of the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment of the present specification shall be included in the scope of the claims of the embodiment of the present specification.

Claims

1. A method for characterizing rock wetting heterogeneity based on imbibition wetting angle distribution, characterized in that: include: Soaking the rock saturated with the first fluid in the second fluid; wherein the first fluid is kerosene and the second fluid is formation water; Measuring the wetting angle of the first fluid on the rock surface under the action of imbibition, specifically, measuring the wetting angles corresponding to oil droplets at different positions of the rock to obtain an oil droplet wetting angle distribution table, wherein the oil droplet wetting angle distribution table is used to characterize the number of oil droplets in different wetting angle intervals; immersing the rock saturated with the second fluid in the first fluid; Measuring the wetting angle of the second fluid on the rock surface under the action of imbibition, specifically, measuring the wetting angles corresponding to water droplets at different positions of the rock to obtain a water droplet wetting angle distribution table, wherein the water droplet wetting angle distribution table is used to characterize the number of water droplets in different wetting angle intervals; wherein the first fluid is immiscible with the second fluid; Convert the water drop wetting angle into the oil drop wetting angle; The distribution law of the wettability of the kerosene phase of the rock in the formation water-kerosene system is characterized according to the oil droplet wetting angle distribution table and the water droplet wetting angle distribution table.

2. The rock wettability heterogeneity characterization method according to claim 1, characterized in that: The measuring of the wetting angle of the first fluid on the rock surface under the action of imbibition comprises: Taking a picture of the droplets of the first fluid flowing out on the rock surface under the imbibition effect to generate a first picture; The wetting angle of the first fluid is calculated based on the first photograph.

3. The rock wettability heterogeneity characterization method according to claim 1, characterized in that: Before immersing the rock saturated with the second fluid in the first fluid, the method further comprises: The rocks are dried until they are of a stable weight.

4. The rock wettability heterogeneity characterization method according to claim 1, characterized in that: The measuring of the wetting angle of the second fluid on the rock surface under the action of imbibition comprises: Taking a picture of the droplets of the second fluid flowing out on the rock surface under the imbibition effect to generate a second picture; The wetting angle of the second fluid is calculated based on the second photograph.

5. The rock wettability heterogeneity characterization method according to claim 1, characterized in that: Methods for saturating rock include: The rock is saturated with the first fluid or the second fluid by using a vacuum and pressurization method.

6. The rock wettability heterogeneity characterization method according to claim 1, characterized in that: Also includes: The rock wetting heterogeneity is characterized according to the wetting angle of the first fluid and the wetting angle of the second fluid.

7. A rock wetting heterogeneity characterization device based on imbibition wetting angle distribution, characterized in that: include: A first soaking module, used for soaking the rock saturated with the first fluid in a second fluid; wherein the first fluid is kerosene and the second fluid is formation water; A first measurement module is used to measure the wetting angle of the first fluid on the rock surface under the action of imbibition, specifically, to measure the wetting angles corresponding to oil droplets at different positions of the rock to obtain an oil droplet wetting angle distribution table, wherein the oil droplet wetting angle distribution table is used to characterize the number of oil droplets in different wetting angle intervals; a second soaking module, for soaking the rock saturated with the second fluid in the first fluid; A second measurement module is used to measure the wetting angle of the second fluid on the rock surface under the action of imbibition, specifically, to measure the wetting angles corresponding to water droplets at different positions of the rock to obtain a water droplet wetting angle distribution table, wherein the water droplet wetting angle distribution table is used to characterize the number of water droplets in different wetting angle intervals; wherein the first fluid is immiscible with the second fluid; Convert the water drop wetting angle into the oil drop wetting angle; The distribution law of the wettability of the kerosene phase of the rock in the formation water-kerosene system is characterized according to the oil droplet wetting angle distribution table and the water droplet wetting angle distribution table.

8. The rock wettability heterogeneity characterization device according to claim 7, characterized in that: The first measurement module comprises: A first photographing unit, used to photograph the droplets of the first fluid flowing out on the rock surface under the action of the imbibition, so as to generate a first photograph; The first wetting angle calculation unit is used to calculate the wetting angle of the first fluid according to the first photo.

9. The rock wettability heterogeneity characterization device according to claim 7, characterized in that: Also includes: Rock drying module, used to dry the rock until the weight is stable.

10. The rock wettability heterogeneity characterization device according to claim 7, characterized in that: The second measurement module comprises: a second photographing unit, for photographing the droplets of the second fluid flowing out on the rock surface under the action of the imbibition, so as to generate a second photograph; The second wetting angle calculation unit is used to calculate the wetting angle of the second fluid according to the second photo.

11. The rock wettability heterogeneity characterization device according to claim 7, characterized in that: Also includes: A rock saturation module, used for saturating rock, comprising: The vacuum unit is used to saturate the rock with the first fluid or the second fluid by using a vacuum pressurization method.

12. The rock wettability heterogeneity characterization device according to claim 7, characterized in that: Also includes: The heterogeneity characterization module is used to characterize the rock wetting heterogeneity according to the wetting angle of the first fluid and the wetting angle of the second fluid.

Images