A method and system for designing gas-liquid interface migration in oil reservoir gas drive linkage library construction

Abstract

The present invention discloses a method and system for designing gas-liquid interface migration of an oil reservoir gas drive linkage library. The method comprises: in a gas drive stage, dividing all wells in an oil reservoir into gas injection wells and oil production wells according to depth; injecting gas into the gas injection wells until a gas cap is formed at the upper part of the reservoir; wherein, in a production process, monitoring the position of the gas-oil interface in real time, and when an oil production well exists at the upper part of the gas-oil interface, converting the oil production well into a gas injection well; in a transition stage, injecting gas into the gas injection wells in a first time period, converting the gas injection wells into gas production wells for gas production in a second time period, and gradually increasing the gas injection volume of the gas injection wells so that the peak-shaving gas volume increases synchronously, wherein the time of the first time period is greater than that of the second time period; in a peak-shaving and increased injection stage, when the stored gas volume reaches a certain level, increasing the peak-shaving gas volume of the gas injection wells, and gradually transitioning to the maximum working gas volume; converting the oil reservoir into a gas storage and operating at the maximum operating pressure and the maximum working gas volume.

Description

Technical Field

[0001] The present invention relates to the technical field of oil reservoir exploitation, and in particular to a method and system for designing gas-liquid interface migration in gas-drive linkage reservoir construction of oil reservoirs, which is suitable for the design of gas storage reservoirs built by gas-drive linkage in thick-layer block oil reservoirs, especially the reasonable migration of gas-liquid interface in gas-drive linkage reservoir construction of fractured block bottom water oil reservoirs. Background Art

[0002] At present, the underground gas storage facilities that have been built in China are mainly depleted oil and gas reservoir type, salt cavern type, aquifer type and abandoned mine pit type. However, there is no precedent for the construction of oil reservoir type gas storage facilities.

[0003] Peak-shaving gas storage requires that the filling and release of reservoir pores must be completed in a short period of time (generally, gas filling is completed once within 8 months, and gas release is completed once within 4 months, forming an injection and production cycle). This high-intensity strong injection and strong production method will change the relative seepage law of the oil, gas and water three-phase fluid in the reservoir. Strong injection causes the injected natural gas to easily enter the oil layer and be wrapped by the oil film to form an "oil-in-gas" form. When passing through the pore throat, it is easy to produce the Jamin effect, reducing the gas drive swept volume; this discontinuous phase causes the gas to escape or be captured, forming lost gas, resulting in the phenomenon of more gas injection and less gas production in the gas storage, and the lost gas is difficult to recover again. The strong injection process causes the gas cap to expand rapidly, the oil-gas interface to fluctuate violently, and the gas cap gas is easy to form a gas channel along the cracks to enter the oil well, reducing the gas drive swept volume and affecting the gas drive recovery rate. During the strong production process, the gas cap deficit is greater than the oil ring deficit, and the oil-gas interface moves rapidly toward the gas zone, resulting in oil invading the gas cap and difficulty in recovering the oil in the oil ring. The rapid production of the gas cap causes the reservoir formation pressure to drop sharply, resulting in serious energy deficit, leading to low-liquid and inefficient production of the oil well. If it drops below the reservoir saturation pressure, the oil ring will be degassed on a large scale, and the crude oil quality will deteriorate, resulting in a significant increase in the reservoir decline rate, which seriously affects the effect of gas drive development.

[0004] In summary, it is quite difficult to tackle the technical issues in the construction of gas storage facilities linked to oil reservoir gas drive, and field tests are still in a blank stage. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention proposes a method and system for designing the migration of gas-liquid interface in the gas-drive linkage construction of reservoirs, which is suitable for the design of gas-drive linkage construction of gas storage in thick-layer blocky reservoirs, especially for the reasonable migration of gas-liquid interface in the gas-drive linkage construction of fractured blocky bottom water reservoirs. In view of reservoir data, the super-thick dual-medium reservoirs have the characteristics of closed cap rock, good reservoir physical properties, and high natural production capacity. Through development practice, it has been confirmed that this type of reservoir is suitable for the top injection of natural gas non-miscible gravity stable drive development method, and has the advantage of expanding the scale of gas drive and building gas storage simultaneously. Both indoor experiments and numerical simulation results have confirmed that gas pressurized overburden displacement can give full play to the deep dialysis oil displacement effect of the reservoir matrix, promote the migration of residual oil in the matrix to the fractures, greatly improve the matrix oil displacement efficiency, and improve the final recovery rate; in the process of gas drive displacement, with the increase of the degree of production, the larger the gas storage volume, the larger the storage capacity, and the more mature the conditions for building a gas storage. To this end, the present invention optimizes the injection and production parameters in the production process, designs a reasonable gas cap downward pressure speed, maintains the smooth and reasonable migration of the gas-liquid interface, greatly improves the gas drive recovery rate while ensuring the peak-shaving working gas volume, and can ensure the smooth construction of oil reservoir-type gas storage.

[0006] In a first aspect of an embodiment of the present invention, a method for designing gas-liquid interface migration in a reservoir gas drive linkage library is proposed, the method comprising:

[0007] In the gas drive stage, all wells in the reservoir are divided into gas injection wells and oil production wells according to their depth;

[0008] Injecting gas into the gas injection well until a gas cap is formed at the top of the reservoir; wherein, during the production process, the position of the gas-oil interface is monitored in real time, and when an oil production well exists above the gas-oil interface, the oil production well is converted to a gas injection well;

[0009] In the transition phase, the gas injection well is injected in the first time period, and the gas injection well is converted into a gas production well for gas production in the second time period, and the gas injection volume of the gas injection well is gradually increased so that the peak-shaving gas volume is increased synchronously, wherein the time of the first time period is greater than that of the second time period;

[0010] In the peak-shaving and injection-increasing stage, when the stored gas volume reaches a certain level, the peak-shaving gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume;

[0011] Convert the oil reservoir into a gas storage and operate it at maximum operating pressure and maximum working gas volume.

[0012] Furthermore, in the gas drive stage, all wells in the reservoir are divided into gas injection wells and oil production wells according to their depth, including:

[0013] The wells are divided into three sections from top to bottom according to their depth. The upper well is used as a gas injection well, and the middle and lower wells are oil production wells.

[0014] Further, injecting gas into the gas injection well until a gas cap is formed on the upper part of the reservoir comprises:

[0015] During the production process, natural gas is injected into the gas injection well until a gas cap is formed at the top of the reservoir, and the gas-oil interface moves downward with the gas injection;

[0016] When the longitudinal span of the formed gas cap is 600m to 800m and the gas drive recovery rate is greater than 15%, the transition stage is started.

[0017] Further, injecting gas into the gas injection well until a gas cap is formed on the upper part of the reservoir comprises:

[0018] During the production process, the injection-production ratio of gas injection wells to oil production wells is 1.1-1.5, the annual gas injection rate of the gas injection wells is 0.015HCPV-0.02HCPV, and the formation pressure recovers 0.3-0.7MPa annually.

[0019] Further, injecting gas into the gas injection well until a gas cap is formed on the upper part of the reservoir, further comprising:

[0020] During the production process, the gas-oil ratio of oil well production is monitored in real time. If the gas-oil ratio is greater than the preset gas-oil ratio threshold, it is determined that gas channeling has occurred, and the gas cap is protected by shutting down the well and adjusting the gas injection rate.

[0021] Furthermore, in the transition phase, the gas injection well is injected with gas in the first time period, and the gas injection well is converted into a gas production well for gas production in the second time period, and the gas injection volume of the gas injection well is gradually increased so that the peak-shaving gas volume is increased synchronously, including:

[0022] Inject gas into the gas injection wells from March to October each year, convert the gas injection wells into gas production wells from November each year to February of the following year to produce gas, and gradually increase the gas injection volume of the gas injection wells, and increase the gas production volume of the gas production wells synchronously with the gas injection volume of the gas injection wells;

[0023] During the production process, the position of the gas-oil interface is monitored in real time. When the gas-oil interface drops to the middle well, the middle well is converted into a gas injection well.

[0024] Furthermore, in the transition phase, the gas injection well is injected with gas in the first time period, and the gas injection well is converted into a gas production well for gas production in the second time period, and the gas injection volume of the gas injection well is gradually increased so that the peak-shaving gas volume is increased synchronously, including:

[0025] The annual peak-shaving gas volume in the oil field is controlled below 400 million cubic meters, the downward movement speed of the gas-oil interface is controlled at 50 to 80 m / year, and the formation pressure recovers by 0.8 to 1.2 MPa each year.

[0026] Furthermore, in the peak-shaving and injection-increasing stage, when the stored gas volume reaches a certain level, the peak-shaving gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume, which also includes:

[0027] During the peak-shaving and injection-increased stage, when the stored gas volume reaches a certain level, the annual gas injection volume of the gas injection well is continuously increased to the maximum gas injection volume, and the annual gas production volume of the gas production well is synchronously increased to the maximum gas production volume along with the annual gas injection volume of the gas injection well; during the production process, the position of the gas-oil interface is monitored in real time, and when the gas-oil interface drops to the lower well, the lower well is converted into a gas injection well.

[0028] Furthermore, in the peak-shaving and injection-increasing stage, when the stored gas volume reaches a certain level, the peak-shaving gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume, including:

[0029] When the gas storage volume accounts for 20% of the estimated total storage capacity, the peak gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume.

[0030] In a second aspect of the embodiment of the present invention, a system for designing gas-liquid interface migration through reservoir gas drive linkage library construction is proposed, the system comprising:

[0031] The gas drive module is used to divide all wells in the reservoir into gas injection wells and oil production wells according to their depths during the gas drive stage;

[0032] A gas injection module is used to inject gas into the gas injection well until a gas cap is formed on the upper part of the reservoir; wherein, during the production process, the position of the gas-oil interface is monitored in real time, and when an oil production well exists on the upper part of the gas-oil interface, the type of the oil production well is converted into a gas injection well;

[0033] A transition module is used to inject gas into the gas injection well in a first time period during the transition phase, convert the gas injection well into a gas production well for gas production in a second time period, and gradually increase the gas injection volume of the gas injection well so that the peak-shaving gas volume increases synchronously, wherein the time of the first time period is greater than that of the second time period;

[0034] Adjust the injection module, which is used to increase the peak gas volume of the injection well when the stored gas volume reaches a certain level during the peak injection stage, and gradually transition to the maximum working gas volume;

[0035] The oil reservoir conversion module is used to convert the oil reservoir into a gas storage and operate it at the maximum operating pressure and maximum working gas volume.

[0036] In a third aspect of an embodiment of the present invention, a computer device is proposed, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements a method for designing gas-liquid interface migration during reservoir gas drive linkage library construction when executing the computer program.

[0037] In a fourth aspect of an embodiment of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, a method for designing gas-liquid interface migration in a reservoir gas drive linkage library is implemented.

[0038] Compared with the prior art, the method and system for designing gas-liquid interface migration in oil reservoir gas drive linkage reservoir construction of the present invention have at least the following advantages:

[0039] 1. By increasing the gas injection volume and expanding the gas cap scale, the oil-gas interface moves downward steadily, and the oil production wells above the oil-gas interface are timely converted into gas injection and production wells, saving drilling costs, facilitating the increase of gas injection scale, and ensuring the peak regulation function of the gas storage reservoir;

[0040] 2. By continuously increasing the amount of gas injected into the reservoir, the reservoir can be restored to its original formation pressure, which is conducive to the overburdening and pressure-increasing displacement effect of gas drive. The injected gas can diffuse and permeate into the micro-cracks on the surface of the matrix and into the micro-pores deep in the matrix, thereby displacing the residual oil in the matrix, enhancing the permeation effect of the matrix into the fractures, and improving the gas drive recovery rate.

[0041] 3. Compared with the existing gas drive method, it can restore the formation pressure in a shorter time, realize the matrix to fracture dialysis in advance, and obtain a greater recovery rate in a shorter time.

[0042] 4. By optimizing the gas injection parameters in the gas drive stage, transition stage and peak regulation stage, we can ensure that the oil-gas interface moves downward steadily, and the gas continuously displaces the remaining oil in the matrix and fractures, thereby reducing the occurrence of the "Jiamin effect", increasing the gas drive swept volume, and improving the gas drive recovery rate and gas storage operation efficiency.

[0043] 5. By optimizing the oil production parameters or gas production parameters in the transition stage and the peak regulation stage, it is ensured that the oil-gas interface moves upward steadily, the gas cap deficit and the oil ring deficit volumes are equivalent, the pressure difference between the gas cap and the oil ring is reduced, and the oil and gas invasion phenomena during the strong injection and strong production process are suppressed, the gas drive swept volume is increased, and the gas drive recovery rate and gas storage operation efficiency are improved.

[0044] 6. It can ensure that the gas-oil interface moves downward steadily and the oil-water interface moves downward slowly synchronously, which can effectively inhibit the invasion of bottom water, relieve the water sealing effect on crude oil, restore the production of oil wells with serious water flooding at the bottom, improve the utilization rate of oil reservoirs, and achieve the effect of controlling water and increasing oil production. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 It is a schematic diagram of a method flow for designing gas-liquid interface migration in oil reservoir gas drive linkage library construction according to an embodiment of the present invention.

[0047] Figure 2 It is a schematic diagram of a dual medium reservoir microscopic unit of a huge thick blocky buried hill reservoir according to a specific embodiment of the present invention.

[0048] Figure 3 It is a schematic diagram of a gas drive linkage reservoir building and development mode for thick-layer block oil reservoirs according to a specific embodiment of the present invention.

[0049] Figure 4 It is a schematic diagram comparing production curves before and after gas injection in a flooded single well according to a specific embodiment of the present invention.

[0050] Figure 5 It is a schematic diagram of a formation pressure prediction curve using the post-gas drive energy supplementation method of the present invention in a specific embodiment of the present invention.

[0051] Figure 6 It is a schematic diagram comparing recovery factor prediction curves of different development methods according to a specific embodiment of the present invention.

[0052] Figure 7 It is a schematic diagram of the system architecture of the gas-liquid interface migration design for oil reservoir gas drive linkage library construction according to one embodiment of the present invention.

[0053] Figure 8 It is a schematic diagram of the structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The principles and spirit of the present invention will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are provided only to enable those skilled in the art to better understand and implement the present invention, and are not intended to limit the scope of the present invention in any way. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0055] Those skilled in the art will appreciate that the embodiments of the present invention may be implemented as a system, device, apparatus, method or computer program product. Therefore, the present disclosure may be specifically implemented in the following forms, namely: complete hardware, complete software (including firmware, resident software, microcode, etc.), or a combination of hardware and software.

[0056] According to an embodiment of the present invention, a method and system for designing gas-liquid interface migration during reservoir gas drive linkage library construction are proposed.

[0057] The principle and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0058] Figure 1 The following is a flow chart of a method for designing gas-liquid interface migration in a reservoir gas drive linkage library according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0059] Step S101, in the gas drive stage, all wells in the reservoir are divided into gas injection wells and oil production wells according to their depths;

[0060] Step S102, injecting gas into the gas injection well until a gas cap is formed at the upper part of the reservoir; wherein, during the production process, the position of the gas-oil interface is monitored in real time, and when an oil production well exists above the gas-oil interface, the type of the oil production well is converted to a gas injection well;

[0061] Step S103, in the transition phase, inject gas into the gas injection well in the first time period, convert the gas injection well into a gas production well for gas production in the second time period, and gradually increase the gas injection volume of the gas injection well so that the peak-shaving gas volume increases synchronously, wherein the time of the first time period is greater than that of the second time period;

[0062] Step S104, in the peak-shaving and injection-increasing stage, when the stored gas volume reaches a certain level, the peak-shaving gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume;

[0063] Step S105, converting the oil reservoir into a gas storage and operating it at the maximum operating pressure and maximum working gas volume.

[0064] In order to explain more clearly the method of designing gas-liquid interface migration in the above-mentioned reservoir gas drive linkage reservoir construction, each step is described in detail below.

[0065] Step S101, gas drive stage:

[0066] In the gas drive stage, the wells are divided into three sections from top to bottom according to the depth. The upper wells are used as gas injection wells, and the middle and lower wells are oil production wells. Horizontal wells have a larger oil leakage area and a higher gas absorption index than vertical wells. After fracturing, the gas injection capacity can be greatly improved, the number of gas injection wells can be saved, and the economic cost can be reduced.

[0067] Specifically, all wells can be divided into three sections according to their depth from top to bottom. In the gas drive stage, the upper wells are used as gas injection wells, and the middle and lower wells are oil production wells.

[0068] Step S102:

[0069] Natural gas is injected into the gas injection well until a gas cap is formed on the upper part of the reservoir. When the longitudinal span of the formed gas cap is 600m to 800m and the gas drive recovery rate is greater than 15%, the transition stage is started.

[0070] Among them, during the production process, when the gas-oil interface drops to the vicinity of the oil production well, the oil production well is converted into a gas injection well; these gas injection wells are the original oil production wells in the oil reservoir, which can improve the utilization rate of the oil well, effectively save drilling investment, and improve resource utilization.

[0071] In the actual production process, the gas-oil ratio of oil well production can be monitored in real time. If the gas-oil ratio is greater than the preset gas-oil ratio threshold, it is determined that gas channeling has occurred. By shutting down the well to protect the gas cap and adjusting the gas injection rate, the number of gas channeling wells can be avoided and the gas-oil interface can be ensured to move downward steadily.

[0072] Step S103, transition phase:

[0073] Gas is injected into the gas injection wells from March to October each year, and converted into gas production wells from November each year to February of the following year for gas production. The gas injection volume of the gas injection wells is gradually increased, and the gas production volume of the gas production wells is increased synchronously with the gas injection volume of the gas injection wells.

[0074] Among them, during the production process, the position of the gas-oil interface is monitored in real time. When the gas-oil interface drops to the middle well, the middle well is converted into a gas injection well. As the gas-oil interface changes, if the first-line oil wells include water-flooded wells, the water-flooded wells can resume production and be converted into oil production wells. The "first-line oil wells" here generally refer to the circle of wells closest to the gas injection wells.

[0075] Step S104, peak load regulation and injection increase phase:

[0076] During the peak-shaving and injection-increasing stage, when the stored gas volume accounts for 20% of the estimated total storage capacity, the annual gas injection volume of the gas injection well is continuously increased to the maximum gas injection volume, and the annual gas production volume of the gas production well is synchronously increased to the maximum gas production volume along with the annual gas injection volume of the gas injection well.

[0077] During the production process, the position of the gas-oil interface is monitored in real time, and when the gas-oil interface drops to the lower well, the lower well is converted into a gas injection well.

[0078] Step S105, converting the oil reservoir into a gas storage and operating it at the maximum operating pressure and maximum working gas volume.

[0079] It should be noted that, although the operations of the method of the present invention are described in a specific order in the above embodiments and the accompanying drawings, this does not require or imply that the operations must be performed in the specific order, or that all the operations shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0080] In order to explain more clearly the method of designing gas-liquid interface migration in the above-mentioned reservoir gas drive linkage reservoir construction, a specific embodiment is described below. However, it is worth noting that this embodiment is only for better illustrating the present invention and does not constitute an improper limitation to the present invention.

[0081] Taking a huge thick blocky buried hill reservoir as an example, refer to Figure 2 , is a schematic diagram of a dual medium reservoir microscopic unit of a thick massive buried hill reservoir according to a specific embodiment of the present invention. Figure 2 In the figure, the matrix 11 and the crack 12 are marked.

[0082] like Figure 2 As shown, the giant thick blocky buried hill reservoir 1 is mostly a dual medium structure. The fracture 12 has a large permeability, and the crude oil accumulated in the fracture is preferentially produced. The matrix 11 has a small permeability, generally below 10mD. The diameter of water molecules is large and it is difficult for them to enter the micro-fractures and matrix. The diameter of gas molecules is relatively small and they can enter the tiny pores to achieve effective displacement. The volume of the matrix of the dual medium reservoir accounts for more than 90%. Therefore, the gas drive development method is usually used to effectively utilize the dual medium reservoir.

[0083] In the process of gas drive development, "increasing injection and increasing pressure" can amplify the seepage effect of gas drive into the matrix, promote the migration of matrix crude oil into the fractures, and improve the effect of gas drive development.

[0084] refer to Figure 3 , is a schematic diagram of a gas drive linkage library development model for thick-layer block oil reservoirs according to a specific embodiment of the present invention. Figure 3 In the figure, the thick massive buried hill reservoir 1, the upper well 2, the middle well 31, the lower well 32, the gas cap 4, the gas-oil interface 41, the oil ring 5, the water invasion zone 6, the oil-water interface 61 and the edge and bottom water 7 are marked. Among them, the upper well 2 can be a gas injection / gas production well, the middle well 31 can be an oil production / gas injection / gas production well, and the lower well 32 can be a water-flooded / oil production / gas injection well.

[0085] like Figure 3 As shown in the figure, the method for designing gas-liquid interface migration of oil reservoir gas drive linkage storage proposed in the present invention can guide the construction of gas drive linkage gas storage in thick block oil reservoirs, and can store injected gas while giving full play to the dialysis effect of gas drive matrix. When the gas cap is large enough, it can play a peak regulation role. The specific process is as follows:

[0086] Step S1:

[0087] All wells are divided into three sections according to their depth from top to bottom. In the gas drive stage, the upper well 2 is used as a gas injection well, the middle well 31 is an oil production well, and the lower well 32 is in a shut-in state due to bottom water intrusion;

[0088] Step S2:

[0089] Gas is injected into the upper well 2 (gas injection well) until a stable gas cap 4 is formed on the upper part of the reservoir. The injected gas is natural gas.

[0090] During the production process, the position of the gas-oil interface 41 is monitored in real time. When the gas-oil interface 41 drops to the vicinity of the middle well 31 (oil production well), the middle well 31 can be converted into a gas injection well. When the first-line oil wells include the lower well 32 (flooded well), the lower well 32 can resume normal production and be converted into an oil production well; the "first-line oil wells" mentioned here generally refer to the circle of wells closest to the gas injection well. The middle well 31 and the lower well 32 are both original oil production wells in the reservoir. During the production process, the conversion of well categories can improve the utilization rate of oil wells, effectively save drilling investment, and improve resource utilization.

[0091] In this embodiment, the upper well 2, the middle well 31 and the lower well 32 are all horizontal wells. Horizontal wells have a larger oil leakage area and a higher gas absorption index than vertical wells. After fracturing transformation, the gas injection capacity can be greatly improved, the number of gas injection wells can be saved, and the economic cost can be reduced.

[0092] In the actual production process, the downward position of the gas-oil interface 41 and the gas-oil ratio of the oil wells in the first line of gas injection wells can be monitored in real time. If the gas-oil ratio is too large, it means that gas channeling has occurred. The well should be shut down in time to protect the gas cap, and the gas injection speed should be adjusted in time to avoid an increase in the number of gas channeling wells and ensure that the gas-oil interface moves downward steadily.

[0093] refer to Figure 4 , which is a schematic diagram comparing production curves before and after gas injection in a flooded single well according to a specific embodiment of the present invention.

[0094] like Figure 4 As shown, the oil wells rely on natural energy to develop serious stratum depletion, and the bottom water invasion causes the oil wells to stop spraying due to water. After gas drive development, large-scale gas injection is used to expand the gas cap. As the gas-oil interface moves downward, the oil-water interface also moves downward steadily, allowing the oil wells in the water invasion zone to resume normal production.

[0095] In this embodiment, the injection-production ratio of the upper well 2 (gas injection well) to the middle well 31 (oil production well) is 1.1-1.5, the annual gas injection rate of the upper well 2 (gas injection well) is 0.015HCPV-0.02HCPV, such as 0.017HCPV, and the formation pressure recovers 0.3-0.7MPa, such as 0.5MPa, every year.

[0096] When the longitudinal span of the gas cap 4 is 600m to 800m, the gas drive production rate is greater than 15%, and the peak regulation function can be started.

[0097] Step S3:

[0098] After the gas cap 4 is formed, the gas injection volume of the upper well 2 (gas injection well) is gradually increased. The gas injection well injects gas from March to October every year, and is converted to a gas production well from November to February of the following year. The peak-shaving gas volume increases continuously with the gas injection volume.

[0099] During the production process, the gas-oil interface 41 is monitored in real time. When the gas-oil interface 41 drops to the vicinity of the middle well 31 (oil production well), the middle well 31 is converted into a gas injection well to exert the gas injection and production functions to ensure the gas injection and production volumes. When the first-line oil wells include the lower well 32 (flooded well), the lower well 32 can resume normal production and be converted into an oil production well.

[0100] In this embodiment, when the upper well 2 and the middle well 31 are injecting gas, the annual gas injection volume gradually increases, and the annual gas injection volume in the oil zone is controlled below 1 billion cubic meters; when the upper well 2 and the middle well 31 are producing gas, the gas production volume increases synchronously with the gas injection volume, the annual peak-shaving working gas volume in the oil zone is controlled below 400 million cubic meters, the downward movement speed of the gas-oil interface 41 is controlled at 50 to 80 m / year, and the formation pressure recovers by 0.8 to 1.2 MPa each year.

[0101] refer to Figure 5 , is a formation pressure prediction curve diagram of a specific embodiment of the present invention using the post-gas drive energy supplementation method of the present invention.

[0102] like Figure 5 As shown in the figure, the optimal formation pressure recovery trend for gas drive to supplement formation energy is optimized through numerical simulation method, which proves that it is most appropriate for the formation pressure to recover 0.5MPa per year in the gas drive stage and 1.0MPa per year in the transition stage. This ensures that the gas reservoir has a high gas production capacity and avoids large-scale gas channeling in the gas drive oil production process as much as possible, ensuring that both gas drive oil production and peak regulation are not affected.

[0103] Step S4:

[0104] When the stored gas volume (gas cap 4) reaches 20%, the peak-shaving gas volume of the upper well 2 (gas injection well) and the middle well 31 (gas injection well) is increased to gradually transition to the maximum working gas volume.

[0105] During the production process, the gas-oil interface 41 and the gas-oil ratio of the first-line oil wells are monitored in real time. When the gas-oil interface 41 drops to the vicinity of the lower well 32, the lower well 32 (oil production well) is converted into a gas injection well.

[0106] In this embodiment, when the upper well 2 and the middle well 31 are gas injection wells, the annual gas injection volume continues to increase to the maximum gas injection volume in 20 to 25 years, and the maximum annual gas injection volume in the oil field is 2.4 to 2.8 billion cubic meters;

[0107] When the upper well 2 and the middle well 31 are gas production wells, the annual gas production increases synchronously with the annual gas injection volume during gas injection to the maximum gas production volume, and the maximum annual gas production volume of the oil field is 2.2 to 2.6 billion cubic meters.

[0108] Step S5:

[0109] The huge thick blocky buried hill reservoir 1 is converted into a gas storage and operated at the maximum operating pressure and maximum working gas volume.

[0110] In this embodiment, the maximum operating pressure of the gas storage is the original formation pressure of 35 MPa, and the maximum working gas volume is 2.2 to 2.6 billion cubic meters.

[0111] refer to Figure 6 , which is a schematic diagram comparing recovery factor prediction curves of different development methods according to a specific embodiment of the present invention.

[0112] like Figure 6 As shown, on the basis of establishing a numerical model of the actual oil reservoir, the entire process of the gas drive linkage gas reservoir construction of the entire oil reservoir is simulated, and the development effects under the same formation conditions and the same well network environment, relying on natural energy development, natural gas drive development and gas drive linkage gas reservoir construction development conditions are compared. The gas drive linkage reservoir construction development method of the present invention has a recovery rate 9.88% higher than that of natural gas drive development, and is 26.29% higher than that of natural energy development.

[0113] After introducing the method of the exemplary embodiment of the present invention, next, refer to Figure 7 A system for designing gas-liquid interface migration through reservoir gas drive linkage and library construction according to an exemplary embodiment of the present invention is introduced.

[0114] The implementation of the system for designing the migration of gas-liquid interface in oil reservoir gas drive linkage library construction can refer to the implementation of the above method, and the repeated parts will not be repeated. The term "module" or "unit" used below can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0115] Based on the same inventive concept, the present invention also proposes a system for designing gas-liquid interface migration in oil reservoir gas drive linkage library, such as Figure 7 As shown, the system includes:

[0116] The gas drive module 710 is used to divide all wells in the oil reservoir into gas injection wells and oil production wells according to their depths during the gas drive stage;

[0117] The gas injection module 720 is used to inject gas into the gas injection well until a gas cap is formed on the upper part of the reservoir; wherein, during the production process, the position of the gas-oil interface is monitored in real time, and when an oil production well exists on the upper part of the gas-oil interface, the type of the oil production well is converted into a gas injection well;

[0118] The transition module 730 is used to inject gas into the gas injection well in the first time period during the transition stage, convert the gas injection well into a gas production well for gas production in the second time period, and gradually increase the gas injection volume of the gas injection well so that the peak-shaving gas volume increases synchronously, wherein the time of the first time period is greater than the second time period;

[0119] The adjustment and injection module 740 is used to increase the peak gas volume of the gas injection well when the stored gas volume reaches a certain level during the peak injection stage, and gradually transition to the maximum working gas volume;

[0120] The oil reservoir conversion module 750 is used to convert the oil reservoir into a gas storage and operate it at the maximum operating pressure and the maximum working gas volume.

[0121] It should be noted that although several modules of the system for designing gas-liquid interface migration of reservoir gas drive linkage library construction are mentioned in the above detailed description, this division is only exemplary and not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules described above can be concretized in one module. Conversely, the features and functions of one module described above can be further divided into multiple modules for concretization.

[0122] Based on the above invention concept, Figure 8 As shown, the present invention also proposes a computer device 800, including a memory 810, a processor 820, and a computer program 830 stored in the memory 810 and executable on the processor 820, wherein the processor 820 implements the aforementioned method for designing gas-liquid interface migration in the reservoir gas drive linkage library when executing the computer program 830.

[0123] Based on the aforementioned inventive concept, the present invention proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the method for designing gas-liquid interface migration in the aforementioned reservoir gas drive linkage library is implemented.

[0124] Compared with the prior art, the method and system for designing gas-liquid interface migration in oil reservoir gas drive linkage reservoir construction of the present invention have at least the following advantages:

[0125] 1. By increasing the gas injection volume and expanding the gas cap scale, the oil-gas interface moves downward steadily, and the oil production wells above the oil-gas interface are timely converted into gas injection and production wells, saving drilling costs, facilitating the increase of gas injection scale, and ensuring the peak regulation function of the gas storage reservoir;

[0126] 2. By continuously increasing the amount of gas injected into the reservoir, the reservoir can be restored to its original formation pressure, which is conducive to the overburdening and pressure-increasing displacement effect of gas drive. The injected gas can diffuse and permeate into the micro-cracks on the surface of the matrix and into the micro-pores deep in the matrix, thereby displacing the residual oil in the matrix, enhancing the permeation effect of the matrix into the fractures, and improving the gas drive recovery rate.

[0127] 3. Compared with the existing gas drive method, it can restore the formation pressure in a shorter time, realize the matrix to fracture dialysis in advance, and obtain a greater recovery rate in a shorter time.

[0128] 4. By optimizing the gas injection parameters in the gas drive stage, transition stage and peak regulation stage, we can ensure that the oil-gas interface moves downward steadily, and the gas continuously displaces the remaining oil in the matrix and fractures, thereby reducing the occurrence of the "Jiamin effect", increasing the gas drive swept volume, and improving the gas drive recovery rate and gas storage operation efficiency.

[0129] 5. By optimizing the oil production parameters or gas production parameters in the transition stage and the peak regulation stage, it is ensured that the oil-gas interface moves upward steadily, the gas cap deficit and the oil ring deficit volumes are equivalent, the pressure difference between the gas cap and the oil ring is reduced, and the oil and gas invasion phenomena during the strong injection and strong production process are suppressed, the gas drive swept volume is increased, and the gas drive recovery rate and gas storage operation efficiency are improved.

[0130] 6. It can ensure that the gas-oil interface moves downward steadily and the oil-water interface moves downward slowly synchronously, which can effectively inhibit the invasion of bottom water, relieve the water sealing effect on crude oil, restore the production of oil wells with serious water flooding at the bottom, improve the utilization rate of oil reservoirs, and achieve the effect of controlling water and increasing oil production.

[0131] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0132] The present invention is described with reference to flowcharts and / or block diagrams of methods and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0133] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0134] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0135] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for designing gas-liquid interface migration in oil reservoir gas drive linkage library construction, characterized in that: The method includes: In the gas drive stage, all wells in the reservoir are divided into gas injection wells and oil production wells according to their depth; Injecting gas into the gas injection well until a gas cap is formed at the top of the reservoir; wherein, during the production process, the position of the gas-oil interface is monitored in real time, and when an oil production well exists above the gas-oil interface, the oil production well is converted to a gas injection well; In the transition phase, the gas injection well is injected in the first time period, and the gas injection well is converted into a gas production well for gas production in the second time period, and the gas injection volume of the gas injection well is gradually increased so that the peak-shaving gas volume is increased synchronously, wherein the time of the first time period is greater than that of the second time period; In the peak-shaving and injection-increasing stage, when the stored gas volume reaches a certain level, the peak-shaving gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume; Convert the oil reservoir into a gas storage facility and operate it at maximum operating pressure and maximum working gas volume; Among them, in the gas drive stage, all wells in the reservoir are divided into gas injection wells and oil production wells according to their depth, including: dividing the wells into three sections from top to bottom according to their depth, with the upper wells as gas injection wells, and the middle wells and lower wells as oil production wells; In the transition phase, the gas injection wells are injected with gas in the first time period, and the gas injection wells are converted into gas production wells for gas production in the second time period, and the gas injection volume of the gas injection wells is gradually increased so that the peak-shaving gas volume is increased synchronously, including: Inject gas into the gas injection wells from March to October each year, convert the gas injection wells into gas production wells from November each year to February of the following year to produce gas, and gradually increase the gas injection volume of the gas injection wells, and increase the gas production volume of the gas production wells synchronously with the gas injection volume of the gas injection wells; During the production process, the position of the gas-oil interface is monitored in real time. When the gas-oil interface drops to the middle well, the middle well is converted into a gas injection well. The annual peak-shaving gas volume in the oil field is controlled below 400 million cubic meters, the downward movement speed of the gas-oil interface is controlled at 50-80 m / year, and the formation pressure is restored by 0.8-1.2 MPa each year; Among them, in the peak-shaving and injection-increasing stage, when the stored gas volume reaches a certain level, the peak-shaving gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume, which also includes: In the peak-shaving and injection-increasing stage, when the gas storage volume reaches a certain level, the annual gas injection volume of the gas injection well is continuously increased to the maximum gas injection volume, and the annual gas production volume of the gas production well is synchronously increased to the maximum gas production volume along with the annual gas injection volume of the gas injection well; during the production process, the position of the gas-oil interface is monitored in real time, and when the gas-oil interface drops to the lower well, the lower well is converted into a gas injection well; When the gas storage volume accounts for 20% of the estimated total storage capacity, the peak gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume.

2. The method for designing gas-liquid interface migration in oil reservoir gas drive linkage library construction according to claim 1, characterized in that: Injecting gas into the gas injection well until a gas cap is formed on the upper part of the reservoir, comprising: During the production process, natural gas is injected into the gas injection well until a gas cap is formed at the top of the reservoir, and the gas-oil interface moves downward with the gas injection; When the longitudinal span of the formed gas cap is 600m to 800m and the gas drive recovery rate is greater than 15%, the transition stage is started.

3. The method for designing gas-liquid interface migration in oil reservoir gas drive linkage library construction according to claim 2 is characterized in that: Injecting gas into the gas injection well until a gas cap is formed on the upper part of the reservoir, comprising: During the production process, the injection-production ratio of gas injection wells to oil production wells is 1.1-1.5, the annual gas injection rate of the gas injection wells is 0.015HCPV-0.02HCPV, and the formation pressure recovers 0.3-0.7MPa annually.

4. The method for designing gas-liquid interface migration in oil reservoir gas drive linkage library construction according to claim 2, characterized in that: Injecting gas into the gas injection well until a gas cap is formed on the upper part of the reservoir, further comprising: During the production process, the gas-oil ratio of oil well production is monitored in real time. If the gas-oil ratio is greater than the preset gas-oil ratio threshold, it is determined that gas channeling has occurred, and the gas cap is protected by shutting down the well and adjusting the gas injection rate.

5. A system for designing gas-liquid interface migration in oil reservoir gas drive linkage library construction, characterized in that: The system includes: The gas drive module is used to divide all wells in the reservoir into gas injection wells and oil production wells according to their depths during the gas drive stage; A gas injection module is used to inject gas into the gas injection well until a gas cap is formed on the upper part of the reservoir; wherein, during the production process, the position of the gas-oil interface is monitored in real time, and when an oil production well exists on the upper part of the gas-oil interface, the category of the oil production well is converted into a gas injection well; A transition module is used to inject gas into the gas injection well in a first time period during the transition phase, convert the gas injection well into a gas production well for gas production in a second time period, and gradually increase the gas injection volume of the gas injection well so that the peak-shaving gas volume increases synchronously, wherein the time of the first time period is greater than that of the second time period; Adjust the injection module, which is used to increase the peak gas volume of the injection well when the stored gas volume reaches a certain level during the peak injection stage, and gradually transition to the maximum working gas volume; Reservoir conversion module, used to convert the reservoir into a gas storage and operate at maximum operating pressure and maximum working gas volume; Among them, the gas drive module is specifically used for: The wells are divided into three sections from top to bottom according to their depth, with the upper wells used as gas injection wells, and the middle and lower wells as oil production wells; The transition module is specifically used for: Inject gas into the gas injection wells from March to October each year, convert the gas injection wells into gas production wells from November each year to February of the following year to produce gas, and gradually increase the gas injection volume of the gas injection wells, and increase the gas production volume of the gas production wells synchronously with the gas injection volume of the gas injection wells; During the production process, the position of the gas-oil interface is monitored in real time. When the gas-oil interface drops to the middle well, the middle well is converted into a gas injection well. The annual peak-shaving gas volume in the oil field is controlled below 400 million cubic meters, the downward movement speed of the gas-oil interface is controlled at 50-80 m / year, and the formation pressure is restored by 0.8-1.2 MPa each year; Among them, the adjustment injection module is specifically used for: In the peak-shaving and injection-increasing stage, when the gas storage volume reaches a certain level, the annual gas injection volume of the gas injection well is continuously increased to the maximum gas injection volume, and the annual gas production volume of the gas production well is synchronously increased to the maximum gas production volume along with the annual gas injection volume of the gas injection well; during the production process, the position of the gas-oil interface is monitored in real time, and when the gas-oil interface drops to the lower well, the lower well is converted into a gas injection well; When the gas storage volume accounts for 20% of the estimated total storage capacity, the peak gas volume of the gas injection well is increased and gradually transitioned to the maximum working gas volume.

6. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 4 is implemented.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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