A design method for improving oil recovery by gas injection in oil reservoirs and coordinating gas storage construction

Abstract

The present invention relates to the technical field of reservoir-type gas storage construction, and discloses a design method for the construction of a gas storage reservoir in coordination with gas injection to improve oil recovery, specifically: on the basis of determining that the plugging property of the reservoir meets the requirements, the gas source of the gas injection is guaranteed, and the gas injection in the reservoir is feasible, it is explained that the reservoir can carry out the construction of a reservoir-type gas storage in coordination with gas injection to improve oil recovery; gas injection to improve oil recovery includes determining the injection pressure, optimizing the injection and production well network, allocating the injection of gas injection wells, and allocating the production of oil production wells; the construction of a reservoir-type gas storage includes operating pressure design, storage capacity design, working gas volume demonstration, operating cycle design, and injection and production capacity evaluation of injection and production wells. The present invention can achieve the improvement of oil recovery rate through gas injection while building a reservoir-type gas storage. Therefore, the construction of a gas storage reservoir in a reservoir to improve oil recovery has important strategic significance: on the one hand, the oil recovery rate can be greatly improved through gas injection and oil displacement, and on the other hand, energy security is ensured by building a gas storage.

Description

Technical Field

[0001] The invention relates to the technical field of reservoir-type gas storage construction, and in particular to a design method for reservoir gas injection to enhance recovery and coordinate gas storage construction. Background Art

[0002] As the demand for natural gas consumption continues to grow, especially in winter, the task of ensuring the supply of natural gas is heavy, which puts forward new requirements for accelerating the construction of gas storage. However, the current peak-shaving capacity of gas storage cannot meet the rapidly growing demand for natural gas peak-shaving and storage. The supply and demand of natural gas has entered a tight balance state. The existing plan cannot meet the future peak-shaving and storage needs, so the construction of gas storage is imminent. Summary of the invention

[0003] The purpose of the present invention is to provide a design method for improving oil recovery by injecting gas into oil reservoirs and coordinating the construction of gas storage facilities, thereby solving the problem that existing planning is difficult to meet the peak load regulation and reserve requirements.

[0004] The present invention is achieved through the following technical solutions:

[0005] A design method for enhancing oil recovery by gas injection in oil reservoirs in coordination with gas storage construction, specifically:

[0006] On the basis of judging that the sealing property of the reservoir meets the requirements, the gas source is guaranteed and the gas injection in the reservoir is feasible, it is determined that the reservoir can be injected with gas to enhance the recovery rate and build a reservoir-type gas storage facility;

[0007] Gas injection to improve oil recovery includes determining the injection pressure, optimizing the injection and production well pattern, allocating injection wells and production wells;

[0008] The construction of reservoir-type gas storage includes operating pressure design, storage capacity design, working gas volume demonstration, operating cycle design and injection and production capacity evaluation of injection and production wells.

[0009] Furthermore, the gas injection pressure is determined specifically as follows: the gas injection pressure during the reservoir gas injection EOR stage is higher than the minimum miscibility pressure; the injection gas front end pressure is maintained above the minimum miscibility pressure;

[0010] The specific optimization of the injection-production well pattern is: using horizontal well injection-production well type for injection-production;

[0011] The specific production allocation of oil wells is as follows: analyzing the two aspects of oil well liquid production control and oil well gas production control, and obtaining the production allocation conditions of oil wells in the gas injection to enhance oil recovery stage.

[0012] Furthermore, the gas injection well allocation is specifically as follows: according to the gas injection capacity equation of the gas injection well, the gas injection amount of the gas injection well in the gas injection enhancement recovery stage is designed;

[0013] The gas injection capacity equation of the gas injection well is as follows:

[0014]

[0015] Where: wf is the pseudo bottom pressure of the gas injection well; ψ is the gas injection formation pressure of the gas injection well; q g1 is the amount of natural gas injected into the gas injection well; T is the temperature; K is the formation permeability; h is the formation gas absorption thickness; r e is the control radius of the gas injection well; r w is the wellbore radius or wellbore radius; S is the skin coefficient; D is the inertia coefficient.

[0016] Furthermore, the operational pressure design is specifically as follows: designing the upper and lower pressure limits during the coordinated construction phase of the gas storage facility;

[0017] Design the storage capacity of the gas storage facility during the coordinated construction phase;

[0018] Design the working gas volume of gas storage construction;

[0019] Design the construction and operation cycle of gas storage;

[0020] Design the gas injection capacity of a single well during the coordinated construction phase of the gas storage facility;

[0021] Design the gas production capacity of a single well during the coordinated construction phase of the gas storage facility.

[0022] Furthermore, the process of determining whether the plugging property of the reservoir meets the requirements, the gas injection source is guaranteed, and the gas injection into the reservoir is feasible includes the following steps:

[0023] S1. Determine whether the plugging property of the reservoir to be evaluated is strong according to the plugging property evaluation of the reservoir;

[0024] S2. If the plugging property of the reservoir to be evaluated is strong, then evaluate whether the gas transmission capacity of the gas pipeline of the reservoir can meet the gas injection and production needs of the reservoir. If so, conduct a feasibility analysis of gas injection in the reservoir;

[0025] S3. If the feasibility analysis result of gas injection in the oil reservoir shows that gas injection in the oil reservoir is feasible, it means that the oil reservoir has the foundation for gas injection to improve oil recovery and gas storage construction.

[0026] Furthermore, the design of the upper limit pressure during the coordinated construction phase of the gas storage reservoir comprehensively considers the factors of reservoir sealing, lateral pressure of the cap rock and safety factor of the gas storage reservoir, operating conditions of the surface gas injection compressor, critical pressure of fracture opening and formation fracture pressure.

[0027] Furthermore, the lower limit pressure value during the coordinated construction stage of the gas storage facility must meet the needs of miscibility under formation conditions; through the evaluation of the formation pressure retention degree, the formation pressure at that time needs to be maintained at 80% of the original formation pressure.

[0028] Furthermore, the storage capacity of the gas storage reservoir in the coordinated construction stage is designed based on the volumetric method and the dynamic method. The reservoir storage capacity is calculated by the volumetric method and the dynamic method respectively, and the average of the two results is taken as the final storage capacity of the gas storage reservoir in the coordinated construction stage.

[0029] Furthermore, the gas injection well suction index is used to represent the gas injection capacity of a single well during the coordinated construction phase of the gas storage reservoir. The calculation process of the gas injection well suction index is as follows:

[0030] Gas absorption index I of gas injection wells in reservoir-type gas storage inj It is defined as the daily gas injection volume under the square difference of pressure, and the formula is as follows:

[0031]

[0032]

[0033] Among them, p wf is the bottom pressure of the gas injection well of the gas storage reservoir; p r is the injection formation pressure of the gas storage injection well; q g2 is the daily gas injection volume; T-temperature; μ-viscosity; Z-injection gas deviation factor; K-formation permeability; h-formation gas absorption thickness; r e -Gas injection well control radius; r w -wellbore radius or wellbore radius; S-skin factor; γ g -Note the relative density of the daily atmosphere.

[0034] Furthermore, the working gas volume of gas injection to enhance oil recovery and coordinated gas storage construction includes two major parts: one part is the natural gas produced from oil wells, and the other part is the natural gas produced from gas injection wells converted into gas production wells; through numerical simulation evaluation, when the gas production volume in winter is 50% of the total gas injection volume of the stage, gas injection to enhance oil reservoir recovery is optimal.

[0035] Compared with the prior art, the present invention has the following beneficial technical effects:

[0036] The present invention discloses a design method for the construction of a gas storage reservoir to enhance the recovery rate by gas injection in oil reservoirs, explores a new mode of the construction of a gas storage reservoir to enhance the recovery rate by gas injection in oil reservoirs for the first time, and realizes the technical exploration of the whole value chain of gas storage reservoirs; the present invention provides a relatively complete set of reservoir-type gas storage reservoir construction parameter design methods for the first time, including operating pressure design, storage capacity design, working gas volume demonstration, operation cycle design, and injection and production capacity evaluation of injection and production wells; the implementation of the project of enhancing the recovery rate by gas injection in oil reservoirs to enhance the recovery rate by gas storage reservoirs can effectively reduce the peak-to-valley difference of the main gas field supplying gas, so that it can maintain stable production, thereby ensuring the high recovery rate of the gas reservoir and the safety of the wellbore; and the injected gas can extract most of the light components from the crude oil, thereby increasing the output of liquefied gas, light hydrocarbons and light crude oil, and achieving the purpose of improving quality and increasing efficiency; the present invention can achieve the improvement of the recovery rate of the oil reservoir and build an oil reservoir-type gas storage reservoir at the same time through gas injection. Therefore, the construction of a gas storage reservoir for enhancing the recovery rate by gas injection in oil reservoirs is of great significance: on the one hand, the recovery rate of the oil reservoir can be greatly improved by gas injection, and on the other hand, energy security can be ensured by building a gas storage reservoir.

[0037] The present invention innovatively designs a set of well patterns for gas injection to improve recovery and coordinate with gas storage to build a platform, which greatly saves the area occupied by the well pattern and solves the problem of well site placement; at the same time, it is convenient for daily management of the gas storage and can improve work efficiency; DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0039] The present invention is further described below by taking the Y reservoir as an example:

[0040] (1) Evaluation of reservoir sealing performance

[0041] The plugging property of oil reservoir mainly includes the fault sealing property and caprock sealing property. The fault sealing property is usually comprehensively analyzed by using the smear factor, mud smearing ability, fault mud ratio and opening critical pressure. The calculation result of the smear factor of Y reservoir is 0.27-1.00. According to the evaluation standard, the fault is completely closed; the calculation result of the mud smear factor of Y reservoir is 37.5-56.25. According to the evaluation standard, the fault sealing property is strong; the calculation result of the fault mud ratio of Y reservoir is 100%-375%. According to the evaluation standard, the fault is completely closed; based on the established three-dimensional geomechanical model, the critical opening pressure of the fault of Y reservoir is quantified to be 67.38MPa, while the current formation pressure of Y reservoir is only 52MPa, indicating that the fault of Y reservoir is not opened; the comprehensive evaluation shows that the fault sealing property of Y reservoir is strong. The breakthrough pressure model based on the acoustic time difference was established to obtain the breakthrough pressure of the cap rock of the Y reservoir, which was 10.39 MPa. According to the empirical value of the minimum breakthrough pressure, the height of the gas column that can be sealed by the cap rock is greater than 500 m, while the amplitude of the Y reservoir trap is only 120 m, so the mudstone cap rock is very effective for the trap. The evaluation results of the fracture sealing and the cap rock sealing show that the Y reservoir has strong sealing properties and has the foundation for gas injection to improve recovery and gas storage construction.

[0042] (2) Gas injection source guarantee

[0043] The main gas pipeline is located near the critical oil reservoir, which is convenient for on-site testing and pipeline network connection, and has considerable economic benefits. At the same time, the main gas pipeline has sufficient gas injection source to meet the gas injection volume requirements for oil reservoir flooding and gas storage construction.

[0044] Specifically, the three main gas pipelines of the Y oil reservoir are relatively close to the reservoir, with an average distance of 40 km. At the same time, the annual gas transmission capacity of the three pipelines is 200×10 8 m 3 It can fully meet the gas injection demand of Y reservoir.

[0045] (3) Feasibility analysis of gas injection into oil reservoirs

[0046] The Y oil reservoir has carried out gas injection capillary experiments and long core displacement experiments. The capillary experiments show that gas injection can achieve miscible displacement under the current formation temperature conditions in the Y oil reservoir, and the minimum miscible pressure of gas injection is 52MPa; the long core displacement experiment shows that the oil recovery efficiency of gas injection is 46% higher than that of water injection, so gas injection in the Y oil reservoir can greatly improve the oil recovery efficiency. Furthermore, the field practice of gas injection in the Y oil reservoir shows that the gas injection effect is significant. In summary, gas injection in the Y oil reservoir is feasible.

[0047] (4) Determination of gas injection pressure during gas injection to enhance oil recovery

[0048] In order to achieve higher recovery rate by gas injection in oil reservoirs, it is necessary to ensure that the injected gas can be miscible, so the injection pressure must be higher than the minimum miscible pressure; at the same time, considering that the pressure profiles of the injection well and the production well are "step-like", the front-end pressure of the injected gas must be kept above the minimum miscible pressure to ensure the realization of miscible drive.

[0049] (5) Optimization of injection and production well type and pattern

[0050] By establishing a high-precision geological model with eight components of tens of millions of grids, numerical simulation mechanism research shows that in the stage of gas injection to improve oil recovery, horizontal well injection and horizontal well production have the best development effect. Compared with vertical well injection and production or mixed injection and production, horizontal well injection and production can effectively delay gas channeling and significantly increase production under the same gas-oil ratio. Considering the characteristics of "strong injection and strong production" in the coordinated construction stage of reservoir-type gas storage, horizontal wells have strong gas injection and production capabilities, small production pressure difference, and can overcome sand production in oil reservoirs; and the use of horizontal well injection and production wells can effectively save drilling investment.

[0051] Furthermore, due to the complex ground conditions at the Y oil reservoir site, a platform well network was designed (this platform well network integrated the injection and production wells into a platform well network for the first time), which can greatly save the area occupied by the well network and solve the problem of well site placement; at the same time, it is convenient for the daily management of the gas storage and can improve work efficiency.

[0052] (6) Gas injection well allocation during the gas injection EOR phase

[0053] The natural gas injection volume of the gas injection wells in the gas injection enhancement recovery stage is designed according to the gas injection capacity equation of the gas injection wells. The derived gas injection capacity equation of the gas injection wells is as follows:

[0054]

[0055] Where: wf is the pseudo bottom pressure of the gas injection well; ψ is the gas injection formation pressure of the gas injection well; q g1 is the daily gas injection volume; T is the temperature; K is the formation permeability; h is the formation air absorption thickness; r e is the control radius of the gas injection well; r w is the wellbore radius or wellbore radius; S is the skin coefficient; D is the inertia coefficient.

[0056] According to the gas injection capacity equation of the gas injection well, the gas injection capacity of the horizontal well in the Y reservoir during the gas injection to enhance oil recovery is calculated to be 20×10 4 m 3 / d.

[0057] Substitute the parameters in the table into the gas injection capacity equation of the gas injection well to obtain the gas injection volume of the gas injection well. The values ​​of each letter are as follows:

[0058]

[0059] (7) Production allocation of oil wells during the gas injection EOR stage

[0060] Reasonable production allocation of oil wells is studied and determined from two aspects: liquid production control and gas production control.

[0061] In terms of the liquid production control of oil wells, multiple factors such as formation sanding, critical liquid-carrying gas volume, prevention of gas cone, production pipe string size and ground supporting technology are comprehensively considered to determine the reasonable production pressure difference. According to the current status of sand production in production wells, the critical sand production pressure difference of Y reservoir formation is 10-15MPa; by calculating the critical liquid-carrying gas volume of wells X1 and X2 under different water content conditions, the reasonable pressure difference is determined to be 7-10MPa. When the tubing size is 2 7 / 8", the daily gas production is 4×10 4 m 3 / d can meet the critical liquid carrying flow requirement; to prevent the formation of vertical gas cone, the corresponding critical production pressure difference is calculated to be 5-6MPa; based on the above demonstration, the horizontal well is allocated to produce 105t / d of liquid.

[0062] The gas production control of oil wells is determined by analyzing the current production status of typical effective wells. After the gas injection in Well X3 was effective, the gas-oil ratio was between 300 and 500 m 3 / t (in the miscible phase zone) rises slowly, the oil-increasing effect is obvious, the production situation is stable, but the daily gas production exceeds 4×10 4 m 3 / d later, the gas-oil ratio rises rapidly, the oil production drops sharply, and the production effect becomes significantly worse; thus, the gas production control conditions of the effective oil wells are determined: the gas-oil ratio reaches 1500m 3 / t adopts intermittent production system, reaching 3000m 3 / t shut down the well and stop production; the daily gas production of a single well is controlled at 4×10 4 m 3 / d or less.

[0063] (8) Upper limit pressure design during the coordinated construction phase of gas storage

[0064] The upper limit of operating pressure during the coordinated construction phase of the gas storage should take into account the safety of the gas storage, and comprehensively consider factors such as the sealing of the reservoir, the lateral pressure of the cap rock and the safety factor of the gas storage, the working conditions of the ground gas injection compressor, the critical pressure of fracture opening and the formation fracture pressure. The upper limit pressure of the Y reservoir is designed to be 56MPa.

[0065] (9) Lower limit pressure design during the coordinated construction phase of gas storage

[0066] The lower limit pressure value in the construction stage of gas injection and oil recovery coordinated gas storage must meet the needs of miscibility under formation conditions; through the evaluation of formation pressure retention, the formation pressure retention level must be guaranteed to be at a level of 80%; at the same time, considering the high pressure at the injection end of the gas injection well, the pressure change law from the gas injection well to the gas production well is analyzed through numerical simulation, and the analysis shows that the lower limit pressure in the construction stage of gas injection and oil recovery coordinated gas storage in the Y oil reservoir is 52MPa.

[0067] Formation pressure is a variable. With development, water injection or gas injection, the pressure value fluctuates. The 80% formation pressure retention level means that the formation pressure at that time needs to be maintained at 80% of the original formation pressure. The original formation pressure refers to the formation pressure when the reservoir was not initially developed.

[0068] (10) Gas storage capacity design during the coordinated construction phase

[0069] The reservoir capacity design is mainly based on the volumetric method and the dynamic method. The volumetric method is based on the conversion of reservoir geological reserves into hydrocarbon pore volume HCPV; the dynamic method is based on the material balance equation, and by introducing the injection of dry gas drive phase to establish a material balance injection and production dynamic prediction model for calculation and solution. The volumetric method calculates the Y reservoir capacity to be 6.217 billion cubic meters, and the dynamic method calculates the Y reservoir capacity to be 6.284 billion cubic meters. After comprehensive evaluation, the Y reservoir capacity is designed to be 6.250 billion cubic meters.

[0070] (11) Design of working gas volume for gas injection to enhance recovery and coordinated gas storage construction

[0071] Different from the working gas volume of conventional gas storage, the working gas volume of gas injection EOR gas storage construction mainly includes two parts: one part is the natural gas produced from oil wells, and the other part is the natural gas produced from gas injection wells converted to gas production wells. In order to meet the needs of gas injection to improve oil reservoir recovery, the total gas volume of natural gas recovered in winter cannot exceed the total gas injection volume. Through numerical simulation evaluation, the optimal gas production volume (working gas volume) in winter is 50% of the total gas injection volume.

[0072] (12) Design of operation cycle of gas storage construction with gas injection to enhance recovery

[0073] During the gas injection EOR coordinated gas storage construction project, the gas injection wells keep injecting gas and the oil production wells keep producing. Due to the effectiveness of gas injection, a considerable amount of natural gas will also be produced by the oil production wells. It is precisely because the injection and production intensity of the gas injection EOR coordinated gas storage construction project is not high that the oil production wells are in production during the gas injection period, which will accelerate gas diffusion and is conducive to the balance of the gas-liquid interface. Therefore, the gas injection EOR coordinated gas storage construction project has a shorter balance period than the pure gas storage during the reservoir-type gas storage construction stage, and is generally designed to be 10 days. During the construction stage of the reservoir-type gas storage, the gas injection period and the gas production period follow the "summer injection and winter production" principle to meet the peak demand for uneven monthly gas consumption. Based on the above analysis, the operation cycle of the reservoir construction is as follows: during the operation, the gas reservoir should try its best to follow the design arrangement of unified gas injection during the injection period of 265 days (February 6th to October 31st), unified gas production during the balance period of 10 days (November 1st to November 10th), and unified gas production during the gas production period of 90 days (November 11th to February 5th of the following year); according to the actual supply of gas sources, flexible adjustments can be made during specific operations.

[0074] (13) Design of single well gas injection capacity during the coordinated construction phase of gas storage

[0075] The derived gas injection capacity equation of the gas injection well in the reservoir-type gas storage is as follows:

[0076]

[0077] Among them, p wf is the bottom pressure of the gas injection well of the gas storage reservoir; p r is the injection formation pressure of the gas storage injection well; q g2 is the daily gas injection volume; T-temperature; μ-viscosity; Z-injection gas deviation factor; K-formation permeability; h-formation gas absorption thickness; r e -Gas injection well control radius; r w -wellbore radius or wellbore radius; S-skin factor; γ g -Note the relative density of the daily atmosphere.

[0078] Gas absorption index I of gas injection wells in reservoir-type gas storage inj It is defined as the daily gas injection volume under the square difference of pressure, and the formula is as follows:

[0079]

[0080] Based on the derived gas injection capacity equation of the gas injection well in the reservoir-type gas storage, the gas injection capacity of a single well in the Y reservoir is 60×10 4 m 3 / d.

[0081] (14) Design of single well gas production capacity during the coordinated construction phase of gas storage

[0082] The open flow rate of a single horizontal well was evaluated by using the empirical formula method (Chen Yuanqian method and Joshi method) and the reservoir engineering method. According to the actual production capacity of the oil and gas reservoir and the IPR production capacity curve of the oil and gas reservoir, the single well gas production capacity of the Y reservoir was designed to be 30×10 4 m 3 / d.

Claims

1. A design method for improving oil recovery by gas injection in oil reservoirs in coordination with gas storage construction, characterized in that: Specifically: On the basis of judging that the sealing property of the reservoir meets the requirements, the gas source is guaranteed and the gas injection in the reservoir is feasible, it is determined that the reservoir can be injected with gas to enhance the recovery rate and build a reservoir-type gas storage facility; Gas injection to improve oil recovery includes determining the injection pressure, optimizing the injection and production well pattern, allocating injection wells and production wells; The construction of reservoir-type gas storage includes operating pressure design, storage capacity design, working gas volume demonstration, operation cycle design and injection and production capacity evaluation of injection and production wells; The process of determining that the plugging property of the reservoir meets the requirements, the gas injection source is guaranteed, and the gas injection of the reservoir is feasible includes the following steps: S1. Determine whether the plugging property of the reservoir to be evaluated is strong according to the plugging property evaluation of the reservoir; S2. If the plugging property of the reservoir to be evaluated is strong, then evaluate whether the gas transmission capacity of the gas pipeline of the reservoir can meet the gas injection and production needs of the reservoir. If so, conduct a feasibility analysis of gas injection in the reservoir; S3. If the feasibility analysis result of gas injection of the oil reservoir shows that gas injection of the oil reservoir is feasible, it is determined that the oil reservoir has the basis for gas injection to improve oil recovery and gas storage construction; The specific steps of gas injection well allocation are: designing the amount of natural gas injected into the gas injection wells during the gas injection to enhance oil recovery according to the gas injection capacity equation of the gas injection wells; The gas injection capacity equation of the gas injection well is as follows: Where: wf is the pseudo pressure at the bottom of the gas injection well; ψ is the gas injection formation pressure of the gas injection well; q g1 is the amount of natural gas injected into the gas injection well; T is the temperature; K is the formation permeability; h is the formation gas absorption thickness; r e is the control radius of the gas injection well; r w is the wellbore radius or wellbore radius; S is the skin coefficient; D is the inertia coefficient; The gas injection well absorption index is used to represent the gas injection capacity of a single well during the coordinated construction phase of the gas storage reservoir. The calculation process of the gas injection well absorption index is as follows: Gas absorption index I of gas injection wells in reservoir-type gas storage inj It is defined as the daily gas injection volume under the square difference of pressure, and the formula is as follows: Among them, p wf is the injection well bottom pressure of the gas storage reservoir; p r is the injection formation pressure of the gas storage injection well; q g2 is the daily gas injection volume; T is the temperature; μ is the viscosity; Z is the injection gas deviation factor; K is the formation permeability; h is the formation air absorption thickness; r e is the control radius of the gas injection well; r w is the wellbore radius or wellbore radius; S is the skin coefficient; γ g is the relative density of the daily atmosphere.

2. The design method for enhancing oil recovery by gas injection in oil reservoirs in coordination with gas storage construction according to claim 1, characterized in that: The specific determination of gas injection pressure is as follows: the gas injection pressure in the reservoir gas injection EOR stage is higher than the minimum miscible pressure; the front end pressure of the injected gas is kept above the minimum miscible pressure; The specific optimization of the injection-production well pattern is: using horizontal well injection-production well type for injection-production; The specific production allocation of oil wells is as follows: analyzing the two aspects of oil well liquid production control and oil well gas production control, and obtaining the production allocation conditions of oil wells in the gas injection to enhance oil recovery stage.

3. The design method for enhancing oil recovery by gas injection in oil reservoirs in coordination with gas storage construction according to claim 1, characterized in that: The specific operation pressure design includes: designing the upper and lower pressure limits of the gas storage coordinated construction phase; Design the storage capacity of the gas storage facility during the coordinated construction phase; Design the working gas volume of gas storage construction; Design the construction and operation cycle of gas storage; Design the gas injection capacity of a single well during the coordinated construction phase of the gas storage facility; Design the gas production capacity of a single well during the coordinated construction phase of the gas storage facility.

4. The design method for enhancing oil recovery by gas injection in oil reservoirs in coordination with gas storage construction according to claim 1, characterized in that: The design of the upper limit pressure during the coordinated construction phase of the gas storage reservoir comprehensively considers the reservoir sealing, the lateral pressure of the cap rock and the safety factor of the gas storage reservoir, the operating conditions of the ground gas injection compressor, the critical pressure of the fracture opening and the formation fracture pressure.

5. The design method for enhancing oil recovery by gas injection in oil reservoirs in coordination with gas storage construction according to claim 1, characterized in that: The lower limit pressure value during the coordinated construction phase of the gas storage facility must meet the needs of miscibility under formation conditions; through the evaluation of the formation pressure retention degree, the formation pressure at that time needs to be maintained at 80% of the original formation pressure.

6. The design method for enhancing oil recovery by gas injection in oil reservoirs in coordination with gas storage construction according to claim 1, characterized in that: The storage capacity of the gas storage reservoir in the coordinated construction stage is designed based on the volumetric method and the dynamic method. The reservoir storage capacity is calculated by the volumetric method and the dynamic method respectively, and the average of the two results is taken as the final storage capacity of the gas storage reservoir in the coordinated construction stage.

7. The design method for enhancing oil recovery by gas injection in oil reservoirs in coordination with gas storage construction according to claim 1, characterized in that: The working gas volume of gas injection to enhance oil recovery and coordinated gas storage construction includes two parts: one part is the natural gas produced from oil wells, and the other part is the natural gas produced from gas injection wells converted into gas production wells; through numerical simulation evaluation, when the gas production volume in winter is 50% of the total gas injection volume of the stage, gas injection to enhance oil reservoir recovery is optimal.

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