Method, device, equipment and medium for evaluating gas flooding adaptability in low permeability reservoirs

Abstract

The present application provides a method, device, equipment and medium for evaluating the gas drive adaptability of low permeability oil reservoirs. The method includes: obtaining the index value of the oil reservoir to be evaluated under each evaluation index; determining the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index; for each evaluation result, according to the weight of each evaluation index, performing weighted summation of the membership of the oil reservoir to be evaluated under each evaluation index under the evaluation result to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result; taking the evaluation result with the largest evaluation value as the gas drive adaptability evaluation result of the oil reservoir to be evaluated. The scheme of the present application can improve the accuracy of the gas drive adaptability evaluation of low permeability oil reservoirs.

Description

Technical Field

[0001] The present application relates to the field of oil and gas field development, and in particular to a method, device, equipment and medium for evaluating the adaptability of low permeability reservoir gas drive. Background Art

[0002] In recent years, as the proportion of low permeability reservoirs in the total oil and gas resources continues to increase, my country has paid more and more attention to the exploration of low permeability reservoir resources. -3 μm 2 The proven geological reserves of the oil reservoir are 40×10 8 t, it can be seen that low permeability reservoirs will be the main direction for increasing production and oil for a long time in the future. Therefore, how to develop and utilize low permeability reservoirs more efficiently is particularly important.

[0003] In the application of water flooding in low permeability reservoirs, due to the characteristics of low permeability reservoirs such as poor porosity and permeability, severe heterogeneity, and weak water absorption capacity, the use of traditional water flooding generally has problems such as high injection pressure, difficulty in establishing an effective displacement system, and strong water sensitivity of the reservoir, and the water flooding recovery rate is generally low. Gas has the functions of easy flow, reducing crude oil viscosity, expanding crude oil volume, and reducing interfacial tension. People began to explore the feasibility of gas injection development in low permeability reservoirs. When developers carry out gas injection development in low permeability reservoirs, they are limited by experimental conditions and the applicability of simulation methods. There is a large deviation between the evaluation of a single method and the actual situation, resulting in inaccurate evaluation results. Summary of the invention

[0004] The present application provides a method, device, equipment and medium for evaluating the adaptability of low permeability oil reservoirs to gas drive, so as to improve the accuracy of the evaluation of the adaptability of low permeability oil reservoirs to gas drive.

[0005] On the one hand, the present application provides a method for evaluating the gas drive adaptability of a low permeability oil reservoir, comprising: obtaining an index value of the oil reservoir to be evaluated under each evaluation index; determining the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index; wherein the gas drive adaptability evaluation standard includes the index value interval of each evaluation index under each first index under each evaluation result; the membership represents the proportion of historical oil reservoirs that meet the index value interval corresponding to the oil reservoir to be evaluated in the historical oil reservoirs corresponding to the evaluation result; for each evaluation result, according to the weight of each evaluation index, weighted summing is performed on the membership of the oil reservoir to be evaluated under each evaluation index under the evaluation result to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result; and the evaluation result with the largest evaluation value is taken as the gas drive adaptability evaluation result of the oil reservoir to be evaluated.

[0006] In a possible implementation, the method also includes: according to a preset assignment range, using the hierarchical analysis method to analyze each first indicator in the gas drive adaptability evaluation standard to obtain the assignment of each first indicator; and, according to the assignment range, using the hierarchical analysis method to analyze each evaluation indicator in the gas drive adaptability evaluation standard to obtain the assignment of each evaluation indicator; based on the assignment of each first indicator, establishing a first judgment matrix and obtaining the weight of each first indicator by solving the first judgment matrix; and, based on the assignment of each evaluation indicator, establishing a second judgment matrix and obtaining the initial weight of each evaluation indicator by solving the second judgment matrix; for each evaluation indicator, calculating the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator to obtain the weight of each evaluation indicator.

[0007] In a possible implementation, the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result is determined according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index, including: according to the oil change rate of the historical oil reservoir, the historical oil reservoir is classified according to each evaluation result to obtain the historical oil reservoir corresponding to each evaluation result; for each evaluation index, according to the index value of the oil reservoir to be evaluated under the evaluation index, the first index value interval in the gas drive adaptability evaluation standard where the index value is located is determined; for the historical oil reservoir corresponding to each evaluation result, the first historical oil reservoir whose index value is in the first index value interval is determined from the historical oil reservoirs, and the ratio of the first historical oil reservoir to the historical oil reservoir corresponding to the evaluation result is calculated to obtain the membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result.

[0008] In a possible implementation, for each evaluation result, according to the weight of each evaluation index, a weighted sum is performed on the membership of the oil reservoir to be evaluated under each evaluation index under the evaluation result to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result, including: establishing a row matrix, the elements of which include the weights of each evaluation index; taking each evaluation result as a column, and establishing a membership matrix according to the membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result; multiplying the row matrix and the membership matrix to obtain an evaluation matrix, the elements of which include the evaluation value of the oil reservoir to be evaluated under each evaluation result.

[0009] In a possible implementation, the gas drive adaptability evaluation standard includes the nitrogen drive adaptability evaluation standard; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development degree; the evaluation indicators under reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under oil reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation dip, fracture development degree, and connectivity; the evaluation indicators under fluid properties include underground crude oil density and underground crude oil viscosity; the evaluation indicators under development degree include well spacing, pre-gas drive production degree, pre-gas drive oil saturation, and pre-gas drive comprehensive water content.

[0010] In a possible implementation, the gas drive adaptability evaluation standard includes the carbon dioxide gas drive adaptability evaluation standard; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development characteristics; the evaluation indicators under the reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under the oil reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation dip, fracture development degree, and connectivity; the evaluation indicators under fluid properties include underground crude oil density, underground crude oil viscosity, formation water mineralization, and formation water type; the evaluation indicators under development characteristics include well spacing, pre-gas drive production degree, pre-gas drive oil saturation, pre-gas drive comprehensive water content, and carbon dioxide source-sink matching degree.

[0011] On the other hand, the present application provides a low permeability oil reservoir gas drive adaptability evaluation device, including: an acquisition module, used to obtain the index value of the oil reservoir to be evaluated under each evaluation index; a first processing module, used to determine the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index; wherein the gas drive adaptability evaluation standard includes the index value interval of each evaluation index under each first index under each evaluation result; the membership represents the proportion of historical oil reservoirs corresponding to the evaluation result that meet the index value interval corresponding to the oil reservoir to be evaluated; the second processing module is used to perform weighted summation of the membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result according to the weight of each evaluation index, so as to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result; the third processing module is used to take the evaluation result with the largest evaluation value as the gas drive adaptability evaluation result of the oil reservoir to be evaluated.

[0012] In a possible implementation, the device also includes: an analysis module, which is used to analyze each first indicator in the gas drive adaptability evaluation standard according to a preset assignment range using a hierarchical analysis method to obtain the assignment of each first indicator; and, according to the assignment range, the evaluation indicators in the gas drive adaptability evaluation standard are analyzed using a hierarchical analysis method to obtain the assignment of each evaluation indicator; a fourth processing module, which is used to establish a first judgment matrix based on the assignment of each first indicator and obtain the weight of each first indicator by solving the first judgment matrix; and, based on the assignment of each evaluation indicator, establish a second judgment matrix and obtain the initial weight of each evaluation indicator by solving the second judgment matrix; a calculation module, which is used to calculate, for each evaluation indicator, the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator to obtain the weight of each evaluation indicator.

[0013] On the other hand, the present application provides an electronic device, including: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the above method.

[0014] On the other hand, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the above method.

[0015] In the method, device, equipment and medium for evaluating the gas drive adaptability of low permeability oil reservoirs provided by the present application, the index value of the oil reservoir to be evaluated under each evaluation index is obtained; then, according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index, the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result is determined; for each evaluation result, according to the weight of each evaluation index, the membership of the oil reservoir to be evaluated under each evaluation index under the evaluation result is weighted and summed to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result; finally, the evaluation result with the largest evaluation value is used as the gas drive adaptability evaluation result of the oil reservoir to be evaluated. The scheme of the present application comprehensively considers the weight of each evaluation index and the membership of the oil reservoir to be evaluated under each evaluation result, and obtains the evaluation value of the oil reservoir to be evaluated under each evaluation result, which can more truly and objectively reflect the gas drive adaptability of the oil reservoir to be evaluated, thereby improving the accuracy of the gas drive adaptability evaluation of low permeability oil reservoirs. In addition, this scheme combines physical experiments, dynamic and static monitoring, and reservoir numerical simulation to conduct a comprehensive evaluation of low permeability reservoirs, overcoming the limitations of a single evaluation method and truly solving the technical problem of how to quickly quantify the gas drive adaptability of low permeability reservoirs in actual mines and perform reasonable optimization and regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0017] Figure 1 Schematic diagram of the process of evaluating the gas flooding adaptability of low permeability reservoirs provided in Example 1 of the present application is shown in FIG.

[0018] Figure 2 Schematic diagram of the process of evaluating the adaptability of low permeability reservoir gas flooding provided in Example 2 of the present application is shown in FIG.

[0019] Figure 3 A flow chart of a method for evaluating the adaptability of nitrogen flooding in low permeability reservoirs provided in Example 3 of the present application;

[0020] Figure 4 A flow chart of a method for evaluating the adaptability of carbon dioxide gas flooding in low permeability reservoirs provided in Example 3 of the present application;

[0021] Figure 5 exemplarily shows a structural schematic diagram of a low permeability reservoir gas flooding adaptability evaluation device provided in Example 4 of the present application;

[0022] Figure 6 This is a schematic diagram of the structure of an electronic device provided in Example 5 of the present application.

[0023] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0024] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0025] The terms "including" and "having" in this application are used to express an open-ended inclusion, and mean that in addition to the listed elements / components / etc., there may be additional elements / components / etc.; the terms "first" and "second" etc. are only used as marks or distinctions, and are not intended to limit the order or quantity of their objects. In addition, the different elements and areas in the drawings are only shown schematically, and are therefore not limited to the sizes or distances shown in the drawings. The technical solution is described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0026] As the proven reserves of low permeability reservoirs in my country become increasingly abundant, accounting for more than 40% of the total oil and gas resources, achieving the efficient development of low permeability reservoirs has practical and strategic significance for alleviating my country's growing demand for oil in the medium and long term. Since the water injection development effect of low permeability reservoirs is not significant, it is a better choice to use gas drive to improve the development effect, but the use of gas drive to drive oil is only suitable for specific low permeability reservoirs. Therefore, before using gas drive to drive oil in low permeability reservoirs, adaptability screening and evaluation are required, which can improve the success rate and economic benefits of gas drive oil, and also save the development cost of low permeability reservoirs.

[0027] As an example, in practical applications, the secondary fine water drive development of low permeability reservoirs combined with well network optimization, stratum reorganization, stratified water injection, gel deep adjustment and drive and other technologies or means can greatly improve the utilization of water drive reserves and improve the effect of water drive development. And using an efficient oil drive method that combines secondary fine water drive and gas drive can supplement the elastic energy of the formation, reduce the interfacial tension between the displacement phase and the displaced phase, reduce the density and viscosity of the formation crude oil, effectively mobilize the remaining oil, and further improve the recovery rate. At this stage, researchers mainly evaluate the gas drive adaptability of low permeability reservoirs based on physical experiments or reservoir numerical simulations. However, this application found that when the gas drive adaptability of low permeability reservoirs was evaluated using a single method of physical experiments or reservoir numerical simulations, the evaluation results obtained were quite different from the actual situation and the results were inaccurate. Therefore, how to accurately obtain the evaluation results of the gas drive adaptability of low permeability reservoirs and guide the mine to carry out effective practice has become an urgent problem to be solved.

[0028] The technical content provided by this application is intended to solve the above-mentioned technical problems of the related technology. In the embodiment of this application, the index value of the oil reservoir to be evaluated under each evaluation index is obtained, and then the membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result is determined according to the gas drive adaptability evaluation standard and the index value. According to the weight of each evaluation index, the membership of the oil reservoir to be evaluated under each evaluation index under the evaluation result is weighted and summed to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result, and the evaluation result with the largest evaluation value is used as the gas drive adaptability evaluation result of the oil reservoir to be evaluated. The scheme of this application comprehensively considers the weight of each evaluation index and the membership of the oil reservoir to be evaluated under each evaluation result, and obtains the evaluation value of the oil reservoir to be evaluated under each evaluation result, which can more truly and objectively reflect the gas drive adaptability of the oil reservoir to be evaluated, thereby improving the accuracy of the gas drive adaptability evaluation of low permeability oil reservoirs. In addition, this scheme combines physical experiments, dynamic and static monitoring, and reservoir numerical simulation to conduct a comprehensive evaluation of low permeability reservoirs, overcoming the limitations of a single evaluation method and truly solving the technical problem of how to quickly quantify the gas drive adaptability of low permeability reservoirs in actual mines and perform reasonable optimization and regulation.

[0029] Some aspects of the embodiments of the present application relate to the above considerations. The following is an example introduction of the solution in combination with some embodiments.

[0030] Embodiment 1

[0031] Figure 1 The flowchart of the method for evaluating the adaptability of low permeability oil reservoir gas drive provided in the first embodiment of the present application is shown in FIG. 1 . The execution subject of this example may be a low permeability oil reservoir gas drive adaptability evaluation device, such as Figure 1 As shown, the method includes:

[0032] Step 101, obtaining the index value of the oil reservoir to be evaluated under each evaluation index;

[0033] Step 102: Determine the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index; wherein the gas drive adaptability evaluation standard includes the index value interval of each evaluation index under each first index under each evaluation result; the membership represents the proportion of historical oil reservoirs corresponding to the evaluation result that meet the index value interval corresponding to the oil reservoir to be evaluated;

[0034] Step 103: for each evaluation result, according to the weight of each evaluation index, weighted sum of the membership degree of the oil reservoir to be evaluated under each evaluation index under the evaluation result is performed to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result;

[0035] Step 104: taking the evaluation result with the largest evaluation value as the gas drive adaptability evaluation result of the oil reservoir to be evaluated.

[0036] In practical applications, the executor of the method can be a low permeability oil reservoir gas drive adaptability evaluation device, and there are many ways to implement it. For example, it can be implemented through a computer program, such as application software, etc.; or, it can be implemented as a medium storing relevant computer programs, such as a USB flash drive, a cloud disk, etc.; or, it can be implemented through a physical device integrated or installed with relevant computer programs, such as a chip, etc.

[0037] Among them, the reservoir to be evaluated refers to the low permeability reservoir that needs to be evaluated for gas drive adaptability. In the process of water drive, when the water content in the low permeability reservoir reaches more than 95%, it means that injecting water into the low permeability reservoir at this time can no longer replace more oil, so it is necessary to inject gas into the low permeability reservoir to replace the oil. The low permeability reservoir that meets the condition that the oil can no longer be replaced with water is selected as the reservoir to be evaluated. Among them, each evaluation index is each second index under the first index, wherein the first index is the first index that characterizes the characteristics of the reservoir itself, the characteristics of the fluid in the reservoir, and the development of the reservoir, and each first index has corresponding second indicators.

[0038] Specifically, the user needs to obtain the index value of the reservoir to be evaluated under each evaluation index, and determine the membership of the reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard. Among them, the gas drive adaptability evaluation standard includes the index value interval of each evaluation index under each first index under each evaluation result, and the gas drive adaptability evaluation standard corresponding to different gases is different. For example, the gas drive adaptability evaluation standard can be a nitrogen drive adaptability evaluation standard, a carbon dioxide gas drive adaptability evaluation standard, etc. The evaluation results can be combined with indoor physical model experiments, dynamic and static monitoring data, and reservoir numerical simulation. A variety of means to determine the influence trend of each evaluation index on the gas drive development effect and quantitatively classify. For example, the evaluation results can be divided into five levels: good, better, medium, poor, and poor, and considering the reservoir characteristics, reservoir characteristics, fluid properties, and water drive development level, the index value interval of each evaluation index under each first index under each evaluation result is determined according to geological and development knowledge. For example, when the first indicator is the evaluation indicator of the thickness of the sublayer under the reservoir characteristics, the evaluation result corresponding to the thickness of the sublayer of 0-8m can be set as good; the evaluation result corresponding to the thickness of the sublayer of 8-16m is good; the evaluation result corresponding to the thickness of the sublayer of 16-24m is medium; the evaluation result corresponding to the thickness of the sublayer of 24-32m is poor; the evaluation result corresponding to the thickness of the sublayer of more than 32m is poor. In the historical reservoirs corresponding to each evaluation result, select the historical reservoirs that meet the index value interval corresponding to the reservoir to be evaluated, and take the ratio of the number of historical reservoirs that meet the index value interval corresponding to the reservoir to be evaluated to the number of historical reservoirs corresponding to each evaluation result as the membership degree of the reservoir to be evaluated under each evaluation indicator under each evaluation result. For example, under a certain evaluation indicator, if the number of historical reservoirs under the better evaluation result is 10, and the number of historical reservoirs that meet the index value interval corresponding to the reservoir to be evaluated is 5, then the membership degree of the reservoir to be evaluated under the evaluation indicator under the better result is 0.5.

[0039] In practical applications, in order to effectively manage and utilize data, some data of low permeability reservoirs are usually stored in a unified manner. For example, they are stored in a database. These data include but are not limited to the index values ​​of the reservoir to be evaluated under various evaluation indicators, gas drive adaptability evaluation standards, and relevant data of historical reservoirs. When required in actual operations, these data can be directly obtained from the database. It should be noted that the above is only an example and does not exclude other ways to obtain low permeability reservoir data.

[0040] Specifically, for each evaluation result, according to the weight of each evaluation index, the membership of the oil reservoir to be evaluated under each evaluation index under the evaluation result is weighted and summed to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result. According to the maximum membership principle, the evaluation result with the largest evaluation value is used as the gas drive adaptability evaluation result of the oil reservoir to be evaluated.

[0041] In the method for evaluating the gas drive adaptability of low permeability reservoirs provided in this embodiment, after obtaining the index value of the reservoir to be evaluated under each evaluation index, the membership of the reservoir to be evaluated under each evaluation index under each preset evaluation result is determined according to the gas drive adaptability evaluation standard and the index value of the reservoir to be evaluated under each evaluation index, and for each evaluation result, according to the weight of each evaluation index, the membership of the reservoir to be evaluated under each evaluation index under the evaluation result is weighted and summed to obtain the evaluation value of the reservoir to be evaluated under each evaluation result, and the evaluation result with the largest evaluation value is used as the gas drive adaptability evaluation result of the reservoir to be evaluated. Through the above scheme, the weight of each evaluation index and the membership of the reservoir to be evaluated under each evaluation result are comprehensively considered to obtain the evaluation value of the reservoir to be evaluated under each evaluation result, which can more truly and objectively reflect the gas drive adaptability of the reservoir to be evaluated, thereby improving the accuracy of the gas drive adaptability evaluation of low permeability reservoirs. In addition, this scheme combines physical experiments, dynamic and static monitoring, and reservoir numerical simulation to conduct a comprehensive evaluation of low permeability reservoirs, overcoming the limitations of a single evaluation method and truly solving the technical problem of how to quickly quantify the gas drive adaptability of low permeability reservoirs in actual mines and perform reasonable optimization and regulation.

[0042] Embodiment 2

[0043] Optionally, there is no limitation on the method for determining the weight of each evaluation index. In one example, Figure 2 The flow chart of the method for evaluating the adaptability of low permeability reservoir gas flooding provided in the second embodiment of the present application is shown in FIG. Figure 2 As shown, based on the first embodiment, the method further includes:

[0044] Step 105: Analyze each first indicator in the gas drive adaptability evaluation standard according to the preset value range using the analytic hierarchy process to obtain the value of each first indicator; and, analyze each evaluation indicator in the gas drive adaptability evaluation standard according to the value range using the analytic hierarchy process to obtain the value of each evaluation indicator;

[0045] Step 106: Based on the values ​​assigned to the first indicators, a first judgment matrix is ​​established and the weights of the first indicators are obtained by solving the first judgment matrix; and based on the values ​​assigned to the evaluation indicators, a second judgment matrix is ​​established and the initial weights of the evaluation indicators are obtained by solving the second judgment matrix;

[0046] Step 107: For each evaluation indicator, calculate the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator to obtain the weight of each evaluation indicator.

[0047] Specifically, the value range can be set to 1-9, and any natural number between 1-9 can be used as the value of each first indicator and each evaluation indicator. The first indicators in the gas drive adaptability evaluation standard are analyzed using the analytic hierarchy process to obtain the value of each first indicator. The analytic hierarchy process is a decision analysis method that combines qualitative and quantitative analysis to solve complex problems with multiple objectives. This method combines quantitative analysis with qualitative analysis and uses the experience of decision makers to judge the relative importance of each measurement target and the standard of whether it can be achieved. For example, if the first indicator is reservoir characteristics, oil reservoir characteristics, fluid properties and development degree, the above four first indicators are compared in pairs according to the experience of researchers. By comparing reservoir characteristics with oil reservoir characteristics, it can be concluded that reservoir characteristics are more important than oil reservoir characteristics; by comparing reservoir characteristics with fluid properties, it can be concluded that reservoir characteristics are more important than fluid properties; by comparing reservoir characteristics with development degree, it can be concluded that reservoir characteristics are more important than development degree. It can be inferred that reservoir characteristics are the most important indicator among the above four first indicators; by comparing reservoir characteristics with fluid properties, it can be concluded that reservoir characteristics are more important than fluid properties; by comparing reservoir characteristics with development degree, it can be concluded that reservoir characteristics are more important than development degree. It can be inferred that reservoir characteristics are the second most important indicator among the above four first indicators; by comparing fluid properties with development degree, it can be concluded that fluid properties are more important than development degree. It can be inferred that fluid properties are the third most important indicator among the above four first indicators. It can be concluded that the four first indicators are ranked from large to small in terms of importance as reservoir characteristics, reservoir characteristics, fluid properties, and development degree, and the values ​​are assigned to 9, 7, 5, and 3 respectively. According to the hierarchical analysis method, each evaluation indicator is analyzed again to obtain the value of each evaluation indicator. After all evaluation indicators are ranked from large to small in terms of importance, each evaluation indicator is assigned a value. The specific ranking method and assignment method are the same as the above method, and no further elaboration is made here. It should be noted that when comparing the evaluation indicators in pairs, two evaluation indicators under the same first indicator can be compared, or two evaluation indicators under different first indicators can be compared. It is only necessary to obtain the ranking of all evaluation indicators according to their importance.

[0048] Specifically, based on the assignment of each first indicator, a first judgment matrix is ​​established and the first judgment matrix is ​​solved to obtain the weight of each first indicator. According to the assignment of each first indicator, the results of the comparison of each first indicator are established as the first judgment matrix, the eigenvalues ​​and eigenvectors of the first judgment matrix are solved, and the eigenvectors of each first indicator are used as the weights of each first indicator. At the same time, based on the assignment of each evaluation indicator, a second judgment matrix is ​​established and the initial weights of each evaluation indicator are obtained by solving the second judgment matrix. According to the assignment of each evaluation indicator, the results of the comparison of each evaluation indicator are established as the second judgment matrix, the eigenvalues ​​and eigenvectors of the second judgment matrix are solved, and the eigenvectors of each evaluation indicator are used as the initial weights of each evaluation indicator. After obtaining the weights of each first indicator and the initial weights of each evaluation indicator, the weight of the first indicator to which the evaluation indicator belongs is multiplied by the weight of the evaluation indicator to obtain the weight of each evaluation indicator. For example, if the first indicator is a reservoir characteristic and the corresponding evaluation indicator is permeability, it is necessary to multiply the initial weight of the permeability obtained by solving the second judgment matrix by the weight of the reservoir characteristic obtained by solving the first judgment matrix to obtain the weight of the permeability indicator. Finally, the weight values ​​of each first indicator and evaluation indicator can be obtained, and a weight table of the first indicator and the second indicator of gas drive can be established. For example, Table 1 is a weight table of the first indicator and the evaluation indicator of nitrogen drive, and Table 2 is a weight table of the first indicator and the evaluation indicator of carbon dioxide gas drive.

[0049] Table 1

[0050]

[0051] Table 2

[0052]

[0053] Through the scheme of this example, the first indicator and the evaluation indicator can be analyzed according to the preset value range by using the hierarchical analysis method to obtain the value of the first indicator and the evaluation indicator, and the weight of the first indicator and the initial weight of the evaluation indicator can be obtained by solving the first judgment matrix and the second judgment matrix, and the weight of the first indicator to which the evaluation indicator belongs is multiplied by the initial weight to obtain the weight of the evaluation indicator. Through the above scheme, the gas drive adaptability of low permeability reservoirs can be evaluated more scientifically, the analysis is more comprehensive, the method is more convenient and quick, and the results obtained are more accurate and reliable.

[0054] Optionally, the method for determining the degree of membership of the reservoir to be evaluated under each evaluation result under each evaluation index is not limited. In one example, the degree of membership can be determined by calculating the ratio of the first historical reservoir located in the first index interval to the historical reservoir corresponding to the evaluation result. Specifically, in step 102, according to the gas drive adaptability evaluation standard and the index value of the reservoir to be evaluated under each evaluation index, the degree of membership of the reservoir to be evaluated under each evaluation index under each preset evaluation result is determined, specifically including:

[0055] According to the oil change rate of the historical oil reservoirs, the historical oil reservoirs are classified according to each evaluation result to obtain the historical oil reservoirs corresponding to each evaluation result; for each evaluation index, according to the index value of the oil reservoir to be evaluated under the evaluation index, the first index value interval in the gas drive adaptability evaluation standard is determined; for the historical oil reservoir corresponding to each evaluation result, the first historical oil reservoir whose index value is located in the first index value interval is determined from the historical oil reservoirs, and the ratio of the first historical oil reservoir to the historical oil reservoir corresponding to the evaluation result is calculated to obtain the membership degree of the oil reservoir to be evaluated under each evaluation index under each evaluation result.

[0056] Specifically, each evaluation result is set to five levels: good, better, medium, poor, and bad. According to the oil change rate of the historical oil reservoir, the historical oil reservoir is divided into five categories according to the five evaluation results. The oil change rate is the ratio of the amount of oil replaced by each cubic meter of gas to the total oil volume of the oil well. For example, the evaluation result of a low permeability oil reservoir with an oil change rate of 80%-90% is set as good, the evaluation result of a low permeability oil reservoir with an oil change rate of 70%-80% is set as better, the evaluation result of a low permeability oil reservoir with an oil change rate of 60%-70% is set as medium, the evaluation result of a low permeability oil reservoir with an oil change rate of 50%-60% is set as poor, and the evaluation result of a low permeability oil reservoir with an oil change rate of less than 50% is set as poor. If there are 30 historical reservoirs, according to the oil change rate of historical reservoirs, it can be classified according to 5 evaluation results, that is, there are 10 historical reservoirs with good evaluation results, 8 historical reservoirs with relatively good evaluation results, 6 historical reservoirs with medium evaluation results, 3 historical reservoirs with medium evaluation results, 2 historical reservoirs with relatively poor evaluation results, and 1 historical reservoir with poor evaluation results. If the evaluation index is the pore throat radius, the index value of the reservoir to be evaluated under the pore throat radius evaluation index is 1.213μm, and the corresponding nitrogen flooding adaptability evaluation standard shows that the pore throat radius of 1.213μm belongs to the index value interval of>1μm. Find historical reservoirs with pore throat radius > 1 μm in the historical reservoirs under each evaluation result. It can be found that under the condition that the evaluation result is good, there are 5 reservoirs with pore throat radius > 1 μm, and the corresponding membership is 0.5; under the condition that the evaluation result is good, there are 2 reservoirs with pore throat radius > 1 μm, and the corresponding membership is 0.25; under the conditions that the evaluation results are medium, poor, and bad, there are no reservoirs with pore throat radius > 1 μm, and the corresponding memberships are all 0.

[0057] In the above example, historical reservoirs are classified according to the oil change rate, and for each evaluation index, the first index value interval where the index value is located is determined according to the index value of the reservoir to be evaluated under the evaluation index, and the first historical reservoir whose index value is located in the first index value interval is determined in the historical reservoirs, and the ratio of the first reservoir located in the first index value interval to the historical reservoir corresponding to the evaluation result is calculated as the membership degree of the reservoir to be evaluated under each evaluation index under each evaluation result. Through the above scheme, the membership degree under each evaluation result corresponding to each evaluation index can be obtained, making the results of the gas drive adaptability evaluation of low permeability reservoirs more accurate and reliable.

[0058] Optionally, after obtaining the membership degree under each evaluation result corresponding to each evaluation indicator and the weight of each evaluation indicator, in one example, in step 103, for each evaluation result, according to the weight of each evaluation indicator, the membership degree of the oil reservoir to be evaluated under each evaluation indicator under the evaluation result is weighted and summed to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result, including: establishing a row matrix, the elements of which include the weight of each evaluation indicator; taking each evaluation result as a column, and establishing a membership matrix according to the membership degree of the oil reservoir to be evaluated under each evaluation indicator under each evaluation result; multiplying the row matrix and the membership matrix to obtain an evaluation matrix, the elements of which include the evaluation value of the oil reservoir to be evaluated under each evaluation result.

[0059] Specifically, the weight of each evaluation index is established as a row matrix, with each evaluation result as a column, and the membership matrix is ​​established according to the membership of the reservoir to be evaluated under each evaluation index under each evaluation result. By multiplying the row matrix with each column in the membership, five evaluation values ​​of good, better, medium, poor, and bad evaluation results can be obtained to form an evaluation matrix. Among them, the row matrix is ​​multiplied with the column vector of the good evaluation result in the membership matrix to obtain the evaluation value of the good evaluation result; the row matrix is ​​multiplied with the column vector of the better evaluation result in the membership matrix to obtain the evaluation value of the better evaluation result; the row matrix is ​​multiplied with the column vector of the medium evaluation result in the membership matrix to obtain the evaluation value of the medium evaluation result; the row matrix is ​​multiplied with the column vector of the poor evaluation result in the membership matrix to obtain the evaluation value of the poor evaluation result; the row matrix is ​​multiplied with the column vector of the poor evaluation result in the membership matrix to obtain the evaluation value of the poor evaluation result. The above scheme obtains the evaluation value of the reservoir to be evaluated under each evaluation result, which can quantitatively analyze the gas drive adaptability of the low permeability reservoir, making the results of the gas drive adaptability evaluation of the low permeability reservoir more accurate and reliable.

[0060] Based on any of the foregoing examples, the gas drive adaptability evaluation standard includes the nitrogen drive adaptability evaluation standard; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development degree; the evaluation indicators under reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation dip, fracture development degree, and connectivity; the evaluation indicators under fluid properties include underground crude oil density and underground crude oil viscosity; the evaluation indicators under development degree include well spacing, production degree before gas drive, oil saturation before gas drive, and comprehensive water content before gas drive.

[0061] Among them, reservoir depth, reservoir temperature and reservoir pressure are the properties of the oil well itself. Based on the water-oil ratio, recovery rate, water content and other indicators, the water drive development level of historical oil reservoirs that have used nitrogen drive for oil is quantitatively analyzed, and the development degree of the oil reservoir under the current development conditions is analyzed, and three evaluation indicators are obtained: the degree of recovery before gas drive, the oil saturation before gas drive, and the comprehensive water content before gas drive. Among them, the water-oil ratio represents the weight of water required to replace 1 ton of water, the recovery rate represents the amount of recovered oil in the total oil volume of the oil well, and the water content represents the mass percentage of water in the produced liquid of the oil well. Analyze the water absorption and production profile test data, analyze the flooding law of the oil well, judge the direction of water breakthrough, and then evaluate the adaptability of the well network, well spacing and layer system, and obtain seven evaluation indicators: small layer thickness, rhythmicity, formation dip, fracture development degree, connectivity, heterogeneity and well spacing. According to the similarity criterion, a physical experiment of nitrogen flooding after water flooding in low permeability reservoirs was designed and carried out. The sweep efficiency, recovery rate and dynamic distribution of oil, gas and water three-phase fluids of nitrogen flooding under different injection timing conditions were compared. The water control and oil increase mechanism of nitrogen flooding after water flooding in low permeability reservoirs was understood. The influence of nitrogen injection on fluid properties such as density and viscosity was analyzed. Seven evaluation indicators, including underground crude oil density, underground crude oil viscosity, porosity, permeability, pore throat radius, water sensitivity and wettability, were obtained. Then, a numerical simulation mechanism model of nitrogen flooding after water flooding in low permeability reservoirs was established to determine the average effect, effect range and factor influence of each evaluation indicator. A cyclone diagram and Pareto diagram were drawn, and ANOVA analysis and regression analysis were carried out to determine the sensitivity and importance of each indicator. Finally, the evaluation criteria for nitrogen flooding adaptability were obtained as shown in Table 3.

[0062] Table 3

[0063]

[0064] In the above example, the evaluation indicators of the adaptability method of nitrogen flooding in low permeability reservoirs are determined through physical experiments, dynamic and static monitoring, and reservoir numerical simulation. The dynamic parameters are combined with the static parameters to comprehensively consider the adaptability of the low permeability reservoir to nitrogen flooding, making the analysis of the adaptability method of gas flooding in low permeability reservoirs more comprehensive and the results more accurate and reliable.

[0065] In another example, the gas drive adaptability evaluation criteria include carbon dioxide gas drive adaptability evaluation criteria; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development characteristics; the evaluation indicators under reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation inclination, degree of fracture development, and connectivity; the evaluation indicators under fluid properties include underground crude oil density, underground crude oil viscosity, formation water mineralization, and formation water type; the evaluation indicators under development characteristics include well spacing, degree of production before gas drive, oil saturation before gas drive, comprehensive water content before gas drive, and carbon dioxide source-sink matching.

[0066] Among them, reservoir depth, reservoir temperature and reservoir pressure are the properties of the oil well itself. Based on the water-oil ratio, recovery rate, water content and other indicators, the water drive development level of historical oil reservoirs that have used carbon dioxide gas drive oil is quantitatively analyzed. The development degree of the oil reservoir under the current development conditions is analyzed, and four evaluation indicators are obtained, namely, the degree of recovery before gas drive, the oil saturation before gas drive, the comprehensive water content before gas drive, and the matching degree of carbon dioxide source and sink. Among them, the water-oil ratio represents the weight of water required to replace 1 ton of water, the recovery rate represents the amount of oil recovered to the total oil volume of the oil well, and the water content represents the mass percentage of water in the produced liquid of the oil well. Analyze the water absorption and production profile test data, analyze the flooding law of the oil well, judge the direction of water breakthrough, and then evaluate the adaptability of the well network, well spacing and layer system. Seven evaluation indicators can be obtained, namely, small layer thickness, rhythmicity, formation dip, fracture development degree, connectivity, heterogeneity and well spacing. Single flash experiment, constant composition expansion experiment, differential release experiment, gas injection expansion experiment and long thin tube displacement experiment were carried out to analyze the phase characteristics of carbon dioxide under historical reservoir conditions and determine the miscible conditions. According to the similarity criterion, physical experiments of carbon dioxide gas injection after water flooding in low permeability reservoirs were designed and carried out. The sweep efficiency, recovery rate and dynamic distribution of oil, gas and water three-phase fluids of carbon dioxide gas injection under different injection timing conditions were compared. The water control and oil increase mechanism of carbon dioxide gas injection after water flooding in low permeability reservoirs was understood. The influence of carbon dioxide injection on fluid properties such as density and viscosity was analyzed, and nine evaluation indicators including underground crude oil density, underground crude oil viscosity, formation water salinity, formation water type, porosity, permeability, pore throat radius, water sensitivity and wettability were obtained. Then, a numerical simulation mechanism model of nitrogen flooding after water flooding in low permeability reservoirs was established to determine the average effect, effect range and factor influence of each evaluation indicator. Cyclone diagram and Pareto diagram were drawn, and ANOVA analysis and regression analysis were carried out to determine the sensitivity and importance of each indicator. In addition, the matching degree of carbon dioxide source and sink directly determines the development cost and has a great influence on the evaluation of the adaptability of carbon dioxide injection gas flooding. The final evaluation criteria for carbon dioxide gas flooding adaptability are shown in Table 4.

[0067] Table 4

[0068]

[0069]

[0070] In the above example, the evaluation indicators of the adaptability method of carbon dioxide gas flooding in low permeability reservoirs are determined by means of physical experiments, dynamic and static monitoring, and reservoir numerical simulation. The dynamic parameters are combined with the static parameters to comprehensively consider the adaptability of the low permeability reservoir to carbon dioxide gas flooding, making the analysis of the adaptability method of gas flooding in low permeability reservoirs more comprehensive and the results more accurate and reliable.

[0071] In the gas drive adaptability evaluation method for low permeability reservoirs provided in the present embodiment, the first indicators and the evaluation indicators in the gas drive adaptability evaluation standard are analyzed according to the preset value range by using the hierarchical analysis method to obtain the value of each first indicator and each evaluation indicator, a judgment matrix is ​​established and solved to obtain the weight of each first indicator and the initial weight of each evaluation indicator, the weight of the first indicator and the initial weight of each evaluation indicator are multiplied to obtain the weight of each evaluation indicator; and according to the oil change rate of the historical reservoirs, the historical reservoirs are classified according to the evaluation results, the first indicator value interval where the indicator value in the gas drive adaptability evaluation standard is located is determined, and the ratio of the first historical reservoir to the historical reservoir corresponding to the evaluation result is calculated to obtain the membership of the reservoir to be evaluated under each evaluation result under each evaluation indicator; the weight and membership of each evaluation indicator are respectively established into matrices and multiplied to obtain the evaluation value of the reservoir to be evaluated under each evaluation result. Through the above scheme, the hierarchical analysis method is used to analyze each first indicator and each evaluation indicator, and the evaluation value of the oil reservoir to be evaluated under each evaluation result is obtained, and the adaptability of gas drive of low permeability oil reservoir is qualitatively and quantitatively analyzed, so that the evaluation results of gas drive adaptability of low permeability oil reservoir are more accurate and reliable, and can more effectively guide mine practice.

[0072] Embodiment 3

[0073] The following two specific examples are used to illustrate the above-mentioned method for evaluating the adaptability of low permeability reservoir gas flooding.

[0074] Taking the H low permeability reservoir in a certain area as the research object, the adaptability of nitrogen flooding in the low permeability reservoir was evaluated by integrating physical experiments, dynamic and static monitoring and reservoir numerical simulation. Figure 3 This is a flow chart of a method for evaluating the adaptability of nitrogen flooding in low permeability reservoirs provided in Example 3 of the present application, as shown in FIG. Figure 3 As shown, the process is as follows:

[0075] Step 301, obtaining the index values ​​of a low permeability oil reservoir in a certain region H under various evaluation indexes;

[0076] Step 302, according to the nitrogen flooding adaptability evaluation standard and the index value of the H low permeability oil reservoir in a certain area under each evaluation index, determine the membership degree of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result;

[0077] Step 303: Analyze each first indicator in the nitrogen flooding adaptability evaluation standard according to a preset value range using the analytic hierarchy process to obtain the value of each first indicator; and, analyze each evaluation indicator in the nitrogen flooding adaptability evaluation standard according to the value range using the analytic hierarchy process to obtain the value of each evaluation indicator;

[0078] Step 304: Based on the values ​​assigned to the first indicators, a first judgment matrix is ​​established and the weights of the first indicators are obtained by solving the first judgment matrix; and based on the values ​​assigned to the evaluation indicators, a second judgment matrix is ​​established and the initial weights of the evaluation indicators are obtained by solving the second judgment matrix.

[0079] Step 305, for each evaluation indicator, calculate the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator to obtain the weight of each evaluation indicator;

[0080] Step 306, for each evaluation result, according to the weight of each evaluation index, weighted sum of the membership degree of the low permeability reservoir H in a certain region under each evaluation index under the evaluation result is performed to obtain the evaluation value of the low permeability reservoir H in a certain region under each evaluation result;

[0081] Step 307, taking the evaluation result with the largest evaluation value as the nitrogen flooding adaptability evaluation result of the low permeability oil reservoir H in a certain region.

[0082] According to the nitrogen flooding adaptability evaluation standard for low permeability reservoirs established in this scheme and the index values ​​of H low permeability reservoirs in a certain area under various evaluation indicators, various parameters of H low permeability reservoirs in a certain area were sorted out and the membership degree of each evaluation index was obtained, as shown in Table 5.

[0083] Table 5

[0084]

[0085] Based on the method of this scheme, the evaluation results of nitrogen flooding adaptability of H low permeability reservoir in a certain area are calculated and shown in Table 6.

[0086] Table 6

[0087]

[0088] According to the principle of maximum membership, it can be seen that the adaptability of nitrogen flooding in a certain area H low permeability reservoir is good, and it is recommended to implement nitrogen flooding. On this basis, based on the numerical simulation of nitrogen flooding, reasonable parameters such as well spacing, injection timing, injection method, and injection-production speed were determined, and a nitrogen flooding development plan for a certain area H low permeability reservoir was formed. The application effect in the mine is very significant, with a cumulative increase of 476,000 tons of oil in three years.

[0089] Taking W low permeability reservoir in a certain area as the research object, the adaptability of CO2 gas flooding in low permeability reservoirs was evaluated by integrating physical experiments, dynamic and static monitoring and reservoir numerical simulation. Figure 4 A flow chart of a method for evaluating the adaptability of carbon dioxide gas flooding in low permeability reservoirs provided in Example 3 of the present application is shown in FIG. Figure 4 As shown, the process is as follows:

[0090] Step 401, obtaining the index value of a low permeability oil reservoir in a certain area W under various evaluation indicators;

[0091] Step 402, according to the carbon dioxide gas flooding adaptability evaluation standard and the index value of the low permeability oil reservoir in a certain area W under each evaluation index, determine the membership degree of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result;

[0092] Step 403: Analyze each first indicator in the carbon dioxide gas flooding adaptability evaluation standard using the analytic hierarchy process according to the preset value range to obtain the value of each first indicator; and, analyze each evaluation indicator in the carbon dioxide gas flooding adaptability evaluation standard using the analytic hierarchy process according to the value range to obtain the value of each evaluation indicator;

[0093] Step 404: Based on the values ​​assigned to the first indicators, a first judgment matrix is ​​established and the weights of the first indicators are obtained by solving the first judgment matrix; and based on the values ​​assigned to the evaluation indicators, a second judgment matrix is ​​established and the initial weights of the evaluation indicators are obtained by solving the second judgment matrix;

[0094] Step 405, for each evaluation indicator, calculate the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator to obtain the weight of each evaluation indicator;

[0095] Step 406, for each evaluation result, according to the weight of each evaluation index, weighted sum of the membership degree of the low permeability oil reservoir in a certain region under each evaluation index under the evaluation result is performed to obtain the evaluation value of the low permeability oil reservoir in a certain region under each evaluation result;

[0096] Step 407, taking the evaluation result with the largest evaluation value as the evaluation result of the carbon dioxide gas flooding adaptability of the low permeability oil reservoir in a certain area W.

[0097] According to the evaluation standard for the adaptability of carbon dioxide gas flooding in low permeability reservoirs established in this scheme and the index values ​​of low permeability reservoir W in a certain area under various evaluation indicators, various parameters of low permeability reservoir W in a certain area were sorted out and the membership degree of each evaluation indicator was obtained, as shown in Table 7.

[0098] Table 7

[0099]

[0100] Based on the method of this scheme, the evaluation results of the adaptability of carbon dioxide gas flooding in a low permeability oil reservoir in a certain area W are calculated and shown in Table 8.

[0101] Table 8

[0102]

[0103] According to the principle of maximum membership, it can be seen that the adaptability of CO2 gas drive in low permeability reservoir W in a certain area is good, and it is recommended to implement CO2 gas drive. On this basis, based on the numerical simulation of CO2 gas drive, reasonable parameters such as well spacing, injection timing, injection method, injection and production speed were determined, and a CO2 gas drive development plan for low permeability reservoir W in a certain area was formed. The application effect of the mine is very significant, with a cumulative increase of 1.486 million tons of oil in three years.

[0104] Embodiment 4

[0105] Figure 5 FIG. 4 is a schematic diagram showing the structure of a low permeability reservoir gas flooding adaptability evaluation device provided in Example 4 of the present application. Figure 5 As shown, the device comprises:

[0106] An acquisition module 51 is used to acquire the index value of the oil reservoir to be evaluated under each evaluation index;

[0107] The first processing module 52 is used to determine the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index; wherein the gas drive adaptability evaluation standard includes the index value interval of each evaluation index under each first index under each evaluation result; the membership degree represents the proportion of historical oil reservoirs corresponding to the evaluation result that meet the index value interval corresponding to the oil reservoir to be evaluated;

[0108] The second processing module 53 is used for performing weighted summation of the membership degree of the oil reservoir to be evaluated under each evaluation index under each evaluation result according to the weight of each evaluation index, so as to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result;

[0109] The third processing module 54 is used to use the evaluation result with the largest evaluation value as the gas drive adaptability evaluation result of the oil reservoir to be evaluated.

[0110] In practical applications, there are many ways to implement the low permeability oil reservoir gas drive adaptability evaluation device. For example, it can be implemented through a computer program, such as application software, etc.; or it can be implemented as a medium storing relevant computer programs, such as a USB flash drive, a cloud disk, etc.; or it can be implemented through a physical device integrated or installed with relevant computer programs, such as a chip, etc.

[0111] Among them, the reservoir to be evaluated refers to the low permeability reservoir from which the gas drive adaptability evaluation is required. Each evaluation index is a second index under the first index. The first index is a first index that characterizes the characteristics of the reservoir itself, the characteristics of the fluid in the reservoir, and the development of the reservoir. Each first index has a corresponding second index. The gas drive adaptability evaluation standard includes the index value range of each evaluation index under each first index under each evaluation result. The gas drive adaptability evaluation standard corresponding to different gases is different. The evaluation results can be combined with indoor physical model experiments, dynamic and static monitoring data, reservoir numerical simulation and other means to determine the influence trend of each evaluation index on the gas drive development effect and quantitatively grade it.

[0112] Through the above scheme, the accuracy of the evaluation results of the gas drive adaptability of low permeability reservoirs can be improved. In addition, in this example, a comprehensive evaluation of low permeability reservoirs is carried out by combining physical experiments, dynamic and static monitoring, and reservoir numerical simulation, overcoming the limitations of a single evaluation method, and the evaluation results of the gas drive adaptability of low permeability reservoirs are more accurate and reliable.

[0113] On the basis of any example, the device further includes: an analysis module, which is used to analyze each first indicator in the gas drive adaptability evaluation standard according to a preset value range using a hierarchical analysis method to obtain the value of each first indicator; and, according to the value range, analyze each evaluation indicator in the gas drive adaptability evaluation standard using a hierarchical analysis method to obtain the value of each evaluation indicator;

[0114] A fourth processing module is used to establish a first judgment matrix based on the assignment of each first indicator and obtain the weight of each first indicator by solving the first judgment matrix; and, based on the assignment of each evaluation indicator, establish a second judgment matrix and obtain the initial weight of each evaluation indicator by solving the second judgment matrix;

[0115] The calculation module is used to calculate, for each evaluation indicator, the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator to obtain the weight of each evaluation indicator.

[0116] It should be noted that when comparing the evaluation indicators in pairs, two evaluation indicators under the same first indicator can be compared, or two evaluation indicators under different first indicators can be compared. It is only necessary to obtain the ranking of all evaluation indicators according to their importance.

[0117] Specifically, the eigenvalues ​​and eigenvectors of the first judgment matrix are solved, and the eigenvectors of each first indicator are used as the weights of each first indicator. The eigenvalues ​​and eigenvectors of the second judgment matrix are solved, and the eigenvectors of each evaluation indicator are used as the initial weights of each evaluation indicator. After obtaining the weights of each first indicator and the initial weights of each evaluation indicator, the weight of the first indicator to which the evaluation indicator belongs is multiplied by the weight of the evaluation indicator to obtain the weight of each evaluation indicator. Finally, the weight values ​​of each first indicator and evaluation indicator can be obtained, and a weight table of the first indicator and the second indicator of gas drive can be established.

[0118] Through the scheme of this example, the first indicator and the evaluation indicator can be analyzed according to the preset value range by using the hierarchical analysis method to obtain the value of the first indicator and the evaluation indicator, and the weight of the first indicator and the initial weight of the evaluation indicator can be obtained by solving the first judgment matrix and the second judgment matrix, and the weight of the first indicator to which the evaluation indicator belongs is multiplied by the initial weight to obtain the weight of the evaluation indicator. Through the above scheme, the gas drive adaptability of low permeability reservoirs can be evaluated more scientifically, the analysis is more comprehensive, the method is more convenient and quick, and the results obtained are more accurate and reliable.

[0119] In one example, the first processing module 52 is specifically used to: classify the historical oil reservoirs according to the oil change rate of the historical oil reservoirs and each evaluation result to obtain the historical oil reservoirs corresponding to each evaluation result; for each evaluation indicator, determine the first indicator value interval in the gas drive adaptability evaluation standard according to the indicator value of the oil reservoir to be evaluated under the evaluation indicator; for the historical oil reservoir corresponding to each evaluation result, determine the first historical oil reservoir whose indicator value is in the first indicator value interval from the historical oil reservoirs, and calculate the ratio of the first historical oil reservoir to the historical oil reservoir corresponding to the evaluation result, so as to obtain the membership degree of the oil reservoir to be evaluated under each evaluation indicator under each evaluation result.

[0120] Specifically, each evaluation result is set to five levels: good, better, medium, poor, and bad. According to the oil change rate of the historical reservoirs, the historical reservoirs are divided into five categories according to the five evaluation results. The oil change rate is the ratio of the amount of oil exchanged for each cubic meter of gas to the total oil volume of the oil well. In the above example, the historical reservoirs are classified according to the oil change rate. For each evaluation index, according to the index value of the reservoir to be evaluated under the evaluation index, the first index value interval where the index value is located is determined, and the first historical reservoir whose index value is in the first index value interval is determined in the historical reservoirs, and the ratio of the first reservoir located in the first index value interval to the historical reservoir corresponding to the evaluation result is calculated as the membership degree of the reservoir to be evaluated under each evaluation index under each evaluation result. Through the above scheme, the membership degree under each evaluation result corresponding to each evaluation index can be obtained, so that the results of the gas drive adaptability evaluation of low permeability reservoirs are more accurate and reliable.

[0121] In one example, the second processing module 53 is specifically used to: establish a row matrix, the elements of which include the weights of each evaluation index; take each evaluation result as a column, and establish a membership matrix according to the membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result; multiply the row matrix and the membership matrix to obtain an evaluation matrix, the elements of which include the evaluation value of the oil reservoir to be evaluated under each evaluation result. The evaluation value of the oil reservoir to be evaluated under each evaluation result is obtained by the above scheme, which can quantitatively analyze the quality of the gas drive adaptability of the low permeability oil reservoir, making the result of the gas drive adaptability evaluation of the low permeability oil reservoir more accurate and reliable.

[0122] Based on any of the foregoing examples, the gas drive adaptability evaluation standard includes the nitrogen drive adaptability evaluation standard; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development degree; the evaluation indicators under reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation dip, fracture development degree, and connectivity; the evaluation indicators under fluid properties include underground crude oil density and underground crude oil viscosity; the evaluation indicators under development degree include well spacing, production degree before gas drive, oil saturation before gas drive, and comprehensive water content before gas drive.

[0123] In the above example, the evaluation indicators of the adaptability method of nitrogen flooding in low permeability reservoirs are determined through physical experiments, dynamic and static monitoring, and reservoir numerical simulation. The dynamic parameters are combined with the static parameters to comprehensively consider the adaptability of the low permeability reservoir to nitrogen flooding, making the analysis of the adaptability method of gas flooding in low permeability reservoirs more comprehensive and the results more accurate and reliable.

[0124] In another example, the gas drive adaptability evaluation criteria include carbon dioxide gas drive adaptability evaluation criteria; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development characteristics; the evaluation indicators under reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation inclination, degree of fracture development, and connectivity; the evaluation indicators under fluid properties include underground crude oil density, underground crude oil viscosity, formation water mineralization, and formation water type; the evaluation indicators under development characteristics include well spacing, degree of production before gas drive, oil saturation before gas drive, comprehensive water content before gas drive, and carbon dioxide source-sink matching.

[0125] In the above example, the evaluation indicators of the adaptability method of carbon dioxide gas flooding in low permeability reservoirs are determined by means of physical experiments, dynamic and static monitoring, and reservoir numerical simulation. The dynamic parameters are combined with the static parameters to comprehensively consider the adaptability of the low permeability reservoir to carbon dioxide gas flooding, making the analysis of the adaptability method of gas flooding in low permeability reservoirs more comprehensive and the results more accurate and reliable.

[0126] In the low permeability reservoir gas drive adaptability evaluation device provided by the present embodiment, after obtaining the index value of the reservoir to be evaluated under each evaluation index, according to the gas drive adaptability evaluation standard and the index value of the reservoir to be evaluated under each evaluation index, the membership of the reservoir to be evaluated under each evaluation index under each preset evaluation result is determined, and for each evaluation result, according to the weight of each evaluation index, the membership of the reservoir to be evaluated under each evaluation index under the evaluation result is weighted and summed to obtain the evaluation value of the reservoir to be evaluated under each evaluation result, and the evaluation result with the largest evaluation value is used as the gas drive adaptability evaluation result of the reservoir to be evaluated. Through the above scheme, the weight of each evaluation index and the membership of the reservoir to be evaluated under each evaluation result are comprehensively considered to obtain the evaluation value of the reservoir to be evaluated under each evaluation result, which can more truly and objectively reflect the gas drive adaptability of the reservoir to be evaluated, thereby improving the accuracy of the gas drive adaptability evaluation of the low permeability reservoir. In addition, this scheme combines physical experiments, dynamic and static monitoring, and reservoir numerical simulation to conduct a comprehensive evaluation of low permeability reservoirs, overcoming the limitations of a single evaluation method and truly solving the technical problem of how to quickly quantify the gas drive adaptability of low permeability reservoirs in actual mines and perform reasonable optimization and regulation.

[0127] Embodiment 5

[0128] Figure 6 This is a schematic diagram of the structure of an electronic device provided in Embodiment 5 of the present application, such as Figure 6 As shown, the electronic device includes:

[0129] The electronic device includes a processor 291 and a memory 292; it may also include a communication interface 293 and a bus 294. The processor 291, the memory 292, and the communication interface 293 may communicate with each other through the bus 294. The communication interface 293 may be used for information transmission. The processor 291 may call the logic instructions in the memory 292 to execute the above-mentioned example method.

[0130] In addition, the logic instructions in the above-mentioned memory 292 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product.

[0131] The memory 292 is a computer-readable storage medium that can be used to store software programs and computer executable programs, such as program instructions / modules corresponding to the methods in the embodiments of the present application. The processor 291 executes functional applications and data processing by running the software programs, instructions, and modules stored in the memory 292, that is, implementing the methods in the above method examples.

[0132] The memory 292 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required for at least one function; the data storage area may store data created according to the use of the terminal device, etc. In addition, the memory 292 may include a high-speed random access memory and may also include a non-volatile memory.

[0133] An embodiment of the present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method in any example.

[0134] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the claims.

[0135] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for evaluating the adaptability of low permeability reservoirs to gas drive, which is applied to oil fields that are converted from water drive to gas drive, and is characterized in that: include: Obtaining the index values ​​of the reservoir to be evaluated under various evaluation indicators through physical experiments, dynamic and static monitoring and reservoir numerical simulation, wherein the parameters of the reservoir to be evaluated are time-varying; According to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index, the membership degree of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result is determined; wherein the gas drive adaptability evaluation standard includes the index value interval of each evaluation index under each first index under each evaluation result, and the first index includes the water drive development level; the membership degree represents the proportion of historical oil reservoirs corresponding to the evaluation result that meet the index value interval corresponding to the oil reservoir to be evaluated; For each evaluation result, according to the weight of each evaluation index, weighted summation is performed on the membership degree of the oil reservoir to be evaluated under each evaluation index under the evaluation result to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result; The evaluation result with the largest evaluation value is used as the gas drive adaptability evaluation result of the oil reservoir to be evaluated; The step of determining the membership degree of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index includes: According to the oil change rate of the historical oil reservoir, the historical oil reservoir is classified according to each evaluation result to obtain the historical oil reservoir corresponding to each evaluation result; For each evaluation index, according to the index value of the oil reservoir to be evaluated under the evaluation index, determine the first index value interval in the gas drive adaptability evaluation standard where the index value is located; For each historical oil reservoir corresponding to an evaluation result, a first historical oil reservoir whose index value is within the first index value interval is determined from the historical oil reservoirs, and a ratio of the first historical oil reservoir to the historical oil reservoir corresponding to the evaluation result is calculated to obtain the degree of membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result.

2. The method according to claim 1, characterized in that The method further comprises: According to a preset value range, the first indicators in the gas drive adaptability evaluation standard are analyzed by using a hierarchy analysis method to obtain the value of each first indicator; and, according to the value range, the evaluation indicators in the gas drive adaptability evaluation standard are analyzed by using a hierarchy analysis method to obtain the value of each evaluation indicator; Based on the values ​​assigned to the first indicators, a first judgment matrix is ​​established and the weights of the first indicators are obtained by solving the first judgment matrix; and based on the values ​​assigned to the evaluation indicators, a second judgment matrix is ​​established and the initial weights of the evaluation indicators are obtained by solving the second judgment matrix; For each evaluation indicator, the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator is calculated to obtain the weight of each evaluation indicator.

3. The method according to claim 1, characterized in that For each evaluation result, according to the weight of each evaluation index, weighted summation is performed on the membership degree of the oil reservoir to be evaluated under each evaluation index under the evaluation result to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result, including: Establishing a row matrix, the elements of which include the weights of the evaluation indicators; Taking each evaluation result as a column, a membership matrix is ​​established according to the membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result; The row matrix and the membership matrix are multiplied to obtain an evaluation matrix, the elements of which include the evaluation value of the oil reservoir to be evaluated under each evaluation result.

4. The method according to any one of claims 1 to 3, characterized in that The gas drive adaptability evaluation standard includes the nitrogen drive adaptability evaluation standard; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development degree; the evaluation indicators under the reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under the oil reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation dip, fracture development degree, and connectivity; the evaluation indicators under the fluid properties include underground crude oil density and underground crude oil viscosity; the evaluation indicators under the development degree include well spacing, pre-gas drive production degree, pre-gas drive oil saturation, and pre-gas drive comprehensive water content.

5. The method according to any one of claims 1 to 3, characterized in that: The gas drive adaptability evaluation standard includes a carbon dioxide gas drive adaptability evaluation standard; the first indicator includes reservoir characteristics, oil reservoir characteristics, fluid properties and development characteristics; the evaluation indicators under the reservoir characteristics include porosity, permeability, wettability, small layer thickness, pore throat radius, water sensitivity, and heterogeneity; the evaluation indicators under the oil reservoir characteristics include reservoir depth, reservoir temperature, reservoir pressure, rhythmicity, formation dip, fracture development degree, and connectivity; the evaluation indicators under the fluid properties include underground crude oil density, underground crude oil viscosity, formation water mineralization, and formation water type; the evaluation indicators under the development characteristics include well spacing, pre-gas drive production degree, pre-gas drive oil saturation, pre-gas drive comprehensive water content, and carbon dioxide source-sink matching degree.

6. A low permeability reservoir gas drive adaptability evaluation device, applied to oil fields that are converted to gas drive after water drive, characterized in that: include: The acquisition module is used to obtain the index values ​​of the reservoir to be evaluated under various evaluation indicators through physical experiments, dynamic and static monitoring and reservoir numerical simulation; The first processing module is used to determine the membership of the oil reservoir to be evaluated under each evaluation index under each preset evaluation result according to the gas drive adaptability evaluation standard and the index value of the oil reservoir to be evaluated under each evaluation index; wherein the gas drive adaptability evaluation standard includes the index value interval of each evaluation index under each first index under each evaluation result, and the first index includes the water drive development level; the membership represents the proportion of historical oil reservoirs corresponding to the evaluation result that meet the index value interval corresponding to the oil reservoir to be evaluated; The second processing module is used for performing weighted summation of the membership degree of the oil reservoir to be evaluated under each evaluation index under each evaluation result according to the weight of each evaluation index, so as to obtain the evaluation value of the oil reservoir to be evaluated under each evaluation result; A third processing module is used to use the evaluation result with the largest evaluation value as the gas drive adaptability evaluation result of the oil reservoir to be evaluated; The first processing module is specifically used for: According to the oil change rate of the historical oil reservoir, the historical oil reservoir is classified according to each evaluation result to obtain the historical oil reservoir corresponding to each evaluation result; For each evaluation index, according to the index value of the oil reservoir to be evaluated under the evaluation index, determine the first index value interval in the gas drive adaptability evaluation standard where the index value is located; For each historical oil reservoir corresponding to an evaluation result, a first historical oil reservoir whose index value is within the first index value interval is determined from the historical oil reservoirs, and a ratio of the first historical oil reservoir to the historical oil reservoir corresponding to the evaluation result is calculated to obtain the degree of membership of the oil reservoir to be evaluated under each evaluation index under each evaluation result.

7. The device according to claim 6, characterized in that The device also includes: An analysis module, configured to analyze the first indicators in the gas drive adaptability evaluation standard using a hierarchical analysis method according to a preset value range to obtain the value of each first indicator; and to analyze the evaluation indicators in the gas drive adaptability evaluation standard using a hierarchical analysis method according to the value range to obtain the value of each evaluation indicator; A fourth processing module, configured to establish a first judgment matrix based on the values ​​assigned to the first indicators and obtain the weights of the first indicators by solving the first judgment matrix; and, based on the values ​​assigned to the evaluation indicators, establish a second judgment matrix and obtain the initial weights of the evaluation indicators by solving the second judgment matrix; The calculation module is used to calculate, for each evaluation indicator, the product of the weight of the first indicator to which the evaluation indicator belongs and the initial weight of the evaluation indicator to obtain the weight of each evaluation indicator.

8. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 5.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 5 when executed by a processor.

Images