A residual oil characterization method based on hydraulic characteristics analysis and its application
Through digital water flooding experiments and image processing technology, a microscopic residual oil characterization method based on hydraulic characteristics was established, which solved the problem that the existing technology failed to effectively consider hydraulic characteristics, and realized scientific exploitation guidance for residual oil in the high water-containing stage of the oil field. Improve mining efficiency.
Patent Information
- Application Number
- CN202211549259.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-05
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2042-12-05
AI Technical Summary
The existing microscopic residual oil characterization methods fail to effectively consider the impact of hydraulic characteristics on residual oil start-up, making it difficult to scientifically guide the mining of residual oil in the oil field during the high water or ultra-high water content stage.
Using digital water-driving experiments, digital images of the core are obtained through computed tomography technology, filtering and graying processing are performed, and parameters such as water-oil contact area and number of channels of the remaining oil are identified and counted, and microscopic based on hydraulic characteristics is established. Residual oil characterization methods are divided into five types of characterization standards to guide oil field mining.
Through detailed hydraulic characteristics analysis, the starting characteristics of residual oil can be more accurately reflected, scientific mining guidance is provided, and the residual oil extraction efficiency in the high water content stage of the oil field is improved.
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Figure CN115807659B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to, but is not limited to, the field of oilfield development technology, relates to, but is not limited to, a method for characterizing residual oil in water drive and its application, and in particular, relates to, but is not limited to, a method for characterizing residual oil in microscopic water drive based on hydraulic property analysis. Background Art
[0002] Water injection is the main means of oilfield development in my country. As oilfields gradually enter the late stage of development, many oilfields have entered the development stage of high or ultra-high water content. At this time, there is still a large amount of residual oil distributed in the reservoir, and long-term water injection development makes the residual oil highly dispersed. Judging the occurrence law of residual oil in the reservoir is the premise for clarifying the distribution characteristics and activation mechanism of residual oil, and is the basis for further tapping the potential of residual oil. Most of the existing research on the characterization method of microscopic residual oil is based on the formation mechanism of residual oil or the identification of residual oil morphological characteristics, and does not consider the influence of the hydraulic characteristics of residual oil groups on the activation of microscopic residual oil. Summary of the invention
[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.
[0004] The present application provides a scheme for quantitatively analyzing the morphological characteristics of microscopic residual oil based on digital water flooding experiments, thereby obtaining characteristic parameters of the hydraulic characteristics of the microscopic residual oil, which can well reflect the start-up characteristics of various types of residual oil.
[0005] The present application provides a method for characterizing residual oil in water flooding, and the method for characterizing residual oil in water flooding comprises the following steps:
[0006] Determine a target stratum, obtain a core of the target stratum, perform a displacement experiment on the core, and obtain a digital image of the oil phase and the water phase of the core at the final moment of the displacement experiment;
[0007] Get the specific surface area α of the residual oil mass, in m -1 ; Obtain the water-oil contact area β of the oil group of the residual oil, the dimension of which is 1; Obtain the number of water-oil channels γ of the oil group of the residual oil, the unit of which is pieces;
[0008] The specific surface area α of the oil cluster of the residual oil, the water-oil contact area β of the oil cluster of the residual oil, and the water-oil channel number γ of the oil cluster of the residual oil characterize the hydraulic properties of the residual oil.
[0009] In one embodiment provided in the present application, the digitized image is filtered, grayed, and processed to identify and divide rock particles, void spaces, water phases, and oil phases. Based on the digitized image, statistical data of the hydraulic properties of microscopic residual oil is obtained. The principle of statistical data selection is to give priority to computer image recognition and extraction, and to reflect the amount of microscopic residual oil stress characteristics (i.e., the total volume of each residual oil group, the total area of the residual oil group in contact with the water phase, the total surface area of the residual oil group, and the number of channels connected to the water phase around each residual oil group).
[0010] In one embodiment provided in the present application, the specific surface area α of the oil mass of the residual oil is calculated according to formula (1):
[0011]
[0012] In formula (1), S is the total surface area of the remaining oil mass, in m 2 ; V is the total volume of the remaining oil mass, unit: m 3 .
[0013] In one embodiment provided in the present application, the water-oil contact area β of the oil mass of the residual oil is obtained and calculated according to formula (2):
[0014]
[0015] In formula (2), S ow is the total area of contact between the remaining oil mass and the water phase, in m 2 ; S is the total surface area of the remaining oil mass, in m 2 .
[0016] In one embodiment provided in the present application, the final moment of the displacement experiment is when the core reaches a high water content or even an extremely high water content period.
[0017] In one embodiment provided in the present application, at the final moment of the displacement experiment, the water content of the mixed liquid at the core outlet exceeds 90%.
[0018] In one embodiment provided in the present application, the method for obtaining digital images of the oil phase and the water phase of the core includes: any one or more of computer tomography technology, scanning electron microscopy imaging technology, nuclear magnetic resonance imaging technology and optical microscopy imaging.
[0019] In another aspect, the present application provides the use of the above-mentioned water flooding residual oil characterization method,
[0020] The gamma of the remaining oil group is greater than 23, and the remaining oil in the target formation is displaced by using any one or more first measures of increasing pressure gradient, reducing viscosity and reducing capillary resistance;
[0021] Alternatively, the oil group of the remaining oil has γ<23, α<0.41, β>0.24, and the remaining oil in the target formation is displaced by using any one or more second measures of increasing pressure gradient, increasing viscosity and reducing capillary resistance;
[0022] Alternatively, the γ of the remaining oil group is less than 23, α is less than 0.41, and β is less than 0.24, and the remaining oil in the target formation is displaced by using a third measure of increasing the pressure gradient and reducing the capillary force;
[0023] Alternatively, the γ of the oil group of the remaining oil is less than 23, α is greater than 0.41, and β is greater than 0.24, and the fourth measure of reducing the capillary force is used to displace the remaining oil in the target formation;
[0024] Alternatively, the remaining oil group has γ<23, α>0.41, β<0.24, and the fifth measure of increasing fluid viscosity is used to displace the remaining oil in the target formation.
[0025] In another aspect, the present application provides the use of the above-mentioned water flooding residual oil characterization method,
[0026] The gamma of the remaining oil group is greater than 23, and the remaining oil in the target formation is displaced by using any one or more first measures of increasing pressure gradient, reducing capillary resistance and reducing viscosity;
[0027] Alternatively, the oil group of the remaining oil has γ<23, α<0.41, β>0.24, and the remaining oil in the target formation is displaced by using any one or more second measures of increasing pressure gradient, increasing viscosity and reducing capillary resistance;
[0028] Alternatively, the γ of the oil group of the remaining oil is less than 23, α is less than 0.41, and β is less than 0.24, and the remaining oil in the target formation is displaced by using a third measure of any one or more of increasing the pressure gradient and reducing the capillary resistance;
[0029] Alternatively, the γ of the oil group of the remaining oil is less than 23, α is greater than 0.41, and β is greater than 0.24, and the fourth measure of reducing capillary resistance is used to displace the remaining oil in the target formation;
[0030] Alternatively, the oil group of the remaining oil has γ<23, α>0.41, and β<0.24, and the fifth measure of increasing viscosity is used to displace the remaining oil in the target formation.
[0031] In one embodiment provided in the present application, the first measure includes any one or more of profile control and flooding control, stratified water injection, cyclic water injection, dense well pattern, increased pressure difference, change of liquid flow direction, surfactant change of wettability, surfactant reduction of surface tension and fracturing and plugging;
[0032] In one embodiment provided in the present application, the second measure includes any one or more of increasing the pressure difference, changing the flow direction, polymer displacement, reducing the surface tension with a surfactant, and pressurizing to break up the plugging;
[0033] In one embodiment provided in the present application, the third measure includes any one or more of increasing pressure difference, profile control and water plugging, polymer flooding, densifying well pattern, and reducing surface tension with surfactant;
[0034] In one embodiment provided in the present application, the fourth measure includes surfactant to reduce surface tension, chemical flooding and microorganisms and CO 2 Any one or more of throughput;
[0035] In an embodiment provided in the present application, the fifth measure includes any one or more of increasing the injection rate, increasing the viscoelasticity, and increasing the production pressure difference.
[0036] In one embodiment provided in the present application, when the reservoir reaches a high water content or even an extremely high water content stage, the water drive residual oil is characterized, and corresponding measures are used to displace the residual oil in the target formation according to the characterization conclusion.
[0037] In one embodiment provided in the present application, when the water content of the reservoir exceeds 90%, the water-driven remaining oil is characterized, and corresponding measures are used to displace the remaining oil in the target formation according to the characterization conclusion.
[0038] This application uses image processing technology to identify and extract the oil-water two-phase distribution at the final moment of the core displacement experiment, fully considers the hydraulic characteristics and startup conditions of the microscopic residual oil, and characterizes the microscopic residual oil into five categories based on three parameters that can comprehensively characterize the hydraulic characteristics of the microscopic residual oil group. Compared with the existing characterization method based on morphology, this method pays more attention to the influence of oil-water connectivity characteristics on the startup of residual oil, and the formed characterization standard can be used as a more scientific guide for guiding the recovery of residual oil in the high water content stage of oil fields.
[0039] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be invented and obtained by the schemes described in the description. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.
[0041] Figure 1 is a CT image used in the embodiment, and the solid part in the figure represents the oil phase.
[0042] Figure 2 It is a schematic diagram of the hydraulic characteristics of five types of residual oil.
[0043] Figure 3A The rule for determining the critical value of α when characterizing residual oil.
[0044] Figure 3B The rule for determining the critical value of β when characterizing residual oil.
[0045] Figure 3C The rule for determining the critical value of γ when characterizing residual oil is presented.
[0046] Figure 4A Schematic diagram of the remaining oil distribution in core A after displacement of 500 PV.
[0047] Figure 4B Schematic diagram of the spatial distribution of oil in core A.
[0048] Figure 4C Schematic diagram of the remaining oil volume distribution in core A.
[0049] Figure 5A Schematic diagram of the remaining oil distribution in core B after displacement of 500 PV.
[0050] Figure 5B Schematic diagram of the spatial distribution of oil in core B.
[0051] Figure 5C Schematic diagram of the remaining oil volume distribution in core B.
[0052] Fig. 6A Schematic diagram of the remaining oil distribution in core C after displacement of 500 PV.
[0053] Figure 6B Schematic diagram of the spatial distribution of oil in core C.
[0054] Figure 6C Schematic diagram of the remaining oil volume distribution in core C. DETAILED DESCRIPTION
[0055] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application are described in detail below. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.
[0056] Example 1: Core flooding experiment
[0057] The grayscale image of the two-phase distribution at the final displacement moment (total injection flow rate of 500 PV) of the core displacement experiment was obtained by computer tomography or imaging technology. The results are shown in the attached figure. Figure 1As shown. The displacement experiment conditions are as follows: the core is saturated with oil by rapid injection and subsequent vacuuming, the oil phase viscosity is 10mPa·s, a 10% sodium iodide aqueous solution is injected at the core inlet, the viscosity of the aqueous solution is 1mPa·s, the injection rate of the aqueous solution at the core inlet is 11μm / s at room temperature, and the outlet is kept at normal pressure. After the cumulative flow rate of the inlet injection reaches 500PV, the injection is stopped, and the displaced core is CT scanned to obtain a grayscale image of the water-oil two-phase distribution in the core. The porosity of the core taken is 29.6%, the average pore size is 62μm, and the permeability is 7449mD.
[0058] Step 2: The digital image representing the distribution state of the two-phase fluid obtained in step 1 is filtered, denoised, and processed by using a watershed algorithm to extract different components, and rock particles, void spaces, water phases, and oil phases are identified and divided (using the non-local means filtering method (Non-Local means) in the identification and division method mentioned in the following literature: Buades A, Coll B, Morel J M. Nonlocal image and moviedenoising [J]. International journal of computer vision, 2008, 76 (2): 123-139.). In this embodiment, the area with a gray value of 0 is identified as the oil phase, the area with a gray value of 255 is identified as the water phase, and the area with a gray value of 128 is identified as solid particles. After image recognition, each area that is not connected to other residual oils becomes a residual oil group.
[0059] Step 3: Obtain statistical data of the hydraulic properties of microscopic residual oil. The principle of statistical data selection is to give priority to the quantity that is easy to recognize and extract by computer images and can reflect the mechanical characteristics of microscopic residual oil, as follows:
[0060] Count the volume V of each remaining oil group in the image in step 2, and the total area S of the remaining oil group in contact with the water phase ow , the total surface area S of the remaining oil clusters and the number of channels connected to the water around each remaining oil cluster (the number of water-oil channels γ of the oil cluster of the remaining oil). Substituting into formula (1) and formula (2) to calculate the three parameters describing the hydrodynamic properties of the microscopic remaining oil are the specific surface area α, the water-oil contact area ratio β and the number of water-oil channels γ.
[0061] Step 4: Establishment of microscopic residual oil characterization standards. Based on the microscopic residual oil optimization parameters and the analysis of the hydraulic characteristics of the oil clusters, a microscopic scientific and easy-to-promote microscopic residual oil characterization standard is established. Combined with the three parameters obtained in step 3 to characterize the hydraulic characteristics of the microscopic residual oil clusters, five types of microscopic residual oil can be characterized. The different types of residual oil are named type a residual oil, type b residual oil, type c residual oil, type d residual oil and type e residual oil in order from high to low according to their utilization degree. The schematic diagram of its hydraulic characteristics is shown in the attached figure. Figure 2 As shown in the figure, the parameter range of microscopic residual oil characterization is shown in the appendix. Figure 3A , Attachment Figure 3B and attached Figure 3C shown.
[0062] The main characteristics of type A residual oil are good connectivity of the water-oil interface, the formation of widely distributed residual oil microclusters in the core, and their volume is generally large. Type A residual oil mainly occurs in areas not affected by the oil displacement agent or in the early stage of the water flooding process, there is a complex "fingering" phenomenon in the core, the residual oil microclusters form a dynamic balance at the interface between the two phases, and the oil displacement agent is difficult to enter the pore space of the residual oil.
[0063] Type B residual oil has insufficient connectivity at the water-oil interface, a high water-oil area ratio, and a smaller residual oil cluster than the surface area; this indicates that the residual oil volume is large, the two-phase interface action area is large, and a water phase "bypass" phenomenon occurs. The residual oil clusters are more affected by fluid shear and are difficult to migrate under water drive.
[0064] The water-oil interface connectivity of type C residual oil is insufficient, the water-oil area ratio is low, and the residual oil microclusters are smaller than the surface area; this indicates that the residual oil volume is large, but the two-phase interface action area is small, and the residual oil microclusters are more affected by the capillary force and the resistance effect caused by the pore size change, thus restricting the migration of the residual oil.
[0065] The D-type residual oil has insufficient connectivity of the water-oil interface, a high water-oil area ratio, and a large specific surface area of the residual oil microclusters; this indicates that the residual oil volume is small but has a relatively large effective surface, and the area of action of the two-phase interfacial tension is relatively large. The oil displacement agent spreads on the surface of the residual oil microclusters, the positive pressure displacement effect is weak, and the residual oil microclusters are difficult to mobilize.
[0066] The water-oil interface connectivity of type E residual oil is insufficient, the water-oil area ratio is low, and the residual oil microclusters have a large specific surface area; this indicates that the residual oil volume is small but has a relatively large effective surface, while the effective area of the two-phase interface is relatively small. The residual oil microclusters are constrained by the pore structure, and it is difficult for the oil displacement agent to enter the pore structure to complete the positive pressure displacement of the residual oil.
[0067] Table 1: Data table A to E residual oil characterization standards
[0068] Microscopic residual oil category Characterization basis a γ>23 b γ<23,α<0.41,β>0.24 c γ<23,α<0.41,β<0.24 d γ<23,α>0.41,β>0.24 e γ<23,α>0.41,β<0.24
[0069] Example 2
[0070] Figure 4A The residual oil distribution of core A after displacement of 500PV according to the method of Example 1 (the gray part is oil, and the water and rock solid parts are treated as background color). The oil-containing volume in the initial state is 5.76μL. After 500PV displacement, the oil-containing volume in the core is 1.38μL. After the above characterization method is used, the characteristic parameters of each residual oil in the core are calculated. By comparing the residual oil type characterization standard in Table 1, it is found that the volume proportions of the five types of residual oil a, b, c, d, and e are 10.6%, 57.3%, 19.3%, 11.2%, and 1.6%, respectively. Therefore, the type of residual oil in core A after displacement of 500PV is mainly type b, that is, the residual oil is characterized by insufficient connectivity of the water-oil interface, a high water-oil area ratio, and a small specific surface area of the residual oil micro-groups.
[0071] In view of the morphological characteristics and stress of the residual oil after characterization, a pore-scale numerical simulation was carried out on core A by simulating an increase in pressure gradient (i.e., increasing the injection rate to 22 μm / s) and reducing capillary resistance (reducing the surface tension of the fluid to 1 mN / s). The initial state of the numerical simulation was consistent with the water-oil distribution at 500 PV in the core displacement experiment of core A. Except for the changes in the injection rate of the aqueous solution and the surface tension, other conditions remained the same until the displacement reached 50 PV. At this time, the oil volume in the numerically simulated core A was 0.17 μL, and the spatial distribution state was as follows: Figure 4B As shown, the volume distribution of the remaining oil at this time is Figure 4C As shown, it is mainly distributed in 10 -5 Compared with the 500 PV moment in the original core A displacement experiment, 21% more residual oil can be recovered according to the guidance given by the residual oil characterization method.
[0072] Example 3
[0073] A core with different properties from the same block as core A was taken and recorded as core B. The porosity of the core was 31.09%, the average pore size was 40 μm, and the permeability was 1594 mD. The remaining oil distribution after displacement of 500 PV according to the method of Example 1 ( Figure 5A ), the oil volume in the initial state is 5.27μL, and after 500PV displacement, the oil volume in core B is 1.75μL; after the above characterization method is processed, the characteristic parameters of each residual oil in core B are calculated, and compared with the residual oil type characterization standard in Table 1, it is found that the volume proportions of the five types of residual oil a, b, c, d, and e are 67.6%, 10.3%, 2%, 19.6%, and 0.5%, respectively. Therefore, the type of residual oil in core B after 500PV displacement is mainly type a, that is, the residual oil is characterized by a higher number of water-oil channels.
[0074] In view of the morphological characteristics and stress of the residual oil after characterization, measures to enhance hydrophilic wettability (i.e., the contact angle was reduced from the average value of 65° for the entire core to 23°) were adopted for subsequent simulation verification. The initial state of the numerical simulation was consistent with the water-oil distribution at 500PV in the core displacement experiment of core B. Other conditions remained the same, and only the wettability contact angle was changed until the displacement reached 50PV. At this time, the oil volume in the numerically simulated core B was 0.26μL, and the spatial distribution state was as follows Figure 5B As shown, the volume distribution of the remaining oil at this time is Figure 5C As shown, it is mainly distributed in 0.56×10 -5 Compared with 500 PV in the original core B displacement experiment, 28% more residual oil can be recovered according to the guidance given by the residual oil characterization method.
[0075] Example 4
[0076] A core with different properties from core A and core B in the same block was taken and recorded as core C. The porosity of the core was 31.09%, the average pore size was 34 μm, and the permeability was 908 mD. The remaining oil distribution after displacement of 500 PV according to the method of Example 1 ( Fig. 6A ), the oil volume in the initial state is 3.83μL, and after 500PV displacement, the oil volume in core C is 1.19μL; after the above characterization method is used to calculate the characteristic parameters of each residual oil in core C, and compared with the residual oil type characterization standard in Table 1, it is found that the volume proportions of the five types of residual oil a, b, c, d, and e are 25.1%, 23.8%, 0.2%, 49.7%, and 1.2%, respectively. Therefore, the type of residual oil in core C after 500PV displacement is mainly type d, that is, the residual oil is characterized by a lower water-oil channel number, a low water-oil contact area ratio, and a high specific surface area.
[0077] In view of the morphological characteristics and stress of the residual oil after characterization, the capillary resistance was reduced (the surface tension of the fluid was reduced to 1mN / s) to carry out subsequent simulation verification. The initial state of the numerical simulation is consistent with the water-oil distribution at 500PV in the core C displacement experiment. Except for the surface tension being reduced to 1mN / m, other conditions remain the same until the displacement reaches 50PV. At this time, the oil volume in the core C of the numerical simulation is 0.52μL, and the spatial distribution state is as follows Figure 6B As shown, the volume distribution of the remaining oil at this time is Figure 6C As shown, it is mainly distributed in 0.9×10 -5 Compared with 500 PV in the original core C flooding experiment, 17% more residual oil can be recovered according to the guidance given by the residual oil characterization method.
Claims
1. A method for characterizing residual oil in water flooding, characterized in that: The water flooding residual oil characterization method comprises the following steps: Determine a target stratum, obtain a core of the target stratum, perform a displacement experiment on the core, and obtain a digital image of the oil phase and the water phase of the core at the final moment of the displacement experiment; Get the specific surface area α of the residual oil mass, in m -1 ; Obtain the water-oil contact area β of the oil group of the residual oil, the dimension of which is 1; Obtain the number of water-oil channels γ of the oil group of the residual oil, the unit of which is pieces; The specific surface area α of the oil cluster of the residual oil, the water-oil contact area β of the oil cluster of the residual oil, and the water-oil channel number γ of the oil cluster of the residual oil characterize the hydraulic properties of the residual oil; Different types of residual oil are named as type A residual oil, type B residual oil, type C residual oil, type D residual oil and type E residual oil according to their utilization degree from high to low: ； The water-oil contact area β of the oil mass of the residual oil is obtained and calculated according to formula (2): In formula (2), S ow is the total area of contact between the remaining oil mass and the water phase, in m 2 ; S is the total surface area of the remaining oil mass, in m 2 .
2. The method for characterizing residual oil in water flooding according to claim 1, characterized in that: The specific surface area α of the oil mass of the residual oil is calculated according to formula (1): In formula (1), S is the total surface area of the remaining oil mass, in m 2 ; V is the total volume of the remaining oil mass, unit: m 3 .
3. The method for characterizing residual oil in water flooding according to any one of claims 1 to 2, characterized in that: The final moment of the displacement experiment is when the core reaches a high water content or even an extremely high water content period.
4. The method for characterizing residual oil in water flooding according to claim 3, characterized in that: The final moment of the displacement experiment is when the water content of the mixed liquid at the core outlet exceeds 90%.
5. The method for characterizing residual oil in water flooding according to any one of claims 1 to 2, characterized in that: The method for obtaining the digital images of the oil phase and the water phase of the core includes: any one or more of computer tomography technology, scanning electron microscope imaging technology, nuclear magnetic resonance imaging technology and optical microscopic imaging.
6. Use of the method for characterizing residual oil in water flooding according to any one of claims 1 to 5, characterized in that: The gamma of the remaining oil group is greater than 23, and the remaining oil in the target formation is displaced by using any one or more first measures of increasing pressure gradient, reducing capillary resistance and reducing viscosity; Alternatively, the oil group of the remaining oil has γ<23, α<0.41, β>0.24, and the remaining oil in the target formation is displaced by using a second measure of any one or more of increasing the pressure gradient, increasing the viscosity, and reducing the capillary resistance; Alternatively, the γ of the oil group of the remaining oil is less than 23, α is less than 0.41, and β is less than 0.24, and the remaining oil in the target formation is displaced by using a third measure of any one or more of increasing the pressure gradient and reducing the capillary resistance; Alternatively, the γ of the oil group of the remaining oil is less than 23, α is greater than 0.41, and β is greater than 0.24, and the fourth measure of reducing capillary resistance is used to displace the remaining oil in the target formation; Alternatively, the oil group of the remaining oil has γ<23, α>0.41, and β<0.24, and the fifth measure of increasing viscosity is used to displace the remaining oil in the target formation.
7. The use of the method for characterizing residual oil in water flooding according to claim 6, characterized in that: The first measure includes any one or more of profile control and flooding control, stratified water injection, cyclic water injection, dense well pattern, increased pressure difference, change of liquid flow direction, surfactant change of wettability, surfactant reduction of surface tension and pressure cracking and plugging; The second measure includes any one or more of increasing the pressure difference, changing the flow direction, polymer displacement, reducing the surface tension with a surfactant, and pressure breaking the plug; The third measure includes any one or more of increasing pressure difference, adjusting profile and plugging water, polymer flooding, increasing well pattern density, and reducing surface tension with surfactant; The fourth measure includes any one or more of surfactant to reduce surface tension, chemical flooding, microorganisms and CO2 throughput; The fifth measure includes any one or more of increasing the injection rate, increasing the viscoelasticity and increasing the production pressure difference.
8. The use of the method for characterizing residual oil in water flooding according to claim 6 or 7, characterized in that: When the reservoir reaches a high water content or even an extremely high water content stage, the water-driven remaining oil is characterized, and corresponding measures are used to displace the remaining oil in the target formation according to the characterization conclusion.
9. The use of the method for characterizing residual oil in water flooding according to claim 8, characterized in that: When the water content of the reservoir exceeds 90%, the water-driven residual oil is characterized, and corresponding measures are used to displace the residual oil in the target formation according to the characterization conclusion.