A heterogeneous reservoir polymer flooding exploitation method, device and computer equipment

Abstract

This specification provides a method, apparatus, and computer equipment for polymer flooding exploitation of heterogeneous oil reservoirs. The method includes: dividing the target heterogeneous oil reservoir into multiple displacement units based on oil displacement efficiency; determining the polymer displacement system for each displacement unit, wherein the molecular weight range and / or concentration range and / or volume range of the displacement system differs between the units; determining the displacement sequence of the multiple displacement units; sequentially injecting the displacement system of each displacement unit according to the displacement sequence, and determining the injection timing of the displacement system of the subsequent displacement unit based on the displacement pressure change curve of the preceding displacement unit, thereby exploiting each displacement unit. This method injects displacement systems with different molecular weights at different injection concentrations, volumes, and pressures into different levels of pore throats within each displacement unit, achieving graded utilization and effective displacement of residual oil in each displacement unit with different microscopic pore sizes, thus improving the reservoir's recovery rate.

Description

Technical Field

[0001] This specification relates to the field of oilfield development technology, and in particular to a polymer flooding method, apparatus and computer equipment for heterogeneous oil reservoirs. Background Technology

[0002] Heterogeneous sandstone reservoirs are highly heterogeneous with complex pore structures. After waterflooding, the remaining oil is highly dispersed, existing at the centimeter level or even lower, and microscopically present as clusters, islands, angular shapes, oil films, and throat residual oil. Inefficient and ineffective water circulation is severe, making further waterflooding difficult. Analysis of the dynamic characteristics of polymer flooding in the field and evaluation of experimental results indicate that existing polymer injection methods have the following drawbacks:

[0003] (1) Due to differences in water absorption index and injection capacity among polymer injection wells, the injection capacity of polymer injection wells varies greatly with the extension of injection time. The injection capacity of some wells drops significantly, and nearly one-third of the wells cannot be injected before reaching the injection volume designed in the injection and production scheme. This exacerbates the imbalance between injection and production in the polymer injection zone and seriously affects the injection and production effect.

[0004] (2) Some formations have formed large or even extra-large channels after long-term water injection and scouring. Low-concentration injection slugs are not effective at sealing large channels and cannot play the role of flow control and profile adjustment. The polymer flows along the large channels, which causes the polymer to form an ineffective circulation in the formation and affects the polymer displacement effect.

[0005] (3) At the beginning of the transition from water injection to polymer injection in the polymer injection zone, due to the severe heterogeneity of the formation plane, there were significant differences in the utilization status within the target layer and on the plane. When the original injection method was implemented, some well areas failed to effectively seal large channels, while other polymer injection wells in the same layer had severely insufficient injection capacity. The contradictions within the layer and on the plane could not be alleviated, and the oil injection and production capacity of low-permeability strips remained low, resulting in poor utilization effects within the layer and on the plane, and failing to achieve the expected oil displacement effect.

[0006] In summary, the existing polymer flooding injection method, which involves direct and large-scale polymer injection, has several drawbacks. It can easily cause the polymer agent to surge along high-permeability units, making it difficult to utilize medium- and low-permeability units, resulting in limited affected volume and low oil displacement efficiency. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, the purpose of the embodiments in this specification is to provide a polymer flooding method, apparatus, and computer equipment for heterogeneous oil reservoirs, thereby solving the problems of existing polymer injection methods where the polymer agent easily penetrates along high-permeability units, is difficult to utilize medium- and low-permeability units, has a limited affected volume, and has low oil displacement efficiency.

[0008] To solve the above-mentioned technical problems, the specific technical solutions of the embodiments in this specification are as follows:

[0009] In a first aspect, embodiments of this specification provide a polymer flooding method for heterogeneous oil reservoirs, comprising:

[0010] Based on the oil displacement efficiency, the target heterogeneous reservoir is divided into multiple displacement units;

[0011] The polymer displacement system of each displacement unit is determined, and the molecular weight, injection concentration, injection volume and injection pressure of the displacement system of each displacement unit are different;

[0012] Determine the displacement order of the multiple displacement units;

[0013] The displacement systems of each displacement unit are injected sequentially according to the displacement sequence, and the injection timing of the displacement system of the next displacement unit is determined according to the displacement pressure change curve of the previous displacement unit in the displacement sequence, so as to carry out mining of each displacement unit.

[0014] In one specific embodiment, the target heterogeneous reservoir is divided into multiple displacement units based on the oil displacement efficiency, including:

[0015] The region in the target heterogeneous oil reservoir with an oil displacement efficiency less than a first oil displacement efficiency threshold but greater than or equal to a second oil displacement efficiency threshold is divided into a first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold.

[0016] The region in the target heterogeneous reservoir where the oil displacement efficiency is less than the second oil displacement efficiency threshold is divided into the second displacement unit.

[0017] In a preferred embodiment, a displacement system is determined for each of the displacement units, wherein the molecular weight, injection concentration, injection volume, and injection pressure of the displacement system for each displacement unit are different, including:

[0018] The molecular weight of each displacement system is determined based on the oil displacement efficiency of each displacement unit.

[0019] Based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curves corresponding to the molecular weight of each displacement unit displacement system, the injection concentration of each displacement system is calculated.

[0020] The injection volume of each displacement system was calculated based on the injection concentration and the relationship curve between injection concentration and injection volume for each displacement system.

[0021] The injection pressure of each displacement system is determined based on its molecular weight, injection concentration, and injection volume.

[0022] In a preferred embodiment, the injection concentration of each displacement system is calculated based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curve corresponding to the molecular weight of each displacement unit's displacement system, further including:

[0023] The surface viscosity of the displacement system is calculated based on the crude oil viscosity of the target heterogeneous reservoir.

[0024] The injection concentration of each displacement system is calculated based on the viscosity-concentration relationship curves corresponding to the ground viscosity of the displacement system and the molecular weight of each displacement unit.

[0025] In a preferred embodiment, the formula for calculating the ground viscosity of the displacement system is:

[0026]

[0027] Where, μ 地面 To displace the ground viscosity of the system, μ 地下 A represents the underground viscosity of the displacement system; B represents the formation shear viscosity loss; C represents the surface pipeline system shear viscosity loss.

[0028] μ 地下 =Cμ 原油 ;

[0029] Where, μ 原油 Let C be the viscosity of the crude oil in the heterogeneous reservoir, where C is a constant coefficient greater than 0.

[0030] In a preferred embodiment, the region in the target heterogeneous reservoir with an oil displacement efficiency less than a second oil displacement efficiency threshold is divided into a second displacement unit, further comprising:

[0031] The region in the target heterogeneous reservoir with an oil displacement efficiency less than the second oil displacement efficiency threshold but greater than or equal to the third oil displacement efficiency threshold is divided into the second displacement unit, wherein the third oil displacement efficiency threshold is less than the second oil displacement efficiency threshold.

[0032] The region within the target heterogeneous reservoir where the oil displacement efficiency is less than a third oil displacement efficiency threshold but greater than or equal to a fourth oil displacement efficiency threshold is designated as a third displacement unit, wherein the fourth oil displacement efficiency threshold is less than the third oil displacement efficiency threshold; and

[0033] The region in the target heterogeneous reservoir with an oil displacement efficiency less than the fourth oil displacement efficiency threshold but greater than or equal to the fifth oil displacement efficiency threshold is divided into the fourth displacement unit, wherein the fifth oil displacement efficiency threshold is less than the fourth oil displacement efficiency threshold.

[0034] In a preferred embodiment, the viscosity-concentration relationship curves corresponding to the molecular weight of the displacement system of each displacement unit are obtained by the following method:

[0035] Multiple core samples were obtained from multiple displacement units of multiple heterogeneous reservoirs with different crude oil viscosities. The oil displacement efficiency of different displacement units was different.

[0036] The displacement system was used to displace each core sample with polymers at different molecular weights and different injection concentrations.

[0037] Obtain the changes in residual oil saturation of each core sample before and after polymer displacement is completed;

[0038] Based on the change in residual oil saturation, determine the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit.

[0039] The injection concentration of the displacement system adapted to each displacement unit is determined based on the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit and the change value of the remaining oil saturation.

[0040] Based on the injection concentration of the displacement system adapted to each displacement unit and the crude oil viscosity of the heterogeneous reservoir corresponding to each displacement unit, a viscosity-concentration relationship curve corresponding to the molecular weight of the displacement system of each displacement unit is fitted.

[0041] In a preferred embodiment, the injection concentration of each displacement system is calculated based on the viscosity-concentration relationship curves corresponding to the ground viscosity of the displacement system and the molecular weight of each displacement unit, further including:

[0042] The injection concentration of the first displacement unit was calculated based on the following viscosity-concentration relationship curve:

[0043] μ 地面 =3×10 -16 x1 5 -5×10 -12 x1 4 +2×10 -8 x1 3 -0.0005x1 2 +0.41x1-50.676;

[0044] The injection concentration of the second displacement unit was calculated based on the following viscosity-concentration relationship curve:

[0045] μ 地面 =2×10 -16 x2 5 -3×10 -12 x2 4 +1×10 -8 x2 3 -0.0002x2 2 +0.1076x2+30.78;

[0046] The injection concentration of the third displacement unit is calculated based on the following viscosity-concentration relationship curve:

[0047] μ 地面 =2×10 -16 x3 5 -1×10 -12 x3 4 +8×10 -10 x3 3 +0.0002x3 2 -0.2287x3+116.84;

[0048] The injection concentration of the fourth displacement unit is calculated based on the following viscosity-concentration relationship curve:

[0049] μ 地面 = -5 × 10 -16 x4 5 +7×10 -12 x4 4 -4×10 -8 x4 3 +0.001x4 2 -0.7676x4+214.78;

[0050] Where, μ 地面 The ground viscosity of the displacement system is given by x1, x2, x3, and x4, which are the injection concentrations of the displacement systems in the first, second, third, and fourth displacement units, respectively.

[0051] In a preferred embodiment, the relationship curve between the injected concentration and the injected volume is as follows:

[0052] x i =kv i +b;

[0053] Where, x i v represents the injection concentration of the displacement system for the i-th displacement unit, in mg / L; i denoted as PV, where PV is the injection volume of the displacement system in the i-th displacement unit; k is the fitting slope, and b is the fitting intercept.

[0054] In a preferred embodiment, before sequentially injecting the displacement system of each displacement unit according to the displacement order, the method further includes:

[0055] The region in the target heterogeneous oil reservoir with an oil displacement efficiency greater than or equal to the first oil displacement efficiency threshold is designated as a plugging layer;

[0056] The sealing layer is used to block or prevent radiation.

[0057] In a preferred embodiment, determining the injection timing of the displacement system for the next displacement unit based on the displacement pressure change curve of the previous displacement unit in the displacement sequence further includes:

[0058] Calculate the rate of change of displacement pressure based on the displacement pressure change curve.

[0059] When the pressure change rate is less than a preset pressure change rate threshold, it is determined that the injection timing of the next displacement unit displacement system has been reached.

[0060] In a preferred embodiment, determining the injection timing of the displacement system for the next displacement unit based on the displacement pressure change curve of the previous displacement unit in the displacement sequence further includes:

[0061] Calculate the rate of change of displacement pressure based on the displacement pressure change curve.

[0062] When the pressure change rate is less than a preset pressure change rate threshold and remains so for a preset duration, it is determined that the injection timing for the next displacement unit displacement system has been reached.

[0063] In a preferred embodiment, the oil displacement efficiency is calculated using the following formula:

[0064]

[0065] Where ED represents the oil displacement efficiency; S or S represents the residual oil saturation of the target heterogeneous reservoir after waterflooding; o The oil saturation of the target heterogeneous reservoir before water displacement.

[0066] Secondly, embodiments of this specification provide a polymer flooding exploitation apparatus for heterogeneous oil reservoirs, comprising:

[0067] The partitioning module is used to divide the target heterogeneous reservoir into multiple displacement units based on the oil displacement efficiency.

[0068] The first determining module is used to determine the polymer displacement system of each displacement unit, wherein the molecular weight, injection concentration, injection volume and injection pressure of the displacement system of each displacement unit are different.

[0069] The second determining module is used to determine the displacement order of the plurality of displacement units;

[0070] The displacement module is used to sequentially inject the displacement system of each displacement unit according to the displacement sequence, and to determine the injection timing of the displacement system of the next displacement unit according to the displacement pressure change curve of the previous displacement unit in the displacement sequence, so as to mine each displacement unit.

[0071] Furthermore, the partitioning module includes:

[0072] The first division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the first oil displacement efficiency threshold and greater than or equal to the second oil displacement efficiency threshold into the first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold.

[0073] The second partitioning unit is used to divide the region in the target heterogeneous reservoir where the oil displacement efficiency is less than the second oil displacement efficiency threshold into the second displacement unit.

[0074] In some preferred embodiments, the partitioning module includes:

[0075] The first division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the first oil displacement efficiency threshold and greater than or equal to the second oil displacement efficiency threshold into the first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold.

[0076] The second division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the second oil displacement efficiency threshold and greater than or equal to the third oil displacement efficiency threshold into the second displacement unit, wherein the third oil displacement efficiency threshold is less than the second oil displacement efficiency threshold.

[0077] The third partitioning unit is used to divide the region in the target heterogeneous reservoir where the oil displacement efficiency is less than the third oil displacement efficiency threshold but greater than or equal to the fourth oil displacement efficiency threshold into a third displacement unit, wherein the fourth oil displacement efficiency threshold is less than the third oil displacement efficiency threshold; and

[0078] The fourth division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the fourth oil displacement efficiency threshold but greater than or equal to the fifth oil displacement efficiency threshold into the fourth displacement unit, wherein the fifth oil displacement efficiency threshold is less than the fourth oil displacement efficiency threshold.

[0079] In some preferred embodiments, the first determining module further includes:

[0080] The molecular weight determination unit is used to determine the molecular weight of each displacement system based on the oil displacement efficiency of each displacement unit.

[0081] The injection concentration determination unit is used to calculate the injection concentration of each displacement system based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curve corresponding to the molecular weight of each displacement system in the displacement unit.

[0082] The injection volume determination unit is used to calculate the injection volume of each displacement system based on the injection concentration and the relationship curve between injection concentration and injection volume of each displacement system.

[0083] The injection pressure determination unit is used to determine the injection pressure of each displacement system based on the molecular weight, injection concentration, and injection volume of each displacement system.

[0084] Thirdly, embodiments of this specification provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method provided by the above-described technical solution.

[0085] Fourthly, embodiments of this specification also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method provided by the above-described technical solution.

[0086] Fifthly, embodiments of this specification also provide a computer program product, including at least one instruction or at least one program segment, wherein the at least one instruction or the at least one program segment is loaded and executed by a processor to implement the method provided by the above-described technical solution.

[0087] By adopting the above technical solution, the polymer flooding exploitation method, apparatus, and computer equipment for heterogeneous oil reservoirs provided in the embodiments of this specification utilize oil displacement efficiency to divide the target heterogeneous oil layer, match each divided displacement unit with a suitable displacement system, and adopt a staged exploitation method, which improves the accuracy and convenience of dividing each displacement unit; and enables the staged injection of displacement systems with different molecular weights into different levels of pore throats in each displacement unit at different injection concentrations, injection volumes, and injection pressures, thereby realizing the staged utilization and effective displacement of each displacement unit with residual oil in micropores of different scales, which is beneficial for the effective adjustment of interlayer heterogeneity.

[0088] To make the above and other objects, features and advantages of the embodiments of this specification more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0089] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0090] Figure 1 This specification illustrates a step diagram of a polymer flooding method for heterogeneous oil reservoirs provided in an embodiment of the present specification.

[0091] Figure 2This specification illustrates a schematic diagram of the steps involved in determining the polymer displacement system for each displacement unit in an embodiment of the present specification.

[0092] Figure 3 A schematic diagram illustrating the steps for calculating the injection concentration of each displacement system in the embodiments of this specification is shown;

[0093] Figure 4 The viscosity-concentration relationship curves corresponding to the molecular weight of each displacement unit in the displacement system are shown.

[0094] Figure 5 The curve showing the relationship between the injected concentration and the injected volume of the displacement system;

[0095] Figure 6 This specification illustrates the steps for determining the injection timing of the displacement system of the displacement unit following the current displacement unit in the displacement sequence, as shown in the embodiments of this specification.

[0096] Figure 7 This diagram illustrates another step in determining the injection timing of the displacement system of the displacement unit following the current displacement unit in the displacement sequence, as shown in the embodiments of this specification.

[0097] Figure 8 This specification shows a schematic diagram of a polymer flooding exploitation device for heterogeneous oil reservoirs provided in an embodiment of the present specification.

[0098] Figure 9 A schematic diagram of the partitioning module in an embodiment of this specification is shown;

[0099] Figure 10 This diagram illustrates yet another structural schematic of the partitioning module in an embodiment of this specification;

[0100] Figure 11 A schematic diagram of the structure of the first determining module in an embodiment of this specification is shown;

[0101] Figure 12 This diagram illustrates the structure of a computer device provided in an embodiment of this specification. Explanation of symbols:

[0102] 81. Divide into modules;

[0103] 811. First division unit;

[0104] 812. Second division unit;

[0105] 813. Third division unit;

[0106] 814. Fourth division unit;

[0107] 82. First Determining Module;

[0108] 821. Molecular weight determination unit;

[0109] 822. Injection Concentration Determination Unit;

[0110] 823. Injection volume determination unit;

[0111] 824. Injection pressure determination unit;

[0112] 83. Second Determination Module;

[0113] 84. Displacement module;

[0114] 1202. Computer equipment;

[0115] 1204, Processor;

[0116] 1206. Memory;

[0117] 1208. Drive mechanism;

[0118] 1210. Input / output module;

[0119] 1212. Input devices;

[0120] 1214. Output devices;

[0121] 1216. Presentation equipment;

[0122] 1218. Graphical User Interface;

[0123] 1220. Network interface;

[0124] 1222. Communication link;

[0125] 1224. Communication bus. Detailed Implementation

[0126] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this specification.

[0127] It should be noted that the terms "first," "second," etc., used in this specification, claims, and the foregoing drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0128] To address the aforementioned issues, this specification provides a polymer flooding method and apparatus for heterogeneous oil reservoirs. This method solves the problems of existing polymer injection methods, such as the polymer agent easily penetrating along high-permeability units, difficulty in utilizing residual oil in medium- and low-permeability units, limited affected volume, and low oil displacement efficiency. Figure 1 This is a schematic diagram illustrating the steps of a polymer flooding method for heterogeneous oil reservoirs provided in the embodiments of this specification. This specification provides the operational steps of the methods described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel. Specifically, as shown in the figures... Figure 1 As shown, the method may include:

[0129] S110: Based on the oil displacement efficiency, the target heterogeneous reservoir is divided into multiple displacement units.

[0130] The oil displacement efficiency can be calculated using the following formula:

[0131]

[0132] Where ED represents the oil displacement efficiency; S or S represents the residual oil saturation of the target heterogeneous reservoir after waterflooding; o The oil saturation of the target heterogeneous reservoir before water displacement.

[0133] It should be noted that after waterflooding of an oil reservoir, the same reservoir may contain one displacement unit or multiple different displacement units. In the embodiments of this specification, the target heterogeneous oil reservoir is divided into multiple displacement units based on the oil displacement efficiency. This ensures high accuracy in the division of each displacement unit while reducing the difficulty of the division operation, making it simple and convenient. In some other possible embodiments, parameters such as water production rate, water saturation, and permeability can also be used to divide the target heterogeneous oil reservoir.

[0134] S120: Determine the displacement system of each displacement unit, wherein the molecular weight, injection concentration, injection volume and injection pressure of the displacement system of each displacement unit are different.

[0135] In the embodiments of this specification, different displacement systems are used for different displacement units, so that the displacement system corresponding to each displacement unit can be effectively injected into the pore throat structure of the displacement unit, avoiding the problem of polymer cross-flow or ineffective injection, which is beneficial to increasing the formation adsorption thickness ratio, improving profile uniformity, and facilitating subsequent mining operations.

[0136] It should be noted that, in this specification, the displacement system corresponding to each displacement unit can be a single polymer, or a mixture of multiple polymers having the same molecular weight range and / or the same concentration range and / or the same volume range.

[0137] S130: Determine the displacement order of the plurality of displacement units.

[0138] In the embodiments described in this specification, each displacement unit is disposed of in descending order of oil displacement efficiency.

[0139] S140: The displacement system of each displacement unit is injected sequentially according to the displacement sequence, and the injection timing of the displacement system of the next displacement unit is determined according to the displacement pressure change curve of the previous displacement unit in the displacement sequence, so as to mine each displacement unit.

[0140] According to the displacement sequence, the displacement unit with the highest oil displacement efficiency is first disposed of, and the displacement pressure change curve of this unit during the displacement process is obtained. Based on the displacement pressure change curve, it is determined whether the next layer of displacement unit (i.e., the second-highest oil displacement unit) has been displaced, i.e., whether the displacement unit with the highest oil displacement efficiency has been completely disposed of. Then, during the displacement of the second-highest oil displacement unit, its displacement pressure change curve is obtained and used to determine whether the next layer of displacement unit has been displaced. The above steps are repeated until all the divided displacement units have been displaced in sequence. In other words, except for the first displacement unit in the displacement sequence which starts displacement automatically, the timing for the start of displacement of other displacement units is determined by the displacement pressure change curve of the displacement unit preceding it in the displacement sequence.

[0141] In the embodiments of this specification, the timing for the next displacement unit to begin displacement is determined based on the displacement pressure change curve of the previous displacement unit in the displacement sequence. This allows for a more accurate determination of the timing for switching the displacement system of each displacement unit, ensuring that each displacement unit can use a displacement system that is compatible with its oil displacement efficiency, pore throat structure, and other characteristics, thus guaranteeing the effectiveness of the displacement system.

[0142] This specification provides an embodiment of a polymer flooding method for heterogeneous oil reservoirs. It utilizes oil displacement efficiency to segment the target heterogeneous oil layer and matches each segmented displacement unit with a suitable displacement system. A staged, tiered extraction approach is employed, allowing displacement systems with different molecular weights to be injected at varying concentrations, volumes, and pressures into different levels of pore throats within each displacement unit at a constant production pressure differential. This achieves staged mobilization and effective displacement of residual oil in each displacement unit with varying micropore sizes, facilitating effective adjustment of inter-layer heterogeneity and maximizing the utilization of polymer flooding reserves in heterogeneous sandstone reservoirs, thereby improving reservoir recovery. Furthermore, intelligent production management enables automatic data acquisition and remote monitoring, automated process control, and timely information feedback, ultimately achieving economical and efficient polymer flooding development.

[0143] Furthermore, in the embodiments of this specification, step S110: dividing the target heterogeneous reservoir into multiple displacement units according to the distribution of oil displacement efficiency range may further include:

[0144] The region in the target heterogeneous reservoir with an oil displacement efficiency less than a first oil displacement efficiency threshold but greater than or equal to a second oil displacement efficiency threshold is divided into a first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold; for example, the first oil displacement efficiency threshold can be set to 45%, and the second oil displacement efficiency threshold can be set to 35%.

[0145] The region in the target heterogeneous reservoir with an oil displacement efficiency less than the second oil displacement efficiency threshold is divided into the second displacement unit.

[0146] If the displacement system corresponding to the first displacement unit is used to displace and develop the entire target heterogeneous reservoir, the displacement system of the first displacement unit will have difficulty penetrating the pore-throat structure of the second displacement unit, resulting in poor displacement of the remaining oil in the second displacement unit. If the displacement system corresponding to the second displacement unit is used to displace and develop the entire target heterogeneous reservoir, the displacement system of the second displacement unit will easily migrate within the pore-throat structure of the first displacement unit; neither approach achieves a good displacement effect. In this application and specification, the target heterogeneous reservoir is divided into at least two displacement units. After the division, the displacement systems corresponding to the two displacement units are used to develop the target heterogeneous reservoir in stages, utilizing the remaining oil in different displacement units in stages, thereby improving the effectiveness and economy of the displacement system, and ultimately achieving the goal of efficient polymer injection development.

[0147] In a preferred embodiment, dividing the region in the target heterogeneous reservoir where the oil displacement efficiency is less than a second oil displacement efficiency threshold into a second displacement unit may further include:

[0148] The region in the target heterogeneous reservoir with an oil displacement efficiency less than a second oil displacement efficiency threshold but greater than or equal to a third oil displacement efficiency threshold is divided into a second displacement unit, wherein the third oil displacement efficiency threshold is less than the second oil displacement efficiency threshold; for example, the third oil displacement efficiency threshold can be set to 25%.

[0149] The region within the target heterogeneous reservoir where the oil displacement efficiency is less than the third oil displacement efficiency threshold but greater than or equal to the fourth oil displacement efficiency threshold is designated as the third displacement unit, wherein the fourth oil displacement efficiency threshold is less than the third oil displacement efficiency threshold; the fourth oil displacement efficiency threshold can be set to 15%, and

[0150] The region in the target heterogeneous reservoir with an oil displacement efficiency less than the fourth oil displacement efficiency threshold but greater than or equal to the fifth oil displacement efficiency threshold is divided into the fourth displacement unit. The fifth oil displacement efficiency threshold is less than the fourth oil displacement efficiency threshold, and the fifth oil displacement efficiency threshold can be set to 5%.

[0151] Preferably, the target heterogeneous reservoir is divided into four displacement units, which makes the control granularity of the displacement system of each displacement unit finer, thereby improving the exploitation effect when using the displacement system corresponding to each displacement unit to displace it.

[0152] It should be noted that the number of displacement units obtained from the division can be adjusted according to the actual needs of reservoir development. The more displacement units there are, the better the graded utilization effect of the displacement system corresponding to each displacement unit when displacing each displacement unit. However, it will increase the complexity of polymer injection operation. Therefore, in the embodiments of this specification, taking into account both the recovery rate and the ease of operation, it is preferable to divide the target into 4 displacement units as shown in Table 1.

[0153] like Figure 2 As shown in the example of this specification, step S120, determining the polymer displacement system of each displacement unit, may include the following steps:

[0154] S210: Determine the molecular weight of each displacement system based on the oil displacement efficiency of each displacement unit.

[0155] In the embodiments of this specification, the molecular weight values ​​of the displacement units with different oil displacement efficiencies are shown in Table 1.

[0156] Table 1

[0157] level Oil displacement efficiency Molecular weight (range) First Displacement Unit 35％-45％ 25-30 million Second Displacement Unit 25％-35％ 20-25 million Third Displacement Unit 15％-25％ 15-20 million Fourth Displacement Unit 5％-15％ 10-15 million

[0158] S220: Based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curves corresponding to the molecular weight of each displacement unit displacement system, the injection concentration of each displacement system is calculated.

[0159] Generally, the injection concentration of the displacement system is positively correlated with the viscosity of the displaced phase (in the embodiments of this specification, the displaced phase is the crude oil of the heterogeneous reservoir). The higher the viscosity of the crude oil in the heterogeneous reservoir, the higher the concentration of the displacement system required to displace the crude oil is needed to achieve optimal flow control and better sweep efficiency. In the embodiments of this specification, the injection concentration of the corresponding displacement system is calculated based on the molecular weight of the displacement system in each displacement unit.

[0160] S230: The injection volume of each displacement system is calculated based on the injection concentration and the relationship curve between injection concentration and injection volume for each displacement system.

[0161] As the injection concentration of the displacement system increases, the viscosity also increases, leading to a smaller displacement band formed by polymer flooding. To ensure the sweep range, the injection volume of the displacement system should increase accordingly with the increase in the injection concentration. Furthermore, as the injection volume of the displacement system increases, the recovery rate and residual resistance coefficient increase. However, when the injection volume reaches a certain value, the recovery rate curve and residual resistance curve tend to flatten out. This is because an excessively large injection volume leads to a decrease in the utilization rate of some displacement systems. An excessively large injection volume increases costs and reduces economic efficiency. Therefore, a reasonable injection volume of the displacement system is necessary to achieve optimal oil recovery. In the embodiments of this specification, the injection volume of the corresponding displacement system is calculated based on the injection concentration of the displacement system in each displacement unit, which is beneficial for improving the displacement effect and increasing the recovery rate.

[0162] S240: Determine the injection pressure of each displacement system based on its molecular weight, injection concentration, and injection volume.

[0163] The higher the molecular weight and injection concentration of the displacement system, the higher the required injection pressure.

[0164] In the embodiments of this specification, the molecular weight of the displacement system applicable to each displacement unit is determined based on the oil displacement efficiency of each displacement unit. Then, the injection concentration, injection volume and injection pressure of the displacement system are calculated based on the molecular weight of the displacement system. Thus, the displacement system of each displacement unit is compatible with the oil displacement efficiency, pore throat structure and other characteristics of that displacement unit, which is beneficial to ensuring the effectiveness of the displacement system.

[0165] Furthermore, such as Figure 3 As shown in the embodiments of this specification, step S220: calculating the injection concentration of each displacement system based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curve corresponding to the molecular weight of each displacement unit displacement system, may include:

[0166] S310: Calculate the surface viscosity of the displacement system based on the crude oil viscosity of the target heterogeneous reservoir.

[0167] The ground viscosity of the displacement system can be calculated using the following formula:

[0168]

[0169] Where, μ 地面 To displace the ground viscosity of the system, μ 地下 A represents the underground viscosity of the displacement system; B represents the formation shear viscosity loss; C represents the shear viscosity loss of the surface pipeline system; the shear viscosity loss of the surface pipeline system may include the shear viscosity loss of surface pump station pipelines, wells, and blast holes.

[0170] μ地下 =Cμ 原油 ;

[0171] Where, μ 原油 Let C be the viscosity of the crude oil in the heterogeneous reservoir, where C is a constant coefficient greater than 0.

[0172] Preferably, when the value of C is in the range of 2 to 5, the displacement system can have a better flowability control effect on crude oil and a better sweeping effect.

[0173] For example, in the embodiments of this specification, the crude oil viscosity of the target heterogeneous reservoir is 14.3 mPa·s, the value of A can be 60%, and the value of B can be 40%. Then, the calculated surface viscosity of the displacement system is in the range of 119.2 mPa·s to 297.9 mPa·s.

[0174] S320: The injection concentration of each displacement system is calculated based on the viscosity-concentration relationship curves corresponding to the ground viscosity of the displacement system and the molecular weight of each displacement unit displacement system.

[0175] For example, in the embodiments of this specification, the molecular weights of the four displacement units obtained from the division of the target heterogeneous reservoir are determined to be 30 million, 25 million, 20 million, and 15 million, respectively. The viscosity-concentration relationship curves corresponding to the molecular weights of the displacement systems of each displacement unit are shown below. Figure 4 As shown, they are respectively:

[0176] The injection concentration of the first displacement unit was calculated based on the following viscosity-concentration relationship curve:

[0177]

[0178]

[0179]

[0180]

[0181] Where, μ 地面 Let x1 be the ground viscosity of the displacement system, and x2, x3, and x4 be the injection concentrations of the displacement systems in the first, second, third, and fourth displacement units, respectively. The calculated injection concentrations x1, x2, x3, and x4 for each displacement system are 2500-000 mg / L, 2000-2500 mg / L, 1500-2000 mg / L, and 1000-1500 mg / L, respectively.

[0182] Furthermore, in the embodiments of this specification, the relationship curve between the injected concentration and the injected volume of the displacement system is as follows:

[0183] x i =kv i +b;

[0184] Where, x i v represents the injection concentration of the displacement system for the i-th displacement unit, in mg / L; i denoted as PV, where PV is the injection volume of the displacement system in the i-th displacement unit; k is the fitting slope, and b is the fitting intercept.

[0185] Preferably, the value of k is 25000 and the value of b is 0, that is, the relationship curve between the injection concentration and the injection volume is:

[0186] x i =25000v i ;

[0187] That is, Figure 5 As shown, the injection volume of each displacement system can be calculated by substituting the calculated injection concentration of each displacement system into the injection concentration vs. injection volume curve.

[0188] It should be noted that the viscosity-concentration curves corresponding to the molecular weights of the displacement systems of the different displacement units, as well as the curves showing the relationship between injected concentration and injected volume, are adapted to the crude oil viscosity of the target heterogeneous reservoir used as an example. Therefore, the specific forms of expression of the above curves will differ for different heterogeneous reservoirs.

[0189] In the embodiments of this specification, the viscosity-concentration relationship curves corresponding to the molecular weight of the displacement system of each displacement unit are obtained by simulation based on a large amount of experimental data. The specific method may include the following steps:

[0190] Multiple core samples were obtained from multiple displacement units of multiple heterogeneous reservoirs with different crude oil viscosities. The oil displacement efficiency of different displacement units was different.

[0191] The displacement system was used to displace each core sample with polymers at different molecular weights and different injection concentrations.

[0192] Obtain the changes in residual oil saturation of each core sample before and after polymer displacement is completed;

[0193] Based on the change in residual oil saturation, determine the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit.

[0194] The injection concentration of the displacement system adapted to each displacement unit is determined based on the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit and the change value of the remaining oil saturation.

[0195] Based on the injection concentration of the displacement system adapted to each displacement unit and the crude oil viscosity of the heterogeneous reservoir corresponding to each displacement unit, a viscosity-concentration relationship curve corresponding to the molecular weight of the displacement system of each displacement unit is fitted.

[0196] Furthermore, the relationship curve between the injected concentration and the injected volume of the displacement system can be obtained through the following steps:

[0197] Multiple core samples were obtained from multiple displacement units of multiple heterogeneous reservoirs with different crude oil viscosities. The oil displacement efficiency of different displacement units was different.

[0198] The displacement system was used to displace each core sample with different molecular weights, different injection concentrations, and different injection volumes;

[0199] Obtain the changes in residual oil saturation of each core sample before and after polymer displacement is completed;

[0200] Based on the change in residual oil saturation, determine the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit.

[0201] The injection concentration of the displacement system adapted to each displacement unit is determined based on the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit and the change value of the remaining oil saturation.

[0202] The injection volume of the displacement system adapted to each displacement unit is determined based on the injection concentration of the displacement system adapted to each displacement unit and the remaining oil saturation.

[0203] Based on the injection concentration and injection volume of the displacement system adapted to each displacement unit, a curve showing the relationship between injection concentration and injection volume is obtained by fitting.

[0204] Table 2 summarizes the molecular weight, injection concentration, and injection volume of each displacement unit's displacement system.

[0205] Table 2

[0206] Displacement unit Oil displacement efficiency Molecular weight (range) concentration Volume range First Displacement Unit 35％-45％ 25-30 million 2500-3000 mg / L 0.1-0.12PV Second Displacement Unit 25％-35％ 20-25 million 2000-2500mg / L 0.08-0.1PV Third Displacement Unit 15％-25％ 15-20 million 1500-2000 mg / L 0.06-0.08PV Fourth Displacement Unit 5％-15％ 10-15 million 1000-1500mg / L 0.04-0.06PV

[0207] It should be noted that the molecular weight, injection concentration, and injection volume of each displacement unit's displacement system calculated and summarized in Table 2 above are adapted to the crude oil viscosity of the target heterogeneous reservoir used as an example. Therefore, for different heterogeneous reservoirs, the molecular weight, injection concentration, and injection volume of their displacement systems will differ from those in Table 2.

[0208] Furthermore, based on the molecular weight, injection concentration, and injection volume of each displacement system, the injection pressure of each displacement system can be determined as follows:

[0209] Injection pressure is positively correlated with injection concentration, and injection pressure is also positively correlated with injection volume.

[0210] Specifically, for the first displacement unit, the injection pressure can be set to a maximum of 12 MPa. The first displacement unit has a high injection concentration and high injection pressure, which can effectively seal its large channels, thereby adjusting the injection profile, preventing the displacement system from breaking through and flowing out of the oil well, and improving the utilization of remaining oil.

[0211] After the displacement operation of the first displacement unit is completed, the second displacement unit is then subjected to displacement in stages. The injection pressure during the displacement of the second displacement unit should be lower than the injection pressure during the displacement of the first displacement unit. The injection concentration of the displacement system in the second displacement unit is adjusted according to the change in injection pressure to ensure that it is lower than the injection concentration of the displacement system in the first displacement unit.

[0212] The third and fourth displacement units are displaced in the same way, and the injection pressure of the displacement system of each displacement unit is less than the injection pressure of the displacement system of the displacement unit preceding it in the displacement sequence.

[0213] As shown in Table 3, the polymer flooding method for heterogeneous reservoirs provided in this specification divides the target heterogeneous reservoir into multiple displacement units and injects displacement systems with different molecular weights into each displacement unit at different injection concentrations, volumes, and pressures, thereby effectively utilizing the remaining oil in each displacement unit. As shown in Table 3, in the embodiments of this specification, the decrease in remaining oil saturation before and after polymer flooding follows the following pattern: third displacement unit > second displacement unit > fourth displacement unit > first displacement unit.

[0214] Table 3

[0215]

[0216] Furthermore, to improve the displacement effect on the remaining oil in each displacement unit, in the above embodiments of this specification, before sequentially injecting the displacement system of each displacement unit according to the displacement order, the following steps are further included:

[0217] The region in the target heterogeneous oil reservoir with an oil displacement efficiency greater than or equal to the first oil displacement efficiency threshold is designated as a plugging layer;

[0218] The sealing layer is used to block or prevent radiation.

[0219] In other words, the plugging layer with an oil displacement efficiency greater than 45% is not the target of the polymer flooding method for heterogeneous reservoirs provided in the embodiments of this specification. Before injecting polymer into other displacement units, the old wells in the plugging layer are plugged first, and the new wells are subjected to anti-percussion treatment to eliminate the interference of the pore throat structure of the plugging layer on the injection of other displacement units.

[0220] Furthermore, in the embodiments of this specification, step S140: sequentially injecting the displacement system of each displacement unit according to the displacement order can be further described as follows:

[0221] Furthermore, such as Figure 6 As shown in the embodiments of this specification, step S140, determining the injection timing of the displacement system of the subsequent displacement unit based on the displacement pressure change curve of the previous displacement unit in the displacement sequence, further includes:

[0222] S610: Calculate the rate of change of displacement pressure based on the displacement pressure change curve;

[0223] S620: When the pressure change rate is less than the preset pressure change rate threshold, it is determined that the injection timing of the next displacement unit displacement system has been reached.

[0224] When the displacement system is first injected into its corresponding displacement unit, it rapidly fills the pore throat structure of that unit, causing the displacement pressure to change rapidly. As the displacement system continues to advance, the pore throat structure of the unit is gradually filled, the advancement speed of the displacement system slows down, and the displacement pressure change rate decreases rapidly. Therefore, when the displacement pressure change rate drops to a preset pressure change rate threshold, it can be determined that the current displacement unit has completed displacement and the next displacement unit can proceed. This means determining the optimal injection timing for the displacement system into the next displacement unit in the displacement sequence.

[0225] Furthermore, such as Figure 7 As shown, in some preferred embodiments, determining the injection timing of the displacement system in the next displacement unit based on the displacement pressure change curve of the previous displacement unit in the displacement sequence further includes:

[0226] S710: Calculate the rate of change of displacement pressure based on the displacement pressure change curve;

[0227] S720: When the pressure change rate is less than the preset pressure change rate threshold and remains so for a preset duration, it is determined that the injection timing of the next displacement unit displacement system has been reached.

[0228] This avoids situations where the pressure change rate is less than the preset pressure change rate threshold, thereby improving the accuracy of judging the timing of the displacement system injection for each displacement unit and improving the displacement efficiency of the displacement system.

[0229] like Figure 8 As shown in the embodiments of this specification, a polymer flooding exploitation device for heterogeneous oil reservoirs is also provided, comprising:

[0230] The partitioning module 81 is used to divide the target heterogeneous reservoir into multiple displacement units based on the oil displacement efficiency.

[0231] The first determining module 82 is used to determine the polymer displacement system of each displacement unit, wherein the molecular weight, injection concentration, injection volume and injection pressure of the displacement system of each displacement unit are different.

[0232] The second determining module 83 is used to determine the displacement order of the plurality of displacement units;

[0233] The displacement module 84 is used to sequentially inject the displacement system of each displacement unit according to the displacement sequence, and to determine the injection timing of the displacement system of the next displacement unit according to the displacement pressure change curve of the previous displacement unit in the displacement sequence, so as to mine each displacement unit.

[0234] like Figure 9 As shown, the partitioning module 81 includes:

[0235] The first division unit 811 is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the first oil displacement efficiency threshold and greater than or equal to the second oil displacement efficiency threshold into the first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold.

[0236] The second division unit 812 is used to divide the region in the target heterogeneous reservoir where the oil displacement efficiency is less than the second oil displacement efficiency threshold into the second displacement unit.

[0237] like Figure 10 As shown, in another feasible embodiment, the partitioning module 81 includes:

[0238] The first division unit 811 is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the first oil displacement efficiency threshold and greater than or equal to the second oil displacement efficiency threshold into the first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold.

[0239] The second division unit 812 is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the second oil displacement efficiency threshold and greater than or equal to the third oil displacement efficiency threshold into a second displacement unit, wherein the third oil displacement efficiency threshold is less than the second oil displacement efficiency threshold.

[0240] The third partitioning unit 813 is used to partition the region in the target heterogeneous reservoir where the oil displacement efficiency is less than the third oil displacement efficiency threshold but greater than or equal to the fourth oil displacement efficiency threshold into a third displacement unit, wherein the fourth oil displacement efficiency threshold is less than the third oil displacement efficiency threshold; and

[0241] The fourth division unit 814 is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the fourth oil displacement efficiency threshold and greater than or equal to the fifth oil displacement efficiency threshold into the fourth displacement unit, wherein the fifth oil displacement efficiency threshold is less than the fourth oil displacement efficiency threshold.

[0242] like Figure 11 As shown, the first determining module 82 further includes:

[0243] The molecular weight determination unit 821 is used to determine the molecular weight of each displacement system based on the oil displacement efficiency of each displacement unit.

[0244] The injection concentration determination unit 822 is used to calculate the injection concentration of each displacement system based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curve corresponding to the molecular weight of each displacement system of the displacement unit.

[0245] The injection volume determination unit 823 is used to calculate the injection volume of each displacement system based on the injection concentration and the relationship curve between injection concentration and injection volume of each displacement system.

[0246] The injection pressure determination unit 824 is used to determine the injection pressure of each displacement system based on the molecular weight, injection concentration and injection volume of each displacement system.

[0247] The beneficial effects obtained by the apparatus provided in the embodiments of this specification are consistent with the beneficial effects obtained by the methods described above, and will not be repeated here.

[0248] like Figure 12As shown, this specification provides a computer device according to an embodiment of the present specification. A polymer flooding exploitation device for heterogeneous oil reservoirs in this specification can be the computer device in this embodiment, executing the methods described above. The computer device 1202 may include one or more processors 1204, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 1202 may also include any memory 1206 for storing information of any kind, such as code, settings, data, etc. Non-limitingly, for example, the memory 1206 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Further, any memory can provide volatile or non-volatile retention of information. Further, any memory can represent a fixed or removable component of the computer device 1202. In one case, when the processor 1204 executes associated instructions stored in any memory or combination of memories, the computer device 1202 can perform any operation of the associated instructions. The computer device 1202 also includes one or more drive mechanisms 1208 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0249] Computer device 1202 may also include an input / output module 1210 (I / O) for receiving various inputs (via input device 1212) and providing various outputs (via output device 1214). A specific output mechanism may include a presentation device 1216 and an associated graphical user interface (GUI) 1218. In other embodiments, the input / output module 1210 (I / O), input device 1212, and output device 1214 may be omitted, and the device may function solely as a computer device within a network. Computer device 1202 may also include one or more network interfaces 1220 for exchanging data with other devices via one or more communication links 1222. One or more communication buses 1224 couple the components described above together.

[0250] Communication link 1222 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 1222 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0251] Corresponding to, for example Figures 1 to 3 and Figure 6In addition to the method shown, embodiments of this specification also provide a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above-described method.

[0252] This specification also provides computer-readable instructions, wherein when a processor executes the instructions, the program therein causes the processor to perform the following... Figures 1 to 3 and Figure 6 The method shown.

[0253] This specification also provides a computer program product, including at least one instruction or at least one program segment, wherein the at least one instruction or the at least one program segment is loaded and executed by a processor to achieve the following: Figures 1 to 3 and Figure 6 The method shown.

[0254] It should be understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0255] It should also be understood that, in the embodiments of this specification, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this specification generally indicates that the preceding and following related objects have an "or" relationship.

[0256] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this specification can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this specification.

[0257] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0258] In the several embodiments provided in this specification, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0259] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described in this specification, depending on actual needs.

[0260] Furthermore, the functional units in the various embodiments of this specification can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0261] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this specification, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this specification. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0262] This specification uses specific embodiments to illustrate the principles and implementation methods of this specification. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this specification. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this specification. Therefore, the content of this specification should not be construed as a limitation of this specification.

Claims

1. A polymer flooding method for developing heterogeneous oil reservoirs, characterized in that, include: Based on the oil displacement efficiency, the target heterogeneous reservoir is divided into multiple displacement units; The polymer displacement system of each displacement unit is determined, and the molecular weight, injection concentration, injection volume and injection pressure of the displacement system of each displacement unit are different; Determine the displacement order of the multiple displacement units; The displacement systems of each displacement unit are injected sequentially according to the displacement sequence, and the injection timing of the displacement system of the next displacement unit is determined according to the displacement pressure change curve of the previous displacement unit in the displacement sequence, so as to mine each displacement unit. The displacement system for each displacement unit includes: The molecular weight of each displacement system is determined based on the oil displacement efficiency of each displacement unit. Based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curves corresponding to the molecular weight of each displacement unit displacement system, the injection concentration of each displacement system is calculated. The injection volume of each displacement system was calculated based on the injection concentration and the relationship curve between injection concentration and injection volume for each displacement system. The injection pressure of each displacement system is determined based on its molecular weight, injection concentration, and injection volume. Specifically, the injection concentration of each displacement system is calculated based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curve corresponding to the molecular weight of each displacement unit's displacement system, further including: The surface viscosity of the displacement system is calculated based on the crude oil viscosity of the target heterogeneous reservoir. Based on the ground viscosity of the displacement system and the viscosity-concentration relationship curves corresponding to the molecular weight of each displacement unit, the injection concentration of each displacement system is calculated. The viscosity-concentration relationship curves corresponding to the molecular weight of each displacement unit's displacement system were obtained using the following method: Multiple core samples were obtained from multiple displacement units of multiple heterogeneous reservoirs with different crude oil viscosities. The oil displacement efficiency of different displacement units was different. The displacement system was used to displace each core sample with polymers at different molecular weights and different injection concentrations. Obtain the changes in residual oil saturation of each core sample before and after polymer displacement is completed; Based on the change in residual oil saturation, determine the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit. The injection concentration of the displacement system adapted to each displacement unit is determined based on the molecular weight of the displacement system that is compatible with the oil displacement efficiency of each displacement unit and the change value of the remaining oil saturation. Based on the injection concentration of the displacement system adapted to each displacement unit and the crude oil viscosity of the heterogeneous reservoir corresponding to each displacement unit, a viscosity-concentration relationship curve corresponding to the molecular weight of the displacement system of each displacement unit is fitted.

2. The polymer flooding method for heterogeneous oil reservoirs according to claim 1, characterized in that, Based on the oil displacement efficiency, the target heterogeneous reservoir is divided into multiple displacement units, further including: The region in the target heterogeneous oil reservoir with an oil displacement efficiency less than a first oil displacement efficiency threshold but greater than or equal to a second oil displacement efficiency threshold is divided into a first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold. The region in the target heterogeneous reservoir with an oil displacement efficiency less than the second oil displacement efficiency threshold is divided into the second displacement unit.

3. The polymer flooding method for heterogeneous oil reservoirs according to claim 2, characterized in that, The formula for calculating the ground viscosity of the displacement system is as follows: Where, μ 地面 To displace the ground viscosity of the system, μ 地下 A represents the underground viscosity of the displacement system; B represents the formation shear viscosity loss; C represents the surface pipeline system shear viscosity loss. μ 地下 =Cμ 原油 ; Where, μ 原油 Let C be the viscosity of the crude oil in the heterogeneous reservoir, where C is a constant coefficient greater than 0.

4. The polymer flooding method for heterogeneous oil reservoirs according to claim 2, characterized in that, The region in the target heterogeneous reservoir with an oil displacement efficiency less than a second oil displacement efficiency threshold is divided into a second displacement unit, further comprising: The region in the target heterogeneous reservoir with an oil displacement efficiency less than the second oil displacement efficiency threshold but greater than or equal to the third oil displacement efficiency threshold is divided into the second displacement unit, wherein the third oil displacement efficiency threshold is less than the second oil displacement efficiency threshold. The region within the target heterogeneous reservoir where the oil displacement efficiency is less than a third oil displacement efficiency threshold but greater than or equal to a fourth oil displacement efficiency threshold is designated as a third displacement unit, wherein the fourth oil displacement efficiency threshold is less than the third oil displacement efficiency threshold; and The region in the target heterogeneous reservoir with an oil displacement efficiency less than the fourth oil displacement efficiency threshold but greater than or equal to the fifth oil displacement efficiency threshold is divided into the fourth displacement unit, wherein the fifth oil displacement efficiency threshold is less than the fourth oil displacement efficiency threshold.

5. The polymer flooding method for heterogeneous oil reservoirs according to claim 4, characterized in that, Based on the ground viscosity of the displacement system and the viscosity-concentration relationship curves corresponding to the molecular weight of each displacement unit, the injection concentration of each displacement system is calculated, further including: The injection concentration of the first displacement unit was calculated based on the following viscosity-concentration relationship curve: The injection concentration of the second displacement unit was calculated based on the following viscosity-concentration relationship curve: The injection concentration of the third displacement unit is calculated based on the following viscosity-concentration relationship curve: The injection concentration of the fourth displacement unit is calculated based on the following viscosity-concentration relationship curve: Where, μ 地面 The ground viscosity of the displacement system is given by x1, x2, x3, and x4, which are the injection concentrations of the displacement systems in the first, second, third, and fourth displacement units, respectively.

6. The polymer flooding method for heterogeneous reservoirs according to claim 2, characterized in that, The curve showing the relationship between the injection concentration and the injection volume is as follows: x i =kv i +b; Where, x i v represents the injection concentration of the displacement system for the i-th displacement unit, in mg / L; i denoted as PV, where PV is the injection volume of the displacement system in the i-th displacement unit; k is the fitting slope, and b is the fitting intercept.

7. The polymer flooding method for heterogeneous reservoirs according to claim 2, characterized in that, Before sequentially injecting the displacement system of each displacement unit according to the displacement order, the process further includes: The region in the target heterogeneous oil reservoir with an oil displacement efficiency greater than or equal to the first oil displacement efficiency threshold is designated as a plugging layer; The sealing layer is used to block or prevent radiation.

8. The polymer flooding method for heterogeneous oil reservoirs according to claim 1, characterized in that, Determining the injection timing of the displacement system in the next displacement unit based on the displacement pressure change curve of the previous displacement unit in the displacement sequence further includes: Calculate the rate of change of displacement pressure based on the displacement pressure change curve. When the pressure change rate is less than a preset pressure change rate threshold, it is determined that the injection timing of the next displacement unit displacement system has been reached.

9. The polymer flooding method for heterogeneous reservoirs according to claim 1, characterized in that, Determining the injection timing of the displacement system in the next displacement unit based on the displacement pressure change curve of the previous displacement unit in the displacement sequence further includes: Calculate the rate of change of displacement pressure based on the displacement pressure change curve. When the pressure change rate is less than a preset pressure change rate threshold and remains so for a preset duration, it is determined that the injection timing for the next displacement unit displacement system has been reached.

10. The polymer flooding method for heterogeneous oil reservoirs according to claim 1, characterized in that, The oil displacement efficiency is calculated using the following formula: Where ED represents the oil displacement efficiency; S or S represents the residual oil saturation of the target heterogeneous reservoir after waterflooding; o The oil saturation of the target heterogeneous reservoir before water displacement.

11. A polymer flooding exploitation device for heterogeneous oil reservoirs, characterized in that, The method applicable to any one of claims 1 to 10, comprising: The partitioning module is used to divide the target heterogeneous reservoir into multiple displacement units based on the oil displacement efficiency. The first determining module is used to determine the polymer displacement system of each displacement unit, wherein the molecular weight, injection concentration, injection volume and injection pressure of the displacement system of each displacement unit are different. The second determining module is used to determine the displacement order of the plurality of displacement units; The displacement module is used to sequentially inject the displacement system of each displacement unit according to the displacement sequence, and to determine the injection timing of the displacement system of the next displacement unit according to the displacement pressure change curve of the previous displacement unit in the displacement sequence, so as to mine each displacement unit.

12. The polymer flooding exploitation device for heterogeneous oil reservoirs according to claim 11, characterized in that, The partitioning module includes: The first division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the first oil displacement efficiency threshold and greater than or equal to the second oil displacement efficiency threshold into the first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold. The second partitioning unit is used to divide the region in the target heterogeneous reservoir where the oil displacement efficiency is less than the second oil displacement efficiency threshold into the second displacement unit.

13. A polymer flooding exploitation device for heterogeneous oil reservoirs according to claim 11, characterized in that, The partitioning module includes: The first division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the first oil displacement efficiency threshold and greater than or equal to the second oil displacement efficiency threshold into the first displacement unit, wherein the second oil displacement efficiency threshold is less than the first oil displacement efficiency threshold. The second division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the second oil displacement efficiency threshold and greater than or equal to the third oil displacement efficiency threshold into the second displacement unit, wherein the third oil displacement efficiency threshold is less than the second oil displacement efficiency threshold. The third partitioning unit is used to divide the region in the target heterogeneous reservoir where the oil displacement efficiency is less than the third oil displacement efficiency threshold but greater than or equal to the fourth oil displacement efficiency threshold into a third displacement unit, wherein the fourth oil displacement efficiency threshold is less than the third oil displacement efficiency threshold; and The fourth division unit is used to divide the region in the target heterogeneous oil reservoir where the oil displacement efficiency is less than the fourth oil displacement efficiency threshold but greater than or equal to the fifth oil displacement efficiency threshold into the fourth displacement unit, wherein the fifth oil displacement efficiency threshold is less than the fourth oil displacement efficiency threshold.

14. The polymer flooding exploitation device for heterogeneous oil reservoirs according to claim 11, characterized in that, The first determining module further includes: The molecular weight determination unit is used to determine the molecular weight of each displacement system based on the oil displacement efficiency of each displacement unit. The injection concentration determination unit is used to calculate the injection concentration of each displacement system based on the viscosity of the crude oil in the target heterogeneous reservoir and the viscosity-concentration relationship curve corresponding to the molecular weight of each displacement system in the displacement unit. The injection volume determination unit is used to calculate the injection volume of each displacement system based on the injection concentration and the relationship curve between injection concentration and injection volume of each displacement system. The injection pressure determination unit is used to determine the injection pressure of each displacement system based on the molecular weight, injection concentration, and injection volume of each displacement system.

15. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 10.

16. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 10.

17. A computer program product, characterized in that, It includes at least one instruction or at least one program segment, said at least one instruction or said at least one program segment being loaded and executed by a processor to implement the method as claimed in any one of claims 1 to 10.

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