Method for improving oil extraction speed through combination of fault block oil reservoir water flooding encryption and polymer flooding

Abstract

The invention discloses a method for improving oil extraction speed through combination of fault block oil reservoir water drive encryption and polymer flooding, relates to the technical field of oil field development, and solves the problems of poor development effect and low oil extraction speed due to economic limitation of a long-well-section oil reservoir which can only adopt one set of well pattern. The method comprises the following steps: S1, preferably selecting an implementation block according to polymer flooding application conditions; s2, implementing block water flooding and polymer flooding collaborative well pattern reconstruction; s3, implementing block water-driven three-dimensional potential tapping; s4, performing an indoor physical model experiment, and screening polymer products suitable for implementation of blocks; s5, implementing block injection parameter optimization; and S6, block selective machine injection is implemented, and the comprehensive mining effect is improved. According to the method for improving the oil extraction speed by combining water drive and polymer drive of the fault block oil reservoir, the development thought that water drive and polymer drive are combined is adopted, after water drive encryption and well pattern reconstruction are conducted on the basis of meeting the polymer drive requirement, three-dimensional potential tapping is conducted on the basis of current water drive, then polymer drive development is conducted in good time, and the oil extraction speed of the oil reservoir is improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to a method for improving oil production rate by combining water flooding and polymer flooding in fault-block reservoirs. Background Technology

[0002] Fault-block reservoirs are an important type of oil reservoir development in my country, accounting for about one-third of the total geological reserves and annual oil production, and occupying a vital position in the country's petroleum resources. Among them, long-section fault-block reservoirs have large oil layer spans and strong heterogeneity. Due to economic constraints, using a single well network for water injection development results in significant inconsistencies in the plane, inter-layer, and intra-layer conditions, leading to poor development efficiency and low oil production rates. Polymer flooding, as an effective means to improve oil production rates, has relatively less stringent requirements on reservoir conditions compared to other tertiary oil recovery technologies. However, compared to water flooding, it requires smaller well spacing for the same permeability. Generally, direct polymer flooding requires well network adjustments, deploying new wells to reduce the injection-production well spacing, resulting in high investment and economic risks. Therefore, carrying out combined water flooding and polymer flooding to improve oil production rates in such reservoirs presents a significant challenge. Summary of the Invention

[0003] This invention addresses the problem in the prior art where long-section oil reservoirs, limited by economic constraints, can only be developed using a single well pattern, resulting in poor development efficiency and low oil production rates. It provides a method for improving oil production rates in fault-block oil reservoirs by combining water-drive infill drilling and polymer flooding. This method employs a combined development approach of water-drive and polymer flooding. Water-drive infill drilling is performed based on meeting polymer flooding requirements. After well pattern reconstruction, the current water-drive system is used for comprehensive potential tapping, and then polymer flooding development is initiated as needed to improve the reservoir's oil production rate.

[0004] The present invention solves its problem through the following technical solution: the method for improving oil production rate by combining waterflooding and polymer flooding in fault-block reservoirs includes the following steps:

[0005] S1: Based on the applicable conditions of polymer flooding, the preferred implementation block is selected;

[0006] S2: Based on the selected implementation blocks, the well network of the implementation blocks is reconstructed in a coordinated manner using water drive and polymer drive.

[0007] S3: Conduct comprehensive exploration of the potential of water drive in the implementation block;

[0008] S4: Screen polymer products suitable for implementation blocks through indoor physical model experiments;

[0009] S5: Optimize the block injection parameters;

[0010] S6: Select an appropriate time to convert the implementation block to polymer injection development to improve the overall mining effect.

[0011] Preferably, step S1, based on the applicable conditions of polymer flooding, preferably includes the following method for implementing blocks:

[0012] S101. Obtain basic geological parameters of the development block;

[0013] S102, Preferred suitable polymer-driven implementation blocks.

[0014] Preferably, the basic geological parameters of the development block obtained in step S101 include: lithology, reservoir temperature, formation water salinity, divalent cation concentration, effective permeability, formation crude oil viscosity, permeability variation coefficient, reservoir depth, and crude oil relative density.

[0015] Preferably, step S102 is suitable for the following conditions for implementing the polymer-driven block:

[0016] Sandstone reservoirs with reservoir temperatures greater than 25℃ and less than 80℃; formation water salinity less than 30,000 mg / L; divalent cation concentration less than 2,000 mg / L; effective permeability greater than 15 mD and less than 3,000 mD; formation crude oil viscosity greater than 1 mPa·s and less than 200 mPa·s; permeability variation coefficient greater than 0.5 and less than 0.9; reservoir depth less than 2,100 m; and crude oil relative density greater than 0.72 and less than 0.97.

[0017] Preferably, step S2, based on a preferred implementation block, involves a method for reconstructing a water-drive and polymer-drive coordinated well network in the implementation block, including:

[0018] S201. Obtain geological and development parameters for the preferred block;

[0019] S202, Perform well network reconstruction.

[0020] Preferably, in step S201, the geological and development parameters of the preferred block are obtained as follows:

[0021] The preferred geological parameters for the block include: the block's structural characteristics, sedimentary characteristics, oil layer development characteristics, microscopic pore throat characteristics, heterogeneity characteristics, oil-water distribution and fluid properties, reservoir pressure and temperature, and geological reserves;

[0022] The optimal block development parameters include: well pattern, well spacing, number of development wells, water drive control level, reservoir utilization status, current injection and production status, water cut, recovery rate, and oil production rate.

[0023] Preferably, the method for well pattern reconstruction in step S202 is as follows:

[0024] The well network is adjusted primarily by forming a five-point polymer flooding well network, supplemented by a flexible well network near faults and structural edges.

[0025] Based on the reservoir geological characteristics, methods such as densification and flexible supplementary well placement were adopted to adjust the well spacing to below 200m, thereby achieving a water drive control rate of over 80%.

[0026] Preferably, the method for implementing block water-drive three-dimensional potential tapping in step S3 is as follows:

[0027] After the well network is adjusted, water flooding is implemented to tap the potential. New wells are perforated and put into production according to the water flooding situation of the oil layer, and old wells are repaired and water is plugged. In the plane, the injection and production system is adjusted by strengthening the adjustment of the injection and production system, and in the vertical direction, the inter-layer adjustment is strengthened to alleviate the contradiction between the plane and the inter-layer. A suitable well network for polymer flooding is gradually formed, so that the polymer flooding layer control degree is more than 70%.

[0028] Preferably, the method for screening polymer products suitable for the implementation block in step S4 is as follows:

[0029] Select polymer products based on the preferred block permeability and pore radius;

[0030] Indoor physical model experiments were conducted to evaluate the basic physicochemical properties, thickening properties, long-term stability, shear resistance, flow properties, and oil displacement performance of polymers. Polymer flooding products with good stability and shear resistance (generally viscosity retention rate above 70%), good flowability (low injection pressure and small resistance coefficient under the same conditions) and good oil displacement performance were selected. Indoor oil displacement experiments improved the recovery rate by more than 8 percentage points.

[0031] Preferably, the project for optimizing block injection parameters in step S5 includes:

[0032] Polymer injection parameter optimization includes injection method optimization, injection concentration optimization, polymer dosage optimization, and injection speed optimization; the injection method generally includes single-stage plug injection or multi-stage plug injection;

[0033] The optimization of polymerization injection parameters generally employs numerical simulation, comparison with similar blocks, or a combination of both methods.

[0034] Preferably, the method for selectively injecting polymer into the implementation block in step S6 to improve the overall mining effect is as follows:

[0035] Based on the water drive potential tapping situation of the block, select an appropriate time to switch to polymer injection development. Generally, water drive potential tapping is followed by polymer drive development after 2 to 3 years.

[0036] The specific method for polymer injection development is as follows: When injecting polymer, first conduct well group test injection to determine the appropriate injection rate and injection concentration, and then carry out full-area polymer injection to ensure the smooth progress of polymer flooding. At the same time, strengthen polymer flooding profile monitoring and corresponding adjustment measures to ensure the polymer flooding effect and achieve the goal of improving oil production rate.

[0037] Compared with the above-mentioned background technology, the present invention has the following beneficial effects:

[0038] This invention, based on the actual conditions of the reservoir, comprehensively considers water-drive infill and polymer flooding. It first restructures the well network to reduce well spacing, then converts polymer injection wells to polymer injection wells in advance, improving water-drive control and maximizing water-drive potential to increase oil production rate. After water cut increases, it switches to polymer flooding to further improve recovery rate, achieving a "1+1>2" development effect. This overcomes the problems of insufficient economic efficiency from simple water-drive infill, limited subsequent adjustment measures due to rapid water cut increases, and high economic risk from simple polymer flooding. It achieves better economic results, meets the needs of oilfield development, improves oilfield development performance, and increases oil production rate and ultimate recovery rate.

[0039] In the field application of the method of this invention on the X35 fault block, by comparing the recovery rate with different development schemes, the combined water-drive infiltration and polymer flooding scheme for the X35 fault block improved the recovery rate by 9.01 percentage points compared with the basic scheme and by 4.5 percentage points compared with the water-drive infiltration scheme. Attached Figure Description

[0040] Figure 1 This is a flowchart of a method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs according to the present invention.

[0041] Figure 2 This is a comparison chart of the extraction degree of different development schemes applied to the X35 block in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0043] like Figure 1 As shown, a method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs includes the following steps:

[0044] S1: Based on the applicable conditions of polymer flooding, the preferred implementation block is selected; specifically, the following steps are included:

[0045] S101. Obtain basic geological parameters of the development block; the basic geological parameters of the development block include: lithology, reservoir temperature, formation water salinity, divalent cation concentration, effective permeability, formation crude oil viscosity, permeability variation coefficient, reservoir depth and crude oil relative density.

[0046] S102, Preferred suitable polymer-driven implementation blocks.

[0047] S2: Based on the selected implementation blocks, perform coordinated well network reconstruction using water-drive and polymer-drive methods; specifically including the following steps:

[0048] S201. Obtain geological and development parameters for the preferred block;

[0049] The preferred geological parameters for the block include: the block's structural characteristics, sedimentary characteristics, oil layer development characteristics, microscopic pore throat characteristics, heterogeneity characteristics, oil-water distribution and fluid properties, reservoir pressure and temperature, and geological reserves;

[0050] The optimal block development parameters include: well pattern, well spacing, number of development wells, water drive control level, reservoir utilization status, current injection and production status, water cut, recovery rate, and oil production rate.

[0051] S202. Perform well network reconstruction. The specific method is as follows:

[0052] The well network is adjusted primarily by forming a five-point polymer flooding well network, supplemented by a flexible well network near faults and structural edges.

[0053] Based on the reservoir geological characteristics, methods such as densification and flexible supplementary well placement were adopted to adjust the well spacing to below 200m, thereby achieving a water drive control rate of over 80%.

[0054] S3: Three-dimensional potential tapping of the water drive implementation block; specific methods are as follows:

[0055] After the well network is adjusted, water flooding is implemented to tap the potential. New wells are perforated and put into production according to the water flooding situation of the oil layer, and old wells are repaired and water is plugged. In the plane, the injection and production system is adjusted by strengthening the adjustment of the injection and production system, and in the vertical direction, the inter-layer adjustment is strengthened to alleviate the contradiction between the plane and the inter-layer. A suitable well network for polymer flooding is gradually formed, so that the polymer flooding layer control degree is more than 70%.

[0056] S4: Screen suitable polymer products for the implementation area through indoor physical model experiments; the specific method is as follows:

[0057] Select polymer products based on the preferred block permeability and pore radius;

[0058] Indoor physical model experiments were conducted to evaluate the basic physicochemical properties, thickening properties, long-term stability, shear resistance, flow properties, and oil displacement performance of polymers. Polymer flooding products with good stability and shear resistance (generally viscosity retention rate above 70%), good flowability (low injection pressure and small resistance coefficient under the same conditions) and good oil displacement performance were selected. Indoor oil displacement experiments improved the recovery rate by more than 8 percentage points.

[0059] S5: Optimize the block injection parameters;

[0060] Polymer injection parameter optimization includes injection method optimization, injection concentration optimization, polymer dosage optimization, and injection speed optimization; the injection method generally includes single-stage plug injection or multi-stage plug injection;

[0061] The optimization of polymerization injection parameters generally employs numerical simulation, comparison with similar blocks, or a combination of both methods.

[0062] S6: Select an appropriate time to convert the implementation block to polymer injection development to improve the overall mining effect.

[0063] Based on the water drive potential tapping situation in the block, select an appropriate time to switch to polymer injection development. Generally, after 2 to 3 years of water drive potential tapping, switch to polymer drive development. When injecting polymer, first conduct well group test injection to determine the appropriate injection rate and injection concentration, and then carry out full-area polymer injection to ensure the smooth progress of polymer drive. At the same time, strengthen polymer drive profile monitoring and corresponding adjustment measures to ensure the polymer drive effect and achieve the goal of improving oil production rate.

[0064] Example 1

[0065] To make the objectives, technical solutions, and advantages of this invention clearer, the following description, taking the X35 fault block of Daqing Oilfield as an example, will be further detailed with reference to the accompanying drawings.

[0066] A method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block oil reservoirs, the specific implementation steps of which are as follows:

[0067] (1) Based on the applicable conditions of polymer flooding, the implementation block is selected in the following two steps:

[0068] First, obtain the basic geological parameters of the development block. These include lithology, reservoir temperature, formation water salinity, divalent cation concentration, effective permeability, formation crude oil viscosity, permeability variation coefficient, reservoir depth, and crude oil relative density.

[0069] Second, select suitable blocks for polymer flooding implementation. General conditions for polymer flooding application include: sandstone reservoirs, reservoir temperature greater than 25℃ and less than 80℃, formation water salinity less than 30000 mg / L, divalent cation concentration less than 2000 mg / L, effective permeability greater than 15 mD and less than 3000 mD, formation crude oil viscosity greater than 1 mPa·s and less than 200 mPa·s, permeability variation coefficient greater than 0.5 and less than 0.9, reservoir depth less than 2100 m, and crude oil relative density greater than 0.72 and less than 0.97. The X35 fault block is a sandstone oil reservoir with a reservoir temperature of 61.5℃, formation water salinity of 4546 mg / L, divalent cation concentration of 15.3 mg / L, effective permeability of 16.5 mD, formation crude oil viscosity of 10.2 mPa·s, permeability variation coefficient between 0.5 and 0.8, reservoir depth of 1625 m, and crude oil relative density greater than 0.82. It is suitable for polymer flooding, and the X35 fault block is the preferred location for implementing this method.

[0070] (2) Implement block-based water-drive and polymer-drive coordinated well network reconstruction; in the following two steps:

[0071] First, obtain the geological and development parameters for the optimal block. Geological parameters include the block's structural characteristics, sedimentary characteristics, oil-bearing reservoir development characteristics, microscopic pore-throat characteristics, heterogeneity characteristics, oil-water distribution and fluid properties, reservoir pressure and temperature, and geological reserves. Development parameters include well pattern, well spacing, number of development wells, degree of water drive control, reservoir activation status, current injection and production status, water cut, recovery rate, and oil production rate.

[0072] Second, well network reconstruction was carried out. The well network was adjusted mainly by forming a five-point polymer flooding well network, supplemented by a flexible well network near faults and structural edges. Based on the reservoir geological characteristics, methods such as densification and flexible supplementary well placement were used to adjust the well spacing of the X35 fault block from 250m to 177m. After the adjustment, the water drive control degree was 92.1%.

[0073] (3) Implement three-dimensional potential tapping of water-driven blocks;

[0074] After the well network is adjusted, water flooding is implemented to tap the potential. Based on the water flooding situation of the oil layer, new wells are perforated and put into production, and old wells are repaired and water is plugged. In the plane, the injection and production system is adjusted by strengthening the adjustment of the layer in the vertical direction, so as to alleviate the contradiction between the plane and the layer and gradually form a suitable polymer flooding well network, so that the polymer flooding layer control degree is more than 70%.

[0075] (4) Indoor physical model experiments to screen polymer products suitable for implementation blocks;

[0076] Based on the permeability and pore radius of the X35 fault block, eight polymer products were selected for indoor physical model experiments. Through evaluation of the polymer's basic physicochemical properties, viscosity-enhancing properties, long-term stability, shear resistance, flow properties, and oil displacement performance, SNF700 polymer flooding was selected as the least likely to clog the oil reservoir, exhibiting good stability and shear resistance (generally with a viscosity retention rate above 70%), good flowability (low injection pressure and low resistance coefficient under the same conditions), and good oil displacement performance. Indoor oil displacement experiments increased the oil recovery rate by 8.6 percentage points.

[0077] (5) Implement block injection parameter optimization;

[0078] The X35 block was optimized using numerical simulation to determine the injection method, injection concentration, polymer dosage, and injection rate. The final decision was to use a single-segment plug injection method with an injection concentration of 1350 mg / L, a polymer dosage of 810 mg / L·PV, and an injection rate of 0.07 PV / a.

[0079] (6) Implement block-based selective injection to improve overall mining efficiency;

[0080] Based on the water drive potential tapping situation in the block, the appropriate time to switch to polymer injection development will be selected. Generally, after 2 to 3 years of water drive potential tapping, the development will switch to polymer injection development. When injecting polymer, well group test injection will be carried out first to determine the appropriate injection rate and injection concentration, and then polymer injection will be carried out in the whole area to ensure the smooth progress of polymer injection. At the same time, polymer injection profile monitoring and corresponding adjustment measures will be strengthened to ensure the polymer injection effect and achieve the goal of improving the oil production rate. It is predicted that the implementation of water drive infiltration combined with polymer injection technology can increase the recovery rate by 9.01 percentage points in 16 years.

[0081] The comparison of the extraction degree of X35 fragments using different development schemes in this embodiment is shown in the figure. Figure 2 The basic scheme refers to no adjustments, with existing production wells continuing production at their current well network, well spacing, and production rate. The water-drive infiltration scheme refers to water-drive extraction only after well network reconstruction. The combined water-drive infiltration and polymer flooding scheme of this invention refers to water-drive potential tapping first after well network reconstruction, followed by polymer injection at an opportune time. The combined water-drive infiltration and polymer flooding scheme in the X35 fault block improved recovery by 9.01 percentage points compared to the basic scheme and by 4.5 percentage points compared to the water-drive infiltration scheme.

[0082] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the implementation methods of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the present invention.

Claims

1. A method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs, characterized in that: Includes the following steps: S1: Based on the applicable conditions of polymer flooding, the preferred implementation block is selected; S2: Based on the selected implementation blocks, the well network of the implementation blocks is reconstructed in a coordinated manner using water drive and polymer drive. S3: Conduct comprehensive exploration of the potential of water drive in the implementation block; S4: Screen polymer products suitable for implementation blocks through indoor physical model experiments; S5: Optimize the block injection parameters; S6: Select an appropriate time to convert the implementation block to polymer injection development to improve the overall mining effect.

2. The method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 1, characterized in that: Step S1, based on the applicable conditions of polymer flooding, preferably implements a block-based method, including: S101. Obtain basic geological parameters of the development block; S102, Preferred suitable polymer-driven implementation blocks.

3. The method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 2, characterized in that: The basic geological parameters of the development block obtained in step S101 include: lithology, reservoir temperature, formation water salinity, divalent cation concentration, effective permeability, formation crude oil viscosity, permeability variation coefficient, reservoir depth, and crude oil relative density.

4. The method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 2, characterized in that: The preferred applicable conditions for step S102 in the polymer-driven implementation block are as follows: Sandstone reservoirs with reservoir temperatures greater than 25℃ and less than 80℃; formation water salinity less than 30,000 mg / L; divalent cation concentration less than 2,000 mg / L; effective permeability greater than 15 mD and less than 3,000 mD; formation crude oil viscosity greater than 1 mPa·s and less than 200 mPa·s; permeability variation coefficient greater than 0.5 and less than 0.9; reservoir depth less than 2,100 m; and crude oil relative density greater than 0.72 and less than 0.

97.

5. The method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 1, characterized in that: Step S2, based on the preferred implementation block, involves a method for reconstructing the well network through coordinated water-drive and polymer-drive operations in the implementation block. S201. Obtain geological and development parameters for the preferred block; S202, Perform well network reconstruction.

6. The method for improving oil production rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 5, characterized in that: The geological and development parameters of the preferred block obtained in step S201 are as follows: The preferred geological parameters for the block include: the block's structural characteristics, sedimentary characteristics, oil layer development characteristics, microscopic pore throat characteristics, heterogeneity characteristics, oil-water distribution and fluid properties, reservoir pressure and temperature, and geological reserves; The optimal block development parameters include: well pattern, well spacing, number of development wells, water drive control level, reservoir utilization status, current injection and production status, water cut, recovery rate, and oil production rate.

7. The method for improving oil production rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 5, characterized in that: The method for well pattern reconstruction in step S202 is as follows: The well network is adjusted primarily by forming a five-point polymer flooding well network, supplemented by a flexible well network near faults and structural edges. Based on the reservoir geological characteristics, methods such as densification and flexible supplementary well placement were adopted to adjust the well spacing to below 200m, thereby achieving a water drive control rate of over 80%.

8. The method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 1, characterized in that: The method for implementing block water-drive three-dimensional potential tapping in step S3 is as follows: After the well network is adjusted, water flooding is implemented to tap the potential. New wells are perforated and put into production according to the water flooding situation of the oil layer, and old wells are repaired and water is plugged. In the plane, the injection and production system is adjusted by strengthening the adjustment of the injection and production system, and in the vertical direction, the inter-layer adjustment is strengthened to alleviate the contradiction between the plane and the inter-layer. A suitable well network for polymer flooding is gradually formed, so that the polymer flooding layer control degree is more than 70%.

9. The method for improving oil production rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 1, characterized in that: The method for screening polymer products suitable for the implementation block in step S4 is as follows: Select polymer products based on the preferred block permeability and pore radius; Indoor physical model experiments were conducted to evaluate the basic physicochemical properties, thickening properties, long-term stability, shear resistance, flow properties, and oil displacement performance of polymers. Polymer flooding products that are not prone to clogging oil reservoirs, have good stability and shear resistance, good flowability, and good oil displacement performance were screened out. Indoor oil displacement experiments improved the recovery rate by more than 8 percentage points. The indicators of good shear resistance are generally a viscosity retention rate of over 70%; good flowability means that the polymer-driven product has a low injection pressure and a small drag coefficient under the same conditions.

10. The method for improving oil recovery rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 1, characterized in that: Step S5 describes the implementation of block injection parameter optimization, which includes: Polymer injection parameter optimization includes injection method optimization, injection concentration optimization, polymer dosage optimization, and injection speed optimization; the injection method generally includes single-stage plug injection or multi-stage plug injection; The optimization of polymerization injection parameters generally employs numerical simulation, comparison with similar blocks, or a combination of both methods.

11. The method for improving oil production rate by combining waterflooding and polymer flooding in fault-block reservoirs according to claim 1, characterized in that: The method for implementing selective polymer injection in the block to improve overall mining efficiency in step S6 is as follows: Based on the water drive potential tapping situation of the block, select an appropriate time to switch to polymer injection development. Generally, water drive potential tapping is followed by polymer drive development after 2 to 3 years. The specific method for polymer injection development is as follows: When injecting polymer, first conduct well group test injection to determine the appropriate injection rate and injection concentration; then carry out full-area polymer injection to ensure the smooth progress of polymer flooding. At the same time, strengthen polymer flooding profile monitoring and corresponding adjustment measures to ensure the polymer flooding effect.

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