A low-permeability fracture type water breakthrough reservoir water injection well profile control dynamic regulation method

Abstract

The application belongs to the technical field of oil exploitation, and discloses a low-permeability fractured water breakthrough reservoir water injection well profile control dynamic regulation method, which comprises the following steps: determining a water breakthrough direction and corresponding water injection well according to dynamic monitoring data or well group production dynamic change conditions; using a particle type plugging agent to perform profile control treatment on the water injection well; after the profile control treatment, adjusting a daily water injection amount of the water injection well according to a formation energy retention condition, controlling liquid production of a main direction well, increasing a parameter of a lateral well, and adjusting a subsequent daily water injection amount according to a well group liquid amount change condition; dynamically monitoring a regulation result, and adjusting well group production parameters based on a fracture plugging effect. The method can directionally plug the main direction fracture, reduce lateral oil layer pollution, promote deep migration of the profile control agent, and effectively balance planar liquid production, and has important significance for treating low-permeability fractured water breakthrough and improving planar water drive unevenness.

Description

Technical Field

[0001] This application belongs to the field of petroleum extraction technology, and in particular relates to a dynamic control method for profile adjustment of water injection wells in low-permeability fractured water-bearing reservoirs. Background Technology

[0002] In recent years, with the advancement of engineering technology, ultra-low permeability and extra-low permeability reservoirs (permeability <10mD) have been put into development and construction. These reservoirs are dense, with well-developed microfractures and strong heterogeneity. The prominent contradiction between water drive and uneven water drive results in a rapid increase in water cut and a large decline in production, making the need to improve water drive increasingly urgent.

[0003] In recent years, scholars have conducted extensive research on profile control and water cutting techniques for low-permeability fractured water-bearing reservoirs. However, most of this research focuses on the development of chemical profile control agents. For example, CN103216211B discloses a slow-swelling, salt-resistant, high-strength water-absorbing resin particle that forms a gel on the surface and reduces damage to microfractures and matrix porosity. However, this method results in a decrease in well fluid volume after profile control, with limited oil production enhancement. CN106351024A discloses a method that fully utilizes existing well networks, transforming "local high-efficiency potential tapping" into "regional high-efficiency control." This method optimizes well networks and injection-production control in different regions to achieve balanced water drive development. However, single injection-production control is insufficient to meet the water drive improvement needs of low-permeability reservoirs. CN114542031A discloses an injection-production control method suitable for irregular edge-water reservoirs with fracture development. This method comprehensively applies injection-production control, well unblocking, water well profile control, and stratified water injection to suppress edge water energy and control water cut rise. However, its implementation is difficult, and it does not address how to control or reduce water breakage after water breakthrough from a technological perspective.

[0004] Therefore, it is necessary to provide a dynamic profile control method for controlling and reducing water breakage after water breakage. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the purpose of this application is to provide a dynamic control method for profile adjustment of water injection wells in low-permeability fractured water-bearing reservoirs, and to solve the problem that the existing technology cannot effectively achieve directional sealing of fractures and balanced planar fluid production.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A dynamic profile control method for water injection wells in low-permeability fractured water-bearing reservoirs includes:

[0008] Determine the direction of water inflow and the corresponding injection well based on dynamic monitoring data or changes in well group production dynamics;

[0009] Particulate plugging agents were used to adjust the profile of water injection wells;

[0010] After profile control and treatment, the daily water injection volume of the injection wells is adjusted according to the formation energy retention. At the same time, the main wells are controlled for fluid production, the parameters of the lateral wells are increased, and the subsequent daily water injection volume is adjusted according to the changes in the fluid volume of the well group.

[0011] The control results are dynamically monitored, and the production parameters of the well group are adjusted based on the fracture sealing effect.

[0012] Furthermore, particulate plugging agents include gel systems and bulked particulate systems.

[0013] Furthermore, the particle size of the bulky particles is 3-8 mm.

[0014] Furthermore, the gel system comprises 0.2 wt% acrylamide and 0.2 wt% crosslinking agent, with the balance being water;

[0015] The bulk-swellable particle system comprises 0.1 wt% acrylamide and 0.4 wt%-0.6 wt% bulk-swellable particles, with the balance being water.

[0016] Furthermore, the anatomical treatment includes:

[0017] To control the pressure rise of the water injection system to >3MPa, first inject the gel system, then inject the bulk-expanded granular system. The injection volume of the granular plugging agent is 1800-2200 mg / L. 3 The injection displacement is 1.2-1.5m³. 3 / h.

[0018] Furthermore, after injecting the gel system and the bulked particle system, additional gel particle slugs are added. The gel particle size is 100-300 μm, the pressure ramp-up space of the water injection system for the gel particle slugs is >2 MPa, the injection concentration is 0.3-0.6 wt%, and the injection volume is 1200-1500 ml. 3 The injection displacement is 0.75-1.5m³. 3 / h.

[0019] Furthermore, during the profile control process, the production parameters of water-bearing oil wells are increased to raise the production pressure differential.

[0020] Furthermore, the daily water injection rate of the injection wells is adjusted based on the formation energy retention, including:

[0021] When the formation energy level is >110%, water injection should be controlled, and the injection intensity should be reduced by 0.1-0.5m. 3 / dm;

[0022] When the formation energy level is between 90% and 110%, the water injection intensity remains unchanged;

[0023] When the formation energy level is <90%, the water injection intensity should be increased by 0.1-0.5m. 3 dm.

[0024] Furthermore, controlled fluid production in the main directional well includes:

[0025] When the water cut of an oil well is >95% before profile control, intermittent oil production is adopted after profile control.

[0026] When the water cut of the oil well is between 60% and 95% before profile control, fluid control production is carried out after profile control by reducing production parameters and raising the pump hanger.

[0027] When the water content of the oil well is less than 60% before profile control, maintain flowing pressure production.

[0028] Furthermore, the results of the regulation will be dynamically monitored, including:

[0029] The control results are dynamically monitored using tracer testing and / or water drive front testing and / or water absorption profile testing and / or water absorption indicator curves and / or well test curves.

[0030] The technical effects and advantages of this application are as follows:

[0031] 1. The dynamic control method for profile control in water injection wells of low-permeability fractured water-bearing reservoirs proposed in this application can directionally seal the main fractures, reduce lateral oil layer contamination, promote the deep migration of profile control agents, and effectively balance the production of fluids in the plane. It is of great significance for managing water breakthrough in low-permeability fractured reservoirs and improving uneven water drive in the plane.

[0032] 2. This application first determines the direction of water breakthrough, and then takes measures to adjust parameters during the profile control process to promote the migration of the plugging agent to the deep reservoir and directionally seal the fractures. After the profile control is completed, dynamic control is used to optimize the production structure and balance the production in the plane, while further protecting the plugging effect and extending the effective period of the plugging agent.

[0033] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating a dynamic profile control method for water injection wells in low-permeability fractured water-bearing oil reservoirs, as described in this application.

[0035] Figure 2 This is a schematic diagram illustrating the water-viewing direction recognition method in an embodiment.

[0036] Figure 3 This is a schematic diagram of the plugging agent transport during the profile adjustment process in an embodiment.

[0037] Figure 4This is a schematic diagram of water flow reversal after profile adjustment in an embodiment.

[0038] Figure 5 The following is an example of the dynamic changes in daily liquid / oil production curves before and after profile control of a certain reservoir. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] like Figure 1 As shown, this application provides a method for dynamic profile control of water injection wells in low-permeability fractured water-bearing reservoirs, including:

[0041] Determine the direction of water inflow and the corresponding injection well based on dynamic monitoring data or changes in well group production dynamics;

[0042] Particulate plugging agents were used to adjust the profile of water injection wells;

[0043] After profile control and treatment, the daily water injection volume of the injection wells is adjusted according to the formation energy retention. At the same time, the main wells are controlled for fluid production, the parameters of the lateral wells are increased, and the subsequent daily water injection volume is adjusted according to the changes in the fluid volume of the well group.

[0044] The control results are dynamically monitored, and the production parameters of the well group are adjusted based on the fracture sealing effect.

[0045] It should be noted that when dynamic monitoring data such as tracer testing and water absorption indicator curves are readily available, the direction of water breakthrough can be determined based on this data. However, considering factors such as operating costs, dynamic monitoring data is often lacking for most well groups. In such cases, it is necessary to rely on the dynamic changes in well group production to determine the direction of water breakthrough. For example, in the Changqing Oilfield, reservoir microfractures extend and develop along the direction of maximum principal stress, and most well networks adopt a diamond-shaped inverse nine-point well network. Water breakthrough in main directional wells is particularly prominent, and the dynamic response after water breakthrough is also quite significant. When water injection in the well group has been effective, the injection wells are injecting water normally according to geological allocation, and no parameter adjustments have been made to the oil wells, if the corresponding oil wells within the well group experience a significant increase in daily fluid production, a rapid rise in overall water cut, or even sudden water flooding within a short period, the direction of water breakthrough in such wells can be clearly identified.

[0046] In some embodiments of this application, the particulate plugging agent includes gel systems and bulked particulate systems.

[0047] In some embodiments of this application, the particle size of the bulky particles is 3-8 mm.

[0048] In some embodiments of this application, the gel system comprises 0.2 wt% acrylamide and 0.2 wt% crosslinking agent, with the balance being water; the bulk-swellable particle system comprises 0.1 wt% acrylamide and 0.4 wt%-0.6 wt% bulk-swellable particles, with the balance being water.

[0049] In some embodiments of this application, profile control includes: controlling the pressure rise space of the water injection system to >3MPa, first injecting the gel system, then injecting the bulk-expanded granular system, with the injection volume of the granular plugging agent being 1800-2200m³. 3 The injection displacement is 1.2-1.5m³. 3 / h.

[0050] In some embodiments of this application, after injecting the gel system and the bulked particle system, a gel particle slug is added. The gel particle size is 100-300 μm, the pressure rise space of the water injection system for the gel particle slug is >2 MPa, the injection concentration is 0.3-0.6 wt%, and the injection volume is 1200-1500 ml. 3 The injection displacement is 0.75-1.5m³. 3 / h.

[0051] During the profile control process, the production parameters of the wells that have reached water are increased to increase the production pressure differential, which promotes the migration of plugging agent to the deeper part of the reservoir and directional sealing of fractures.

[0052] In some embodiments of this application, the daily water injection rate of the injection wells is adjusted according to the formation energy retention, and the water injection rate of the well group is gradually optimized, including: when the formation energy level is >110%, water injection control measures are taken, and the water injection intensity is reduced by 0.1-0.5m. 3 / dm; When the formation energy level is between 90% and 110%, the water injection intensity remains unchanged; when the formation energy level is <90%, the water injection intensity is increased by 0.1-0.5m. 3 dm.

[0053] The formation energy level is represented by the ratio of the current formation pressure to the original formation pressure.

[0054] In some embodiments of this application, controlled fluid production in the main directional well includes: when the water cut of the oil well before profile control is >95%, it is a high-volume water-flooded well, and after profile control, intermittent oil production is adopted; when the water cut of the oil well before profile control is between 60% and 95%, it is a high-volume, high-water-cut well, and after profile control, controlled fluid production is carried out by adjusting production parameters and raising the pump hanger; when the water cut of the oil well before profile control is <60%, it is a low-volume well, and production is carried out by maintaining reasonable flowing pressure.

[0055] In some embodiments of this application, the lateral well parameters are increased to produce fluid, which can optimize the fluid production structure and balance the planar fluid production.

[0056] In some embodiments of this application, dynamic monitoring of the control results includes:

[0057] The control results are dynamically monitored using tracer testing and / or water drive front testing and / or water intake profile testing and / or water intake indicator curves and / or well test curves. In-depth analysis of the dynamic monitoring data provides a basis for subsequent dynamic parameter adjustments.

[0058] To better explain this solution, the following embodiments are provided.

[0059] Example

[0060] Taking a certain lithological reservoir as an example, the main development stratum is the Chang 6 layer, with an average effective thickness of 12.2m, a porosity of 11.7%, and a permeability of 1.2mD. As of the end of 2021, the geological reserve recovery rate was 14.69%, the comprehensive water cut was 56.6%, and the formation energy retention level was 106%. This reservoir has well-developed natural microfractures, and injected water is prone to rush along the microfractures and high-permeability zones, causing water flooding of oil wells. To date, a total of 31 water-flooded wells have been discovered (22 main directional wells and 9 lateral wells).

[0061] In October 2021, the water cut of oil wells in a certain well group increased significantly. Based on dynamic monitoring data or changes in the production dynamics of the well group, the following results were obtained: Figure 1 The diagram shown illustrates the water breakthrough direction identification. To determine the water breakthrough direction and corresponding injection well, a granular plugging agent is used to modify the injection well profile, controlling the pressure rise space of the injection system to >3MPa. First, a gel system (0.2wt% acrylamide and 0.2wt% crosslinking agent, balance water) is injected, followed by a bulk-swellable particle system (0.1wt% acrylamide and 0.4wt%-0.6wt% bulk-swellable particles, balance water; particle size of the bulk-swellable particles is 3-8mm). The injection volume of the granular plugging agent is 1800-2200 mg / m³. 3 The injection displacement is 1.2-1.5m³. 3 / h, after injecting the gel system and the bulked particle system, add PEG gel particle slugs. The particle size of the PEG gel particles is 100-300μm, the pressure rise space of the water injection system for the PEG gel particle slugs is >2MPa, the injection concentration is 0.3-0.6wt%, and the injection volume is 1200-1500m³. 3 The injection displacement is 0.75-1.5m³. 3 / h, simultaneously during profile control, the production parameters of water-bearing oil wells are increased to raise the production differential pressure, promoting the migration of plugging agents to deeper reservoirs and directional sealing of fractures. The migration of plugging agents during profile control is as follows: Figure 3As shown. The formation energy level is between 90% and 110%, and the water injection intensity remains unchanged. Simultaneously, fluid production is controlled in the main directional wells. When the water cut of the well before profile control is >95%, it is a high-volume water-flooded well; after profile control, intermittent production is adopted. When the water cut of the well before profile control is between 60% and 95%, it is a high-volume, high-water-cut well; after profile control, fluid production is controlled by reducing production parameters and raising the pump hanger. When the water cut of the well before profile control is <60%, it is a low-volume well, maintaining reasonable flowing pressure for production. Lateral well parameters are increased for fluid-lifting production, which can rationally determine the fluid production structure and balance planar production. The subsequent daily water injection volume is adjusted according to the changes in well group fluid volume. The water flow direction after profile control is as follows: Figure 4 As shown.

[0062] After a period of time, tracer testing, water drive front testing, water absorption profile testing, water absorption indicator curves, and well test curves were used to dynamically monitor the control results, and the well group production parameters were adjusted based on the fracture plugging effect. The dynamic changes in daily fluid / oil production in the reservoir before and after the implementation of this method are shown in the following figures. Figure 5 As shown, the daily oil production of the well group increased from 1.9 t / d to 2.9 t / d, and the water cut decreased from 65.8% to 62.6%, demonstrating a significant effect of reducing water content and increasing oil production.

[0063] In summary, the dynamic profile control method for water injection wells in low-permeability fractured water-bearing reservoirs proposed in this application has advantages over other common practices that directly inject gels or gel particles without considering injection and production strategies. These advantages include directional sealing of main fractures, reduction of lateral reservoir contamination, promotion of deep migration of profile control agents, and effective equalization of production fluids in the plane. This method is of great significance for managing water breakthroughs in low-permeability fractured reservoirs and improving uneven water drive in the plane.

[0064] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for dynamic profile control of water injection wells in low-permeability fractured water-bearing reservoirs, characterized in that, include: Determine the direction of water inflow and the corresponding injection well based on dynamic monitoring data or changes in well group production dynamics; The injection well was treated with a particulate plugging agent to adjust its profile. After the profile control treatment, the daily water injection volume of the injection wells is adjusted according to the formation energy retention. At the same time, the main wells are controlled for fluid production, the parameters of the lateral wells are increased, and the subsequent daily water injection volume is adjusted according to the changes in the fluid volume of the well group. Dynamically monitor the control results and adjust well group production parameters based on the fracture plugging effect; The particulate plugging agent includes gel systems and bulk-swellable particulate systems; The profile control includes: To control the pressure rise space of the water injection system to >3MPa, first inject the gel system, then inject the bulk-expanded granular system. The injection volume of the granular plugging agent is 1800-2200 mg / L. 3 The injection displacement is 1.2-1.5m³. 3 / h; The method of adjusting the daily water injection volume of the injection well based on the formation energy retention includes: When the formation energy level is >110%, water injection should be controlled, and the injection intensity should be reduced by 0.1-0.5m. 3 / dm; When the formation energy level is between 90% and 110%, the water injection intensity remains unchanged; When the formation energy level is <90%, the water injection intensity should be increased by 0.1-0.5m. 3 / dm; The aforementioned main directional well fluid control production includes: When the water cut of an oil well is >95% before profile control, intermittent oil production is adopted after profile control. When the water cut of the oil well is between 60% and 95% before profile control, fluid control production is carried out after profile control by reducing production parameters and raising the pump hanger. When the water content of the oil well is less than 60% before profile control, maintain flowing pressure production.

2. The method for dynamic profile control of injection wells in low-permeability fractured water-bearing reservoirs according to claim 1, characterized in that, The particle size of the bulky particles is 3-8 mm.

3. The method for dynamic profile control of injection wells in low-permeability fractured water-bearing reservoirs according to claim 1, characterized in that, The gel system comprises 0.2 wt% acrylamide and 0.2 wt% crosslinking agent, with the balance being water; The bulk-swellable particle system comprises 0.1 wt% acrylamide and 0.4 wt%-0.6 wt% bulk-swellable particles, with the balance being water.

4. The method for dynamic profile control of injection wells in low-permeability fractured water-bearing reservoirs according to claim 1, characterized in that, After injecting the gel system and the bulked particle system, a gel particle slug is added. The gel particles have a particle size of 100-300 μm, the water injection system pressure rise space of the gel particle slug is >2 MPa, the injection concentration is 0.3-0.6 wt%, and the injection volume is 1200-1500 ml. 3 The injection displacement is 0.75-1.5m³. 3 / h.

5. The method for dynamic profile control of injection wells in low-permeability fractured water-bearing reservoirs according to claim 1, characterized in that... During the profile control process, the production parameters of the wells that have reached water are increased to increase the production pressure differential.

6. The method for dynamic profile control of injection wells in low-permeability fractured water-bearing reservoirs according to claim 1, characterized in that, The aforementioned dynamic monitoring of the control results includes: The control results are dynamically monitored using tracer testing and / or water drive front testing and / or water absorption profile testing and / or water absorption indicator curves and / or well test curves.

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