Method and system for predicting limit degree of recovery ratio improvement of gas drive reservoir

Abstract

The method comprises the following steps that an injection model of the oil reservoir is built, and the change relation among the accumulated gas injection amount of the oil reservoir, the accumulated oil production amount of gas injection and the recovery degree is obtained based on the injection model; a recovery model of the oil reservoir is constructed, and the change relation among the oil reservoir gas injection cumulative gas production rate, the gas injection cumulative oil production rate and the recovery degree is obtained based on the recovery model; a gas storage proportion model of the oil reservoir is built, and based on the gas storage proportion model, the oil reservoir accumulated gas injection amount and the change relation between the gas injection accumulated gas production amount and the accumulated gas injection amount are obtained; constructing a gas storage proportion function model based on the injection model, the extraction model and the gas storage proportion model; and obtaining a prediction model based on the gas storage proportion function model and the gas storage proportion model, and obtaining a prediction result based on the prediction model. According to the method disclosed by the invention, the gas drive recoverable reserves can be accurately predicted and accurately calibrated, so that the influence on oil field investment and decision-making due to reserve reporting and gas drive development scheme compiling work is supported.

Description

Technical Field

[0001] The invention belongs to the technical field of gas drive oil reservoir recovery, and relates to a method and a system for predicting the limit degree of gas drive oil reservoir recovery. Background Art

[0002] The recovery factor refers to the percentage of oil (gas) produced from an oil (gas) field to the original geological reserves; the enhanced recovery factor refers to the percentage of additional oil and gas produced through development methods that enhance the recovery factor, such as chemical flooding often used in tertiary oil recovery, to the original geological reserves.

[0003] After natural energy development, the formation pressure of oil reservoirs decreases and the output decreases. In order to increase the recovery rate of crude oil, water injection is generally used for development. However, for oil reservoirs in the late stage of water injection development, they are in a high water content stage and continued water injection is ineffective. Theoretical research and field development practice have shown that gas injection is one of the effective means to improve the recovery rate after water injection.

[0004] For gas-driven oil reservoirs, the predicted degree of enhanced oil recovery determines the economic benefits. Until now, the industry has lacked an accurate theoretical prediction method for gas-driven enhanced oil recovery, especially a method for predicting the ultimate degree of gas-driven enhanced oil recovery. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the existing methods in the prior art have inaccurate prediction results of the recovery factor, and to provide a method and system for predicting the limit degree of recovery factor improvement of gas-driven oil reservoirs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for predicting the limit of oil recovery of a gas-driven oil reservoir comprises the following steps:

[0008] S1: Construct an injection model for the reservoir, and obtain the changing relationship between the cumulative gas injection volume, the cumulative oil production from gas injection and the degree of recovery based on the injection model;

[0009] S2: Constructing a production model for the oil reservoir, and obtaining the changing relationship between the cumulative gas production of the oil reservoir after gas injection, the cumulative oil production after gas injection and the degree of recovery based on the production model;

[0010] S3: constructing a gas storage ratio model of the reservoir, and obtaining the changing relationship between the cumulative gas injection volume, the cumulative gas production and the cumulative gas injection volume of the reservoir based on the gas storage ratio model;

[0011] S4: Construct a gas storage ratio function model based on the injection model, the production model and the gas storage ratio model;

[0012] S5: Obtain a prediction model based on the gas storage ratio function model and the gas storage ratio model, and obtain a prediction result based on the prediction model.

[0013] A further improvement of the present invention is:

[0014] The step S1 further comprises the following steps:

[0015] The injection model of the reservoir is constructed by formula (1), and the relationship between the ratio of the cumulative gas injection volume to the cumulative oil production of the gas injection and the recovery degree is obtained:

[0016]

[0017] In the formula, G i is the cumulative gas injection volume; N p2 is the total cumulative oil production; N p1 is the cumulative oil production of the oil field before gas injection; o is the crude oil density; R is the recovery degree; a1 and b1 are fitting parameters.

[0018] The step S2 comprises the following steps:

[0019] The recovery model is constructed by formula (2), and the relationship between the ratio of the cumulative gas production of the reservoir to the cumulative oil production of the reservoir and the recovery degree is obtained by formula (2):

[0020]

[0021] In the formula, G p2 is the total cumulative gas production; G p1 N is the cumulative gas production before gas injection in the oil field; p2 is the total cumulative oil production; N p1 is the cumulative oil production of the oil field before gas injection; o is the crude oil density; R is the recovery degree; a2 and b2 are fitting parameters.

[0022] The step S3 comprises the following steps:

[0023] The gas storage ratio model is constructed by formula (3), and the ratio of the difference between the cumulative gas injection volume and the cumulative gas production volume to the cumulative gas injection volume is obtained by formula (3):

[0024]

[0025] In the formula, C g G is the gas storage ratio; i G is the cumulative gas injection volume; p G is the cumulative gas production; p2 is the total cumulative gas production; G p1 It is the cumulative gas production of the oil field before gas injection.

[0026] The step S4 comprises the following steps:

[0027] The gas storage ratio function model is constructed by formula (4):

[0028]

[0029] In the formula, C g is the gas storage ratio; R is the recovery degree; a3 and b3 are fitting parameters.

[0030] The step S4 further comprises the following steps:

[0031] Simplify formula (4):

[0032] ln(1-C g )=a3+b3R(5).

[0033] In step S5, a prediction model is constructed by formula (6):

[0034]

[0035] A system for predicting the limit of enhanced oil recovery in a gas-driven oil reservoir, comprising:

[0036] An injection model building module, a production model building module, a gas storage ratio model building module, a gas storage ratio function model building module and a prediction model building module;

[0037] The injection model building module builds the injection model of the oil reservoir and obtains the changing relationship between the cumulative gas injection volume, the cumulative oil production of gas injection and the recovery degree based on the injection model;

[0038] The production model building module is used to build the production model of the oil reservoir, and obtain the changing relationship between the cumulative gas production of the oil reservoir, the cumulative oil production of the gas injection and the degree of production based on the production model;

[0039] A gas storage ratio model building module is used to build a gas storage ratio model of the oil reservoir, and obtain the changing relationship between the cumulative gas injection volume of the oil reservoir, the cumulative gas production of gas injection and the cumulative gas injection volume based on the gas storage ratio model;

[0040] Gas storage ratio function model construction module: used to construct a gas storage ratio function model based on the injection model, the production model and the gas storage ratio model;

[0041] The prediction model building module is used to obtain a prediction model based on the gas storage ratio function model and the gas storage ratio model, and to obtain a prediction result based on the prediction model.

[0042] A terminal device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any method described in the present invention when executing the computer program.

[0043] A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of any method described in the present invention.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention discloses a method for predicting the limit degree of enhanced oil recovery of a gas-driven oil reservoir. The method comprises the following steps: obtaining a gas storage ratio function model by constructing an injection model, a production model and a gas storage ratio model of the oil reservoir, and then obtaining a prediction model by using the gas storage ratio function model and the gas storage ratio model. In later use, the limit degree of enhanced oil recovery of the gas-driven oil reservoir is accurately predicted based on the cumulative production data of the oil reservoir. The method disclosed in the present invention can accurately predict and calibrate the recoverable reserves of gas-driven oil reservoirs, thereby supporting the reporting of reserves and the preparation of gas-driven development plans, and further affecting oilfield investment and decision-making. The method has high efficiency and short time consumption, does not require a large number of basic experiments and numerical simulations, and the acquired data is more objective and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 This is a model diagram of the recovery factor limit degree of an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0051] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0052] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0053] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0055] The embodiment of the invention discloses a method for predicting the limit of enhanced oil recovery of a gas-driven oil reservoir, comprising the following steps:

[0056] First, collect relevant data, including:

[0057] Cumulative gas injection volume G i Measured in volume units of 100 million cubic meters, total cumulative gas production G p2 Measured in volume units of 100 million cubic meters and including the cumulative gas production before gas injection in the oil field G p1 Total cumulative oil production N p2 Measured in tons of mass and including the cumulative oil production before gas injection in the oil field N p1 ;

[0058] In order to facilitate calculation, the unit needs to be unified as ten thousand cubic meters, so the cumulative gas injection volume G iThe report data needs to be multiplied by 10000, and the total gas production needs to be the total cumulative gas production G p2 Subtract the cumulative gas production before gas injection in the oil field G p1 Multiply it by 10000, and the total oil production of gas injection needs to be the total oil production N p2 Subtract the cumulative oil production before gas injection in the oil field N p1 Divide by the density of crude oil.

[0059] Based on the collected data, the following steps are performed:

[0060] Step 1: Construct an injection model for the reservoir, and obtain the changing relationship between the cumulative gas injection volume, the cumulative oil production from gas injection and the degree of recovery based on the injection model;

[0061] Specifically include:

[0062] Through the injection model, the variation curve between the ratio of cumulative gas injection volume to cumulative oil production and the degree of recovery is defined, and formula (7) is obtained:

[0063]

[0064] Transform formula (7) to obtain formula (1)

[0065]

[0066] In the formula, G i is the cumulative gas injection volume, billion cubic meters; N p2 is the total cumulative oil production, 10,000 tons; N p1 is the cumulative oil production of the oil field before gas injection, 10,000 tons; o is the density of crude oil, grams per cubic centimeter; R is the recovery rate, percentage; a1 and b1 are fitting parameters.

[0067] Step 2: Construct a production model for the oil reservoir, and obtain the changing relationship between the cumulative gas production of the oil reservoir after gas injection, the cumulative oil production after gas injection, and the degree of recovery based on the production model;

[0068] Specifically include:

[0069] The production model is defined as the relationship curve between the cumulative gas production of gas injection and the cumulative oil production of gas injection and the degree of recovery. Based on this, formula (8) is constructed:

[0070]

[0071] Transform formula (8) to obtain formula (2):

[0072]

[0073] Where: G p2 is the total cumulative gas production, billion cubic meters; Gp1 is the cumulative gas production before gas injection in the oil field, billion cubic meters; N p2 is the total cumulative oil production, 10,000 tons; N p1 is the cumulative oil production of the oil field before gas injection, 10,000 tons; o is the density of crude oil, grams per cubic centimeter; R is the recovery rate, percentage; a2 and b2 are fitting parameters.

[0074] Step 3: Construct a gas storage ratio model of the reservoir, and obtain the changing relationship between the cumulative gas injection volume, the cumulative gas production of the gas injection and the cumulative gas injection volume based on the gas storage ratio model;

[0075] Specifically:

[0076] The gas storage ratio is defined as the ratio of the difference between the cumulative gas injection volume and the cumulative gas production volume to the cumulative gas injection volume:

[0077]

[0078] In the formula, C g G is the gas storage ratio, percentage; i is the cumulative gas injection volume, ten thousand cubic meters; G p is the cumulative gas production, 10,000 cubic meters; G p2 is the total cumulative gas production, billion cubic meters; G p1 The cumulative gas production of the oil field before gas injection is billion cubic meters.

[0079] Step 4: Construct a gas storage ratio function model based on the injection model, the production model and the gas storage ratio model;

[0080] Specifically:

[0081] The gas storage ratio function is the relationship curve between the gas storage ratio and the recovery degree. Substituting the injection model and the recovery model into formula (4):

[0082]

[0083] In the formula: Cg is the storage ratio, percentage; R is the recovery degree, percentage; a3 and b3 are fitting parameters;

[0084] Simplifying the gas storage ratio function and taking the logarithm, we get formula (5):

[0085] ln(1-C g )=a3+b3R(5).

[0086] Step 5: Obtain a prediction model based on the gas storage ratio function model and the gas storage ratio model, and obtain a prediction result based on the prediction model.

[0087] Specifically:

[0088] The prediction model is constructed by formula (6):

[0089]

[0090] The embodiment of the present invention also discloses a specific application:

[0091] Processing X reservoir gas injection development case data, X reservoir crude oil density 0.863 × 10 3 kg / m 3 , geological reserves 980×10 4 m 3 , gas injection production data is shown in Table 1, the specific calculation process is shown in Table 1, and the fitting expression is formula (9):

[0092]

[0093] The model derived from Figure 1 It can be seen that the fitting accuracy is 0.9701, which means that the fitting accuracy is high and the model is relatively accurate.

[0094] In the later stage of gas injection development, as the recovery rate increases, the gas exhaust rate increases, the corresponding gas storage ratio decreases, and the role of injected gas as an oil displacement medium decreases; obviously, when the cumulative gas production Gp is ​​approximately equal to the cumulative gas injection volume Gi, the injected gas is completely exhausted, and the corresponding recovery rate is considered to be the limit of gas drive enhanced oil recovery. For the X gas injection development reservoir, the limit of gas drive enhanced oil recovery is 13.22%.

[0095] Table 1 Gas injection production data

[0096]

[0097]

[0098]

[0099]

[0100] The method disclosed in the embodiment of the present invention establishes a prediction model of a gas-driven oil reservoir by constructing an injection model, a production model, a gas storage ratio model, and a gas storage ratio function model of the oil reservoir, and accurately predicts the limit of the gas-driven oil reservoir to improve the recovery rate based on the cumulative production data of the oil reservoir. In the past, the prediction of the recovery rate of gas-driven oil reservoirs and the limit of the gas-driven oil reservoir to improve the recovery rate were mainly carried out through indoor experiments and reservoir numerical simulations. The indoor experimental prediction method requires a large number of basic laboratory experiments, which is not only time-consuming and expensive, but also because the experimental conditions can hardly reach the formation conditions, resulting in extremely low prediction accuracy; numerical simulation requires the collection of a large amount of basic data such as earthquakes, geology, and well logging to establish a geological model for gas injection development oil reservoirs, which is extremely inefficient, and because the gas injection development oil reservoir is a multi-component numerical simulation of tens of millions of grids, the numerical simulation of the oil reservoir is generally inaccurate.

[0101] Taking the X gas drive reservoir as an example, the rough prediction of the limit of gas drive to improve oil recovery is only 5% through indoor experiments and reservoir numerical simulation; while the limit of gas drive to improve oil recovery predicted by the patent of this invention is as high as 13.22%. In comparison, the limit of gas drive to improve oil recovery is 8.22%, which is more than doubled; thus, the recoverable reserves of gas drive are increased by more than 800,000 cubic meters, which is quite beneficial.

[0102] The model establishment method for predicting the limit of recovery of gas-driven oil reservoirs provided by the present invention can accurately predict and calibrate the recoverable reserves of gas-driven oil reservoirs, thereby supporting the reporting of reserves and the preparation of gas-driven development plans, and further affecting oilfield investment and decision-making.

[0103] The embodiment of the present invention also discloses a system for predicting the limit degree of recovery of gas-driven oil reservoirs, including an injection model construction module, a production model construction module, a gas storage ratio model construction module, a gas storage ratio function model construction module and a prediction model construction module;

[0104] The injection model building module builds the injection model of the oil reservoir and obtains the changing relationship between the cumulative gas injection volume, the cumulative oil production of gas injection and the recovery degree based on the injection model;

[0105] The production model building module is used to build the production model of the oil reservoir, and obtain the changing relationship between the cumulative gas production of the oil reservoir, the cumulative oil production of the gas injection and the degree of production based on the production model;

[0106] A gas storage ratio model building module is used to build a gas storage ratio model of the oil reservoir, and obtain the changing relationship between the cumulative gas injection volume of the oil reservoir, the cumulative gas production of gas injection and the cumulative gas injection volume based on the gas storage ratio model;

[0107] Gas storage ratio function model construction module: used to construct a gas storage ratio function model based on the injection model, the production model and the gas storage ratio model;

[0108] The prediction model building module is used to obtain a prediction model based on the gas storage ratio function model and the gas storage ratio model, and to obtain a prediction result based on the prediction model.

[0109] A schematic diagram of a terminal device provided in an embodiment of the present invention. The terminal device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules / units in the above-mentioned device embodiments are implemented.

[0110] The computer program may be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to accomplish the present invention.

[0111] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0112] The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0113] The memory may be used to store the computer programs and / or modules, and the processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory.

[0114] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0115] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for predicting the limit of oil recovery of a gas-driven oil reservoir, characterized in that: The following steps are involved: S1: Construct an injection model for the reservoir, and obtain the changing relationship between the cumulative gas injection volume, the cumulative oil production from gas injection and the degree of recovery based on the injection model; S2: Constructing a production model for the oil reservoir, and obtaining the changing relationship between the cumulative gas production of the oil reservoir after gas injection, the cumulative oil production after gas injection and the degree of recovery based on the production model; S3: constructing a gas storage ratio model of the reservoir, and obtaining the changing relationship between the cumulative gas injection volume, the cumulative gas production and the cumulative gas injection volume of the reservoir based on the gas storage ratio model; S4: Construct a gas storage ratio function model based on the injection model, the production model and the gas storage ratio model; S5: Obtain a prediction model based on the gas storage ratio function model and the gas storage ratio model, and obtain a prediction result based on the prediction model.

2. A method for predicting the limit of oil recovery of a gas-driven oil reservoir according to claim 1, characterized in that: The step S1 further comprises the following steps: The injection model of the reservoir is constructed by formula (1), and the relationship between the ratio of the cumulative gas injection volume to the cumulative oil production of the gas injection and the recovery degree is obtained: In the formula, G i is the cumulative gas injection volume; N p2 is the total cumulative oil production; N p1 is the cumulative oil production of the oil field before gas injection; o is the crude oil density; R is the recovery degree; a1 and b1 are fitting parameters.

3. The method for predicting the limit of oil recovery of a gas-driven oil reservoir according to claim 1, characterized in that: The step S2 comprises the following steps: The recovery model is constructed by formula (2), and the relationship between the ratio of the cumulative gas production of the reservoir to the cumulative oil production of the reservoir and the recovery degree is obtained by formula (2): In the formula, G p2 is the total cumulative gas production; G p1 N is the cumulative gas production before gas injection in the oil field; p2 is the total cumulative oil production; N p1 is the cumulative oil production of the oil field before gas injection; o is the crude oil density; R is the recovery degree; a2 and b2 are fitting parameters.

4. The method for predicting the limit of oil recovery of a gas-driven oil reservoir according to claim 1, characterized in that: The step S3 comprises the following steps: The gas storage ratio model is constructed by formula (3), and the ratio of the difference between the cumulative gas injection volume and the cumulative gas production volume to the cumulative gas injection volume is obtained by formula (3): In the formula, C g G is the gas storage ratio; i G is the cumulative gas injection volume; p G is the cumulative gas production; p2 is the total cumulative gas production; G p1 It is the cumulative gas production of the oil field before gas injection.

5. A method for predicting the limit of enhanced oil recovery in a gas-driven oil reservoir according to claim 4, characterized in that: The step S4 comprises the following steps: The gas storage ratio function model is constructed by formula (4): In the formula, C g is the gas storage ratio; R is the recovery degree; a3 and b3 are fitting parameters.

6. A method for predicting the limit of enhanced oil recovery in a gas-driven oil reservoir according to claim 5, characterized in that: The step S4 further comprises the following steps: Simplify formula (4): <h2 style=";text-align:left;direction:ltr">ln(1-C<h2 style=";text-align:left;direction:ltr"> g <h2 style=";text-align:left;direction:ltr"> )=a3+b3R(5)。 7. A method for predicting the limit of enhanced oil recovery in a gas-driven oil reservoir according to claim 5, characterized in that: In step S5, a prediction model is constructed by formula (6):

8. The system for predicting the limit of enhanced oil recovery of gas-driven oil reservoirs according to claim 1, characterized in that: It includes an injection model building module, a production model building module, a gas storage ratio model building module, a gas storage ratio function model building module and a prediction model building module; The injection model building module builds the injection model of the oil reservoir and obtains the changing relationship between the cumulative gas injection volume, the cumulative oil production of gas injection and the recovery degree based on the injection model; The production model building module is used to build the production model of the oil reservoir, and obtain the changing relationship between the cumulative gas production of the oil reservoir, the cumulative oil production of the gas injection and the degree of production based on the production model; A gas storage ratio model building module is used to build a gas storage ratio model of the oil reservoir, and obtain the changing relationship between the cumulative gas injection volume of the oil reservoir, the cumulative gas production of gas injection and the cumulative gas injection volume based on the gas storage ratio model; Gas storage ratio function model construction module: used to construct a gas storage ratio function model based on the injection model, the production model and the gas storage ratio model; The prediction model building module is used to obtain a prediction model based on the gas storage ratio function model and the gas storage ratio model, and to obtain a prediction result based on the prediction model.

9. A terminal 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 steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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