Method, system, apparatus, and medium for determining chemical system for multilayer reservoirs

Abstract

The application relates to the technical field of oil and gas field development, and discloses a chemical system determination method, system, device and medium for a multilayer reservoir, the method comprising the following steps: obtaining the current high-permeability layer seepage resistance of a core existing chemical system of the multilayer reservoir; determining whether the chemical system plays a resistance adjustment role based on the current high-permeability layer seepage resistance and a first preset threshold value; in the case that the chemical system plays the resistance adjustment role, obtaining the actual injection amount of the chemical system; determining whether the actual injection amount of the chemical system is greater than or equal to a set injection amount; in the case that the actual injection amount is greater than or equal to the set injection amount, obtaining a small-layer producing coefficient; and in the case that the small-layer producing coefficient is less than or equal to a second preset threshold value, determining that the current chemical system is an effective chemical system for the multilayer reservoir. The application is suitable for various reservoir types by using the seepage capacity of different chemical systems in the reservoir and the demand of each layer of the multilayer reservoir for different seepage resistance systems.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas field development, in particular to a method, system and device for determining a chemical system for a multi-layer reservoir and a medium. BACKGROUND

[0002] Heterogeneity is generally strong in continental reservoirs, but the characteristics are different. In the process of improving recovery by a chemical system for a multi-layer reservoir, it is difficult to apply one chemical system to the whole process of developing a multi-layer reservoir. Selecting a chemical system and determining the combination method of multiple chemical systems are the keys to chemical flooding of a multi-layer reservoir.

[0003] Existing methods for determining a chemical system for a multi-layer reservoir are mostly applicable to specific reservoir types. Numerical simulation or core experiments are used to optimize the chemical system for a multi-layer reservoir. The process is cumbersome and has no universal guidance significance for field implementation. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a method, system, device and medium for determining a chemical system for a multi-layer reservoir, to solve the problem that existing methods for determining a chemical system for a multi-layer reservoir are mostly applicable to specific reservoir types, and the process of optimizing the chemical system for a multi-layer reservoir through numerical simulation or core experiments is cumbersome and has no universal guidance significance for field implementation.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a method for determining a chemical system for a multi-layer reservoir, comprising:

[0006] obtaining the current high-permeability layer flow resistance of a core of a multi-layer reservoir in the presence of a chemical system;

[0007] determining whether the chemical system plays a resistance adjustment role based on the current high-permeability layer flow resistance and a first preset threshold value;

[0008] obtaining the actual injection amount of the chemical system in the case where the chemical system plays a resistance adjustment role;

[0009] determining whether the actual injection amount of the chemical system is greater than or equal to a set injection amount;

[0010] obtaining a small-layer producing coefficient in the case where the actual injection amount is greater than or equal to the set injection amount;

[0011] determining that the current chemical system is an effective chemical system for a multi-layer reservoir in the case where the small-layer producing coefficient is less than or equal to a second preset threshold value.

[0012] In the embodiments of the present application, the current high-permeability layer flow resistance of a core of a multi-layer reservoir in the presence of a chemical system is obtained, comprising:

[0013] Obtain the seepage resistance of the first low-permeability layer and the first high-permeability layer filled with water from the core sample;

[0014] Based on the seepage resistance of the first low-permeability layer and the seepage resistance of the first high-permeability layer, the flow distribution of the first high-permeability layer with a chemical system in the core is obtained.

[0015] Based on the flow distribution of the first high-permeability layer, the fluid distribution of the first high-permeability layer containing the chemical system in the core is obtained;

[0016] Based on the fluid distribution in the first high-permeability layer, the seepage resistance of the high-permeability layer containing the chemical system in the core was obtained.

[0017] In this embodiment of the application, based on the seepage resistance of the first low-permeability layer and the seepage resistance of the first high-permeability layer, the flow distribution of the first high-permeability layer containing the chemical system in the core is obtained, including:

[0018] Based on the seepage resistance of the first low-permeability layer, the seepage resistance of the first high-permeability layer, and the first formula, the flow distribution of the first high-permeability layer is obtained, wherein the first formula includes:

[0019]

[0020] In the first formula, Show Flow distribution in the first high-permeability layer at any given time. express The first low-permeability layer seepage resistance at any given time. express The first high-permeability layer seepage resistance at any given time. This indicates the core injection rate.

[0021] In this embodiment of the application, based on the fluid distribution of the first high-permeability layer, the seepage resistance of the high-permeability layer where a chemical system exists in the core is obtained, including:

[0022] Based on the fluid distribution in the first high-permeability layer and the second formula, the seepage resistance of the high-permeability layer is obtained. The second formula includes:

[0023]

[0024] In the second formula, Indicates the seepage resistance of the high-permeability layer. This represents the viscosity of the i-th chemical system. This represents the fluid distribution of the i-th chemical system in the core within a high-permeability layer. This indicates the fluid distribution of all chemical systems in the high-permeability layer within the core. Indicates the area of ​​the core end. Indicates the viscosity of the aqueous phase. Indicates the length of the rock core. This indicates the maximum penetration rate.

[0025] In the embodiment of the present application, whether the chemical system plays a resistance adjustment role is determined based on the high-permeability layer seepage resistance and the first preset threshold, including:

[0026] Based on the current high-permeability layer seepage resistance and the high-permeability layer seepage resistance at the previous time, the relative change rate of the high-permeability layer seepage resistance at the adjacent time step is obtained.

[0027] In the case where the relative change rate of the high-permeability layer seepage resistance is greater than or equal to the first preset threshold, it is determined that the chemical system plays a resistance adjustment role.

[0028] In the case where the relative change rate of the high-permeability layer seepage resistance is less than the first preset threshold, it is determined that the chemical system does not play a resistance adjustment role.

[0029] In the embodiment of the present application, the sublayer producing coefficient is obtained, including:

[0030] The high-permeability layer shunt ratio and the core liquid injection speed are obtained.

[0031] Based on the high-permeability layer shunt ratio and the core liquid injection speed, the sublayer producing coefficient is obtained.

[0032] In the embodiment of the present application, it further includes:

[0033] In the case where the chemical system does not play a resistance adjustment role or the sublayer producing coefficient is greater than the second preset threshold, the chemical system is replaced until the actual injection amount is greater than or equal to the set injection amount and the sublayer producing coefficient is less than or equal to the second preset threshold.

[0034] Based on all the effective chemical systems, the effective chemical system combination of the multilayer reservoir is determined.

[0035] The second aspect of the present application provides a chemical system determination system for a multilayer reservoir, including:

[0036] The first obtaining module is configured to obtain the current high-permeability layer seepage resistance of the core of the multilayer reservoir in the presence of a chemical system.

[0037] The first determining module is configured to determine whether the chemical system plays a resistance adjustment role based on the current high-permeability layer seepage resistance and the first preset threshold.

[0038] The second obtaining module is configured to obtain the actual injection amount of the chemical system in the case where the chemical system plays a resistance adjustment role.

[0039] The second determining module is configured to determine whether the actual injection amount of the chemical system is greater than or equal to the set injection amount.

[0040] The third obtaining module is configured to obtain the sublayer producing coefficient in the case where the actual injection amount is greater than or equal to the set injection amount.

[0041] The third determining module is configured to determine that the current chemical system is an effective chemical system of the multi-layer reservoir when the small-layer producing coefficient is less than or equal to the second preset threshold.

[0042] The third aspect of the present application provides a chemical system determination device for a multi-layer reservoir, comprising:

[0043] a memory configured to store instructions;

[0044] a processor configured to call the instructions from the memory and implement the chemical system determination method for a multi-layer reservoir according to the first aspect as described above when the instructions are executed.

[0045] The fourth aspect of the present application provides a machine-readable storage medium having instructions stored thereon, the instructions being used to cause a machine to execute the chemical system determination method for a multi-layer reservoir according to the first aspect as described above.

[0046] Through the above technical solution, the scheme design of the chemical system of the multi-layer reservoir is determined in combination with the percolation capacity of the reservoir under different chemical systems and the demand of each layer of the multi-layer reservoir for different percolation resistance systems.

[0047] Other features and advantages of the embodiments of the present application will be described in detail in the following specific implementation part. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings are used to provide further understanding of the embodiments of the present application and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific implementation, but do not constitute a limitation to the embodiments of the present application. In the drawings:

[0049] Figure 1 The accompanying drawings are used to provide further understanding of the embodiments of the present application and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific implementation, but do not constitute a limitation to the embodiments of the present application. In the drawings:

[0050] Figure 2 The accompanying drawings are used to provide further understanding of the embodiments of the present application and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific implementation, but do not constitute a limitation to the embodiments of the present application. In the drawings:

[0051] Figure 3 The accompanying drawings are used to provide further understanding of the embodiments of the present application and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific implementation, but do not constitute a limitation to the embodiments of the present application. In the drawings:

[0052] Figure 4 The accompanying drawings are used to provide further understanding of the embodiments of the present application and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific implementation, but do not constitute a limitation to the embodiments of the present application. In the drawings:

[0053] Figure 5 The accompanying drawings are used to provide further understanding of the embodiments of the present application and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific implementation, but do not constitute a limitation to the embodiments of the present application. In the drawings: DETAILED DESCRIPTION

[0054] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiments of the present application, and is not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0055] It should be noted that the acquisition, transmission, storage, use, processing and the like of data in the technical solutions of the present application comply with the relevant provisions of laws and regulations. In the embodiments of the present application, some industry existing solutions such as software, components, models and the like may be mentioned, which should be considered as exemplary, and the purpose is only to illustrate the feasibility of the implementation of the technical solutions of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0056] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, motion condition and the like between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0057] In addition, if the embodiments of the present application involve descriptions such as "first", "second", etc., the descriptions of "first", "second" and the like are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present application.

[0058] Figure 1 A flowchart of a method for determining a chemical system of a multi-layer oil reservoir according to an embodiment of the present application is schematically shown. As shown in Figure 1 The method for determining a chemical system of a multi-layer oil reservoir provided by the embodiments of the present application can include the following steps:

[0059] Step S110: Obtain the current high-permeability layer flow resistance of the core of the multi-layer oil reservoir in the presence of the chemical system;

[0060] Step S120: Determine whether the chemical system plays a resistance adjustment role based on the current high-permeability layer flow resistance and a first preset threshold.

[0061] Step S130: obtaining the actual injection amount of the chemical system in the case that the chemical system plays a resistance adjustment role;

[0062] Step S140: determining whether the actual injection amount of the chemical system is greater than or equal to the set injection amount;

[0063] Step S150: obtaining the small layer producing coefficient in the case that the actual injection amount is greater than or equal to the set injection amount;

[0064] Step S160: determining that the current chemical system is an effective chemical system of the multi-layer reservoir in the case that the small layer producing coefficient is less than or equal to the second preset threshold.

[0065] In step S110, it is determined that the core of the multi-layer reservoir exists current high-permeability layer flow resistance of the chemical system. The multi-layer reservoir refers to a plurality of independent or partially connected oil and gas reservoirs contained in an oil field or reservoir, which are usually composed of different lithology, physical properties (such as permeability, porosity) or fluid properties of geological layers, and may be separated by impermeable barriers (such as mudstone, shale) between each other. The chemical system (such as polymer, surfactant, alkali, etc.) is injected into the core of the multi-layer reservoir to improve the oil flowability and enhance the displacement efficiency of enhanced oil recovery.

[0066] In step S120, the size relationship between the current high-permeability layer flow resistance and the first preset threshold is determined to determine whether the chemical system plays a resistance adjustment role.

[0067] In step S130, if it is determined that the chemical system plays a resistance adjustment role, the actual injection amount of the chemical system is determined. The actual injection amount of the chemical system calculation formula includes:

[0068]

[0069] In the actual injection amount of the chemical system calculation formula, represents the actual injection amount of the chemical system, represents the core liquid injection speed, represents the injection time.

[0070] In step S140, it is determined whether the actual injection amount of the chemical system reaches the set injection amount, to determine whether the actual injection amount of the chemical system reaches the injection amount requirement.

[0071] In step S150, in the case that the actual injection amount of the chemical system is greater than or equal to the set injection amount, the small layer producing coefficient is determined.

[0072] In step S160, the second preset threshold value can be 0.3. When the small-layer producing coefficient is less than or equal to 0.3, it indicates that the interlayer displacement effect of the chemical system in the multi-layer reservoir is small in the displacement process, the chemical system can uniformly enter each reservoir, and the displacement effect is good. Therefore, it can be determined that the current chemical system is an effective chemical system for the multi-layer reservoir, and the chemical system can be used for chemical flooding development of the reservoir condition.

[0073] The above scheme determines the flow resistance of the chemical system in each layer of the reservoir, determines the migration state of different chemical systems in the multi-layer reservoir, and compares and determines according to the size of the small-layer producing coefficient and the second preset threshold value. The flow capacity of the reservoir under different chemical systems is considered, and the demand of each layer of the multi-layer reservoir for different flow resistance systems is combined. The scheme design and agent selection of the field chemical system can be guided.

[0074] In an optional implementation, step S110 can include the following steps:

[0075] Step S111: obtaining the first low-permeability layer flow resistance and the first high-permeability layer flow resistance of the core filled with water;

[0076] Step S112: obtaining the first high-permeability layer flow distribution of the core with the chemical system based on the first low-permeability layer flow resistance and the first high-permeability layer flow resistance;

[0077] Step S113: obtaining the first high-permeability layer fluid distribution of the core with the chemical system based on the first high-permeability layer flow distribution;

[0078] Step S114: obtaining the high-permeability layer flow resistance of the core with the chemical system based on the first high-permeability layer fluid distribution.

[0079] In step S111, the first low-permeability layer flow resistance of the core filled with water is determined by a first low-permeability layer flow resistance calculation formula, wherein the first low-permeability layer flow resistance calculation formula includes:

[0080]

[0081] In the first low-permeability layer flow resistance calculation formula, represents the first low-permeability layer flow resistance, represents the pressure when water is driven, represents the injection water flow rate, represents the viscosity when the core is filled with water, represents the core length, represents the minimum permeability, represents the core end area.

[0082] The seepage resistance of the first high-permeability layer filled with water in the core is determined by the calculation formula for the seepage resistance of the first high-permeability layer, which includes:

[0083]

[0084] In the formula for calculating the seepage resistance of the first high-permeability layer This indicates the seepage resistance of the first high-permeability layer. Indicates the pressure during water drive. Indicates the injection water flow rate. Indicates the viscosity of the core when it is filled with water. Indicates the length of the rock core. Indicates the maximum penetration rate. This indicates the area at the core end.

[0085] In one optional implementation, step S112 may include the following steps:

[0086] Step S112a: Based on the seepage resistance of the first low-permeability layer, the seepage resistance of the first high-permeability layer, and the first formula, the flow distribution of the first high-permeability layer is obtained, wherein the first formula includes:

[0087]

[0088] In the first formula, Show The first high-permeability layer flow distribution at time t+1 (the amount of liquid entering the high-permeability layer at time t+1). express The first low-permeability layer seepage resistance at any given time. express The first high-permeability layer seepage resistance at any given time. This indicates the core injection rate.

[0089] Step S112b: Based on the seepage resistance of the first low-permeability layer, the seepage resistance of the first high-permeability layer, and the flow distribution calculation formula of the first low-permeability layer, the flow distribution of the first low-permeability layer is obtained, wherein the flow distribution calculation formula of the first low-permeability layer includes:

[0090]

[0091] In the formula for calculating the flow distribution of the first low-permeability layer Show The first low-permeability layer flow distribution at time t+1 (the amount of liquid entering the low-permeability layer at time t+1). express The first low-permeability layer seepage resistance at any given time. express The first high-permeability layer seepage resistance at any given time. This indicates the core injection rate.

[0092] In steps S112a-S112b, the flow distribution at the next time (t+1 time) can be determined using the proportional relationship of the seepage resistance at time t.

[0093] In an alternative embodiment, taking a double-layer reservoir as an example, step S113 can include the following steps:

[0094] Step S113a: obtaining the first high-permeability layer fluid distribution of the core with the chemical system according to the first high-permeability layer flow distribution and the first high-permeability layer fluid distribution calculation formula, wherein the first high-permeability layer fluid distribution calculation formula includes:

[0095]

[0096] In the first high-permeability layer fluid distribution calculation formula, represents the fluid distribution of the i th chemical system in the core in the high-permeability layer, represents the first high-permeability layer flow distribution of the i th chemical system into the high-permeability layer at time t, represents the length of the core, represents the porosity of the high-permeability layer, represents the end area of the core.

[0097] Step S113b: obtaining the first low-permeability layer fluid distribution of the core with the chemical system according to the first low-permeability layer flow distribution and the first low-permeability layer fluid distribution calculation formula, wherein the first low-permeability layer fluid distribution calculation formula includes:

[0098]

[0099] In the first low-permeability layer fluid distribution calculation formula, represents the fluid distribution of the i th chemical system in the core in the low-permeability layer, represents the first low-permeability layer flow distribution of the i th chemical system into the low-permeability layer at time t, represents the length of the core, represents the porosity of the low-permeability layer, represents the end area of the core.

[0100] In an alternative embodiment, step S114 can include the following steps:

[0101] Step S114a: obtaining the high-permeability layer seepage resistance based on the first high-permeability layer fluid distribution and the second formula, wherein the second formula includes:

[0102]

[0103] In the second formula, represents the high-permeability layer seepage resistance, viscosity of the i th chemical system, fluid distribution of the i th chemical system in the high permeable layer in the core, fluid distribution of all chemical systems in the high permeable layer in the core, core end area, viscosity of the water phase, core length, permeability of the high permeable layer.

[0104] Step S114b: determining the low permeable layer permeation resistance of the core existing the chemical system based on the low permeable layer fluid distribution and the low permeable layer permeation resistance calculation formula, wherein the low permeable layer permeation resistance calculation formula comprises:

[0105]

[0106] In the low permeable layer permeation resistance calculation formula, first low permeable layer permeation resistance, viscosity of the i th chemical system, fluid distribution of the i th chemical system in the low permeable layer in the core, minimum permeability, core end area, viscosity when the core is full of water, core length, fluid distribution of all chemical systems in the low permeable layer in the core.

[0107] In the embodiment of the application, the reservoir level difference can be determined based on the ratio of the maximum permeability and the minimum permeability in the multi-layer reservoir, and the reservoir level difference refers to the significant difference in reservoir properties (mainly permeability) between different small layers (or single layers) in the same reservoir, wherein the maximum permeability and the minimum permeability represent the maximum difference in interlayer exploitation of the multi-layer reservoir, so the minimum permeability and the maximum permeability are selected to determine the low permeable layer permeation resistance and the high permeable layer permeation resistance of the multi-layer reservoir.

[0108] In an alternative embodiment, step S120 can comprise the following steps:

[0109] Step S121: obtaining the relative change rate of the high permeable layer permeation resistance at the adjacent time step based on the current high permeable layer permeation resistance and the high permeable layer permeation resistance at the previous time;

[0110] Step S122: determining that the chemical system plays a resistance adjustment role in the case that the relative change rate of the high permeable layer permeation resistance is greater than or equal to a first preset threshold;

[0111] Step S123: In the case that the relative change rate of the high-permeability layer flow resistance is less than the first preset threshold, it is determined that the chemical system does not play a role in adjusting the resistance.

[0112] In step S121, the relative change rate of the high-permeability layer flow resistance at all adjacent time steps is calculated according to the current high-permeability layer flow resistance, the high-permeability layer flow resistance at the previous time and the relative change rate calculation formula of the high-permeability layer flow resistance. The relative change rate calculation formula of the high-permeability layer flow resistance includes:

[0113]

[0114] In the relative change rate calculation formula of the high-permeability layer flow resistance, represents the relative change rate of the high-permeability layer flow resistance, represents the high-permeability layer flow resistance of the i th chemical system at t-1 time, represents the high-permeability layer flow resistance of the i th chemical system at t time.

[0115] In steps S122-S123, the first preset threshold can be 1%. In the case that the relative change rate of the high-permeability layer flow resistance is greater than or equal to 1%, the chemical system still plays a role in adjusting the resistance in the multi-layer reservoir. In the case that the relative change rate of the high-permeability layer flow resistance is less than 1%, the role of the chemical system in adjusting the resistance in the multi-layer reservoir is almost ineffective.

[0116] The embodiment compares the relative change rate of the high-permeability layer flow resistance with the first preset threshold to determine whether the current chemical system still has a role in adjusting the resistance. If there is no role in adjusting the resistance, the next chemical system needs to be replaced. If there is still a role in adjusting the resistance, the current chemical system is continued to be used.

[0117] In an alternative embodiment, step S150 can include the following steps:

[0118] Step S151: Obtain the high-permeability layer diversion ratio and the core liquid injection speed.

[0119] Step S152: Obtain the small-layer producing coefficient based on the high-permeability layer diversion ratio and the core liquid injection speed.

[0120] In steps S151-S152, the small-layer producing coefficient can be obtained by substituting the obtained high-permeability layer diversion ratio and the core liquid injection speed into the small-layer producing coefficient calculation formula. The small-layer producing coefficient calculation formula includes:

[0121]

[0122] In the small-layer producing coefficient calculation formula, represents the small-layer producing coefficient, represents a high permeable layer diversion ratio, represents a core liquid injection rate, represents a number of reservoirs. Illustratively, the small layer producing coefficient = (high permeable layer diversion ratio-average diversion ratio) / average diversion ratio, and the number of reservoirs is 2.

[0123] In an alternative embodiment, the method further comprises the following steps:

[0124] Step S210: in the case that the chemical system does not play a resistance adjustment role or the small layer producing coefficient is greater than the second preset threshold value, the chemical system is replaced until the actual injection amount is greater than or equal to the set injection amount and the small layer producing coefficient is less than or equal to the second preset threshold value.

[0125] Step S220: based on all the effective chemical systems, an effective chemical system combination of the multi-layer reservoir is determined.

[0126] In steps S210-S220, in the case that the chemical system does not play a resistance adjustment role or the small layer producing coefficient is greater than the second preset threshold value, the chemical system is replaced and the above steps S110-S160 are repeated until the actual injection amount of the chemical system is greater than or equal to the set injection amount and the small layer producing coefficient is less than or equal to the second preset threshold value, the replacement of the chemical system is stopped, and all the effective chemical systems are determined as the effective chemical system combination of the multi-layer reservoir.

[0127] In the chemical system enhanced oil recovery process of the multi-layer reservoir, it is often difficult to achieve the best effect by applying one chemical system throughout. Therefore, the embodiments of the present application obtain the effective chemical system combination of the multi-layer reservoir by replacing the chemical system and repeating the above steps S110-S160, and achieve the best recovery rate by using the effective chemical system combination of the multi-layer reservoir.

[0128] In an alternative embodiment, the method further comprises the following steps:

[0129] Step S310: in the case that the actual injection amount is less than the set injection amount, the viscosity of the chemical system at the current time and the viscosity of the chemical system at the previous time are obtained;

[0130] Step S320: based on the viscosity of the chemical system at the current time and the viscosity of the chemical system at the previous time, it is determined whether the chemical system is replaced;

[0131] Step S330: in the case that the chemical system is replaced, the number of the chemical systems is recorded.

[0132] In steps S310-S330, in the case that the viscosity of the chemical system at the current time is equal to the viscosity of the chemical system at the previous time, the chemical system is not replaced. In the case that the viscosity of the chemical system at the current time is not equal to the viscosity of the chemical system at the previous time, the chemical system is replaced, and the number of the replaced chemical systems is recorded.

[0133] The method for determining a chemical system of a multi-layer oil reservoir provided in the application is described in detail below through three specific examples.

[0134] Example 1

[0135] Block information: minimum permeability of the reservoir , permeability differential , the maximum permeability of the reservoir is the product of the minimum permeability and the permeability differential, the maximum permeability and the minimum permeability reservoir represent the maximum difference in interlayer production of the multi-layer oil reservoir, and therefore the maximum permeability layer and the minimum permeability layer in the multi-layer oil reservoir are selected for development.

[0136] Set the minimum permeability of the reservoir , permeability differential , the maximum permeability of the reservoir , the thickness of each reservoir is equal, the viscosity of the water phase is 1 mPa·s, the viscosity of the oil phase is 10 mPa·s, and the set injection amount of the chemical system is 0.7 PV. The resistance coefficients of different chemical systems in different reservoirs and the corresponding effective viscosities are shown in Table 1. Different chemical systems are defined by different permeabilities, different reservoirs are defined by different viscosities, and the viscosity of the determined initial chemical system is 65 mPa·s.

[0137] Table 1

[0138]

[0139] The seepage resistance, flow distribution, and fluid distribution in each layer of the core are calculated. Among them, Figure 2 Fig. 2 schematically shows a flow distribution diagram in a chemical system injection process according to an example of the application, as shown in Figure 2 , the abscissa represents the actual injection amount (PV), and the ordinate represents the flow distribution. Figure 2

[0140] The small layer producing coefficient is calculated, and if the small layer producing coefficient meets the set displacement requirement (small layer producing coefficient ≤ 0.3%), the chemical system does not need to be replaced, and the chemical system with an initial viscosity of 65 mPa·s can meet the set displacement requirement (small layer producing coefficient ≤ 0.3%) for displacing the permeability combination of 1000 mD and 3300 mD.

[0141] Example 2

[0142] Set the minimum permeability of the reservoir​ , permeability difference , maximum permeability of the reservoir , the viscosity of the selected chemical system is 65 mPa s, and other basic parameters are set to remain the same as in Example 1, which will not be repeated here.

[0143] The seepage resistance, flow distribution, and fluid distribution in each layer of the core are calculated. Among them, Figure 3 schematically shows the flow distribution during the injection of another chemical system according to an embodiment of the present application, as shown in Figure 3 , the abscissa represents the actual injection amount (PV), and the ordinate represents the flow distribution. Figure 3

[0144] When the actual injection amount reaches 0.17 PV, the chemical system is replaced to 22 mPa s; when the actual injection amount reaches 0.3 PV, the chemical system is replaced to 65 mPa s; when the actual injection amount is 0.52 PV, the chemical system is replaced to 22 mPa s. During this process, the sublayer producing coefficient is calculated, Figure 4 schematically shows another sublayer producing coefficient according to an embodiment of the present application, as shown in Figure 4 , finally meets the set displacement requirements (sublayer producing coefficient ≤ 0.3%), to obtain an effective chemical system combination for a multi-layer reservoir.

[0145] Example 3:

[0146] change the minimum permeability of the reservoir and the reservoir difference , the above steps S110~S160 are repeated several times, and an effective chemical system scheme design for a multi-layer reservoir can be obtained. Figure 5 schematically shows the effective chemical system scheme design for a multi-layer reservoir according to an embodiment of the present application, as shown in Figure 5 , the gray zone selects a single chemical system displacement to meet the displacement requirements; the scheme design of the circular area needs to alternate chemical systems to adjust the seepage difference between high and low layers; the scheme design of the diamond area adopts a gradient viscosity reduction polymer flooding scheme design; the scheme design of the star area belongs to high-quality reservoirs, the permeability of the high-permeability layer and the permeability of the low-permeability layer are both high, and the high-viscosity polymer flooding needs to be used multiple times.

[0147] The embodiment of the present application also provides a chemical system determination system for a multi-layer reservoir, comprising:

[0148] The first acquisition module is configured to acquire the seepage resistance of the current high-permeability layer of the core of the multi-layer reservoir in the presence of the chemical system.

[0149] The first determination module is configured to determine whether the chemical system plays a resistance adjustment role based on the current high-permeability layer seepage resistance and the first preset threshold.​

[0150] The second acquisition module is configured to acquire the actual injection amount of the chemical system when the chemical system plays a resistance adjustment role.

[0151] The second determination module is configured to determine whether the actual injection amount of the chemical system is greater than or equal to the set injection amount.

[0152] The third acquisition module is configured to acquire the small layer producing coefficient when the actual injection amount is greater than or equal to the set injection amount.

[0153] The third determination module is configured to determine that the current chemical system is an effective chemical system of the multi-layer oil reservoir when the small layer producing coefficient is less than or equal to the second preset threshold.

[0154] It can be understood that the chemical system determination system for the multi-layer oil reservoir provided in the embodiments of the present application can realize the processes of the chemical system determination method for the multi-layer oil reservoir in the above embodiments, and can achieve the same technical effects. To avoid repetition, details are not repeated here.

[0155] The embodiments of the present application also provide a chemical system determination device for a multi-layer oil reservoir, which comprises:

[0156] The memory is configured to store instructions.

[0157] The processor is configured to call the instructions from the memory and can realize the chemical system determination method for the multi-layer oil reservoir according to the above when the instructions are executed.

[0158] It can be understood that the chemical system determination device for the multi-layer oil reservoir provided in the embodiments of the present application can realize the processes of the chemical system determination method for the multi-layer oil reservoir in the above embodiments, and can achieve the same technical effects. To avoid repetition, details are not repeated here.

[0159] The embodiments of the present application also provide a machine readable storage medium, which stores instructions for causing a machine to execute the chemical system determination method for the multi-layer oil reservoir according to the above.

[0160] It can be understood that the machine readable storage medium provided in the embodiments of the present application can realize the processes of the chemical system determination method for the multi-layer oil reservoir in the above embodiments, and can achieve the same technical effects. To avoid repetition, details are not repeated here.

[0161] Those skilled in the art will appreciate that embodiments of the present application can be readily used as a method, a system or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer readable storage media (including, but not limited to, disk memory, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0162] The present application is described in reference to the flow diagrams and / or block diagrams of the methods, apparatus (systems), computer program products according to embodiments of the application. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams 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 processing element or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks.

[0163] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flow diagram and / or block diagram block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks.

[0164] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow diagram and / or block diagram block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks. Figure 1 one or more functions specified in the flow diagram and / or block diagram block or blocks.

[0165] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0166] The memory can include non-persistent memory, random access memory (RAM), and / or non-volatile memory, such as read only memory (ROM) or flash memory, among others. The memory is an example of computer readable media.

[0167] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0168] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover non-exclusive inclusions, so that a process, method, article or apparatus that includes a list of elements does not only include those elements, but also includes other elements not explicitly listed, or further includes elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0169] The above only is an embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A method for determining the chemical system of a multi-layered oil reservoir, characterized in that, include: Obtain the current high-permeability layer seepage resistance of the core chemical system of the multi-layered reservoir; Based on the current seepage resistance of the high-permeability layer and the first preset threshold, determine whether the chemical system plays a resistance adjustment role; Under the condition that the chemical system plays a resistance adjustment role, the actual injection volume of the chemical system is obtained; Determine whether the actual injection volume of the chemical system is greater than or equal to the set injection volume; When the actual injection amount is greater than or equal to the set injection amount, the small layer utilization coefficient is obtained; If the utilization coefficient of the sublayer is less than or equal to the second preset threshold, the current chemical system is determined to be the effective chemical system of the multi-layer reservoir. The step of obtaining the current high-permeability layer seepage resistance of the core chemical system of the multi-layered reservoir includes: Obtain the seepage resistance of the first low-permeability layer and the first high-permeability layer filled with water from the core sample; Based on the seepage resistance of the first low-permeability layer and the seepage resistance of the first high-permeability layer, the flow distribution of the first high-permeability layer containing the chemical system in the core is obtained. Based on the flow distribution of the first high-permeability layer, the fluid distribution of the first high-permeability layer containing the chemical system in the core is obtained; Based on the fluid distribution of the first high-permeability layer, the seepage resistance of the high-permeability layer containing the chemical system in the core is obtained; The step of obtaining the flow distribution of the first high-permeability layer with a chemical system in the core based on the seepage resistance of the first low-permeability layer and the seepage resistance of the first high-permeability layer includes: Based on the seepage resistance of the first low-permeability layer, the seepage resistance of the first high-permeability layer, and the first formula, the flow distribution of the first high-permeability layer is obtained, wherein the first formula includes: In the first formula, Show Flow distribution in the first high-permeability layer at any given time. express The first low-permeability layer seepage resistance at any given time. express The first high-permeability layer seepage resistance at any given time. Indicates the core injection rate; The step of obtaining the seepage resistance of the high-permeability layer with a chemical system in the core based on the fluid distribution of the first high-permeability layer includes: Based on the fluid distribution of the first high-permeability layer and the second formula, the seepage resistance of the high-permeability layer is obtained, wherein the second formula includes: In the second formula, This indicates the seepage resistance of the high-permeability layer. This represents the viscosity of the i-th chemical system. This represents the fluid distribution of the i-th chemical system in the core within the high-permeability layer. This indicates the fluid distribution of all chemical systems in the high-permeability layer within the core. Indicates the area of ​​the core end. Indicates the viscosity of the aqueous phase. Indicates the length of the rock core. This indicates the maximum penetration rate.

2. The method according to claim 1, characterized in that, The step of determining whether the chemical system plays a resistance-adjusting role based on the seepage resistance of the high-permeability layer and a first preset threshold includes: Based on the current seepage resistance of the high-permeability layer and the seepage resistance of the high-permeability layer at the previous moment, the relative change rate of the seepage resistance of the high-permeability layer at adjacent time steps is obtained. When the relative change rate of the seepage resistance of the high-permeability layer is greater than or equal to the first preset threshold, it is determined that the chemical system plays a role in resistance adjustment. If the relative rate of change of the seepage resistance of the high-permeability layer is less than the first preset threshold, it is determined that the chemical system does not play a resistance adjustment role.

3. The method according to claim 1, characterized in that, The process of obtaining the small-layer mobilization coefficient includes: To obtain the diversion rate of high-permeability layers and the core injection rate; The utilization coefficient of the sublayer is obtained based on the diversion rate of the high-permeability layer and the core injection rate.

4. The method according to claim 1, characterized in that, Also includes: If the chemical system does not play a resistance adjustment role or the small layer mobilization coefficient is greater than the second preset threshold, the chemical system is replaced until the actual injection volume is greater than or equal to the set injection volume and the small layer mobilization coefficient is less than or equal to the second preset threshold. Based on all effective chemical systems, the combination of effective chemical systems for the multi-layered reservoir is determined.

5. A system for determining the chemical system of a multi-layered oil reservoir, characterized in that, The chemical system determination system employs the chemical system determination method for multi-layered reservoirs as described in any one of claims 1 to 4, including: The first acquisition module is used to acquire the current high-permeability layer seepage resistance of the core chemical system of the multi-layered reservoir; The first determining module is used to determine whether the chemical system plays a resistance adjusting role based on the current high-permeability layer seepage resistance and a first preset threshold. The second acquisition module is used to acquire the actual injection volume of the chemical system when the chemical system plays a resistance adjustment role; The second determining module is used to determine whether the actual injection amount of the chemical system is greater than or equal to the set injection amount; The third acquisition module is used to acquire the small layer utilization coefficient when the actual injection amount is greater than or equal to the set injection amount; The third determining module is used to determine that the current chemical system is an effective chemical system of the multi-layer reservoir when the utilization coefficient of the sublayer is less than or equal to a second preset threshold.

6. An apparatus for determining the chemical system of a multi-layered oil reservoir, characterized in that, include: The memory is configured to store instructions; The processor is configured to retrieve the instructions from the memory and, when executing the instructions, to implement the method for determining the chemical system of a multilayer reservoir according to any one of claims 1 to 4.

7. A machine-readable storage medium, characterized in that, The machine-readable storage medium stores instructions for causing the machine to perform the method for determining the chemical system of a multilayer reservoir according to any one of claims 1 to 4.

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