A method, system, and readable medium for determining a range of polymer flood injection rates in unconsolidated sandstone reservoirs

Abstract

The present application relates to a kind of methods, systems and readable medium for determining polymer flooding injection rate range in loose sandstone reservoir, comprising: collecting the basic physical parameters of known loose sandstone reservoir and polymer solution physical parameters;By loose sandstone reservoir polymer flooding numerical simulation model, obtain the optimal polymer flooding injection rate range;Change basic physical parameters and polymer solution physical parameters, obtain the optimal polymer flooding injection rate range corresponding to different loose sandstone reservoir basic physical parameters and polymer solution parameters, generate the relationship model of basic physical parameters and polymer solution physical parameters and optimal polymer flooding injection rate range;The basic physical parameters and polymer solution physical parameters of the loose sandstone reservoir to be measured are input into the relationship model, and the optimal polymer flooding injection rate range of the loose sandstone reservoir to be measured is obtained.It is simple to operate, and the principle is clear, which can provide guidance for studying the multi-stage phase change law of hydrate in pores of different diameters.

Description

Technical Field

[0001] This invention relates to a method, system, and readable medium for determining the injection rate range of polymer flooding in loose sandstone reservoirs, belonging to the field of polymer flooding technology. Background Technology

[0002] Polymer flooding is a production enhancement measure that involves injecting polymers into the formation to displace oil. Macroscopically, it mainly increases the viscosity of the displacing fluid and reduces the mobility ratio between the displacing fluid and the displaced fluid, thereby expanding the swept volume. Microscopically, due to its inherent viscoelasticity, the polymer generates a stretching effect on the oil film or oil droplets during flow, increasing the carrying capacity and improving the microscopic oil washing efficiency.

[0003] The main oilfields in the Bohai Bay are primarily composed of loose sandstone. These reservoirs have poor cementation, making them prone to particle blockage during polymer flooding development, leading to a decline in injection and production capacity. Due to numerous constraints in offshore oilfield development, the cost of new facilities is high, while existing facilities provide limited injection and production pressure. Therefore, given the current difficulty in increasing injection pump power, adjusting the injection and production regime to improve the polymer flooding capacity of the oilfield and increase the injection and production volume over the platform's lifespan has become a pressing issue that needs to be addressed in offshore loose sandstone reservoirs. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method, system, and readable medium for determining the injection rate range of polymer flooding in loose sandstone reservoirs. The method is simple to operate and has a clear principle, and can provide guidance for studying the multi-stage phase transition law of hydrates in pores of different pore sizes.

[0005] To achieve the above objectives, the present invention proposes the following technical solution: a method for determining the polymer flooding injection rate range in loose sandstone reservoirs, comprising the following steps: collecting basic physical property parameters and polymer solution physical property parameters of known loose sandstone reservoirs; obtaining the optimal polymer flooding injection rate range through a numerical simulation model of polymer flooding in loose sandstone reservoirs; changing the basic physical property parameters and polymer solution physical property parameters to obtain the optimal polymer flooding injection rate range corresponding to different basic physical property parameters and polymer solution parameters of loose sandstone reservoirs, generating a relationship model between the basic physical property parameters and polymer solution physical parameters and the optimal polymer flooding injection rate range; inputting the basic physical property parameters and polymer solution physical parameters of the loose sandstone reservoir to be tested into the relationship model to obtain the optimal polymer flooding injection rate range of the loose sandstone reservoir to be tested.

[0006] Furthermore, the basic physical properties include porosity, permeability, initial temperature, initial pressure, residual drag coefficient, water content at transfer, number of grids, and grid size; the polymer solution physical properties include solution viscosity, polymer slug, and injection rate.

[0007] Furthermore, the relational model is constructed using machine learning methods.

[0008] Furthermore, the machine learning methods include linear regression, logistic regression, support vector machine, decision tree, neural grid, K-means clustering, and hierarchical clustering.

[0009] Furthermore, the optimal polymer flooding injection rate range is obtained through a polymer flooding numerical simulation model for loose sandstone reservoirs: when the water flooding development of the loose sandstone reservoir reaches the threshold, a larger polymer flooding injection rate range is input into the polymer flooding numerical simulation model for loose sandstone reservoirs, and the production index decrease and recovery degree within the preset range are calculated. A graph is plotted with the basic physical property parameters and polymer solution physical property parameters as the horizontal axis and the production index decrease and recovery degree as the vertical axis. The optimal polymer flooding injection rate range is determined from the larger polymer flooding injection rate range using the production index decrease limit and recovery degree limit as the standard.

[0010] Furthermore, the threshold for waterflooding development of the loose sandstone reservoir is when the water content of the loose sandstone reservoir reaches 60-95%.

[0011] Furthermore, the larger polymer-driven injection rate range is 0.0 to 0.1 PV / a, with an interval of 0.02 PV / a.

[0012] Furthermore, the standard uses a 15%-30% decrease in the liquid production index as a threshold to determine the development speed of polymer flooding.

[0013] This invention also discloses a system for determining the polymer flooding injection rate range in loose sandstone reservoirs, comprising: a data acquisition module for acquiring basic physical property parameters and polymer solution physical property parameters of known loose sandstone reservoirs; an optimal injection rate calculation module for obtaining the optimal polymer flooding injection rate range through a numerical simulation model of polymer flooding in loose sandstone reservoirs; a relational model construction module for changing the basic physical property parameters and polymer solution physical property parameters to obtain the optimal polymer flooding injection rate range corresponding to different basic physical property parameters and polymer solution parameters of loose sandstone reservoirs, and generating a relational model between the basic physical property parameters and polymer solution physical parameters and the optimal polymer flooding injection rate range; and a result output module for inputting the basic physical property parameters and polymer solution physical parameters of the loose sandstone reservoir to be tested into the relational model to obtain the optimal polymer flooding injection rate range of the loose sandstone reservoir to be tested.

[0014] The present invention also discloses a computer-readable storage medium storing a computer program, which is executed by a processor to implement the method for determining the polymer flooding injection rate range in loose sandstone reservoirs as described in any of the preceding claims.

[0015] The technical solution of the present invention has at least the following technical effects or advantages: The present invention uses machine learning methods to construct a training model of reasonable injection rate range and basic physical property parameters and polymer solution parameters of loose sandstone reservoirs. By inputting the physical property parameters and polymer solution physical property parameters of any loose sandstone reservoir, the reasonable injection rate range can be quickly predicted through the training model. Attached Figure Description

[0016] Figure 1 This is a curve showing the determination of the initial injection rate in one embodiment of the present invention;

[0017] Figure 2 This is a curve showing the determination of injection speed of 6.25×6.25×1.4 in one embodiment of the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is described in detail through specific embodiments. However, it should be understood that the specific embodiments are provided only for a better understanding of the present invention and should not be construed as limiting the present invention. In the description of the present invention, it should be understood that the terminology used is for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] To address the challenges of increasing injection-production pump power, effectively adjusting injection-production regimes to enhance polymer flooding capabilities, and increasing injection-production fluid volume throughout the platform's lifespan in existing technologies, this invention proposes a method, system, and readable medium for determining the injection rate range in loose sandstone reservoirs. It utilizes machine learning to construct a training model that establishes a reasonable injection rate range in relation to the fundamental physical properties of the loose sandstone reservoir and polymer solution parameters, enabling rapid prediction of the appropriate injection rate range. This invention uses the recovery degree and the production index decline threshold as standards, employing machine learning to construct the training model for the reasonable injection rate range in relation to the fundamental physical properties of the loose sandstone reservoir and polymer solution parameters. The following detailed description, in conjunction with accompanying drawings and embodiments, illustrates the invention in detail.

[0020] Example 1

[0021] This embodiment discloses a method for determining the injection rate range of polymer flooding in loose sandstone reservoirs, including the following steps:

[0022] S1 collects basic physical property parameters and polymer solution physical property parameters of known loose sandstone reservoirs.

[0023] Basic physical property parameters and polymer solution physical property parameters of known loose sandstone reservoirs were collected, as shown in Table 1. The basic physical property parameters include porosity, permeability, initial temperature, initial pressure, residual drag coefficient, water cut at the time of transfer, number of grids, and grid size; the polymer solution physical property parameters include solution viscosity, polymer slug, and injection rate.

[0024] Table 1. Values ​​of main parameters for reservoir model in vertical well development.

[0025]

[0026] S2 uses a numerical simulation model of polymer flooding in loose sandstone reservoirs to obtain the optimal range of polymer flooding injection rates.

[0027] like Figure 1 As shown, in this embodiment, when waterflooding development of a loose sandstone reservoir reaches a threshold, the threshold is defined as a water cut of 60-95%. In this embodiment, when waterflooding development reaches a water cut of 60%, polymer flooding development is switched to. Since the method in this embodiment selects a smaller, optimal polymer flooding injection rate range from a relatively large range, the specific method is as follows: The larger polymer flooding injection rate range is input into the polymer flooding numerical simulation model of the loose sandstone reservoir. The production index decrease and recovery rate within the preset range are calculated. A graph is plotted with the basic physical properties and polymer solution physical properties as the horizontal axis and the production index decrease and recovery rate as the vertical axis. The optimal polymer flooding injection rate range is determined from the larger range using the production index decrease limit and recovery rate limit as standards.

[0028] In this embodiment, the larger polymer flooding injection rate range is 0.0–0.1 PV / a, with intervals of 0.02 PV / a. The preset range in this embodiment is 25 years, but it can be determined according to actual needs. The standard uses a 15%–30% decrease in the production index as the boundary to determine the development rate of the polymer flooding. In this embodiment, using a 15% decrease in the production index as the standard, the optimal polymer flooding injection rate range obtained is 0.022–0.06 PV / a. -1 .

[0029] S3 changes the basic physical property parameters and polymer solution physical property parameters to obtain the optimal polymer flooding injection rate range corresponding to different basic physical property parameters and polymer solution parameters of loose sandstone reservoirs, and generates a relationship model between the basic physical property parameters, polymer solution physical property parameters and the optimal polymer flooding injection rate range.

[0030] like Figure 2As shown, the relationship model is constructed using machine learning methods. These methods include linear regression, logistic regression, support vector machines, decision trees, neural grids, K-means clustering, and hierarchical clustering. In this embodiment, a neural grid method is used to construct a model relating the optimal polymer flooding injection rate range to the basic physical properties and polymer solution parameters of the loose sandstone reservoir. The grid size for the loose sandstone reservoir is changed to 6.25 × 6.25 × 1.4. Through model training, a reasonable injection rate range of 0.022–0.072 PV·a is determined. -1 .

[0031] S4 inputs the basic physical property parameters and polymer solution physical property parameters of the loose sandstone reservoir to be tested into the relational model to obtain the optimal polymer flooding injection rate range for the loose sandstone reservoir to be tested.

[0032] Example 2

[0033] Based on the same inventive concept, this embodiment discloses a system for determining the polymer flooding injection rate range in loose sandstone reservoirs, comprising:

[0034] The data acquisition module is used to collect basic physical property parameters and polymer solution physical property parameters of known loose sandstone reservoirs;

[0035] The optimal injection rate calculation module is used to obtain the optimal polymer flooding injection rate range through a numerical simulation model of polymer flooding in loose sandstone reservoirs.

[0036] The relational model building module is used to change the basic physical property parameters and polymer solution physical property parameters to obtain the optimal polymer flooding injection rate range corresponding to different basic physical property parameters and polymer solution parameters of loose sandstone reservoirs, and generate a relational model between the basic physical property parameters, polymer solution physical parameters and the optimal polymer flooding injection rate range.

[0037] The results output module is used to input the basic physical property parameters and polymer solution physical property parameters of the loose sandstone reservoir to be tested into the relational model to obtain the optimal polymer flooding injection rate range for the loose sandstone reservoir to be tested.

[0038] Example 3

[0039] Based on the same inventive concept, this embodiment discloses a computer-readable storage medium storing a computer program, which is executed by a processor to implement the method for determining the polymer flooding injection rate range in any of the above-mentioned loose sandstone reservoirs.

[0040] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied 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.

[0041] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0042] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0043] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific embodiments of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention. The above content is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims

1. A method for determining the injection rate range of polymer flooding in loose sandstone reservoirs, characterized in that, Includes the following steps: Collect basic physical property parameters and polymer solution physical property parameters of known loose sandstone reservoirs; The optimal polymer flooding injection rate range was obtained through a numerical simulation model of polymer flooding in loose sandstone reservoirs. By changing the basic physical property parameters and polymer solution physical property parameters, the optimal polymer flooding injection rate range corresponding to different basic physical property parameters and polymer solution parameters of loose sandstone reservoirs is obtained, and a relationship model between the basic physical property parameters and polymer solution physical property parameters and the optimal polymer flooding injection rate range is generated. By inputting the basic physical property parameters and polymer solution physical property parameters of the loose sandstone reservoir to be tested into the relational model, the optimal polymer flooding injection rate range of the loose sandstone reservoir to be tested can be obtained. The method for obtaining the optimal polymer flooding injection rate range using a numerical simulation model of polymer flooding in loose sandstone reservoirs is as follows: When the waterflooding development of loose sandstone reservoirs reaches the threshold, a large range of polymer flooding injection rates is input into the polymer flooding numerical simulation model of the loose sandstone reservoirs. The production index decrease and recovery rate within the preset range are calculated. The basic physical property parameters and polymer solution physical property parameters are plotted on the horizontal axis, and the production index decrease and recovery rate are plotted on the vertical axis. The optimal polymer flooding injection rate range is determined from the large range of polymer flooding injection rates, based on the production index decrease limit and recovery rate limit. The larger polymer-driven injection rate range is 0.0~0.1PV / a, with an interval of 0.02PV / a.

2. The method for determining the polymer flooding injection rate range in loose sandstone reservoirs as described in claim 1, characterized in that, The basic physical properties include porosity, permeability, initial temperature, initial pressure, residual drag coefficient, water content at transfer, number of grids, and grid size; the polymer solution physical properties include solution viscosity, polymer slug, and injection rate.

3. The method for determining the polymer flooding injection rate range in loose sandstone reservoirs as described in claim 1, characterized in that, The relational model is constructed using machine learning methods.

4. The method for determining the polymer flooding injection rate range in loose sandstone reservoirs as described in claim 3, characterized in that, The machine learning methods include linear regression, logistic regression, support vector machine, decision tree, neural grid, K-means clustering, and hierarchical clustering.

5. The method for determining the polymer flooding injection rate range in loose sandstone reservoirs as described in claim 1, characterized in that, The threshold for waterflooding development of loose sandstone reservoirs is when the water content of the loose sandstone reservoir reaches 60-95%.

6. The method for determining the polymer flooding injection rate range in loose sandstone reservoirs as described in claim 1, characterized in that, The standard uses a 15%-30% decrease in the liquid production index as a threshold to determine the development speed of polymer flooding.

7. A system for determining the injection rate range of polymer flooding in loose sandstone reservoirs, characterized in that, include: The data acquisition module is used to collect basic physical property parameters and polymer solution physical property parameters of known loose sandstone reservoirs; The optimal injection rate calculation module is used to obtain the optimal polymer flooding injection rate range through a numerical simulation model of polymer flooding in loose sandstone reservoirs. The relational model construction module is used to change the basic physical property parameters and polymer solution physical property parameters to obtain the optimal polymer flooding injection rate range corresponding to different basic physical property parameters and polymer solution parameters of loose sandstone reservoirs, and generate a relational model between the basic physical property parameters and polymer solution physical parameters and the optimal polymer flooding injection rate range. The results output module is used to input the basic physical property parameters and polymer solution physical property parameters of the loose sandstone reservoir to be tested into the relational model to obtain the optimal polymer flooding injection rate range of the loose sandstone reservoir to be tested. The method for obtaining the optimal polymer flooding injection rate range using a numerical simulation model of polymer flooding in loose sandstone reservoirs is as follows: When the waterflooding development of loose sandstone reservoirs reaches the threshold, a large range of polymer flooding injection rates is input into the polymer flooding numerical simulation model of the loose sandstone reservoirs. The production index decrease and recovery rate within the preset range are calculated. The basic physical property parameters and polymer solution physical property parameters are plotted on the horizontal axis, and the production index decrease and recovery rate are plotted on the vertical axis. The optimal polymer flooding injection rate range is determined from the large range of polymer flooding injection rates, based on the production index decrease limit and recovery rate limit. The larger polymer-driven injection rate range is 0.0~0.1PV / a, with an interval of 0.02PV / a.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is executed by a processor to implement the method for determining the range of polymer flooding injection rates in loose sandstone reservoirs as described in any one of claims 1-6.

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