A method for judging water absorbing subzones of water injection wells in low-permeability sandstone oil reservoirs

Abstract

The application provides a method for judging water absorption of a small layer of a water injection well in a low-permeability sandstone reservoir, and belongs to the technical field of oil and gas field development. The water injection well is divided into multiple small layers in the vertical direction. The following method is performed for each small layer: obtaining logging data of the water injection well and water absorption profile data of other water injection wells in the area where the water injection well is located; obtaining formation physical property parameters of the small layer based on the logging data; obtaining single-factor water absorption probabilities corresponding to the formation physical property parameters of the area where the water injection well is located based on the water absorption profile data of the other water injection wells in the area; obtaining a comprehensive evaluation index value of the small layer based on the single-factor water absorption probabilities corresponding to the formation physical property parameters of the area where the water injection well is located and the formation physical property parameters of the small layer; and determining a water absorption result of the small layer based on the comprehensive evaluation index value. The application aims to judge the water absorption of the small layer of the water injection well with less or discontinuous water absorption profile data.

Description

Technical Field

[0001] This application relates to the field of oil and gas field development technology, and more specifically, to a method for determining the water absorption layer in injection wells of low-permeability sandstone reservoirs. Background Technology

[0002] With the depletion of oil resources and the continuous consumption of formation energy, waterflooding technology, as a method to stabilize reservoir pressure and achieve high and stable production, is widely used in oilfield development worldwide. In China, oilfield reservoirs are highly concentrated, mostly consisting of continental clastic sedimentary rocks with strong vertical heterogeneity. This makes them prone to water channeling in high-permeability layers during water injection, leading to ineffective water circulation and affecting injection efficiency. To enhance water injection in low- and medium-permeability layers and ensure the effectiveness of waterflooding technology, stratified water injection techniques are widely adopted.

[0003] However, for a long time, the determination of the segmentation of water injection in stratified injection wells has mainly relied on reservoir physical property data or the production experience of on-site personnel. For water injection wells with water absorption profile data, this data can be directly used as the basis for segmentation of stratified water injection. Mine water absorption profile testing involves injecting isotopes into the well under water injection conditions and obtaining the difference in radioactivity intensity between different sub-layers, which indicates the amount of water absorbed. This method yields water absorption profiles that best match the actual water absorption of the sub-layers. However, it requires shutting down the well and ceasing production for measurement, resulting in a long testing cycle and high costs. Consequently, the amount of water absorption profile data obtained on-site is limited and discontinuous, and many injection wells even lack water absorption profile data altogether. Therefore, how to effectively predict the water absorption profile of injection wells with limited and discontinuous water absorption profile data has become a challenge. Summary of the Invention

[0004] This application provides a method for judging the water absorption sub-layers of injection wells in low-permeability sandstone reservoirs, which aims to judge the water absorption results of sub-layers in injection wells with limited and discontinuous water absorption profile data.

[0005] In a first aspect, embodiments of this application provide a method for determining water-absorbing sub-layers in injection wells of low-permeability sandstone reservoirs, including:

[0006] The injection well is longitudinally divided into multiple sub-layers, and the following method is performed for each sub-layer:

[0007] Obtain logging data of the injection well and water intake profile data of other injection wells in the area where the injection well is located;

[0008] Based on the well logging data, the formation physical parameters of the sub-layer are obtained, including resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content.

[0009] Based on the water absorption profile data of other water injection wells in the area where the water injection well is located, the single-factor water absorption probability corresponding to each formation physical parameter in the area where the water injection well is located is obtained. The single-factor water absorption probability is used to characterize the influence of each formation physical parameter on the water absorption of the middle and lower layers of the water injection well.

[0010] Based on the single-factor water absorption probability corresponding to the physical properties of each formation in the area where the injection well is located and the physical properties of the formation of the sub-layer, the comprehensive evaluation index value of the sub-layer is obtained.

[0011] Based on the comprehensive evaluation index values, the water absorption result of this sublayer is determined.

[0012] Optionally, determining the water absorption result of the sublayer based on the comprehensive evaluation index value includes:

[0013] Obtain the average value of the comprehensive evaluation index of all sub-layers in the injection well;

[0014] Based on the average value and the comprehensive evaluation index value, the water absorption result of the sublayer is determined.

[0015] Optionally, the step of obtaining the single-factor water absorption probability corresponding to each formation property parameter in the area where the injection well is located based on the water absorption profile data of other injection wells in the area includes:

[0016] The water intake profile data of other water injection wells in the area where the aforementioned water injection well is located are screened;

[0017] The values ​​of each of the aforementioned formation physical parameters are divided into multiple numerical segments;

[0018] Based on the screening results, the number of water-absorbing sublayers and the number of non-water-absorbing sublayers in each numerical range of each formation physical property parameter are obtained.

[0019] Based on the number of water-absorbing and non-water-absorbing sublayers in each numerical range of each of the formation physical parameters, the single-factor water absorption probability corresponding to each formation physical parameter is obtained.

[0020] Optionally, the step of screening the water intake profile data of other water injection wells in the area where the injection well is located includes:

[0021] Select and retain the water intake profile data corresponding to water injection wells that did not undergo formation modification measures before water injection;

[0022] Select and retain the water intake profile data of water injection wells that have not undergone fracturing measures before the water intake profile test;

[0023] Water intake profile data for injection wells in perforated sections with known formation properties were selected and retained.

[0024] Optionally, obtaining the single-factor water absorption probability corresponding to each formation property parameter based on the number of water-absorbing sublayers and the number of non-water-absorbing sublayers in each numerical range of each formation property parameter includes:

[0025] The following formula is used to determine it:

[0026]

[0027] In the formula, Δf is the single-factor water absorption probability; S1 is the number of water-absorbing sublayers in each numerical segment; and S2 is the number of non-water-absorbing sublayers in each numerical segment.

[0028] Optionally, the step of obtaining the comprehensive evaluation index value of the sub-layer based on the single-factor water absorption probability corresponding to the formation properties of each formation in the area where the injection well is located and the formation properties of the sub-layer includes:

[0029] Based on the single-factor water absorption probability corresponding to each of the formation physical parameters, a fitting formula is obtained. The fitting formula is used to characterize the relationship between the single-factor water absorption probability and each of the formation physical parameters.

[0030] Based on the fitting formula, the single-factor water absorption probability corresponding to the physical property parameters of each stratum in the sub-layer is obtained.

[0031] Obtain a comprehensive evaluation table for a sub-layer. The comprehensive evaluation table for a sub-layer is used to characterize the relationship between the single-factor water absorption probability corresponding to each formation physical parameter of the sub-layer and the comprehensive evaluation index value of the sub-layer.

[0032] Based on the comprehensive evaluation table of the sublayer and the single-factor water absorption probability corresponding to each stratum physical property parameter of the sublayer, the comprehensive evaluation index value of the sublayer is obtained.

[0033] Optionally, the fitting formula includes:

[0034] Porosity fitting formula:

[0035] Permeability fitting formula: f2 = 0.0508lnK + 0.4772;

[0036] Oil saturation fitting formula: f3 = 0.0044S o +0.3311;

[0037] The fitting formula for clay content is: f4 = 0.0239NR + 0.7612;

[0038] Resistivity fitting formula: f5 = 0.0172R + 0.2764;

[0039] Acoustic time difference fitting formula: f6=0.0043AC-0.6589;

[0040] Density fitting formula: f7 = -0.1347DEN + 0.7388;

[0041] In the formula, f1 is the single-factor probability of porosity; f2 is the single-factor probability of permeability; f3 is the single-factor probability of oil saturation; f4 is the single-factor probability of clay content; f5 is the single-factor probability of resistivity; f6 is the single-factor probability of acoustic transit time; f7 is the single-factor probability of density; φ is porosity; K is permeability; S o 1 represents oil saturation; NR represents clay content; R represents resistivity; AC represents acoustic transit time; and DEN represents density.

[0042] Optionally, judging the water absorption result of the sublayer based on the average value and the comprehensive evaluation index value includes:

[0043] If the average value of the sublayer is greater than the value of the comprehensive evaluation index, then the water absorption result of the sublayer is a non-absorbent sublayer.

[0044] If the average value of the sublayer is less than or equal to the value of the comprehensive evaluation index, then the water absorption result of the sublayer is a water-absorbing sublayer.

[0045] Secondly, embodiments of this application provide a device for determining the water absorption layer of an injection well in a low-permeability sandstone reservoir, comprising: a data acquisition module, a parameter acquisition module, a probability acquisition module, an index acquisition module, and a judgment module, wherein...

[0046] The data acquisition module is used to acquire the logging data of the injection well and the water intake profile data of other injection wells in the area where the injection well is located;

[0047] The parameter acquisition module is used to acquire the formation physical parameters of the sub-layer based on the well logging data. The formation physical parameters include resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content.

[0048] The probability acquisition module is used to acquire the single-factor water absorption probability corresponding to each formation property parameter in the area where the water injection well is located, based on the water absorption profile data of other water injection wells in the area where the water injection well is located. The single-factor water absorption probability is used to characterize the influence of each formation property parameter on the water absorption of the middle and lower layers of the water injection well.

[0049] The index acquisition module obtains the comprehensive evaluation index value of the sub-layer based on the single-factor water absorption probability corresponding to the physical property parameters of each stratum in the area where the injection well is located and the physical property parameters of the sub-layer.

[0050] The judgment module is used to determine the water absorption result of the sublayer based on the value of the comprehensive evaluation index.

[0051] Thirdly, an electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method as described in any one of the first aspects.

[0052] Beneficial effects: After dividing the injection well into multiple sub-layers, when judging one of the sub-layers, firstly, the formation physical parameters of each sub-layer are obtained through well logging data; then, the single-factor water absorption probability corresponding to each formation physical parameter is obtained through water absorption profile data of other injection wells in the same area. Combining the formation physical parameters and the corresponding single-factor water absorption probabilities of each formation physical parameter of the sub-layer, a comprehensive evaluation index value can be obtained. The comprehensive evaluation index value can reflect the water absorption result of the sub-layer, thus completing the judgment of the water absorption result of the sub-layer. During the judgment process, because the single-factor water absorption probabilities corresponding to each formation physical parameter of the sub-layer are obtained through water absorption profile data of other injection wells in the same area, the incompleteness or discontinuity of the water absorption profile data will not affect the judgment of the water absorption result of the sub-layer. This achieves the effect of judging the water absorption result of injection well sub-layers with limited and discontinuous water absorption profile data. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a flowchart of the steps for determining the water-absorbing sub-layers in injection wells of low-permeability sandstone reservoirs according to an embodiment of this application;

[0055] Figure 2 This is a numerical classification of porosity proposed in one embodiment of this application;

[0056] Figure 3 This is a single-factor water absorption probability corresponding to porosity in various numerical ranges, as proposed in an embodiment of this application;

[0057] Figure 4 This refers to the comprehensive evaluation index values ​​of multiple sub-layers of a water injection well as proposed in one embodiment of this application;

[0058] Figure 5 This is an embodiment of the present application that describes the determination of water absorption results in multiple sub-layers of a water injection well;

[0059] Figure 6 This is a schematic diagram of a device for determining the water absorption layer of an injection well in a low-permeability sandstone reservoir, as proposed in one embodiment of this application. Detailed Implementation

[0060] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0061] Example 1

[0062] Reference Figure 1 This document illustrates a flowchart of a method for determining water-absorbing sub-layers in injection wells of low-permeability sandstone oil reservoirs, as described in an embodiment of the present invention. The injection wells are vertically divided into multiple sub-layers, and the following method is performed for each sub-layer. The method may specifically include the following steps:

[0063] S101, Obtain the well logging data of the injection well and the water intake profile data of other injection wells in the area where the injection well is located;

[0064] When acquiring water absorption profile data, it is necessary to shut down the well and stop production for measurement. Furthermore, the testing cycle is long, and the obtained water absorption profile data may be limited and discontinuous. In such cases, the prediction results based on the acquired water absorption profile data may be inaccurate. However, in this embodiment, by acquiring water absorption profile data from other injection wells in the same area as the injection well, and combining this data with well logging data, the water absorption results of multiple sub-layers within the injection well can be assessed. This can compensate for the possibility of limited or discontinuous water absorption profile data for the injection well to be predicted.

[0065] S102. Based on the well logging data, obtain the formation physical parameters of the sub-layer. The formation physical parameters include resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content.

[0066] Well logging data is obtained from well logging tests of water injection wells. It can accurately reflect the physical properties of the formation at the water injection well. In this embodiment, resistivity, sonic transit time, density, porosity, permeability, oil saturation and clay content of the formation physical parameters were selected to analyze the sublayer.

[0067] S103, based on the water absorption profile data of other water injection wells in the area where the water injection well is located, obtain the single-factor water absorption probability corresponding to each formation physical parameter in the area where the water injection well is located. The single-factor water absorption probability is used to characterize the influence of each formation physical parameter on the water absorption of the middle and lower layers of the water injection well.

[0068] By using the water absorption profile data of other water injection wells in the same area, we can obtain the single-factor water absorption probability corresponding to each formation property parameter in the sub-layer of other water injection wells. The single-factor water absorption probability can reflect the influence of each formation property parameter on the water absorption of the sub-layer.

[0069] S104. Based on the single-factor water absorption probability corresponding to the physical property parameters of each formation in the area where the injection well is located and the physical property parameters of the formation of the sub-layer, obtain the comprehensive evaluation index value of the sub-layer.

[0070] The comprehensive evaluation index value of this sub-layer is obtained by using the single-factor water absorption probability corresponding to each formation physical parameter of the sub-layer. The single-factor water absorption probability reflects the influence of each formation physical parameter on the water absorption of the sub-layer. By combining the single-factor water absorption probabilities, the comprehensive evaluation value can reflect the water absorption of the sub-layer.

[0071] S105, Based on the comprehensive evaluation index values, determine the water absorption result of the sublayer.

[0072] By comprehensively evaluating the numerical values ​​of the indicators, the water absorption results of the sub-layer are judged. The obtained water absorption results can reflect the water absorption situation of the sub-layer in the injection well. Based on the prediction results, the basic guidance can be provided for the effective water injection of the injection well and the rational water injection development of the oilfield.

[0073] In this embodiment, after dividing the injection well into multiple sub-layers, when judging one of the sub-layers, the formation physical parameters of each sub-layer are first obtained through well logging data; then, the single-factor water absorption probability corresponding to each formation physical parameter is obtained through water absorption profile data of other injection wells in the same area as the injection well; combining the formation physical parameters and the corresponding single-factor water absorption probabilities of the sub-layer, a comprehensive evaluation index value can be obtained. The comprehensive evaluation index value can reflect the water absorption result of the sub-layer, thus completing the judgment of the water absorption result of the sub-layer; during the judgment process, since the single-factor water absorption probability corresponding to each formation physical parameter of the sub-layer is obtained through water absorption profile data of other injection wells in the same area as the injection well, the incompleteness or discontinuity of the water absorption profile data will not affect the judgment of the water absorption result of the sub-layer, achieving the effect of judging the water absorption result of injection well sub-layers with limited and discontinuous water absorption profile data.

[0074] Example 2

[0075] Reference Figure 1 This document illustrates a flowchart of a method for determining water-absorbing sub-layers in injection wells of low-permeability sandstone oil reservoirs, as described in an embodiment of the present invention. The injection wells are vertically divided into multiple sub-layers, and the following method is performed for each sub-layer. The method may specifically include the following steps:

[0076] S101, Obtain the well logging data of the injection well and the water intake profile data of other injection wells in the area where the injection well is located.

[0077] In the development of water injection wells, logging data is obtained in the early stages of development through logging. Logging is used during the exploration and extraction of oil to measure the physical parameters of the rock formations downhole and the technical condition of the well, and to analyze the recorded data for geological and engineering studies of the water injection well. In this embodiment, perforation logging is used. Water absorption profile data is obtained through water absorption profile testing. By conducting water absorption profile testing, the water absorption situation of each sub-layer in the water injection well can be understood.

[0078] Normally, water absorption profile data is sufficient to determine the water absorption status of the smaller layers in a water injection well. However, in this embodiment, the water absorption profile data is limited and discontinuous. If the water absorption profile data of a water injection well is limited or discontinuous, it is not possible to determine the water absorption status of the smaller layers in the well based solely on the water absorption profile data. Therefore, when making a judgment, it is necessary to combine the well logging data of the water injection well with the water absorption profile data of other water injection wells in the same area as the water injection well.

[0079] S102. Based on the well logging data, obtain the formation physical parameters of the sub-layer. The formation physical parameters include resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content.

[0080] This sub-layer is one of the sub-layers within the water injection well after vertical division. The formation physical parameters are obtained through well logging data. By logging the water injection well, various formation physical parameters can be obtained from the logging results. These parameters can reflect the formation conditions at each sub-layer within the water injection well. In this embodiment, the seven formation physical parameters selected—resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content—all affect the water absorption of the sub-layer. This embodiment judges the water absorption results of the sub-layer by combining these seven formation physical parameters from the well logging data.

[0081] S103, based on the water absorption profile data of other water injection wells in the area where the water injection well is located, obtain the single-factor water absorption probability corresponding to each formation physical parameter in the area where the water injection well is located. The single-factor water absorption probability is used to characterize the influence of each formation physical parameter on the water absorption of the middle and lower layers of the water injection well.

[0082] In the area where the injection well is located, there are multiple injection wells, and these multiple injection wells are mostly the same in terms of formation physical parameters, and there will not be significant differences.

[0083] The method of obtaining the single-factor water absorption probability corresponding to each formation property parameter in the area where the injection well is located, based on the water absorption profile data of other injection wells in the area, includes:

[0084] The water intake profile data of the injection wells are screened, including:

[0085] Select and retain the water intake profile data corresponding to water injection wells that did not undergo formation modification measures before water injection;

[0086] If the strata in the area where the injection well is located have been modified before the injection, the obtained water absorption profile data will not accurately reflect the strata in the area where the injection well is located, which will cause deviation. Therefore, this part of the water absorption profile data needs to be screened and removed to avoid affecting the judgment of the water absorption results of the sublayer.

[0087] Select and retain the water intake profile data of water injection wells that have not undergone fracturing measures before the water intake profile test;

[0088] Fracturing involves using a surface high-pressure pump unit to inject a high-viscosity fluid into a water injection well at a rate far exceeding the formation's absorption capacity. This creates high pressure at the bottom of the well. When this pressure exceeds the in-situ stress near the well wall and the tensile strength of the formation rock, fractures are generated in the formation near the well bottom. Continued injection of proppant-laden fluid causes the fractures to extend forward and fill with proppant. After the well is closed, the fractures close on the proppant, thus forming a sand-filled fracture with specific geometric dimensions and high conductivity in the formation near the well bottom, achieving the goal of increasing water production and injection. However, if a small layer within the water injection well undergoes fracturing, the formation containing that small layer will develop fractures. This will result in discrepancies between the obtained water absorption profile data and the obtained well logging data, failing to accurately reflect the formation conditions of each small layer within the water injection well. Therefore, it is necessary to filter and discard this portion of the water absorption profile data.

[0089] Water intake profile data for injection wells in perforated sections with known formation properties were selected and retained.

[0090] If the formation properties of a sub-layer are missing, the water absorption profile data for that part cannot be combined with the obtained well logging data. This part of the water absorption profile data cannot be used in the method provided in this embodiment. Therefore, only the water absorption profile data corresponding to the injection wells for which all formation properties of each sub-layer in the perforated section are known are selected and retained.

[0091] The values ​​of each of the aforementioned formation physical parameters are divided into multiple numerical segments;

[0092] like Figure 2 As shown, Figure 2 The numerical division of porosity is shown, where the porosity ranges from 2% to 24%. When dividing, it starts from 2% and divides into numerical segments every 2% for a total of 11 numerical segments.

[0093] Based on the screening results, the number of water-absorbing sublayers and the number of non-water-absorbing sublayers in each numerical range of each formation physical property parameter are obtained.

[0094] After dividing the porosity into numerical ranges, and based on the screening results of water absorption profile data from other injection wells in the injection well area, it is possible to statistically obtain data such as... Figure 2 The diagram shows the number of absorbent and non-absorbent sublayers.

[0095] Based on the number of water-absorbing and non-water-absorbing sublayers in each numerical segment of each of the aforementioned formation physical parameters, the single-factor water absorption probability corresponding to each formation physical parameter in each numerical segment is obtained.

[0096] The following formula is used to determine it:

[0097]

[0098] In the formula, Δf is the single-factor water absorption probability; S1 is the number of water-absorbing sublayers in each numerical segment; and S2 is the number of non-water-absorbing sublayers in each numerical segment.

[0099] like Figure 2 As shown, in the numerical range of 2%-4% porosity, the number of water-absorbing sublayers is 3 and the number of non-water-absorbing sublayers is 2. Therefore, the single-factor water absorption probability in the 2%-4% porosity range is 60%. Based on the above method, the single-factor water absorption probability in all numerical ranges is calculated.

[0100] S104. Based on the single-factor water absorption probability corresponding to the physical property parameters of each formation in the area where the injection well is located and the physical property parameters of the formation of the sub-layer, obtain the comprehensive evaluation index value of the sub-layer.

[0101] Based on the single-factor water absorption probability corresponding to each formation physical parameter in each numerical range, a fitting formula for each formation physical parameter is obtained. The fitting formula is used to characterize the relationship between the single-factor water absorption probability and each formation physical parameter.

[0102] like Figure 3 As shown, Figure 3The single-factor water absorption probability corresponding to porosity in various numerical ranges is shown. In this embodiment, the formation physical parameters used include resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content. After calculating the single-factor water absorption probability corresponding to each of these seven formation physical parameters in various numerical ranges, fitting curves of the relationship between the water absorption probability and parameter values ​​of these seven formation physical parameters are plotted to obtain the fitting formulas corresponding to these seven formation physical parameters.

[0103] The fitting formulas include:

[0104] Porosity fitting formula:

[0105] Permeability fitting formula: f2 = 0.0508lnK + 0.4772;

[0106] Oil saturation fitting formula: f3 = 0.0044S o +0.3311;

[0107] The fitting formula for clay content is: f4 = 0.0239NR + 0.7612;

[0108] Resistivity fitting formula: f5 = 0.0172R + 0.2764;

[0109] Acoustic time difference fitting formula: f6=0.0043AC-0.6589;

[0110] Density fitting formula: f7 = -0.1347DEN + 0.7388;

[0111] In the formula, f1 is the single-factor probability of porosity; f2 is the single-factor probability of permeability; f3 is the single-factor probability of oil saturation; f4 is the single-factor probability of clay content; f5 is the single-factor probability of resistivity; f6 is the single-factor probability of acoustic transit time; f7 is the single-factor probability of density; φ is porosity; K is permeability; S o 1 represents oil saturation; NR represents clay content; R represents resistivity; AC represents acoustic transit time; and DEN represents density.

[0112] Based on the fitting formula, the single-factor water absorption probability corresponding to the physical property parameters of each stratum in the sub-layer is obtained.

[0113] When calculating the single-factor water absorption probability corresponding to each formation property parameter of the sub-layer, the formation property parameters of the sub-layer are first obtained through well logging data. Then, each formation property parameter is substituted into the fitting formula of the formation property parameter to obtain the single-factor water absorption probability of each formation property parameter of the sub-layer.

[0114] Obtain a comprehensive evaluation table for the sublayer, which is used to characterize the relationship between the single-factor water absorption probability of the sublayer and the comprehensive evaluation index value of the sublayer;

[0115] In this embodiment, the comprehensive evaluation table for the sub-layer is shown in the following table:

[0116] probability / % Fraction S <30 0 30-40 2 40-50 4 50-60 8 60-70 16 >70 32

[0117] Based on the comprehensive evaluation table of the sublayer and the single-factor water absorption probability, the comprehensive evaluation index value of the sublayer is obtained.

[0118] The single-factor water absorption probability of each formation property parameter in the sub-layer is obtained, and then the single-factor water absorption probability of each formation property parameter in the sub-layer is substituted into the table to obtain the comprehensive evaluation index value of each formation property parameter.

[0119] S105, Based on the comprehensive evaluation index values, determine the water absorption result of this sublayer. This includes:

[0120] Obtain the average value of the comprehensive evaluation index of all sub-layers in the injection well;

[0121] The injection well is vertically divided into multiple sub-layers. After obtaining the comprehensive evaluation index values ​​of all sub-layers in the injection well through the above step S103, the comprehensive evaluation index values ​​of all sub-layers in the injection well are added together and divided by the number of sub-layers in the injection well to obtain the average value of the comprehensive evaluation index values ​​of all sub-layers in the injection well.

[0122] like Figure 4 As shown, Figure 4 The diagram shows the comprehensive evaluation index values ​​for multiple sub-layers of one injection well. Injection well NP43-4829 is divided into 15 sub-layers, numbered 1-15. Its comprehensive evaluation index values ​​are shown in Figure 4. The average value for this injection well is the sum of the comprehensive evaluation index values ​​for these 15 sub-layers, divided by 15.

[0123] Based on the average value and the comprehensive evaluation index value, the water absorption result of the sublayer is determined.

[0124] If the average value of the sublayer is greater than the value of the comprehensive evaluation index, then the water absorption result of the sublayer is a non-absorbent sublayer.

[0125] If the average value of the sublayer is less than or equal to the value of the comprehensive evaluation index, then the water absorption result of the sublayer is a water-absorbing sublayer.

[0126] After obtaining the average value and comprehensive evaluation index value of each sub-layer in the injection well, the water absorption result of that sub-layer can be obtained by comparing the average value of each sub-layer with the comprehensive evaluation index value.

[0127] like Figure 5 As shown, Figure 5 This shows the judgment of water absorption results in multiple sub-layers of one of the injection wells; in Figure 5 In the determination of the effectiveness of the water-absorbing sublayer, the predicted water absorption result is the sublayer water absorption result obtained by the method in this embodiment, while the actual measured water absorption result is the sublayer water absorption result obtained by the on-site measurement method. By comparison, it can be seen that the sublayer water absorption result predicted by this method is small in difference from the actual measured sublayer water absorption result, indicating that the method provided in this embodiment is effective for predicting the water absorption result of the sublayer in the injection well.

[0128] In this embodiment, after dividing the injection well into multiple sub-layers, when judging one of the sub-layers, the formation physical parameters of each sub-layer are first obtained through well logging data; then, the single-factor water absorption probability corresponding to each formation physical parameter is obtained through water absorption profile data of other injection wells in the same area as the injection well; combining the formation physical parameters and the corresponding single-factor water absorption probabilities of the sub-layer, a comprehensive evaluation index value can be obtained. The comprehensive evaluation index value can reflect the water absorption result of the sub-layer, thus completing the judgment of the water absorption result of the sub-layer; during the judgment process, since the single-factor water absorption probability corresponding to each formation physical parameter of the sub-layer is obtained through water absorption profile data of other injection wells in the same area as the injection well, the incompleteness or discontinuity of the water absorption profile data will not affect the judgment of the water absorption result of the sub-layer, achieving the effect of judging the water absorption result of injection well sub-layers with limited and discontinuous water absorption profile data.

[0129] Example 3

[0130] Based on the same inventive concept Figure 6 The diagram shown is a structural schematic of a device for determining the water absorption layer in an injection well of a low-permeability sandstone oil reservoir. (Refer to...) Figure 6 It includes: a data acquisition module, a parameter acquisition module, a probability acquisition module, an indicator acquisition module, and a judgment module, among which,

[0131] The data acquisition module is used to acquire the logging data of the injection well and the water intake profile data of other injection wells in the area where the injection well is located;

[0132] The parameter acquisition module is used to acquire the formation physical parameters of the sub-layer based on the well logging data. The formation physical parameters include resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content.

[0133] The probability acquisition module is used to acquire the single-factor water absorption probability corresponding to each formation property parameter in the area where the water injection well is located, based on the water absorption profile data of other water injection wells in the area where the water injection well is located. The single-factor water absorption probability is used to characterize the influence of each formation property parameter on the water absorption of the middle and lower layers of the water injection well.

[0134] The index acquisition module obtains the comprehensive evaluation index value of the sub-layer based on the single-factor water absorption probability corresponding to the physical property parameters of each stratum in the area where the injection well is located and the physical property parameters of the sub-layer.

[0135] The judgment module is used to determine the water absorption result of the sublayer based on the value of the comprehensive evaluation index.

[0136] Example 4

[0137] Based on the same inventive concept, Embodiment 4 of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the steps of the method for determining the water absorption layer of a water injection well in a low-permeability sandstone reservoir as described in any one of Embodiments 1 and 2.

[0138] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0139] Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus, or computer program products. Therefore, embodiments of this application can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of this application can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0140] This application describes embodiments with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1A device that provides the functions specified in one or more boxes.

[0141] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0142] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal equipment, causing a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0143] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0144] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0145] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for judging water intake subzone of a water injection well of a low permeability sandstone reservoir, characterized by, The injection well is longitudinally divided into multiple sub-layers, and the following method is performed for each sub-layer: Obtain logging data of the injection well and water intake profile data of other injection wells in the area where the injection well is located; Based on the well logging data, the formation physical parameters of the sub-layer are obtained, including resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content. Based on the water absorption profile data of other water injection wells in the area where the water injection well is located, the single-factor water absorption probability corresponding to each formation physical parameter in the area where the water injection well is located is obtained. The single-factor water absorption probability is used to characterize the influence of each formation physical parameter on the water absorption of the middle and lower layers of the water injection well. Based on the single-factor water absorption probability corresponding to the physical properties of each formation in the area where the injection well is located and the physical properties of the formation of the sub-layer, the comprehensive evaluation index value of the sub-layer is obtained. Based on the comprehensive evaluation index values, the water absorption result of this sublayer is determined; The method of obtaining the single-factor water absorption probability corresponding to each formation property parameter in the area where the injection well is located, based on the water absorption profile data of other injection wells in the area, includes: The water intake profile data of other water injection wells in the area where the aforementioned water injection well is located are screened; The values ​​of each of the aforementioned formation physical parameters are divided into multiple numerical segments; Based on the screening results, the number of water-absorbing sublayers and the number of non-water-absorbing sublayers in each numerical range of each of the aforementioned formation physical property parameters are obtained. Based on the number of water-absorbing and non-water-absorbing sublayers in each numerical segment of each of the formation physical parameters, the single-factor water absorption probability corresponding to each formation physical parameter in each numerical segment is obtained. The process of obtaining the comprehensive evaluation index value of a sub-layer based on the single-factor water absorption probability corresponding to the formation properties of each formation in the area where the injection well is located and the formation properties of that sub-layer includes: Based on the single-factor water absorption probability corresponding to each formation physical parameter in each numerical range, a fitting formula for each formation physical parameter is obtained. The fitting formula is used to characterize the relationship between the single-factor water absorption probability and each formation physical parameter. Based on the fitting formula, the single-factor water absorption probability corresponding to the physical property parameters of each stratum in the sub-layer is obtained. Obtain a comprehensive evaluation table for a sub-layer. The comprehensive evaluation table for a sub-layer is used to characterize the relationship between the single-factor water absorption probability corresponding to each formation physical parameter of the sub-layer and the comprehensive evaluation index value of the sub-layer. Based on the comprehensive evaluation table of the sublayer and the single-factor water absorption probability corresponding to each stratum physical property parameter of the sublayer, the comprehensive evaluation index value of the sublayer is obtained.

2. The method of claim 1, wherein, The determination of the water absorption result of the sublayer based on the comprehensive evaluation index value includes: Obtain the average value of the comprehensive evaluation index of all sub-layers in the injection well; Based on the average value and the comprehensive evaluation index value, the water absorption result of the sublayer is determined.

3. The method of claim 1, wherein, The screening of water intake profile data from other water injection wells in the area where the injection well is located includes: Select and retain the water intake profile data corresponding to water injection wells that did not undergo formation modification measures before water injection; Select and retain the water intake profile data of water injection wells that have not undergone fracturing measures before the water intake profile test; Water intake profile data for injection wells in perforated sections with known formation properties were selected and retained.

4. The method of claim 3, wherein, The method of obtaining the single-factor water absorption probability corresponding to each formation physical parameter in each numerical segment based on the number of water-absorbing and non-water-absorbing sublayers in each numerical segment includes: The following formula is used to determine it: ； wherein is the single factor water absorption probability; is the number of water-absorbing small particles for each value segment; is the number of non-water-absorbing small particles for each value segment.

5. The method according to claim 1, characterized in that, The fitting formula includes: Porosity fitting formula: ; Permeability fitting formula: ; Oil saturation fitting formula: ; Formula for fitting clay content: ; Resistivity fitting formula: ; Formula for fitting acoustic time difference: ; Density fitting formula: ; In the formula, f1 is the single-factor probability of porosity; The single-factor probability of penetration rate; The single-factor probability of oil saturation; The single-factor probability of mud content; The single-factor probability of resistivity; The single-factor probability of the sound wave time difference; The single-factor probability of density; Porosity; For penetration rate; Oil saturation; The content of clay; Resistivity; For sound wave time difference; For density.

6. The method according to claim 2, characterized in that, The step of determining the water absorption result of the sublayer based on the average value and the comprehensive evaluation index value includes: If the average value of the sublayer is greater than the value of the comprehensive evaluation index, then the water absorption result of the sublayer is a non-absorbent sublayer. If the average value of the sublayer is less than or equal to the value of the comprehensive evaluation index, then the water absorption result of the sublayer is a water-absorbing sublayer.

7. A device for determining the water absorption layer in injection wells of low-permeability sandstone oil reservoirs, characterized in that, include: The module includes a data acquisition module, a parameter acquisition module, a probability acquisition module, an indicator acquisition module, and a judgment module. The data acquisition module is used to acquire the logging data of the injection well and the water intake profile data of other injection wells in the area where the injection well is located; The parameter acquisition module is used to acquire the formation physical parameters of the sub-layer based on the well logging data. The formation physical parameters include resistivity, sonic transit time, density, porosity, permeability, oil saturation, and clay content. The probability acquisition module is used to acquire the single-factor water absorption probability corresponding to each formation property parameter in the area where the water injection well is located, based on the water absorption profile data of other water injection wells in the area where the water injection well is located. The single-factor water absorption probability is used to characterize the influence of each formation property parameter on the water absorption of the middle and lower layers of the water injection well. The index acquisition module obtains the comprehensive evaluation index value of the sub-layer based on the single-factor water absorption probability corresponding to the physical property parameters of each stratum in the area where the injection well is located and the physical property parameters of the sub-layer. The judgment module is used to determine the water absorption result of the sublayer based on the value of the comprehensive evaluation index. The probability acquisition module includes: The water intake profile data of other water injection wells in the area where the aforementioned water injection well is located are screened; The values ​​of each of the aforementioned formation physical parameters are divided into multiple numerical segments; Based on the screening results, the number of water-absorbing sublayers and the number of non-water-absorbing sublayers in each numerical range of each of the aforementioned formation physical property parameters are obtained. Based on the number of water-absorbing and non-water-absorbing sublayers in each numerical segment of each of the formation physical parameters, the single-factor water absorption probability corresponding to each formation physical parameter in each numerical segment is obtained. The indicator acquisition module includes: Based on the single-factor water absorption probability corresponding to each formation physical parameter in each numerical range, a fitting formula for each formation physical parameter is obtained. The fitting formula is used to characterize the relationship between the single-factor water absorption probability and each formation physical parameter. Based on the fitting formula, the single-factor water absorption probability corresponding to the physical property parameters of each stratum in the sub-layer is obtained. Obtain a comprehensive evaluation table for a sub-layer. The comprehensive evaluation table for a sub-layer is used to characterize the relationship between the single-factor water absorption probability corresponding to each formation physical parameter of the sub-layer and the comprehensive evaluation index value of the sub-layer. Based on the comprehensive evaluation table of the sublayer and the single-factor water absorption probability corresponding to each stratum physical property parameter of the sublayer, the comprehensive evaluation index value of the sublayer is obtained.

8. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method of any one of claims 1 to 6.

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