Method for identifying high-consumption and low-efficiency displacement zones

Abstract

The present invention provides a method for identifying high-water-consumption, low-efficiency displacement zones, comprising: step 1, collecting and organizing reservoir geological, production, and testing data; step 2, analyzing the injection-production connectivity relationship; step 3, determining evaluation factors; step 4, weighting the evaluation factors; step 5, calculating the seepage resistance coefficient of each connected injection-production displacement zone; step 6, calculating the water injection rate of each injection-production displacement zone in each well layer; step 7, calculating the liquid production rate of each connected injection-production displacement zone in each well layer; step 8, determining the cumulative injection-production volume of the injection-production displacement zone; step 9, calculating the degree of membership of each factor in each displacement zone to the evaluation area; and step 10, identifying displacement zones with high water consumption and low displacement efficiency. This method uses a fuzzy hierarchical analysis method to identify displacement zones with high water consumption and low displacement efficiency, forming a complete calculation method that plays an important role in helping to improve water flooding development efficiency, reduce energy consumption, and improve quality and efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield development, and in particular to a method for distinguishing a high-consumption and low-efficiency displacement zone. Background Art

[0002] Many mature oilfields have entered the late stage of ultra-high water cut, characterized by high overall water consumption ratios, rapid rise rates, low waterflooding efficiency, and significant energy consumption. Addressing this high water consumption is an urgent need, but existing analytical methods are often limited and incomplete, with poor applicability. Due to the varying number of layers perforated by water injection wells and the corresponding number of oil wells per layer, as well as lateral and vertical heterogeneity and complex injection-production relationships, the injected water is unevenly distributed horizontally and vertically, leading to significant differences in water consumption across the displacement zones corresponding to each injection-production relationship. Furthermore, high water consumption does not necessarily mean inefficient operation. If high water consumption is achieved, there is no need to address such high-water-consuming displacement zones. Therefore, it is necessary to analyze the historical displacement history of the injection-production displacement zone and the production performance of the corresponding oil wells. Furthermore, even if a water well injects a large amount of water, the corresponding oil well's liquid production is low. Due to the complex connectivity, this indicates that the water well has not significantly impacted the oil well.

[0003] In the Chinese patent application with application number: N202110281019.8, a method for determining high water consumption zones in oil reservoirs is involved, which belongs to the field of oil development technology. The method includes the following steps: characterizing geological parameters through a fuzzy comprehensive evaluation method to obtain a first potential high water consumption zone; characterizing water saturation through an injection-production well network in the first potential high water consumption zone, and obtaining a second potential high water-containing zone with a water saturation mutation zone as the boundary; obtaining a high water-containing zone with a fluid displacement multiple mutation zone as the boundary in the second potential high water consumption zone. This invention provides a method for identifying high water consumption zones, providing a reference basis for the efficient development of water-injected oil fields. At the same time, the three methods of the invention make further judgments based on the previous judgment in turn, and the judgment range of each judgment method is narrowed and the judgment accuracy is improved in turn, thereby reducing the amount of calculation while maintaining a high calculation accuracy.

[0004] The Chinese patent application, application number CN202011429465.0, involves a method and system for identifying high-water-consumption zones. The identification method includes: identifying high-water-consumption well points using a multi-parameter fuzzy evaluation method; identifying high-water-consumption intervals using qualitative and quantitative analysis of multiple data sources; and determining the distribution of high-water-consumption zones in combination with seepage resistance analysis. Using this approach, the invention establishes a three-dimensional zone determination method, from point to surface to volume, organically linking the points represented by well points, the surfaces represented by intervals, and the volumes represented by bands. The goal is to save late-stage, fully assembled oilfields with extremely high water content, accurately identify and manage high-water-consumption zones, improve recovery rates, and extend the economic life of extremely high-water-content oilfields. Therefore, this method has high market application value.

[0005] In the Chinese patent application with application number: CN202011468218.1, a mining method for identifying high-water-consumption zones by combining dynamic and static methods is involved, which includes: judging whether the oil and water wells are connected, otherwise judging that there is no high-water-consumption zone, and if so, executing the next step; judging whether there is flow between the oil and water wells, otherwise judging that there is no high-water-consumption zone, and if so, executing the next step; calculating the seepage resistance coefficient between the oil and water wells; calculating the stratified water injection volume; and statistically analyzing the flow distribution to determine whether there is a high-water-consumption zone. Using the above scheme, the invention takes the water injection well as the starting point and the oil production well as the end point, studies the role of the passage between the oil and water wells, and accurately, quickly, and simply realizes the identification of high-water-consumption zones. The purpose is to save the late-stage integrated oilfield with ultra-high water content, accurately identify and control the high-water-consumption zone, improve the recovery rate, and extend the economic life of the ultra-high water-content oilfield. Therefore, it has high market application value.

[0006] In the Chinese patent application with application number: CN201910870315.4, a method and system for identifying water-consuming zones in high-water-cut oil reservoirs are involved. The identification method includes: based on the geological data of the target area in the high-water-cut oil reservoir, the production dynamic data of the oil wells and water wells in the target area, using a reservoir numerical simulator to fit the production dynamics of the oil wells and the water wells to obtain a reservoir numerical simulation model; based on the reservoir numerical simulation model, calculating the identification coefficient of the water-consuming zone between each water well and the oil wells located around the water well; and based on the identification coefficient of the water-consuming zone, identifying the development level of the water-consuming zone. This invention can quickly identify the development level of the water-consuming zone and quantitatively characterize it, thereby effectively identifying the development direction of the high-water-consuming zone and playing an effective guiding role in the design of control plans in the subsequent oilfield development stage.

[0007] The above existing technologies are all significantly different from the present invention and fail to solve the technical problem we want to solve. Therefore, we have invented a new method for identifying high-consumption and low-efficiency displacement zones. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for identifying high-consumption and low-efficiency displacement zones with good practicality, which can help reduce the cost of replacement mining and calculate its input-output and their relationship.

[0009] The purpose of the present invention can be achieved by the following technical measures: a high-consumption and low-efficiency displacement zone discrimination method, which includes:

[0010] Step 1: Collect and organize reservoir geology, production and testing data;

[0011] Step 2: Analyze the injection-production connectivity relationship;

[0012] Step 3, determine the evaluation factors;

[0013] Step 4: weight analysis of evaluation factors;

[0014] Step 5, calculating the seepage resistance coefficient of each injection-production connected displacement zone;

[0015] Step 6, calculating the water injection rate of each injection-production displacement zone in each well layer;

[0016] Step 7, calculating the liquid production rate of each injection-production connected displacement zone in each well layer;

[0017] Step 8, determining the cumulative injection and production volume of the injection and production displacement zone;

[0018] Step 9, calculating the membership degree of each factor in each displacement zone to the assessment area;

[0019] Step 10: Identify the displacement zone with high water consumption and low displacement efficiency.

[0020] The purpose of the present invention can also be achieved by the following technical measures:

[0021] In step 1, collect and organize static reservoir data: thickness, permeability, small layer plan, well location data; development and production data: injection and production well pattern map, injection and production data, well history data; and test data: water absorption profile test data, layer test data, viscosity data, tracer test data.

[0022] In step 2, the sub-layer plan with injection and production well points and tracer test data are used to determine whether the oil and water wells in each sub-layer and sand body can form an injection and production connectivity relationship, establish an injection and production correspondence table, and thus find all displacement zones.

[0023] In step 3, the monitoring indicators that can most directly reflect high consumption and low efficiency are selected: injection and production rates reflect energy consumption; the water content of the produced fluid reflects the displacement efficiency; the cumulative injection and production volume can reflect both energy consumption and displacement efficiency.

[0024] In step 3, since the oil and water well data are formed by multiple displacement zones, it is necessary to use geological data, production data, and test data to split the oil and water well data into each displacement zone to directly reflect the high consumption and low efficiency problem of the displacement zone.

[0025] In step 4, the hierarchical analysis method is used to compare the degree to which each evaluation factor reflects the high consumption and low efficiency problem of the displacement zone, establish a judgment matrix, and after performing a consistency test, obtain the weight value of each evaluation factor.

[0026] In step 5, based on the seepage mechanics theory and reservoir engineering theory, Darcy's formula is used, with the water injection well as the center and the average parameter value of the oil and water well as the parameter value of the seepage resistance coefficient on the injection-production displacement zone, to calculate the seepage resistance on each displacement zone.

[0027] In step 5, the formula for calculating the seepage resistance of the displacement zone formed by the water injection well in the i-th layer and the effective j-th oil well is:

[0028]

[0029] Where R ij : Seepage resistance between the injection well in layer i and the jth oil well, m 3 / pa.s;L ij : the distance between the i-th layer and the j-th oil well, m; H i 、H j : effective thickness of the water injection well and the jth oil well in the i-th layer, m; K i , K j : Permeability of the water injection well and the jth oil well in the i-th layer, D; μ i , viscosity of the oil phase in layer i, mPa.s; μ w , aqueous phase viscosity, mPa.s; f w , water content of oil well produced fluid, 1.

[0030] In step 6, the injection velocity in each displacement zone is calculated using the water absorption profile test data or the layered water absorption test data and the seepage resistance coefficient method and the hydropower similarity principle.

[0031] In step 6, when there is water absorption profile test data or layered water absorption test data, the water absorption ratio λi of the i-th layer can be directly determined based on the test data. Z When the water injection well injects water into the displacement zone formed by the jth effective oil well in the i-th layer, the injection rate W ij The calculation formula is:

[0032]

[0033] Where R ij : Seepage resistance between the injection well in layer i and the jth oil well, m 3 / pa.s;

[0034] If such data are not available, the calculation is performed entirely using the seepage resistance coefficient method and the hydropower similarity principle. The injection velocity W of the water injection well in the displacement zone formed by the effective oil well at the i-th layer is ij The calculation formula is:

[0035]

[0036] In step 7, the injection rate in each displacement zone is calculated based on the calculated seepage resistance in each displacement zone by using the hydroelectric similarity principle. At the same time, the water content of the produced fluid of the oil well is taken as the average water content of the displacement zone.

[0037] In step 7, with the oil well as the center, the oil well production rate is Q C When the oil well in the first layer and the kth corresponding water well form a displacement zone, the liquid production rate W lk The calculation formula is:

[0038]

[0039] Where R lk : Seepage resistance between the oil well in the lth layer and the corresponding water well in the kth layer, m 3 / pa.s;

[0040] Q C : Oil well fluid production rate, d / t.

[0041] At the same time, the water content of the produced fluid of the oil well is taken as the average water content of the displacement zone.

[0042] In step 8, for reservoirs where split production and injection have been carried out, the split production and injection data are collected and organized. If the split production and injection work has not been carried out, it is necessary to re-carry out the split production and injection work to organize and calculate the cumulative injection and cumulative production volumes of the injection-production wells in the displacement zone layer when the injection-production displacement zone exists in the development history.

[0043] In step 9, first determine the high-consumption and low-consumption, low-efficiency and high-efficiency classification intervals to which each evaluation factor belongs; establish and use the membership functions of low-consumption and high-efficiency and high-consumption and low-efficiency, and calculate the fuzzy matrix of the membership of each evaluation factor in each displacement zone to each interval.

[0044] In step 9, the membership function U of low consumption and high efficiency is established, and the membership function of high consumption and low efficiency is 1-U. Then, the fuzzy matrix of the membership of each evaluation factor in each displacement zone to each interval is calculated:

[0045]

[0046] Where a i ,b i is the boundary value between low consumption and high efficiency and high consumption and low efficiency of factor i; x ij is the judgment value of factor i in driving zone j.

[0047] In step 10, the fuzzy matrix of the membership of each evaluation factor of each displacement zone to each interval in step 9 is multiplied by the weight of each factor obtained in step 4 to obtain the fuzzy comprehensive evaluation value of each displacement zone for the high-consumption and low-efficiency interval and the low-consumption and high-efficiency interval; by comparing the evaluation values of each evaluation area, it is determined whether each displacement zone belongs to the high-consumption and low-efficiency displacement zone.

[0048] The method for identifying high-water-consumption and low-efficiency displacement zones in the present invention collects reservoir geological, production and testing data, comprehensively analyzes injection-production problems based on the seepage resistance coefficient and the hydropower similarity principle, and combines dynamic and static factors to fully and reasonably reflect the energy consumption and displacement efficiency of each injection-production displacement zone. It uses a fuzzy hierarchical analysis method to identify displacement zones with high water consumption and low displacement efficiency, forming a complete calculation method that plays an important role in helping to improve water flooding development efficiency, save energy and reduce consumption, and improve quality and efficiency.

[0049] The method for identifying high-consumption and low-efficiency displacement zones developed by this invention comprehensively considers the static, development and production, and test data of the oil reservoir, selects monitoring indicators that can directly reflect the high-consumption and low-efficiency problems, and conducts a detailed analysis of the displacement zones. It uses a variety of theoretical and mathematical methods to form a method for identifying high-consumption and low-efficiency displacement zones. It is a practical method for identifying displacement zones that need to be reduced or weakened. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a flow chart of a specific embodiment of the method for identifying a high-consumption and low-efficiency displacement zone of the present invention;

[0051] Figure 2 Ng5 in a specific embodiment 2 of the present invention 3 Schematic diagram of the high-consumption and low-efficiency displacement zone of a layer on its small layer plane;

[0052] Figure 3 Ng5 in a specific embodiment 2 of the present invention 4 Schematic diagram of the high-consumption and low-efficiency displacement zone of a layer on its small layer plane;

[0053] Figure 4 Ng5 in a specific embodiment 2 of the present invention 5 Schematic diagram of the high-consumption and low-efficiency displacement zone of a layer on its small layer plane. DETAILED DESCRIPTION

[0054] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0055] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0056] To improve the efficiency of water flooding development in oil fields, the present invention comprehensively considers reservoir static data, development and production data, and testing data, selects monitoring indicators that can directly reflect the problem of high consumption and low efficiency, and conducts detailed analysis of the displacement zone. Using multiple theoretical and mathematical methods, a method for identifying high-consumption and low-efficiency displacement zones is formed. This is a practical method for identifying displacement zones that need to be reduced or weakened.

[0057] like Figure 1 As shown, Figure 1 This is a flow chart of a specific embodiment of the present invention's method for identifying high-consumption, low-efficiency displacement zones. This method comprehensively considers reservoir static data, development and production data, and testing data, selects monitoring indicators that directly reflect high-consumption, low-efficiency issues, and then conducts a detailed analysis of displacement zones. Using multiple theoretical and mathematical methods, this method forms a practical approach for identifying displacement zones that need to be reduced or weakened.

[0058] In step 101, static reservoir data, development and production data, and test data are collected and organized. The process then proceeds to step 102.

[0059] In step 102, a sub-layer plan view with injection and production well points in each sub-layer and tracer test data are used to create an injection-production correspondence table to locate all displacement zones. The process then proceeds to step 103.

[0060] In step 103, the most direct monitoring indicators reflecting high consumption and low efficiency are selected: injection, production rate, produced fluid water content, and cumulative injection and production volume. The oil and water well data is split into displacement zones to directly reflect high consumption and low efficiency issues in these displacement zones. The process then proceeds to step 104.

[0061] In step 104, a hierarchy analysis method is used to establish a judgment matrix and obtain the weight value of each evaluation factor. The process then proceeds to step 105.

[0062] In step 105, based on seepage mechanics and reservoir engineering theory, Darcy's formula is used to calculate the seepage resistance coefficient parameter value for each displacement zone, with the injection well as the center. The average parameter value of the oil and water wells is used as the seepage resistance coefficient parameter value for the injection-production displacement zone. The process then proceeds to step 106.

[0063] In step 106, the injection rate in each displacement zone is calculated using the water absorption profile test data or the layered water absorption test data, using the seepage resistance coefficient method and the hydroelectric similarity principle. The process then proceeds to step 107.

[0064] In step 107, the injection rate in each displacement zone is calculated based on the calculated seepage resistance in each displacement zone and the principle of hydroelectric similarity. At the same time, the water content of the produced fluid from the oil well is used as the average water content of the displacement zone. The process then proceeds to step 108.

[0065] In step 108, the production and injection splitting data are used to sort out the cumulative injection and production volumes of the strata in which the injection-production displacement zone exists. The process then proceeds to step 109.

[0066] In step 109, the high-consumption and low-consumption, low-efficiency and high-efficiency classification intervals for each evaluation factor are first determined. Membership functions for low-consumption and high-efficiency and high-consumption and low-efficiency are established and used to calculate a fuzzy matrix representing the membership of each evaluation factor in each displacement zone to each interval. The process then proceeds to step 110.

[0067] In step 110 , the fuzzy matrix is multiplied by the weights of each factor to obtain the fuzzy comprehensive evaluation value for each displacement zone in the high-consumption, low-efficiency and low-consumption, high-efficiency ranges. The evaluation values of each evaluation area are compared to determine whether each displacement zone is a high-consumption, low-efficiency displacement zone. The process ends.

[0068] This method for identifying high-water-consumption and low-efficiency displacement zones collects reservoir geological, production, and testing data. Based on the seepage resistance coefficient and the principle of hydropower similarity, it comprehensively analyzes injection-production problems in combination with dynamic and static factors. It fully and reasonably reflects the energy consumption and displacement efficiency of each injection-production displacement zone. It uses the fuzzy hierarchical analysis method to identify displacement zones with high water consumption and low displacement efficiency, forming a complete calculation method that plays an important role in helping to improve waterflood development efficiency, save energy and reduce consumption, and improve quality and efficiency.

[0069] In order to make the above contents of the present invention more clearly understood, the following is a detailed description using actual cases:

[0070] Example 1

[0071] In a specific embodiment 1 of the present invention, the method for identifying a high-consumption and low-efficiency drive zone includes the following steps:

[0072] 1. Collect and organize reservoir static parameters, including: reservoir thickness, permeability, small layer plan, well location data; also collect and organize reservoir development and production data, including: injection and production well network map, injection and production data, well history data; as well as water absorption profile test data, layer test data, viscosity data, and tracer test data.

[0073] Second, a sub-layer plan view with injection and production well points and tracer test data are needed to determine whether the oil and water wells in each sub-layer and sand body correspond to each other and whether an injection-production connection relationship can be formed, so as to find and establish a displacement zone table (Table 3).

[0074] 3. Select the most direct monitoring indicators that reflect high consumption and low efficiency: Injection and production rates reflect energy consumption; the current water content of the produced fluid reflects displacement efficiency. The cumulative injection and production volume can reflect both energy consumption and displacement efficiency. Oil and water well data are formed by multiple displacement zones, so it is necessary to split the oil and water well data into each displacement zone so that the evaluation indicators reflect each displacement zone. The significance of the four evaluation factors is as follows:

[0075] 1) Displacement zone water injection rate: reflects the rate at which water is consumed by the displacement zone when injected into the reservoir;

[0076] 2) Fluid production rate in the displacement zone: reflects the rate at which water is consumed in the reservoir produced in the displacement zone;

[0077] 3) Moisture content of the displacement zone: reflects the displacement efficiency of the displacement zone.

[0078] 4) Cumulative injection and production volume of the displacement zone: reflects the displacement degree of the displacement zone, thus reflecting the displacement efficiency of the displacement zone and also reflecting the energy consumption problem;

[0079] Fourth, we used the analytic hierarchy process to compare the degree to which each evaluation factor reflects the high consumption and low efficiency of the injection-production displacement zone. A judgment matrix was established, and after a consistency test, the weights of the evaluation factors were determined. The weights of each factor in our method were 0.160 for water injection rate, 0.104 for cumulative injection-production volume, 0.510 for water cut, and 0.226 for liquid production rate (Table 1).

[0080] Table 1 Weight of each factor

[0081] Influencing factors Water injection speed Liquid production speed Moisture content Cumulative injection and production volume Weight 0.160 0.226 0.510 0.104

[0082] 5. Based on the theory of seepage mechanics and reservoir engineering, using the Darcy formula, with the water injection well as the center and the average parameter value of the oil and water wells in the displacement zone as the seepage resistance parameter value in the injection-production displacement zone, the relevant parameters include: the well spacing of each displacement zone, the average effective thickness, the average permeability, and the average viscosity. Calculate the seepage resistance of the displacement zone formed by the water injection well in the i-th layer and the effective oil well j:

[0083]

[0084] Where R ij : Seepage resistance between the injection well in layer i and the jth oil well, m 3 / pa.s;L ij : the distance between the i-th layer and the j-th oil well, m; H i 、H j : effective thickness of the water injection well and the jth oil well in the i-th layer, m; K i , K j : Permeability of the water injection well and the jth oil well in the i-th layer, D; μi , viscosity of the oil phase in layer i, mPa.s; μ w , aqueous phase viscosity, mPa.s; f w , water content of oil well produced fluid, 1.

[0085] 6. If there is water absorption profile test data or layered water absorption test data, the water absorption ratio λ of the i-th layer can be directly determined based on the test data i If such data is not available, the seepage resistance coefficient method is used for calculation. First, the total seepage resistance R of the i-th layer of the injection well is calculated according to the hydropower similarity principle. i .

[0086]

[0087] Then add up the resistance of each layer to calculate the total resistance R of the injection well:

[0088]

[0089] Thus, the injection ratio λ of the i-th layer of the injection well can be calculated i :

[0090] λ i =R / R i Formula 4

[0091] Continuing to calculate the water injection ratio coefficient λ of the water injection well in the i-th layer to the j-th effective oil well according to the hydropower similarity principle ij .

[0092] λ ij =R i / R ij Formula 5

[0093] Then according to the water well injection rate (Q Z , m 3 / d) can calculate the amount of water W injected from the water injection well to the jth effective oil well in the i-th layer ij The calculation formulas are (Table 3):

[0094]

[0095]

[0096] 7. Calculate the production rate of each well layer and each injection-production connected displacement zone. First, the seepage resistance coefficient method is still used. According to the calculated seepage resistance on each displacement zone, with the oil well as the center, the production ratio of each layer and each injection-production displacement zone is determined step by step through the principle of hydropower similarity. The oil well production rate is Q C When (t / d), the liquid production rate W of the oil well in the displacement zone formed by the lth layer and the kth corresponding water well islk The calculation formula is (Table 3 below):

[0097]

[0098] Where R lk : Seepage resistance between the injection well in the lth layer and the kth oil well, m 3 / pa.s;Q C : Oil well production rate, m 3 / d; R, total seepage resistance of the oil well, m 3 / pa.s;R l , oil well seepage resistance in layer l, m 3 / pa.s.

[0099] At the same time, the water content of the produced fluid of the oil well is taken as the average water content of the displacement zone.

[0100] 8. For reservoirs where split production and injection have already been conducted, only the split production and injection data need to be collected and organized. If not, split production and injection work needs to be re-performed. This data can be used to calculate the cumulative injection and cumulative production volumes of injection-production wells in the displacement zone during the development history when the displacement zone existed (Table 3).

[0101] 9. Determine the high-consumption, low-consumption, low-efficiency, and high-efficiency classification intervals for each evaluation factor (Table 2).

[0102] Table 2 Table of threshold values for each factor

[0103]

[0104] Formula 9 is the membership function U of low consumption and high efficiency used in this case, and the membership function of high consumption and low efficiency is 1-U, which is then used to calculate the fuzzy matrix of the membership of each evaluation factor in each displacement zone to each evaluation area.

[0105]

[0106] 10. Multiply the fuzzy matrix of the degree of membership of each evaluation factor in each displacement zone to each interval by the weight of each factor to obtain the fuzzy comprehensive evaluation value of each displacement zone for high-consumption, low-efficiency and low-consumption, high-efficiency zones. By comparing the evaluation values, each displacement zone is determined to be a high-consumption, low-efficiency zone. In this case, 62 high-consumption, low-efficiency displacement zones were identified (Table 3).

[0107] Table 3 Displacement belt high consumption and low efficiency judgment table

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115] Example 2:

[0116] In the specific embodiment 2 of the present invention, the classification limit value of step 9 in embodiment 1 is changed to the low-consumption high-efficiency and high-consumption low-efficiency classification intervals shown in Table 4 below. The high-consumption low-efficiency displacement zone is judged as follows: Figure 2 、 3 4. There are 49 high-consumption and low-efficiency displacement zones identified. 3 、Ng5 4 、Ng5 5 Layer, among which the largest main layer is Ng5 3 There are 31 high-consumption and low-efficiency displacement zones, accounting for 63%, while the poorly developed Ng5 1 、Ng5 2 、Ng5 6 Not a single one.

[0117] Table 4 Table of threshold values for each factor

[0118]

[0119]

[0120] The method for identifying high-consumption and low-efficiency displacement zones of the present invention first establishes an injection-production connectivity relationship table after collecting reservoir static data, development and production data, and test data; then determines evaluation factors and uses the analytic hierarchy process to perform factor weight analysis; then calculates the seepage resistance coefficient of each injection-production connected displacement zone, and on this basis uses test data or calculates the water injection rate of each injection-production displacement zone in each well layer, and calculates the liquid production rate of each injection-production connected displacement zone in each well layer; uses split-production and split-injection data to determine the cumulative injection and production volume of the injection-production displacement zone; calculates the membership of each factor in each displacement zone to the evaluation area, establishes a fuzzy matrix, and finally uses the matrix multiplied by the factor weight to identify displacement zones with high water consumption and low displacement efficiency. This method uses the fuzzy analytic hierarchy process to identify displacement zones with high water consumption and low displacement efficiency, forming a complete calculation method, which plays an important role in helping to improve water drive development efficiency, save energy and reduce consumption, and improve quality and efficiency.

[0121] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0122] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A method for identifying high-consumption and low-efficiency displacement zones, characterized in that: The high-consumption and low-efficiency displacement zone identification method includes: Step 1: Collect and organize reservoir geology, production and testing data; Step 2: Analyze the injection-production connectivity relationship; Step 3, determine the evaluation factors; Step 4: weight analysis of evaluation factors; Step 5, calculating the seepage resistance coefficient of each injection-production connected displacement zone; Step 6, calculating the water injection rate of each injection-production displacement zone in each well layer; Step 7, calculating the liquid production rate of each injection-production connected displacement zone in each well layer; Step 8, determining the cumulative injection and production volume of the injection and production displacement zone; Step 9, calculating the membership degree of each factor in each displacement zone to the assessment area; Step 10, identifying a displacement zone with high water consumption and low displacement efficiency; In step 4, the hierarchical analysis method is used to compare the degree to which each evaluation factor reflects the high consumption and low efficiency problem of the displacement zone, establish a judgment matrix, perform a consistency test, and then calculate the weight value of each evaluation factor; In step 5, based on the theory of seepage mechanics and reservoir engineering theory, Darcy's formula is used, with the water injection well as the center and the average parameter value of the oil and water wells as the parameter value of the seepage resistance coefficient in the injection-production displacement zone, to calculate the seepage resistance in each displacement zone; In step 5, the formula for calculating the seepage resistance of the displacement zone formed by the water injection well in the i-th layer and the effective j-th oil well is: Where R ij : Seepage resistance between the injection well in layer i and the jth oil well, m 3 / pa.s;L ij : the distance between the i-th layer and the j-th oil well, m; H i 、H j : effective thickness of the water injection well and the jth oil well in the i-th layer, m; K i , K j : Permeability of the water injection well and the jth oil well in the i-th layer, D; μ i , viscosity of the oil phase in layer i, mPa.s; μ w , aqueous phase viscosity, mPa.s; f w , water content of oil well produced fluid, 1; In step 9, first determine the high-consumption and low-consumption, low-efficiency and high-efficiency classification intervals to which each evaluation factor belongs; establish and use the membership functions of low-consumption and high-efficiency and high-consumption and low-efficiency, and calculate the fuzzy matrix of the membership of each evaluation factor in each displacement zone to each interval; In step 9, the membership function U of low consumption and high efficiency is established, and the membership function of high consumption and low efficiency is 1-U. Then, the fuzzy matrix of the membership of each evaluation factor in each displacement zone to each interval is calculated: Where a i ,b i is the boundary value between low consumption and high efficiency and high consumption and low efficiency of factor i; x ij is the judgment value of factor i in displacement zone j; In step 10, the fuzzy matrix of the membership of each evaluation factor of each displacement zone to each interval in step 9 is multiplied by the weight of each factor obtained in step 4 to obtain the fuzzy comprehensive evaluation value of each displacement zone for the high-consumption and low-efficiency interval and the low-consumption and high-efficiency interval; by comparing the evaluation values of each evaluation area, it is determined whether each displacement zone belongs to the high-consumption and low-efficiency displacement zone.

2. The method for identifying high-consumption and low-efficiency displacement zones according to claim 1, characterized in that: In step 1, collect and organize static reservoir data: thickness, permeability, small layer plan, well location data; development and production data: injection and production well pattern map, injection and production data, well history data; and test data: water absorption profile test data, layer test data, viscosity data, tracer test data.

3. The method for identifying high-consumption and low-efficiency displacement zones according to claim 1, characterized in that: In step 2, the sub-layer plan with injection and production well points and tracer test data are used to determine whether the oil and water wells in each sub-layer and sand body can form an injection and production connectivity relationship, establish an injection and production correspondence table, and thus find all displacement zones.

4. The method for identifying high-consumption and low-efficiency displacement zones according to claim 1, characterized in that: In step 3, the monitoring indicators that can most directly reflect high consumption and low efficiency are selected: injection and production rates reflect energy consumption; the water content of the produced fluid reflects the displacement efficiency; the cumulative injection and production volume can reflect both energy consumption and displacement efficiency.

5. The method for identifying high-consumption and low-efficiency displacement zones according to claim 4, characterized in that: In step 3, since the oil and water well data are formed by multiple displacement zones, it is necessary to use geological data, production data, and test data to split the oil and water well data into each displacement zone to directly reflect the high consumption and low efficiency problem of the displacement zone.

6. The method for identifying high-consumption and low-efficiency displacement zones according to claim 1, characterized in that: In step 6, the injection velocity in each displacement zone is calculated using the water absorption profile test data or the layered water absorption test data and the seepage resistance coefficient method and the hydropower similarity principle.

7. The method for identifying high-consumption and low-efficiency displacement zones according to claim 6, characterized in that: In step 6, when there is water absorption profile test data or layered water absorption test data, the water absorption ratio λi of the i-th layer can be directly determined based on the water absorption profile test data or layered water absorption test data. Z When the water injection well injects water into the displacement zone formed by the jth effective oil well in the i-th layer, the injection rate W ij The calculation formula is: Where R ij : Seepage resistance between the injection well in layer i and the jth oil well, m 3 / pa.s; If there is no water absorption profile test data or layered water absorption test data, the calculation is completely based on the seepage resistance coefficient method and the hydropower similarity principle. The injection velocity W of the water injection well in the displacement zone formed by the jth effective oil well in the i-th layer is ij The calculation formula is:

8. The method for identifying high-consumption and low-efficiency displacement zones according to claim 1, characterized in that: In step 7, the injection rate in each displacement zone is calculated based on the calculated seepage resistance in each displacement zone by using the hydroelectric similarity principle. At the same time, the water content of the produced fluid of the oil well is taken as the average water content of the displacement zone.

9. The method for identifying a high-consumption and low-efficiency displacement zone according to claim 8, characterized in that: In step 7, with the oil well as the center, the oil well production rate is Q C When the oil well in the first layer and the kth corresponding water well form a displacement zone, the liquid production rate W lk The calculation formula is: Where R lk : Seepage resistance between the oil well in the lth layer and the corresponding water well in the kth layer, m 3 / pa.s; Q C : Oil well fluid production rate, d / t. At the same time, the water content of the produced fluid of the oil well is taken as the average water content of the displacement zone.

10. The method for identifying a high-consumption and low-efficiency displacement zone according to claim 1, wherein: In step 8, for reservoirs where split production and injection have been carried out, the split production and injection data are collected and organized. If the split production and injection work has not been carried out, it is necessary to re-carry out the split production and injection work to organize and calculate the cumulative injection and cumulative production volumes of the injection-production wells in the displacement zone layer when the injection-production displacement zone exists in the development history.

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