Quantitative evaluation method for occurrence state of gas drive microscopic remaining oil after water drive and related device

Abstract

The invention discloses a quantitative evaluation method and related device for the occurrence state of gas-driven microscopic remaining oil after water drive, and the method comprises the steps: determining and manufacturing a glass etching model of a specific pore throat structure, and carrying out water drive and gas drive experiments; drawing a relational graph of the pressure at the two ends of the chip injection and the image recording time under different displacement time; according to the principle of video frame extraction storage, frame-by-frame reading processing is carried out on image data in the water drive stage and the gas drive stage; and establishing a rectangular graph, and quantitatively characterizing the occurrence state of the crude oil. The invention provides a method for quantitatively evaluating the occurrence state of gas-driven microscopic remaining oil after water drive of a deep reservoir, and aims to solve the problems that only the relative quantity of microscopic remaining oil in different occurrence states under the conventional normal pressure condition can be obtained and the absolute quantity of microscopic remaining oil in different occurrence states in the deep reservoir cannot be represented at present.

Description

Technical Field

[0001] The patent of this invention belongs to the technical field of gas injection development of deep oil reservoirs, and specifically relates to a quantitative evaluation method and related devices for the storage state of microscopic residual oil in gas drive after water drive. Background Art

[0002] In recent years, with the continuous deepening of exploration of complex reservoirs in deep oil reservoirs, the development of deep oil reservoirs has received widespread attention. However, with the long-term development of water drive, the remaining oil has gradually changed from concentrated distribution to dispersed distribution, resulting in a significant decrease in production. The study of the distribution law of remaining oil is an important means of the water control and oil stabilization development strategy in the middle and late stages of oil field development, and is a strong guarantee for the efficient exploitation of crude oil. At present, the research on the macroscopic distribution law of remaining oil and the simulation development with the help of numerical simulation software has been relatively in-depth. In terms of microscopic remaining oil research, China began research in 1978, and successfully developed a photolithography simulation microscopic model in 1985, providing an intuitive and clear means of observation. At present, there are three commonly used methods for macroscopic quantification of residual oil in different microscopic occurrence states. The first is to conduct displacement experiments on a microfluidic chip with a porous network structure that can simulate the pore structure through microscopic experimental observation, and obtain the microscopic occurrence state and proportional relationship of the crude oil; the second is the digital core method, which uses CT quantitative and three-dimensional visualization to test the occurrence state of reservoir tight oil, obtains a three-dimensional image through digital reconstruction of two-dimensional slice images, divides the tight oil into different occurrence states, and statistically calculates the volume of tight oil in each occurrence state, and analyzes the volume or mass of tight oil in each occurrence state; the third is to combine macroscopic numerical simulation with microscopic observation experiments to conduct macroscopic quantification of microscopic residual oil in different microscopic occurrence states. Existing studies are mainly aimed at statistically analyzing the occurrence state of microscopic residual oil in the water flooding process at normal temperature and pressure, and obtaining the relative amount of microscopic residual oil in different occurrence states under conventional normal pressure conditions. It is impossible to quantitatively, quickly and accurately evaluate the occurrence state of microscopic residual oil in gas flooding after water flooding in deep oil reservoirs. Summary of the invention

[0003] The purpose of the present invention is to provide a quantitative evaluation method and related devices for the occurrence state of microscopic residual oil after water drive and gas drive, so as to solve the problem that it is impossible to quantitatively, quickly and accurately evaluate the occurrence state of microscopic residual oil after water drive and gas drive in deep oil reservoirs.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive, comprising:

[0006] Obtain the pore structure of the real core, determine and make a glass etching model of the specific pore throat structure, and conduct water drive and gas drive experiments;

[0007] Analyze the pressure and injection time data in the experiment, and draw a relationship diagram between the pressure at both ends of the chip injection and the image recording time at different displacement times;

[0008] According to the principle of video frame extraction and storage, the image data of the water drive and gas drive stages are read and processed frame by frame respectively;

[0009] The target pixels of the color image are statistically calculated to extract the size and shape characteristic parameters of the remaining oil. The spatial resolution and edge data of each area and the distribution of quality data collected during the production process are combined to establish a histogram to quantitatively characterize the occurrence state of crude oil.

[0010] Optionally, core casting thin section experiments are performed to obtain the pore structure of the real core.

[0011] Optionally, water drive and gas drive experiments under different injection and production parameters are carried out based on a high-temperature and high-pressure micro-displacement experimental device for deep oil reservoirs to obtain static and dynamic experimental data of micro-displacement.

[0012] Optionally, according to the relationship diagram between the pressure at both ends of the chip injection and the image recording time at different displacement times, the image range of different displacement stages is determined, and different injection stages such as water drive and gas drive are divided.

[0013] Optionally, the spatial resolution and edge data of each region are used to classify the remaining oil types; a connected histogram with the group interval as the base and the frequency as the height is established.

[0014] Optional steps to quantitatively characterize the state of occurrence of crude oil:

[0015] Input color image to perform statistical calculation of target pixels;

[0016] Calculate the distance distribution of each grid point from the boundary of the remaining oil using the Matlab bwdist function;

[0017] Filtering processing Matlab imgaussfilt3 function;

[0018] Watershed calculation Matlab watershed function;

[0019] When preprocessing the irregular geometric shape of residual oil in the image, the shape factor is used to distinguish each adhesion area and accurately divide the residual oil type; by identifying the spatial resolution and edges of each area, the equivalent area and perimeter of the residual oil are calculated respectively;

[0020] The remaining oil area of ​​each block is statistically calculated to obtain the area probability distribution and to establish a statistical data analysis histogram.

[0021] Optionally, calculate the equivalent area and perimeter of the remaining oil separately:

[0022] First, calculate the sum of the number of pixels in each connected area, which is the equivalent area of ​​the residual oil connected area; then use the chain code principle to calculate the perimeter of each area. The shape factor F is calculated by the following formula:

[0023] F=4πS / L 2

[0024] Among them, S is the area of ​​a connected region; L is its perimeter.

[0025] In a second aspect, the present invention provides a quantitative evaluation system for the microscopic residual oil storage state after water flooding and gas flooding, comprising:

[0026] Etching model building module, used to obtain the pore structure of real core, determine and make glass etching models of specific pore throat structures, and conduct water drive and gas drive experiments;

[0027] A relationship diagram building module is used to analyze the pressure and injection time data in the experiment and to draw a relationship diagram between the pressure at both ends of the chip injection and the image recording time at different displacement times;

[0028] A processing module is used to read and process the image data of the water drive and gas drive stages frame by frame according to the principle of video frame extraction and storage;

[0029] The output module is used to perform statistical calculations on the target pixels of the color image to extract the size and shape characteristic parameters of the remaining oil. By combining the spatial resolution and edge data of each area with the distribution of quality data collected during the production process, a histogram is established to quantitatively characterize the occurrence state of the crude oil.

[0030] In a third aspect, the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the processor implements the steps of a method for quantitatively evaluating the occurrence state of microscopic residual oil in gas drive after water drive.

[0031] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a method for quantitatively evaluating the microscopic residual oil storage state of gas drive after water drive.

[0032] Compared with the prior art, the present invention has the following technical effects:

[0033] The present invention provides a method for quantitatively evaluating the occurrence state of microscopic residual oil in deep oil reservoirs after water flooding and gas flooding, aiming to solve the problem that currently only the relative amount of microscopic residual oil in different occurrence states under conventional normal pressure conditions can be obtained, but the absolute amount of microscopic residual oil in different occurrence states in deep oil reservoirs cannot be characterized.

[0034] The method of the present invention uses a residual oil quantitative analysis system to extract residual oil occurrence state information, and discriminates the residual oil distribution state in the pores by processing color images, so as to characterize the characteristics of the residual oil microscopic distribution with the results.

[0035] The present invention combines the results of high-temperature and high-pressure microscopic displacement experiments with the microscopic residual oil occurrence state through image processing, thereby achieving quantitative, rapid and accurate characterization of microscopic residual oil in different occurrence states, progressing from non-quantitative conceptual research to quantitative precision research, and having strong promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the core casting thin slice of the present invention.

[0037] Figure 2 To obtain the size and shape parameter diagram of the remaining oil.

[0038] Figure 3 This is the distribution characteristic diagram of the remaining oil occurrence state under three cores with different injection methods. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings:

[0040] See also Figures 1 to 3 The present invention provides a quantitative evaluation method and related device for the microscopic residual oil occurrence state after water flooding and gas flooding. It includes the following steps: the distribution state of crude oil in the porous network structure is obtained, and the target pixels of the color image are statistically calculated to obtain the size and shape of the residual oil and other parameters, so as to obtain the occurrence state of the crude oil according to the proportional relationship. Based on the high temperature and high pressure microscopic visualization experimental platform, the residual oil quantitative analysis system is used to complete the extraction of the residual oil occurrence state information, and the distribution state of the residual oil in the pores is judged by observing the color image. The result characterizes the characteristics of the microscopic distribution of the residual oil, and provides technical support for the adaptability evaluation of gas injection to enhance the recovery rate after water flooding in deep oil reservoirs.

[0041] The present invention provides a quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive, which comprises the following steps:

[0042] S1. Use core casting thin section experiments to obtain the pore structure of the real core, determine and make a glass etching model of the specific pore throat structure. Based on the high temperature and high pressure micro-displacement experimental device for deep oil reservoirs, water and gas drive experiments under different injection and production parameters are carried out to obtain static and dynamic experimental data of micro-displacement.

[0043] S2. Analyze the pressure and injection time data in the data, draw a relationship diagram between the pressure at both ends of the chip injection and the image recording time at different displacement times, clarify the image range of different displacement stages, and divide different injection stages such as water drive and gas drive;

[0044] S3, according to the principle of video frame extraction and storage, the image data of the water drive and gas drive stages are read and processed frame by frame respectively;

[0045] S4, statistically calculate the target pixels of the color image to extract the characteristic parameters such as the size and shape of the remaining oil, classify the remaining oil types according to the spatial resolution and edge data of each area, and establish a series of connected histograms with group interval as the base and frequency as the height according to the distribution of quality data collected from the production process to quantitatively characterize the occurrence state of crude oil. Its main steps are:

[0046] Input color image to perform statistical calculation of target pixels;

[0047] ② Calculate the distance distribution of each grid point from the boundary of the remaining oil using the Matlab bwdist function;

[0048] This function calculates the Euclidean distance transform of a binary image, as well as the nearest pixel map of the image. The syntax is:

[0049] D = bwdist(BW)

[0050] [D,idx]=bwdist(BW)

[0051] [D,idx]=bwdist(BW,method)

[0052] ③ Filtering processing Matlab imgaussfilt3 function;

[0053] This function performs a 3D Gaussian filter on a 3D image (spatial filter function)

[0054] Syntax: B = imgaussfilt3(A)

[0055] B = imgaussfilt3(A, sigma)

[0056] B=imgaussfilt3(——, Name, Value)

[0057] ④ Watershed calculation Matlab watershed function;

[0058] L = WATERSHED(A) computes a label matrix that identifies the watersheds of the input matrix A. A can be of any dimension. The elements of L are all integers greater than or equal to 0. Elements with a label value of 0 do not belong to any watershed, and are called "watersheds". Elements with a label value of 1 belong to the first watershed, elements with a label value of 2 belong to the second watershed, and so on.

[0059] ⑤ When preprocessing the irregular geometric shape of residual oil in the image, the shape factor is used to distinguish each adhesion area and accurately divide the residual oil type. Here, it is necessary to calculate the equivalent area and perimeter of the residual oil by identifying the spatial resolution and edges of each area: first, calculate the sum of the number of pixels in each connected area, which is the equivalent area of ​​the connected area of ​​the residual oil; then use the chain code principle to calculate the perimeter of each area. The shape factor F is calculated by the following formula:

[0060] F=4πS / L 2

[0061] Among them, S is the area of ​​a connected region; L is its perimeter.

[0062] ⑥ Statistically calculate the remaining oil area of ​​each block, obtain the area probability distribution, and establish a statistical data analysis histogram.

[0063] like Figure 1 As shown, the pore structure of the real core is obtained by using the core casting thin section experiment, and the glass etching model of the specific pore throat structure is determined and produced by preprocessing, segmenting, restoring and correcting the core scanning image, so that the glass etching model has a porous network structure that can simulate the pore structure;

[0064] The microfluidic chip is observed through a microscope to obtain the distribution state of crude oil in the porous network structure, and the target pixels of the color image are statistically calculated to obtain parameters such as the size and shape of the remaining oil, so as to obtain the occurrence state of the crude oil according to the proportional relationship. The main steps are:

[0065] Oil, gas and water distribution, red represents residual oil;

[0066] Calculate the distance distribution of each grid point from the boundary of the remaining oil using the Matlab bwdist function;

[0067] Filtering processing Matlab imgaussfilt3 function;

[0068] Watershed calculation Matlab watershed function;

[0069] Statistically calculate the remaining oil area of ​​each block and obtain the area probability distribution;

[0070] like Figure 3 As shown, the microscopic crude oil occurrence states of three different cores under different injection methods are obtained.

[0071] In another embodiment of the present invention, a quantitative evaluation system for the occurrence state of microscopic residual oil in gas drive after water drive is provided, which can be used to implement the quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive mentioned above. Specifically, the system comprises:

[0072] Etching model building module, used to obtain the pore structure of real core, determine and make glass etching models of specific pore throat structures, and conduct water drive and gas drive experiments;

[0073] A relationship diagram building module is used to analyze the pressure and injection time data in the experiment and to draw a relationship diagram between the pressure at both ends of the chip injection and the image recording time at different displacement times;

[0074] A processing module is used to read and process the image data of the water drive and gas drive stages frame by frame according to the principle of video frame extraction and storage;

[0075] The output module is used to perform statistical calculations on the target pixels of the color image to extract the size and shape characteristic parameters of the remaining oil. By combining the spatial resolution and edge data of each area with the distribution of quality data collected during the production process, a histogram is established to quantitatively characterize the occurrence state of the crude oil.

[0076] The division of modules in the embodiments of the present invention is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present invention may be integrated into one processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0077] In another embodiment of the present invention, a computer device is provided, the computer device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may 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 gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of a quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive.

[0078] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the computer device and the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive in the above embodiment.

[0079] 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.

[0080] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), 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.

[0081] 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.

[0082] 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 The steps for the functions specified in one or more boxes.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A quantitative evaluation method for the microscopic residual oil storage state after water flooding and gas flooding, characterized in that: include: Obtain the pore structure of the real core, determine and make a glass etching model of the specific pore throat structure, and conduct water drive and gas drive experiments; Analyze the pressure and injection time data in the experiment, and draw a relationship diagram between the pressure at both ends of the chip injection and the image recording time at different displacement times; According to the principle of video frame extraction and storage, the image data of the water drive and gas drive stages are read and processed frame by frame respectively; The target pixels of the color image are statistically calculated to extract the size and shape characteristic parameters of the remaining oil. The spatial resolution and edge data of each area and the distribution of quality data collected during the production process are combined to establish a histogram to quantitatively characterize the occurrence state of crude oil.

2. The quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive according to claim 1 is characterized in that: The core casting thin section experiment is used to obtain the pore structure of the real core.

3. The quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive according to claim 1 is characterized in that: Based on the high-temperature and high-pressure micro-displacement experimental device for deep oil reservoirs, water-displacement and gas-displacement experiments were carried out under different injection-production parameters to obtain static and dynamic experimental data of micro-displacement.

4. The quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive according to claim 1 is characterized in that: According to the relationship diagram between the chip injection pressure at both ends and the image recording time at different displacement times, the image range of different displacement stages is determined, and different injection stages such as water drive and gas drive are divided.

5. The quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive according to claim 1 is characterized in that: The spatial resolution and edge data of each area are used to classify the remaining oil types; a connected histogram with the group interval as the base and the frequency as the height is established.

6. The quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive according to claim 1 is characterized in that: Steps to quantitatively characterize the occurrence state of crude oil: Input color image to perform statistical calculation of target pixels; Calculate the distance distribution of each grid point from the boundary of the remaining oil using the Matlab bwdist function; Filtering processing Matlab imgaussfilt3 function; Watershed calculation Matlab watershed function; When preprocessing the irregular geometric shape of residual oil in the image, the shape factor is used to distinguish each adhesion area and accurately divide the residual oil type; by identifying the spatial resolution and edges of each area, the equivalent area and perimeter of the residual oil are calculated respectively; The remaining oil area of ​​each block is statistically calculated to obtain the area probability distribution and to establish a statistical data analysis histogram.

7. The quantitative evaluation method for the occurrence state of microscopic residual oil in gas drive after water drive according to claim 6 is characterized in that: Calculate the equivalent area and perimeter of the remaining oil respectively: First, the sum of the number of pixels in each connected area is calculated, which is the equivalent area of ​​the residual oil connected area; then the chain code principle is used to calculate the perimeter of each area; the shape factor F is calculated by the following formula: F=4πS / L 2 Among them, S is the area of ​​a connected region; L is its perimeter.

8. A quantitative evaluation system for the microscopic residual oil storage state after water flooding and gas flooding, characterized in that: include: Etching model building module, used to obtain the pore structure of real core, determine and make glass etching models of specific pore throat structures, and conduct water drive and gas drive experiments; A relationship diagram building module is used to analyze the pressure and injection time data in the experiment and to draw a relationship diagram between the pressure at both ends of the chip injection and the image recording time at different displacement times; A processing module is used to read and process the image data of the water drive and gas drive stages frame by frame according to the principle of video frame extraction and storage; The output module is used to perform statistical calculations on the target pixels of the color image to extract the size and shape characteristic parameters of the remaining oil. By combining the spatial resolution and edge data of each area with the distribution of quality data collected during the production process, a histogram is established to quantitatively characterize the occurrence state of the crude oil.

9. 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 steps of the method for quantitatively evaluating the occurrence state of microscopic residual oil in gas flooding after water flooding as claimed in 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 for quantitatively evaluating the occurrence state of microscopic residual oil in gas flooding after water flooding as claimed in any one of claims 1 to 7 are implemented.

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