Method and device for determining residual oil distribution

Abstract

The present disclosure provides a method for determining the distribution of residual oil, which belongs to the technical field of oil and gas field development. The determination method comprises: determining the stratified residual oil saturation of each oil production layer of the oil production well and the stratified residual oil saturation of each water injection layer of the water injection well; and determining the distribution of residual oil in the work area based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well. The present disclosure can improve the accuracy of the prediction of the distribution of residual oil in the work area through the determination method.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas field development, and in particular relates to a method and device for determining residual oil distribution. Background Art

[0002] Residual oil is the remaining movable crude oil, which refers to the underground movable crude oil that cannot be extracted temporarily under the existing mining technology conditions. During the development of oil fields, the movable crude oil remaining underground still accounts for a large proportion, and in many cases, it is even comparable to the cumulative oil produced. After long-term water injection development of oil fields, the distribution of residual oil is very complicated, which leads to great difficulties in later production. Therefore, quantitative analysis of the distribution of residual oil is an important measure to improve oil recovery.

[0003] In the related technologies, the main method for determining the distribution of the remaining oil in the oil field is the oil field dynamic monitoring technology. The so-called oil field dynamic monitoring is to use various instruments and meters, adopt different testing means and measurement methods to measure the dynamic and static data of the oil reservoir during the oil field development process. Then, based on the relevant data, the distribution of the remaining oil in the oil field is predicted.

[0004] However, due to the different mining histories of the oil wells put into development in the oil field, the complex geological conditions, and the many factors that restrict the collection of data during the oil field development process, the dynamic monitoring data of the oil field is incomplete and the accuracy of the remaining oil distribution prediction is low. Summary of the invention

[0005] The embodiment of the present disclosure provides a method for determining the residual oil distribution, which can improve the accuracy of predicting the distribution position of the residual oil in the work area. The technical solution is as follows:

[0006] The embodiment of the present disclosure provides a method for determining the distribution of residual oil, which is used to determine the distribution of residual oil in a work area, wherein at least one water injection well and multiple oil production wells are arranged in the work area, wherein the water injection well includes multiple water injection layers, and the oil production well includes multiple oil production layers, and each oil production layer of the oil production well is connected to a water injection layer of at least one of the water injection wells; the determination method comprises:

[0007] Determining the stratified residual oil saturation of each oil-producing layer of the oil production well and the stratified residual oil saturation of each water injection layer of the water injection well;

[0008] The distribution of the remaining oil in the work area is determined based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well.

[0009] In another implementation of the present disclosure, the determining of the stratified residual oil saturation of each oil producing layer of the oil producing well includes:

[0010] Determine the seepage resistance coefficient of each water injection layer of the target water injection well in multiple directions, wherein the multiple directions include directions from the water injection layer of the target water injection well to the oil production layers of multiple oil production wells connected to the water injection layer, and the target water injection well is one of the at least one water injection well;

[0011] The stratified residual oil saturation of each of the oil production wells is determined according to the seepage resistance coefficient and the daily water injection volume of the target water injection well.

[0012] In another implementation of the present disclosure, determining the seepage resistance coefficient of each water injection layer of the target water injection well in multiple directions includes:

[0013] The seepage resistance coefficient is determined by the following formula:

[0014]

[0015] Among them, R ij μ is the seepage resistance coefficient from the i-th water injection layer of the target water injection well to the j-th oil production well connected to the i-th water injection layer; o is the viscosity of crude oil; L j M is the well distance between the jth oil production well connected to the i-th water injection layer of the target water injection well and the target water injection well; ij is the transformation measure coefficient between the i-th water injection layer of the target water injection well and the j-th oil production well connected to the i-th water injection layer; H ij is the effective sandstone thickness of the oil production layer of the jth oil production well connected to the i-th water injection layer of the water injection well; K ij is the effective permeability between the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer; Z ij It is the connectivity coefficient between the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer.

[0016] In another implementation of the present disclosure, determining the stratified residual oil saturation of each of the oil production wells according to the seepage resistance coefficient and the daily water injection volume of the water injection well includes:

[0017] Determining the vertical splitting coefficient of the target water injection well according to the seepage resistance coefficient;

[0018] According to the daily water injection volume and the vertical splitting coefficient, the layered water injection volume of each water injection layer of the target water injection well is obtained;

[0019] Determining the plane distribution coefficient of the oil production well connected to each water injection layer of the water injection well according to the seepage resistance coefficient;

[0020] According to the plane distribution coefficient of the oil production well and the stratified water injection volume of the water injection well, the stratified water injection volume of the oil production well is obtained;

[0021] Based on the stratified water injection volume of the oil production well, obtaining the stratified liquid production volume of the oil production well;

[0022] Determining the stratified oil production of the oil production well according to the stratified liquid production of the oil production well;

[0023] The layered residual oil saturation of the oil production well is determined according to the layered oil production of the oil production well.

[0024] In another implementation of the present disclosure, determining the vertical splitting coefficient of the water injection well according to the seepage resistance coefficient includes:

[0025] The vertical splitting coefficient of the water injection well is determined by the following formula:

[0026]

[0027] Where i represents the i-th injection layer of the target injection well; C i is the vertical splitting coefficient of the i-th injection layer of the target injection well; M i is the transformation measure coefficient of the i-th injection layer of the target injection well; H i is the effective sandstone thickness of the i-th injection layer of the target injection well; K i is the effective permeability of the i-th injection layer of the target injection well; m is the number of oil production wells connected to the i-th injection layer of the target injection well; n is the number of injection layers used by the target injection well; j represents the j-th oil production well connected to the i-th injection layer of the target injection well; R ij It is the seepage resistance coefficient in the direction from the i-th water injection layer of the target water injection well to the j-th oil production well connected to the i-th water injection layer.

[0028] In another implementation of the present disclosure, the determining of the stratified residual oil saturation of each water injection layer of the water injection well includes:

[0029] Determining the pore volume of each injection layer of the injection well;

[0030] According to the pore volume of each water injection layer of the water injection well, determining the relationship function between the water injection multiple and the decrease value of oil saturation of each water injection layer;

[0031] According to the relationship function and the water injection multiple of each water injection layer of the water injection well, the oil saturation reduction value of the water injection well in different water injection layers is obtained;

[0032] Determine the oil saturation and physical residual oil saturation of each injection layer of the injection well;

[0033] The stratified residual oil saturation of each water injection layer of the water injection well is obtained according to the oil saturation decrease value, the drilled oil saturation and the physical residual oil saturation.

[0034] In another implementation of the present disclosure, the determining the distribution of the residual oil in the work area based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well includes:

[0035] According to the layered residual oil saturation of the water injection well and the layered residual oil saturation of the oil production well, a residual oil saturation distribution map of each oil production layer in the work area is obtained;

[0036] Determining the average value of the residual oil saturation of each oil-producing layer in the work area according to the residual oil saturation distribution map of the work area;

[0037] In the residual oil saturation distribution map of each oil-producing layer, the position corresponding to the residual oil saturation greater than the average value of the residual oil saturation is regarded as the position where the residual oil exists.

[0038] In another implementation of the present disclosure, a residual oil determination device is also provided, the determination device comprising:

[0039] A layered residual oil saturation determination module, used to determine the layered residual oil saturation of each oil production layer of the oil production well and the layered residual oil saturation of each water injection layer of the water injection well;

[0040] The residual oil distribution determination module is used to determine the distribution of the residual oil in the work area based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well.

[0041] In yet another implementation of the present disclosure, a computer device is provided. The computer device includes a processor and a memory configured to store instructions executable by the processor. The processor is configured to execute the above-mentioned method for determining the remaining oil distribution.

[0042] In yet another implementation of the present disclosure, a computer storage medium is provided, on which computer instructions are stored. When the computer instructions are executed by a processor, the above-mentioned method for determining the residual oil distribution is implemented.

[0043] The technical solution provided by the embodiments of the present disclosure brings the following beneficial effects:

[0044] The method for determining the residual oil distribution provided by the embodiment of the present disclosure is used to determine the distribution of residual oil in a certain work area. The residual oil saturation of all oil production wells and water injection wells in the work area is used as a basis to scientifically determine the distribution of residual oil, which can greatly improve the accuracy of judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 is a schematic diagram of a well group in a certain work area provided by an embodiment of the present disclosure;

[0047] Figure 2 is a flow chart of a method for determining residual oil distribution provided by an embodiment of the present disclosure;

[0048] Figure 3 is a flow chart of another method for determining residual oil distribution provided by an embodiment of the present disclosure;

[0049] Figure 4 is a graph showing the relationship between water saturation and relative permeability provided by an embodiment of the present disclosure;

[0050] Figure 5 is a function of the relationship between water saturation and recovery degree provided in the embodiment of the present disclosure;

[0051] Figure 6 is a relationship diagram between the decrease value of oil saturation and the water injection multiple provided in the embodiment of the present disclosure;

[0052] Figure 7 is a structural schematic diagram of a device for determining residual oil distribution provided by an embodiment of the present disclosure;

[0053] Figure 8 It is a structural diagram of a computer device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0054] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0055] In order to clearly illustrate the remaining oil determination method provided by the embodiment of the present disclosure, the arrangement relationship between the water injection wells and the oil production wells in the oil field and some related terms are first introduced.

[0056] After an oil field is put into production, as the exploitation time increases, the energy of the oil layer itself will be continuously consumed, which will cause the pressure of the oil-producing layer to continue to drop. The drop in the pressure of the oil-producing layer will cause a large amount of underground crude oil to degas and increase viscosity, which will greatly reduce the output of the oil field. In order to maintain or increase the pressure of the oil-producing layer and achieve high and stable production of the oil field, it is necessary to inject water into the oil-producing layer. Among them, during the production process of the oil field, water can be injected into the oil-producing layer of the oil well through a water injection well.

[0057] Specifically, each water injection well can be connected to at least one oil production well. The water injected into the water injection well can flow into the oil production well connected to the water injection well. Each water injection well includes multiple water injection layers, and correspondingly, each oil production well includes multiple oil production layers, and the oil production layers of each oil production well are interconnected with a water injection layer of at least one water injection well. In other words, one of the oil production layers of an oil production well can be connected one-to-one with the water injection layers of multiple water injection wells at the same time, and one of the oil production layers of an oil production well can be connected with the water injection layer of a water injection well.

[0058] For example, see Figure 1 In the figure, O is a water injection well, which uses the No. 1 and No. 2 water injection layers. A, B, C, and D are oil production wells connected to the water injection well O. The A, B, and D oil production wells and the water injection wells use the No. 1 and No. 2 production layers respectively. Well C uses the No. 2 production layer.

[0059] Since each water injection well is connected to at least one oil production well, the water injection volume in the water injection well will be split to different water injection layers, and then split to different oil production wells. Splitting refers to the amount of water injection allocated to different oil production wells. The splitting coefficient is the proportional coefficient of the allocated water injection volume.

[0060] As the energy of oil layer is exhausted during oil field development, there will still be crude oil in the pores of the formation even after water injection. This oil is called residual oil.

[0061] The embodiment of the present disclosure provides a method for determining the distribution of residual oil, which is used to determine the distribution of residual oil in a work area, where at least one water injection well and multiple oil production wells are arranged. Figure 2 As shown, the method for determining the remaining oil distribution includes:

[0062] S201: Determine the stratified residual oil saturation of each oil-producing layer of the oil production well and the stratified residual oil saturation of each water injection layer of the water injection well.

[0063] The residual oil saturation is the ratio of the residual oil volume to the pore volume. The stratified residual oil saturation is the percentage of the volume of the rock pores in each production layer or water injection layer corresponding to the production layer.

[0064] S202: Determine the distribution of the remaining oil in the work area based on the stratified remaining oil saturation of the oil production well and the stratified remaining oil saturation of the water injection well.

[0065] The method for determining the residual oil distribution provided by the embodiment of the present disclosure is used to determine the distribution of residual oil in a certain work area. The residual oil saturation of all oil production wells and water injection wells in the work area is used as a basis to scientifically determine the distribution of residual oil, which can greatly improve the accuracy of judgment.

[0066] Figure 3 is a flow chart of another method for determining residual oil distribution provided by an embodiment of the present disclosure, combined with Figure 3 , the determination method includes:

[0067] S301: Determine the stratified residual oil saturation of each production layer of the oil production well.

[0068] Step S301 includes:

[0069] 3011: Determine the seepage resistance coefficient of each injection layer of the target water injection well in multiple directions, the multiple directions include the direction from the injection layer of the target water injection well to the oil production layers of multiple oil production wells connected to the water injection layer, and the target water injection well is one of at least one water injection well arranged in the work area.

[0070] Since each water injection well is connected to multiple oil production wells, the water injected by the water injection well can flow to each oil production well connected to the water injection well. However, due to the different geological structures in different directions, the resistance encountered by the water in each water injection well when flowing to the surrounding connected production wells is also different.

[0071] The seepage resistance coefficient is used to indicate the ability of soil or cracked rock to hinder water flow. The larger the seepage resistance coefficient, the greater the resistance to water flow.

[0072] In this embodiment, step 3011 is obtained by the following formula:

[0073]

[0074] Among them, R ij is the seepage resistance coefficient from the i-th injection layer of the target injection well to the j-th oil production well connected to the i-th injection layer; μ o is the viscosity of crude oil; L j M is the distance between the jth oil production well connected to the i-th water injection layer of the target water injection well and the target water injection well; ij is the transformation measure coefficient between the i-th injection layer of the target injection well and the j-th oil production well connected to the i-th injection layer; H ijK is the effective sandstone thickness of the oil production layer of the jth oil production well connected to the i-th water injection layer of the water injection well; ij is the effective permeability between the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer; Z ij It is the connectivity coefficient between the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer.

[0075] The connectivity coefficient in the above formula (1) represents the connectivity between the target water injection well and the surrounding oil production wells, and is a dimensionless relative value. The connectivity coefficient Z is mainly related to geological factors such as sedimentary phase, permeability, and faults. The connectivity coefficient can be calculated using the following formula (2):

[0076]

[0077] Where Z is the connectivity coefficient, V is the development volume of the i-th injection layer of the target injection well, which can be calculated by the following formula (3); V max It is the maximum value of the development volume in the oil production wells connected to the i-th injection layer of the target injection well.

[0078]

[0079] Among them, H o H is the effective sandstone thickness of the oil production layer of the oil production well connected to the i-th water injection layer of the target water injection well; w is the effective sandstone thickness of the i-th injection layer of the target injection well; K o K is the effective permeability of the oil production layer of the oil production well connected to the i-th water injection layer of the target water injection well; w is the effective permeability of the i-th injection layer of the target injection well; L is the well distance between the j-th oil production well connected to the i-th injection layer of the target injection well and the target injection well; F is the microfacies parameter. If the connectivity is very good, the microfacies coefficient F is 1, and if the connectivity is poor, the microfacies coefficient F is 0.5.

[0080] 3012: Determine the stratified residual oil saturation of each oil production well based on the seepage resistance coefficient and the daily water injection volume of the target injection well.

[0081] In this embodiment, step 3012 includes:

[0082] (1) Determine the vertical splitting coefficient of the target injection well based on the seepage resistance coefficient.

[0083] The vertical split coefficient refers to the coefficient of the water injection volume allocated to each injection layer in the injection well. In other words, the proportion of water volume in each injection layer to the water injection volume of the injection well.

[0084] In this embodiment, the vertical splitting coefficient of the water injection well is determined by the following formula.

[0085]

[0086] Where i represents the i-th injection layer of the target injection well; C i is the vertical splitting coefficient of the i-th injection layer of the target injection well; M i is the transformation measure coefficient of the i-th injection layer of the target injection well; H i is the effective sandstone thickness of the i-th injection layer of the target injection well; K i is the effective permeability of the i-th injection layer of the target injection well; m is the number of oil production wells connected to the i-th injection layer of the target injection well; n is the number of injection layers used by the target injection well (here, the use refers to the injection layers currently in use); j represents the j-th oil production well connected to the i-th injection layer of the target injection well; R ij It is the seepage resistance coefficient in the direction from the i-th water injection layer of the target water injection well to the j-th oil production well connected to the i-th water injection layer.

[0087] (2) Based on the daily water injection volume and the vertical splitting coefficient, the stratified water injection volume of each injection layer of the target water injection well is obtained.

[0088] Exemplarily, the stratified water injection rate of the water injection well is determined by the following formula:

[0089] Q wi =Q w C i ; (5)

[0090] Among them, Q wi is the injection volume of the i-th layer of the target injection well; Q w is the daily water injection volume of the target water injection well; C i is the vertical splitting coefficient of the i-th injection layer of the target injection well.

[0091] (3) Based on the seepage resistance coefficient, determine the plane distribution coefficient of the oil production wells connected to each injection layer of the injection well.

[0092] In this embodiment, the plane distribution coefficient of the oil production well is determined by the following formula.

[0093]

[0094] Among them, α j is the plane distribution coefficient of the j-th oil production well in the i-th water injection layer; △P is the production pressure difference of the oil production layer of the oil production well interconnected with the i-th water injection layer; m is the number of oil production wells interconnected with the i-th water injection layer of the water injection well; R ij It is the seepage resistance coefficient from the i-th injection layer of the injection well to the j-th oil production well connected to the injection layer.

[0095] (4) According to the planar distribution coefficient of the oil production well and the stratified water injection volume of the water injection well, the stratified water injection volume of the oil production well is obtained.

[0096] Exemplarily, the stratified water injection volume of the oil production well is determined by the following formula.

[0097] Q k =Q wi α j ; (7)

[0098] Among them, Q k Q is the stratified water injection volume of the oil well; wi is the injection volume of the i-th layer of the target injection well; α j is the plane distribution coefficient of the j-th oil production well in the i-th water injection layer.

[0099] (5) Based on the stratified water injection volume of the oil production well, the stratified liquid production volume of the oil production well is obtained.

[0100] Taking the oil production well as the center, the stratified water injection volumes of each water injection well connected to the oil production well in each production layer of the oil production well are added up to obtain the stratified liquid production of the oil production well.

[0101] Assuming that there are w water injection wells connected to the i-th production layer of the oil production well, the stratified liquid production of the i-th production layer of the oil production well can be obtained by the following formula:

[0102]

[0103] Among them, Q owi is the calculated stratified liquid production of the i-th production layer of the oil well; Q k is the stratified water injection volume of the oil well; w is the number of water injection wells around the i-th water injection layer of the oil well.

[0104] Since the calculated stratified liquid production of the oil production well is different from the actual stratified liquid production of the oil production well, it is necessary to correct the calculated stratified liquid production of the oil production well.

[0105] In this embodiment, according to the actual liquid production Q at the wellhead of the oil production well, l (That is, the sum of the actual liquid production of all production layers in the oil well), and the above-calculated stratified liquid production is corrected.

[0106] For example, if the oil well perforates n production layers, the corrected layered liquid production of the i-th production layer is:

[0107]

[0108] Among them, Q li is the corrected liquid production of the ith oil-producing layer; Ql is the actual liquid production at the wellhead of the oil well; Q owi is the stratified liquid production of the ith production layer of the oil well calculated in formula (8); n is the number of production layers perforated by the oil well.

[0109] (6) Determine the stratified oil production of the oil well based on the stratified liquid production of the oil well.

[0110] The liquid produced by oil wells includes both water and oil, so it is necessary to determine the stratified oil production based on the stratified liquid production.

[0111] Step (6) comprises:

[0112] 6.1: Determine the initial water content of each producing layer of the oil well.

[0113] For example, according to Darcy's law of oil-water two-phase flow, the initial water content is calculated by the following formula:

[0114]

[0115] Among them, f wi is the initial water content of the i-th oil-producing layer of the oil well; μ w is the viscosity of the formation water in the i-th production layer of the oil well; μ 0 is the viscosity of the crude oil in the i-th production layer of the oil well; k ro is the relative permeability of the oil phase; k rw is the relative permeability of water phase.

[0116] In this embodiment, according to the core displacement test, a water saturation and relative permeability curve can be drawn, see Figure 4 . Figure 4 The horizontal axis is water saturation and the vertical axis is permeability.

[0117] Among them, curve a is the relationship curve between oil phase relative permeability and water saturation, curve b is the relationship curve between water phase relative permeability and water saturation. Curve c is the relationship curve between water content and water saturation, wherein curve c is calculated by curve a and curve b through formula (10).

[0118] 6.2: According to the initial water content of each production layer of the oil well and the corrected stratified liquid production, the initial water content of each production layer is corrected to obtain the actual water content of each production layer.

[0119] In this embodiment, the corrected stratified liquid production Q li Multiply by the initial moisture content of the layer f wi , the water production Q of each oil-producing layer can be calculated wi. By adding up the water production of each oil-producing layer, the total water production of the oil well Q can be obtained. w , and then compared with the actual water production at the wellhead of the oil well Q ws Compare to get the actual water content f of the oil well layer wi .

[0120] In this embodiment, the actual water content of each oil-producing layer is calculated in the following manner:

[0121]

[0122] Among them, f wi(实际) is the actual water content of the i-th oil-producing layer of the oil well; f wi(计算) is the initial water content of the i-th production layer of the oil well calculated in formula (10); Q ws is the actual water production at the wellhead of the oil well; Q w is the calculated total water production of the oil well.

[0123] 6.3: According to the actual water content of each oil-producing layer and combined with the relative permeability data, the recovery degree R of each oil-producing layer of the oil well is obtained. i And the current layer remaining oil saturation and the current layer water saturation.

[0124] In this embodiment, the actual moisture content obtained is again matched to Figure 4 From the curve c in the figure, we can get the moisture protection degree S corresponding to the actual moisture content. w , and bound water saturation S wc Immune water saturation S wc It is the saturation degree corresponding to the intersection of curve c and the abscissa.

[0125] According to the water saturation S w , and bound water saturation S wc The recovery degree, remaining oil saturation and current stratified water saturation are calculated by the following formula.

[0126]

[0127] s oi =s oip (1-R i ); (13)

[0128] s wi =1-s oi ; (14)

[0129] Among them, R i is the production degree of the i-th production layer of the oil well; S w is the water saturation of the i-th production layer of the oil well; Swc is the irreducible water saturation of the ith production layer of the oil well; S oi is the current layered residual oil saturation of the i-th production layer of the oil well; S oip is the original stratum saturation of the i-th oil-producing layer of the oil well; S wi is the current stratified water saturation of the i-th producing layer of the oil well.

[0130] 6.4: Based on the current stratified water saturation, obtain the stratified oil production of the oil well.

[0131] The current stratified water saturation is regarded as the initial water saturation of the next calculation time step, and is substituted back into step 6.1 to start the cyclic calculation of the stratified water content and stratified oil production of the next time step, thereby obtaining the stratified water content and stratified oil production of all time steps, and accumulating the stratified oil production of all time steps to obtain the stratified oil production of the oil well.

[0132] (7) Determine the residual oil saturation of the oil well according to the oil production of the oil well.

[0133] Step (7) comprises:

[0134] 7.1: According to the stratified oil production of the oil well, determine the actual degree of production of each production layer of the oil well.

[0135] Exemplarily, actual recovery degree=layered oil production / layered well-controlled reserves.

[0136] Layered well controlled reserves = effective sandstone thickness of the oil-producing layer * porosity * original oil saturation * crude oil density / volume coefficient. The volume coefficient is the ratio of the underground crude oil volume to the crude oil volume under standard conditions on the ground.

[0137] 7.2: Determine the relationship function between the water saturation rise value and the degree of recovery of the oil well.

[0138] The relative permeability and oil recovery efficiency curves of cores with different physical properties were statistically analyzed, and the relationship function between water saturation and recovery degree was fitted.

[0139] In this embodiment, through the core displacement test, multiple sets of data corresponding to the recovery degree and the water saturation increase value are obtained, such as Figure 5 As shown. Among them, Figure 5 The horizontal axis is the degree of recovery, and the vertical axis is the increase in water saturation. Figure 5 Each black dot in is a set of data. According to these data, the relationship curve is fitted to obtain the relationship function, such as curve a.

[0140] 7.3: Based on the relationship function and the actual production degree, the water saturation increase value of each production layer of the oil well is obtained.

[0141] 7.4: Determine the oil saturation and physical residual oil saturation of each producing layer in the oil well.

[0142] The oil saturation of each layer in the oil production well is determined based on the secondary interpretation results of fine logging. At the same time, the physical residual oil saturation is determined using the coring well data.

[0143] 7.5: Based on the water saturation rise value of each production layer of the oil well, the oil saturation encountered and the physical residual oil saturation, the stratified residual oil saturation of the oil well is obtained.

[0144] In this embodiment, the layered residual oil saturation of each production layer of the oil production well = the oil saturation encountered during drilling - the water saturation increase value - the physical residual oil saturation.

[0145] S302: Determine the remaining oil saturation of each injection layer of the injection well.

[0146] In this embodiment, step S302 includes:

[0147] 2.1: Determine the pore volume of each injection layer of the injection well.

[0148] For example, the pore volume of each injection layer of the injection well can be calculated according to the following formula:

[0149] V 孔 =H wi *φS; (15)

[0150] Among them, V 孔 is the pore volume of each injection layer of the injection well; H wi is the effective sandstone thickness of the i-th injection layer of the injection well; φ is the porosity of the i-th injection layer of the injection well; S is the single well control area of ​​the i-th injection layer of the injection well.

[0151] 2.2: According to the pore volume of each injection layer of the injection well, determine the relationship function between the injection multiple of each injection layer and the decline value of oil saturation.

[0152] First, different water injection multiples are obtained through pore volume, where injection multiple = cumulative water injection / pore volume of each water injection layer in the water injection well. Then, cores of each water injection layer corresponding to the water injection well are taken, and through displacement experiments, the corresponding oil saturation decrease values ​​of the cores of each water injection layer under different water injection multiples are obtained. Then, according to multiple water injection multiples and the corresponding oil saturation decrease values, linear fitting is performed to obtain the relationship function.

[0153] for example, Figure 6 The relationship between the decrease in oil saturation and the water injection multiple provided in the embodiment of the present disclosure is shown in FIG. Figure 6The horizontal axis is the water injection multiple, and the vertical axis is the water saturation decrease value. Curves a, b, c, and d are the curves corresponding to the relationship functions of different water injection layers. According to the relationship function, it can be seen that as the water injection multiple increases, the water saturation decrease value gradually increases.

[0154] 2.3: According to the relationship function and the injection multiples of each injection layer of the injection well, the oil saturation decrease value of the injection well in different injection layers is obtained.

[0155] In this embodiment, the water injection multiple of each water injection layer of the water injection well is substituted into the corresponding relationship function to obtain the oil saturation reduction value of each water injection layer of the water injection well.

[0156] 2.4: Determine the drilled oil saturation and physical residual oil saturation of each injection layer of the injection well.

[0157] According to the secondary interpretation results of fine logging, the oil saturation of each injection layer of the water injection well is determined. At the same time, the physical residual oil saturation is determined using the core well data.

[0158] 2.5: Based on the oil saturation decline value, the encountered oil saturation and the physical residual oil saturation, the stratified residual oil saturation of each injection layer of the injection well is obtained.

[0159] In this embodiment, the layered residual oil saturation of each injection layer of the water injection well = the oil saturation encountered during drilling - the oil saturation decrease value - the physical residual oil saturation.

[0160] S303: Obtain a distribution map of the residual oil saturation of each production layer in the work area according to the residual oil saturation of each layer of the water injection well and the residual oil saturation of each layer of the oil production well.

[0161] According to the stratified residual oil saturation of the water injection well and the stratified residual oil saturation of the oil production well, the residual oil saturation distribution map of each oil production layer in the work area (that is, the residual oil saturation contour map) is obtained.

[0162] That is to say, by analyzing the stratified residual oil saturation of the water injection wells and the stratified residual oil saturation of the oil production wells in each layer, a plurality of residual oil saturation distribution maps of each oil production layer can be obtained.

[0163] S304: Determine the average value of the remaining oil saturation of each production layer in the work area according to the remaining oil saturation distribution map of the work area.

[0164] In the residual oil saturation distribution map of the work area, determine the average value of the residual oil saturation.

[0165] S305: The position corresponding to the residual oil saturation greater than the average value of the residual oil saturation in the residual oil saturation distribution map of each oil-producing layer is regarded as the position where the residual oil exists.

[0166] By calculating the average value of the remaining oil saturation of each oil-producing layer, the average value of the remaining oil saturation can be used as a reference value. When the remaining oil saturation corresponding to a certain location is greater than the average value of the remaining oil saturation, the remaining oil corresponding to this location is more and it is easier to develop. That is, this location has considerable development potential and should be developed in the future.

[0167] The implementation process of the above method for determining the residual oil distribution is specifically described below with reference to the following examples:

[0168] See again Figure 1 A well group in a certain work area includes water injection well O and oil production wells A, B, C, and D. The basic parameters of the well group are shown in Table 1.

[0169] Table 1 is the basic parameters of the well group

[0170]

[0171] First, according to the basic parameters in Table 1, the seepage resistance coefficient R around each injection layer in the injection well O in the direction of each oil production well is calculated using formula (1): ij , the calculation results are shown in Table 2.

[0172] Table 2 is the relevant parameter table obtained by calculation for this well group

[0173]

[0174] Among them, the No. 2 production layer of the D oil well adopts fracturing measures. According to the production changes before and after the measures, the fracturing production increase coefficient is determined to be 1.5 using the scissors difference method. By substitution calculation, the seepage resistance coefficients of the No. 1 injection layer of the injection well O corresponding to the oil well A, B, C, and D directions are 0.34, 0.14, 0.15, and 0.78 respectively. The seepage resistance coefficients of the No. 2 injection layer corresponding to the oil well A, B, and D directions are 0.54, 0.11, and 0.41 respectively.

[0175] Secondly, according to the seepage resistance coefficient, the vertical splitting coefficient Ci of the injection well in each injection layer is determined. The calculation results are shown in Table 2.

[0176] Substituting the basic parameters and seepage resistance coefficient of each injection layer of injection well O into formula (4), the vertical splitting coefficients of injection layers 1 and 2 of injection well O are 0.35 and 0.65 respectively. Correspondingly, the stratified injection volumes of injection layers 1 and 2 of injection well O are 20.93 and 39.07 m 3 / d.

[0177] Secondly, according to the seepage resistance coefficient, determine the plane distribution coefficient α of the injection volume of the injection well to each oil production well j , the calculation results are shown in Table 2.

[0178] The plane distribution coefficients of the No. 1 injection layer of water well O in the directions of oil production wells A, B, C, and D are 0.15, 0.45, 0.34, and 0.05, and the plane distribution coefficients of the No. 1 injection layer of water well O in the directions of oil production wells A, B, and D are 0.13, 0.74, and 0.13. The split injection volumes of the No. 1 injection layer of water well O in the directions of oil production wells A, B, C, and D are 3.18, 9.48, 7.17, and 1.10, respectively. The split injection volumes of the No. 2 injection layer of water well O in the directions of oil production wells A, B, and D are 4.94, 28.91, and 5.22, respectively. After correcting the water injection volume according to the actual liquid production at the wellhead of the oil well, the split water injection volumes of the No. 1 water injection layer of water well O in the directions of oil wells A, B, C, and D are 3.92, 4.94, 15, and 2.61, respectively, and the split water injection volumes of the No. 2 water injection layer of water well O in the directions of oil wells A, B, and D are 6.08, 15.06, and 12.39, respectively.

[0179] Next, the initial water content f of each layer of the oil well is calculated wi , see Table 2.

[0180] In addition, the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well are calculated, see Table 3 and Table 4.

[0181] Table 3 Quantitative parameters of remaining oil in water injection wells

[0182]

[0183] Table 4 Quantitative parameters of remaining oil in oil producing wells

[0184]

[0185] Then, the residual oil saturation distribution map of each layer in the work area is obtained through the stratified residual oil saturation of the water injection well and the stratified residual oil saturation of the oil production well, and the distribution position of the residual oil in the work area is determined based on the residual oil saturation distribution map of the work area.

[0186] Optionally, the embodiment of the present disclosure further provides a device for determining the residual oil distribution, such as Figure 7 As shown, the determining device includes:

[0187] The layered residual oil saturation determination module 701 is used to determine the layered residual oil saturation of each oil production layer of the oil production well and the layered residual oil saturation of each water injection layer of the water injection well;

[0188] The residual oil distribution determination module 702 is used to determine the distribution of the residual oil in the work area based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well.

[0189] Optionally, the layered remaining oil saturation determination module 701 is used to determine the seepage resistance coefficient of each water injection layer of the target water injection well in multiple directions, the multiple directions including the direction from the water injection layer of the target water injection well to the oil production layers of multiple oil production wells connected to the water injection layer, and the target water injection well is one of the at least one water injection well. It is also used to determine the layered remaining oil saturation of each oil production well according to the seepage resistance coefficient and the daily water injection volume of the target water injection well.

[0190] Optionally, the layered residual oil saturation determination module 701 is used to determine the seepage resistance coefficient by using the following formula (1).

[0191] Optionally, the stratified residual oil saturation determination module 701 determines the vertical splitting coefficient of the target water injection well according to the seepage resistance coefficient; obtains the stratified water injection amount of each water injection layer of the target water injection well according to the daily water injection amount and the vertical splitting coefficient; determines the plane distribution coefficient of the oil production well connected to each water injection layer of the water injection well according to the seepage resistance coefficient; obtains the stratified water injection amount of the oil production well according to the plane distribution coefficient of the oil production well and the stratified water injection amount of the water injection well; obtains the stratified liquid production of the oil production well based on the stratified water injection amount of the oil production well; determines the stratified oil production of the oil production well according to the stratified liquid production of the oil production well; determines the stratified residual oil saturation of the oil production well according to the stratified oil production of the oil production well.

[0192] Optionally, the layered residual oil saturation determination module 701 is used to determine the vertical splitting coefficient of the water injection well by using formula (4).

[0193] Optionally, the stratified residual oil saturation determination module 701 is used to determine the pore volume of each injection layer of the water injection well; determine the relationship function between the water injection multiple and the oil saturation decrease value of each injection layer according to the pore volume of each injection layer of the water injection well; obtain the oil saturation decrease value of the water injection well in different injection layers according to the relationship function and the water injection multiple of each injection layer of the water injection well; determine the drilled oil saturation and physical residual oil saturation of each injection layer of the water injection well; obtain the stratified residual oil saturation of each injection layer of the water injection well according to the oil saturation decrease value, the drilled oil saturation and the physical residual oil saturation.

[0194] Optionally, the residual oil distribution determination module 702 is used to obtain a residual oil saturation distribution map of each oil-producing layer in the work area according to the stratified residual oil saturation of the water injection well and the stratified residual oil saturation of the oil production well. According to the residual oil saturation distribution map of the work area, the average value of the residual oil saturation of each oil-producing layer in the work area is determined; and the position corresponding to the residual oil saturation greater than the average value of the residual oil saturation in the residual oil saturation distribution map of each oil-producing layer is taken as the position where the residual oil exists.

[0195] The above determination device has the same beneficial effects as the above determination method, which will not be described in detail here.

[0196] Figure 8 is a schematic diagram of a computer device provided by an embodiment of the present disclosure, combined with Figure 8 , the computer device 800 may include one or more of the following components: a processor 801 , a memory 802 , a communication interface 803 , and a bus 804 .

[0197] The processor 801 includes one or more processing cores, and the processor 801 executes various functional applications and information processing by running software programs and modules. The memory 802 and the communication interface 803 are connected to the processor 801 through the bus 804. The memory 802 can be used to store at least one instruction, and the processor 801 is used to execute the at least one instruction to implement each step in the above method.

[0198] In addition, the memory 802 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, and the volatile or non-volatile storage device includes but is not limited to: a magnetic disk or an optical disk, an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a static random access memory (SRAM), a read-only memory (ROM), a magnetic memory, a flash memory, and a programmable read-only memory (PROM).

[0199] Those skilled in the art will understand that Figure 8 The structure shown in the figure does not constitute a limitation on the computer device, and may include more or less components than shown in the figure, or combine some components, or adopt a different component arrangement.

[0200] The embodiments of the present disclosure also provide a non-temporary computer-readable storage medium. When the instructions in the storage medium are executed by a processor of a computer device, the computer device is able to execute the above method for determining the residual oil distribution provided in the embodiments of the present application.

[0201] A computer program product comprising instructions, when running on a computer, enables the computer to execute the above method for determining the residual oil distribution provided in the embodiment of the present application.

[0202] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for determining residual oil distribution, characterized in that: Used to determine the distribution of remaining oil in a work area, wherein at least one water injection well and a plurality of oil production wells are arranged in the work area, wherein the water injection well comprises multiple water injection layers, and the oil production well comprises multiple oil production layers, and each oil production layer of the oil production well is connected to a water injection layer of at least one of the water injection wells; The determination method comprises: Determine the seepage resistance coefficient of each water injection layer of the target water injection well in multiple directions by the following formula, wherein the multiple directions include directions from the water injection layer of the target water injection well to the oil production layers of multiple oil production wells connected to the water injection layer of the target water injection well, wherein the target water injection well is one of the at least one water injection well; Among them, R ij μ is the seepage resistance coefficient from the i-th water injection layer of the target water injection well to the j-th oil production well connected to the i-th water injection layer; o is the viscosity of crude oil; L j M is the well distance between the jth oil production well connected to the i-th water injection layer of the target water injection well and the target water injection well; ij is the transformation measure coefficient between the i-th water injection layer of the target water injection well and the j-th oil production well connected to the i-th water injection layer; H ij is the effective sandstone thickness of the oil production layer of the jth oil production well connected to the i-th water injection layer of the water injection well; K ij is the effective permeability between the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer; Z ij is the connectivity coefficient of the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer; According to the seepage resistance coefficient, the vertical splitting coefficient of the water injection well is determined by the following formula: Where i represents the i-th injection layer of the target injection well; C i is the vertical splitting coefficient of the i-th injection layer of the target injection well; M i is the transformation measure coefficient of the i-th injection layer of the target injection well; H i is the effective sandstone thickness of the i-th injection layer of the target injection well; K i is the effective permeability of the i-th injection layer of the target injection well; m is the number of oil production wells connected to the i-th injection layer of the target injection well; n is the number of injection layers used by the target injection well; j represents the j-th oil production well connected to the i-th injection layer of the target injection well; R ij is the seepage resistance coefficient in the direction from the i-th water injection layer of the target water injection well to the j-th oil production well connected to the i-th water injection layer; According to the daily water injection volume and the vertical splitting coefficient, the layered water injection volume of each water injection layer of the target water injection well is obtained; Determining the plane distribution coefficient of the oil production well connected to each water injection layer of the water injection well according to the seepage resistance coefficient; According to the plane distribution coefficient of the oil production well and the stratified water injection volume of the water injection well, the stratified water injection volume of the oil production well is obtained; Based on the stratified water injection volume of the oil production well, obtaining the stratified liquid production volume of the oil production well; Determining the stratified oil production of the oil production well according to the stratified liquid production of the oil production well; Determining the residual oil saturation of the oil production well according to the oil production of the oil production well; Determining the pore volume of each injection layer of the injection well; According to the pore volume of each water injection layer of the water injection well, determining the relationship function between the water injection multiple and the decrease value of oil saturation of each water injection layer; According to the relationship function and the water injection multiple of each water injection layer of the water injection well, the oil saturation reduction value of the water injection well in different water injection layers is obtained; Determine the oil saturation and physical residual oil saturation of each injection layer of the injection well; Obtaining the stratified residual oil saturation of each water injection layer of the water injection well according to the oil saturation decrease value, the drilled oil saturation and the physical residual oil saturation; The distribution of the remaining oil in the work area is determined based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well.

2. The determination method according to claim 1, characterized in that: The determining the distribution of the residual oil in the work area based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well comprises: According to the layered residual oil saturation of the water injection well and the layered residual oil saturation of the oil production well, a residual oil saturation distribution map of each oil production layer in the work area is obtained; Determining the average value of the residual oil saturation of each oil-producing layer in the work area according to the residual oil saturation distribution map of the work area; In the residual oil saturation distribution map of each oil-producing layer, the position corresponding to the residual oil saturation greater than the average value of the residual oil saturation is regarded as the position where the residual oil exists.

3. A device for determining the distribution of residual oil, used for determining the distribution of residual oil in a work area, characterized in that: The determining device is implemented based on the determining method according to any one of claims 1 to 2, and the determining device includes: A layered remaining oil saturation determination module is used to determine the seepage resistance coefficient of each water injection layer of a target water injection well in multiple directions by using the following formula, wherein the multiple directions include directions from the water injection layer of the target water injection well to the oil production layers of multiple oil production wells connected to the water injection layer of the target water injection well, and the target water injection well is one of the at least one water injection well; Among them, R ij μ is the seepage resistance coefficient from the i-th water injection layer of the target water injection well to the j-th oil production well connected to the i-th water injection layer; o is the viscosity of crude oil; L j M is the well distance between the jth oil production well connected to the i-th water injection layer of the target water injection well and the target water injection well; ij is the transformation measure coefficient between the i-th water injection layer of the target water injection well and the j-th oil production well connected to the i-th water injection layer; H ij K is the effective sandstone thickness of the oil production layer of the jth oil production well connected to the i-th water injection layer of the water injection well; ij is the effective permeability between the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer; Z ij is the connectivity coefficient of the i-th injection layer of the injection well and the j-th oil production well connected to the injection layer; According to the seepage resistance coefficient, the vertical splitting coefficient of the water injection well is determined by the following formula: Where i represents the i-th injection layer of the target injection well; C i is the vertical splitting coefficient of the i-th injection layer of the target injection well; M i is the transformation measure coefficient of the i-th injection layer of the target injection well; H i is the effective sandstone thickness of the i-th injection layer of the target injection well; K i is the effective permeability of the i-th injection layer of the target injection well; m is the number of oil production wells connected to the i-th injection layer of the target injection well; n is the number of injection layers used by the target injection well; j represents the j-th oil production well connected to the i-th injection layer of the target injection well; R ij is the seepage resistance coefficient from the i-th water injection layer of the target water injection well to the j-th oil production well connected to the i-th water injection layer; according to the daily water injection volume and the vertical splitting coefficient, the stratified water injection volume of each water injection layer of the target water injection well is obtained; according to the seepage resistance coefficient, the plane distribution coefficient of the oil production well connected to each water injection layer of the water injection well is determined; according to the plane distribution coefficient of the oil production well and the stratified water injection volume of the water injection well, the stratified water injection volume of the oil production well is obtained; based on the stratified water injection volume of the oil production well, the stratified liquid production of the oil production well is obtained; according to the stratified liquid production of the oil production well, the stratified oil production of the oil production well is determined; according to the stratified oil production of the oil production well Determine the stratified residual oil saturation of the oil production well according to the stratified oil production; determine the pore volume of each injection layer of the water injection well; determine the relationship function between the water injection multiple and the oil saturation decrease value of each injection layer according to the pore volume of each injection layer of the water injection well; obtain the oil saturation decrease value of the water injection well in different injection layers according to the relationship function and the water injection multiple of each injection layer of the water injection well; determine the drilled oil saturation and physical residual oil saturation of each injection layer of the water injection well; obtain the stratified residual oil saturation of each injection layer of the water injection well according to the oil saturation decrease value, the drilled oil saturation and the physical residual oil saturation; The residual oil distribution determination module is used to determine the distribution of the residual oil in the work area based on the stratified residual oil saturation of the oil production well and the stratified residual oil saturation of the water injection well.

4. A computer device, characterized in that: The computer device comprises a processor and a memory configured to store instructions executable by the processor; the processor is configured to execute the method for determining the remaining oil distribution according to any one of claims 1 to 2.

5. A computer storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the method for determining the remaining oil distribution according to any one of claims 1 to 2 is implemented.

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