Evaluation method and system for shale non-tectonic fracture development degree under multiple coupling factors

Abstract

The invention relates to the technical field of crack research, and particularly discloses a method and system for evaluating the development degree of non-structural cracks of shale under multiple coupling factors, and the method comprises the steps: calculating the crack development index of the non-structural cracks of the shale; the fracture development index is a product of four indexes including fracture linear density, Poisson's ratio, brittle mineral component content and organic carbon content coefficient, and establishing a relation between the shale gas yield and the non-tectonic fracture development degree. When the fracture development index is less than or equal to 0.005, the fracture development degree is poor; when the fracture development index is 0.005-0.20, the fracture development degree is general; when the fracture development index is 0.20-0.55, the fracture development degree is good; and when the fracture development index is greater than or equal to 0.55, the fracture development degree is very good. According to the method, an experimental instrument and a testing technology are combined, the testing precision is higher, the fracture development index evaluation error of a single factor is reduced, and the actual requirements of oil and gas exploration and development, especially fracture type and unconventional oil and gas exploration and development can be better met.

Description

Technical Field

[0001] This invention relates to the field of fracture research technology, and in particular to a method and system for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors. Background Technology

[0002] Natural cracks are divided into tectonic cracks and non-tectonic cracks. Tectonic cracks are natural cracks formed under the action of tectonic stress fields. Due to the directionality of stress, the development of tectonic cracks exhibits certain regularities to some extent, and previous studies on this topic are relatively in-depth. In contrast to tectonic cracks, non-tectonic cracks are a type of structure formed under non-tectonic factors, induced by rock volume forces, gravity, or diagenesis. They are unrelated to or indirectly related to tectonic stress. Their formation is complex, and their morphology is generally irregular, tortuous, and discontinuous. They are mostly microcracks, and most non-tectonic cracks have rough and uneven surfaces, limited longitudinal cutting depth, varying sizes, and good extension and connectivity.

[0003] Non-tectonic fractures often occur simultaneously with tectonic fractures, forming a fracture network system that jointly influences hydrocarbon accumulation and preservation. They directly affect not only the quality of shale reservoirs and the production of shale gas, but also the subsequent exploitation efficiency of shale gas reservoirs. Effective and accurate characterization of non-tectonic fractures is a necessary prerequisite for fracture evaluation. Only by establishing a non-tectonic fracture characterization scheme that is easy to implement, quantitatively describable, and comparable across different regions can correct guidance be provided for subsequent reservoir evaluation and production decisions. Non-tectonic fracture evaluation, especially in unconventional oil and gas reservoirs with extremely low porosity and permeability, has become an important task in selecting favorable oil and gas exploration areas and formulating subsequent development plans.

[0004] Many scholars have conducted detailed research on the description and evaluation of non-tectonic fractures. The commonly used evaluation methods are: (1) calculating the fracture linear density of the core (i.e., the total number of fractures developed per unit core length) and evaluating the degree of fracture development through the fracture linear density; (2) quantitatively characterizing the degree of foliation fracture development through the foliation fracture comprehensive index (fracture density × fracture width); (3) evaluating the fracture development index based on fracture linear density, fracture filling type, and fracture dip angle type. Some of the above evaluation methods use a single index, while others use multiple indexes. All of them are based on data obtained from core samples. However, in practice, since the core diameter of the core sample is only 10 cm, it is difficult to obtain accurate statistics on the characteristics of non-tectonic fractures. In particular, the fracture width and dip angle of non-tectonic fractures also show irregular changes, resulting in large errors in the statistical results and making it difficult to accurately and quantitatively evaluate the degree of fracture development. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems in existing evaluation methods, such as the difficulty in obtaining accurate statistics on non-tectonic fracture characteristics, large errors in statistical results, and difficulty in quantitatively evaluating the development degree of non-tectonic fractures. This invention provides an evaluation method and system for the development degree of non-tectonic fractures in mudstone and shale under multiple coupled factors.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] The evaluation method for the development degree of non-tectonic fractures in shale under multiple coupling factors includes: calculating the fracture development index of non-tectonic fractures in shale, and evaluating the fracture development degree of non-tectonic fractures based on the fracture development index.

[0008] The formula for calculating the crack development index is:

[0009] F fz =F m *v*A*B

[0010] In the formula F fz F is the crack development index. m ρ is the crack linear density; v is the homogenized Poisson's ratio; A is the homogenized brittle mineral component content; B is the homogenized organic carbon content;

[0011] When the crack development index is ≤0.005, the crack development degree is poor; when the crack development index is 0.005 to 0.20, the crack development degree is average; when the crack development index is 0.20 to 0.55, the crack development degree is good; when the crack development index is ≥0.55, the crack development degree is very good.

[0012] In the technical solution of this invention, a fracture development index is established to characterize the degree of fracture development at the core scale of mudstone and shale. The index is the product of four indicators: fracture linear density, Poisson's ratio, brittle mineral component content, and organic carbon content coefficient. For the first time, the index of non-tectonic fracture development is characterized by multiple factors and parameters. This combines the internal and external factors affecting the development of non-tectonic fractures, forming a new method for characterizing non-tectonic fractures that is convenient for core measurement, has uniform measurement accuracy, allows for vertical and continuous characterization of different strata in a single borehole or region, and allows for horizontal and quantitative comparison of the same or different strata in different boreholes or regions. This method can meet the actual needs of early-stage oil and gas exploration.

[0013] In a preferred embodiment of the present invention, the crack linear density is the ratio of the total crack length to the unit area, and the formula for calculating the crack linear density is:

[0014]

[0015] In the formula F mLet L be the linear density of cracks, and L be the total length of cracks per unit area, where L = L1 + L2 + L3 + ... + L n Ln is the length of the nth crack, and A is the unit area. In this invention, crack linear density characterizes the degree of crack development within a unit area.

[0016] As a preferred embodiment of the present invention, the method for determining the crack length is as follows: conducting multi-phase three-dimensional seismic exploration of the study area to obtain seismic data, processing and analyzing the seismic data, and identifying geological features to obtain the crack length.

[0017] As a preferred embodiment of the present invention, Poisson's ratio is an elastic constant reflecting the lateral deformation of a material, and the method for calculating Poisson's ratio is as follows:

[0018]

[0019] In the formula, v is Poisson's ratio, V p V is the longitudinal wave velocity. s This refers to the transverse wave velocity. Poisson's ratio is an inherent property of materials and is dimensionless.

[0020] As a preferred embodiment of the present invention, Poisson's ratio is calculated using shear wave velocity and longitudinal wave velocity. The method for obtaining the ratio is as follows: geological and well logging analysis is performed on the shale reservoir in the study area, relevant geological parameters are collected, and shear wave velocity and longitudinal wave velocity data are obtained. If there is no direct shear wave data in conventional well logging, it can be obtained by converting the relationship between longitudinal wave and shear wave data.

[0021] As a preferred embodiment of the present invention, the brittle mineral components include feldspar, quartz, carbonate minerals, pyrite, etc., and the formula for calculating the content of the brittle mineral components is as follows:

[0022] A = (m1 / m2) × 100%

[0023] A represents the content of brittle mineral components, m1 represents the weight of brittle mineral components, and m2 represents the total weight of the rock. The method for obtaining the weight of brittle mineral components is as follows: rock cores are obtained through drilling, and the cores are prepared into thin sections. These sections are then observed using a polarizing microscope to identify the brittle mineral components in the rock. By using point counting under the microscope or image analysis software, the proportion of brittle minerals in the rock is determined. X-ray diffraction analysis is then performed on the thin section samples to determine the types and relative contents of brittle mineral components, ultimately determining the proportion and weight of different brittle mineral components.

[0024] As a preferred embodiment of the present invention, the formula for calculating organic carbon content is:

[0025] B = TC - IC

[0026] In the formula, B represents the organic carbon content (mg / L); TC represents the total carbon concentration (mg / L); and IC represents the inorganic carbon concentration (mg / L). The organic carbon concentration equals the total carbon concentration minus the inorganic carbon concentration. In actual measurements, rock core samples are obtained through drilling. After processing, the concentrations of total carbon and inorganic carbon are measured, and then the difference is calculated to obtain the organic carbon content in the sample. Organic carbon mainly exists in the organic matter of mudstone and shale, while inorganic carbon exists in the form of carbonate minerals. The total carbon concentration is measured using the combustion method, specifically by burning the sample to convert all forms of carbon into carbon dioxide, and then measuring the amount of carbon dioxide to determine the total carbon concentration. The inorganic carbon concentration is measured using the acidification method, specifically by reacting the sample with acid to release inorganic carbon in the form of carbon dioxide, and then measuring the amount of carbon dioxide released to determine the inorganic carbon concentration.

[0027] Another aspect of the present invention provides an evaluation system for the degree of development of non-tectonic fractures in shale under multiple coupling factors, the system comprising:

[0028] The first data module is used to obtain the crack development index;

[0029] The second data module is used to obtain the Poisson ratio and to normalize it.

[0030] The third data module is used to obtain the content of brittle mineral components and to homogenize the content of brittle mineral components.

[0031] The fourth data module is used to obtain the organic carbon content and homogenize it.

[0032] The calculation module is used to calculate the fracture development index of non-structural fractures in mudstone and shale;

[0033] The evaluation module is used to calculate the fracture development index of non-tectonic fractures in shale. When the fracture development index is ≤0.005, the fracture development degree is poor; when the fracture development index is 0.005 to 0.20, the fracture development degree is average; when the fracture development index is 0.20 to 0.55, the fracture development degree is good; and when the fracture development index is ≥0.55, the fracture development degree is very good.

[0034] The present invention also provides an electronic device, including at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the above-described method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors.

[0035] The present invention also provides a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or instruction set is loaded and executed by a processor to implement the above-mentioned method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] 1. This invention establishes a multi-factor comprehensive index for the development of non-structural fractures in shale reservoirs, namely the fracture development index, which accurately and quantitatively characterizes the degree of non-structural fracture development in shale under the coupling of multiple factors.

[0038] 2. Existing technologies are quantitative methods based on crack linear density. These methods are too cumbersome to record and have low statistical accuracy due to the non-directional nature of cracks. The method of this invention combines crack linear density, brittle mineral component content, organic carbon content, and Poisson's ratio to determine the degree of development of non-tectonic cracks, resulting in higher testing accuracy and reducing the evaluation error of crack development index based on a single factor.

[0039] 3. The fracture line density of this invention is the ratio of the total fracture length to the unit area. The fracture length is obtained through multi-phase three-dimensional seismic exploration of the study area. This invention combines three experimental fracture parameters—brittle mineral component content, organic carbon content, and Poisson's ratio—with the fracture line density with the actual field characterization accuracy. This forms a new method for characterizing non-tectonic fractures, which can be characterized vertically and continuously at different strata in a single borehole or region, and can be compared laterally and quantitatively at the same or different strata in different boreholes or different regions. This method can better meet the actual needs of oil and gas exploration and development, especially fractured and unconventional oil and gas exploration and development. Attached Figure Description

[0040] Figure 1 A flowchart illustrating the evaluation method for the development degree of non-tectonic fractures in mudstone and shale under multiple coupling factors;

[0041] Figure 2 This is a graph showing the relationship between the comprehensive index of mudstone and shale fractures and the contents of clay minerals and siliceous minerals in a certain well No. 6 in the Jiaoshiba area.

[0042] The diagram is labeled as follows: 1-First data module, 2-Second data module, 3-Third data module, 4-Fourth data module, 5-Calculation module, 6-Evaluation module. Detailed Implementation

[0043] To more clearly describe the inventive objectives, technical solutions, and advantages of the specific embodiments of this invention, the solutions in the specific embodiments will be described in detail below with reference to the accompanying drawings. The specific technical solutions involved in the following embodiments are merely for the purpose of clearly and completely describing the innovative technical solutions of this invention. They are only a part of the specific implementation methods that this invention can adopt, not all embodiments, and should not be construed as limiting the innovative solutions of this invention. Any solution that adopts the same inventive concept as this invention should be included within the protection scope of this invention.

[0044] Secondly, the descriptions in the accompanying drawings of the specific embodiments of this invention are merely for the convenience of those skilled in the art to understand the invention. The details shown in the drawings are for the purpose of clearly presenting the technical solution, and should not be construed as including all technical features in the drawings in the specific implementation examples, nor should the details in the drawings be considered as additional limitations on the innovative technical solution of this invention. The components in the various embodiments described and shown in the drawings can be combined and arranged in different configurations. These variations in combination and arrangement should be considered as part of all embodiments of the innovative solution of this invention and included within the scope of protection of this invention.

[0045] In summary, the solutions or descriptions presented in the specific embodiments and accompanying drawings of this invention are not intended to limit the scope of protection claimed, but merely to illustrate selected embodiments / examples to help those skilled in the art understand the relevant innovative solutions. All other equivalent or parallel embodiments obtained by those skilled in the art based on these embodiments without inventive effort are within the scope of protection claimed by this invention.

[0046] Example 1

[0047] In shale gas production, the production rate is closely related to the degree of fracture development. The degree of development of non-tectonic fractures determines the output of shale gas. This is because more developed non-tectonic fractures facilitate the formation of channels for shale gas migration, which is beneficial for shale gas extraction. Conversely, fewer non-tectonic fractures make fracturing operations difficult, hindering shale gas extraction and resulting in low output. Therefore, using shale gas output to characterize the degree of fracture development is feasible and intuitive. Based on the relationship between shale gas production and fracture development, shale gas output is graded into four levels: poor, average, good, and very good. Poor output is defined as less than 10,000 cubic meters per day; average output is 10,000 to 100,000 cubic meters per day; good output is 100,000 to 200,000 cubic meters per day; and very good output is 200,000 to 300,000 cubic meters per day.

[0048] To study the relationship between crack linear density and crack development degree, the inventors first used a single-factor crack linear density index to conduct a quantitative analysis of crack linear density in a certain region of Sichuan. Crack linear density is an indicator reflecting the degree of crack development, based on statistics of crack development within a certain range. Crack linear density is the ratio of the total crack length (L) to the unit area (A). The formula for calculating crack linear density is:

[0049]

[0050] In the formula F m Let L be the linear density of cracks, and L be the total length of cracks per unit area, where L = L1 + L2 + L3 + ... + L n Let Ln be the length of the nth crack, and A be the unit area. In this invention, crack linear density characterizes the degree of crack development per unit area. The crack length is determined as follows: seismic data is obtained by conducting multi-phase three-dimensional seismic exploration in a certain area of ​​Sichuan. The seismic data is then processed and analyzed, and geological features are identified to obtain the crack length.

[0051] By randomly selecting the production data of some shale gas wells in a certain region of Sichuan, this study aimed to establish the relationship between fracture linear density, fracture development degree, and shale gas production, and to conduct correlation analysis. The shale gas production of seven randomly selected wells in this region was analyzed. Geologically, these seven wells are located on the southern flank and core of anticlines, significantly affected by multiple tectonic superpositions, and are all situated in areas with relatively well-developed tectonic deformation. Furthermore, the main production strata of these seven wells are the black shale of the Wufeng-Longmaxi Formation (O3w-S1l). The correlation analysis between the mean linear density values ​​of the shale gas wells and shale gas production is shown in Table 1. Shale gas production was classified into four levels: poor, average, good, and very good. Poor production was <10,000 cubic meters per day; average production was 10,000–100,000 cubic meters per day; good production was 100,000–200,000 cubic meters per day; and very good production was 200,000–300,000 cubic meters per day. Based on the relationship between shale gas production and fracture development, shale gas production is graded into four levels: poor, average, good, and very good fracture development.

[0052] Table 1. Correlation Analysis of Mean Linear Density Values ​​of Shale Gas Wells and Shale Gas Production

[0053]

[0054] As can be seen from the data in Table 1, the correlation coefficient is a parameter characterizing the correlation between fracture linear density and shale gas production, and the correlation coefficient R is... 2The value of 0.018 indicates that the correlation between the fracture linear density values ​​of these 7 wells and shale gas production is not strong. This suggests that using the fracture linear density value as a single factor to characterize the degree of fracture development has limitations, the statistical results have a large error, and it is difficult to accurately and quantitatively evaluate the degree of fracture development.

[0055] To address the aforementioned issues, this embodiment proposes using a multi-factor comprehensive index, namely the fracture development index, to accurately and quantitatively characterize the degree of non-tectonic fracture development in shale under the coupling of multiple factors. For example... Figure 1 As shown, the crack development index integrates four factors: crack linear density, Poisson's ratio, brittle mineral content, and organic carbon content. The formula for calculating the crack development index is:

[0056] F fz =F m *v*A*B

[0057] In the formula F fz F is the crack development index. m ρ is the crack linear density; v is the homogenized Poisson's ratio; A is the homogenized brittle mineral component content; B is the homogenized organic carbon content;

[0058] The fracture linear density is the ratio of the total fracture length to the area per unit area. The fracture length is determined by conducting multi-phase 3D seismic exploration of the study area to obtain seismic data, processing and analyzing the seismic data, and identifying geological features to obtain the fracture length. In some embodiments, the fracture linear density is obtained by calculation through field or core observation or by topological analysis methods.

[0059] Poisson's ratio is an important indicator reflecting the degree of crack development. Shale with a low Poisson's ratio is brittle and prone to crack formation. Poisson's ratio is the absolute value of the ratio of transverse strain to longitudinal strain in a material, also called the transverse deformation coefficient. It is an elastic constant reflecting the transverse deformation of a material. The method for calculating Poisson's ratio is as follows:

[0060]

[0061] In the formula, v is Poisson's ratio, V p V is the longitudinal wave velocity. s The value represents the shear wave velocity. Poisson's ratio is an inherent property of materials and is dimensionless. According to the formula for calculating Poisson's ratio, it is calculated using shear wave velocity and longitudinal wave velocity. The method for obtaining these values ​​is as follows: geological and well logging analysis of the shale reservoir in the study area is conducted to collect relevant geological parameters, obtaining shear wave velocity and longitudinal wave velocity data. If direct shear wave data is not available in conventional well logging, it can be obtained through the relationship between longitudinal and shear wave data.

[0062] Brittle mineral components include feldspar, quartz, carbonate minerals, pyrite, etc. The content and structure of brittle mineral components determine the mechanical properties and brittleness of shale reservoirs, and are an intrinsic factor in rock fracture formation. The content of brittle mineral components is considered one of the most critical factors affecting the development of non-tectonic fractures. The higher the content of brittle mineral components in shale, the less strain the shale experiences before fracturing, and the easier it is to form fractures. Studies have shown that the content of brittle mineral components and the degree of fracture development have a segmented relationship. This may be because the burial depth of the research target varies, and the mechanical properties of the rock change from brittle to ductile at deeper depths, which affects the development of non-tectonic fractures. This issue may be due to considering only a single factor; a quantitative characterization of fracture development requires a combination of multiple factors. The formula for calculating the content of brittle mineral components is:

[0063] A = (m1 / m2) × 100%

[0064] A represents the brittle mineral component content (%), m1 represents the weight of the brittle mineral component, and m2 represents the total weight of the rock. The brittle mineral component content is the percentage of the weight of the brittle mineral component relative to the total weight of the rock. The method for obtaining the weight of the brittle mineral component is as follows: rock cores are obtained through drilling, and the cores are prepared into thin sections. These sections are observed using a polarizing microscope to identify the brittle mineral components in the rock. The proportion of brittle minerals in the rock is determined through point counting under the microscope or image analysis software. X-ray diffraction analysis is then performed on the thin section samples to determine the types and relative contents of the brittle mineral components, ultimately determining the proportion and weight of different brittle mineral components. The process of preparing thin sections includes cutting, grinding, and polishing to ensure that the surface of the rock core sample is smooth and suitable for microscopic observation.

[0065] Organic carbon content refers to the total organic carbon (TOC) content in shale. Organic matter content and the degree of thermal evolution jointly control the development of non-tectonic fractures in shale reservoirs. Under the same sedimentary environment, shale with higher organic matter content has more developed laminae, which is conducive to the formation of bedding fractures. The degree of thermal evolution also controls the development of non-tectonic fractures in shale. As the degree of thermal evolution increases, the hydrocarbon generation and expulsion intensity of marine shale rich in organic matter increases, the anomalous fluid pressure increases, and bedding fractures or anomalous high-pressure fractures become more developed. The formula for calculating organic carbon content is:

[0066] B = TC - IC

[0067] In the formula, B represents the organic carbon content (mg / L); TC represents the total carbon concentration (mg / L); and IC represents the inorganic carbon concentration (mg / L). The organic carbon concentration equals the total carbon concentration minus the inorganic carbon concentration. In actual measurements, rock core samples are obtained through drilling. After processing, the concentrations of total carbon and inorganic carbon are measured, and then the difference is calculated to obtain the organic carbon content in the sample. Organic carbon mainly exists in the organic matter of mudstone and shale, while inorganic carbon exists in the form of carbonate minerals. The total carbon concentration is measured using the combustion method, specifically by burning the sample to convert all forms of carbon into carbon dioxide, and then measuring the amount of carbon dioxide to determine the total carbon concentration. The inorganic carbon concentration is measured using the acidification method, specifically by reacting the sample with acid to release inorganic carbon in the form of carbon dioxide, and then measuring the amount of carbon dioxide released to determine the inorganic carbon concentration.

[0068] In the calculation of the crack development index, Poisson's ratio, brittle mineral component content, and organic carbon content are obtained through experimental analysis. The Poisson's ratio, brittle mineral component content, and organic carbon content are data after data normalization. Data normalization adjusts the data to a uniform scale. In this embodiment, the data normalization uses min-max normalization, with the formula:

[0069]

[0070] Here, x represents the original data points, and min(X) and max(X) are the minimum and maximum values ​​in the dataset, respectively. This method maps all data points to the interval 0, 1.

[0071] After calculating the crack linear density, Poisson's ratio, brittle mineral component content, and organic carbon content, a crack development index was calculated. The degree of crack development in non-tectonic cracks was evaluated based on the crack development index. A crack development index ≤ 0.005 indicates poor crack development; 0.005–0.20 indicates moderate crack development; 0.20–0.55 indicates good crack development; and ≥ 0.55 indicates excellent crack development. The degree of non-tectonic crack development is not necessarily a single positive correlation with different influencing factors; it may also be a segmented relationship. This embodiment used four indicators to quantitatively characterize the degree of crack development, and the results are shown in Table 2.

[0072] Table 2. Structure for evaluating crack development.

[0073]

[0074] As shown in Table 2, the results of calculating the degree of non-tectonic fracture development using multiple coupling factors have a very good match with shale gas production, with a correlation coefficient R0. 2The value also increased from around 0.01 to 0.86, indicating a strong positive correlation between the multi-factor non-tectonic fracture development calculation results and shale gas production. It also shows that the multi-factor calculation of non-tectonic fracture development degree is more reliable than the single-factor calculation.

[0075] Example 2

[0076] This embodiment provides an evaluation system for the development degree of non-tectonic fractures in shale under multiple coupling factors, such as... Figure 2 As shown, the system includes:

[0077] First data module 1 is used to obtain the crack development index;

[0078] The second data module 2 is used to obtain the Poisson ratio and to normalize the Poisson ratio;

[0079] The third data module 3 is used to obtain the content of brittle mineral components and to homogenize the content of brittle mineral components;

[0080] The fourth data module 4 is used to obtain the organic carbon content and homogenize the organic carbon content;

[0081] Calculation module 5 is used to calculate the fracture development index of non-tectonic fractures in mudstone and shale;

[0082] Evaluation module 6 is used to calculate the fracture development index of non-tectonic fractures in mudstone and shale. When the fracture development index is ≤0.1, the fracture development degree is poor; when the fracture development index is 0.5 to 0.1, the fracture development degree is moderate; when the fracture development index is 0.5 to 1, the fracture development degree is relatively well developed; and when the fracture development index is ≥1, the fracture development degree is good.

[0083] The systems or modules described in the above embodiments can be implemented by computer chips or physical entities, or by products with certain functions. For ease of description, the above devices are described in terms of function, divided into various modules. Of course, in implementing this application, the functions of each module can be implemented in one or more software and / or hardware, or a module that performs the same function can be implemented by a combination of multiple sub-modules, etc.

[0084] This embodiment also provides an electronic device, including at least one processor, a memory communicatively connected to the at least one processor, and at least one input / output interface communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enables the at least one processor to perform the evaluation method for the development degree of non-tectonic fractures in shale under multiple coupling factors described in the foregoing embodiment. The input / output interface may include a display, keyboard, mouse, and USB interface for inputting and outputting data.

[0085] The electronic device can be an electronic device for the client, such as a mobile phone, laptop, tablet, desktop computer, etc., to perform the evaluation method for the development degree of non-tectonic fractures in shale under multiple coupling factors in Example 1.

[0086] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0087] When the integrated units of this invention are implemented as software functional units and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this invention, or the parts that contribute to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROM, magnetic disks, or optical disks.

[0088] This embodiment also provides a computer-readable storage medium storing at least one instruction, at least one program, code set, or instruction set. The at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to implement the above-mentioned method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors.

[0089] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof.

[0090] For those skilled in the art, when understanding the solutions described in the specific embodiments of the present invention, conventional technical manuals in the field can be consulted. At the same time, appropriate understandings or adjustments can be made to the above-mentioned terms to deduce the same or similar technical solutions without creative effort.

[0091] The above embodiments describe only the basic principles, main features and / or advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and the description of the invention content in the specification are only the principles or specific cases of the present invention. Without departing from the essence of the innovative idea of ​​the present invention, there are various changes and improvements to the innovative solution of the present invention, and all such changes and improvements fall within the scope of protection claimed by the present invention.

Claims

1. A method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors, characterized in that: Calculate the fracture development index of non-tectonic fractures in shale and evaluate the degree of fracture development of non-tectonic fractures based on the fracture development index. The formula for calculating the crack development index is: F fz =F m *v*A*B In the formula F f z is the fracture development index, Fm is the fracture linear density; v is the homogenized Poisson's ratio; A is the homogenized brittle mineral component content; B is the homogenized organic carbon content. When the crack development index is ≤0.005, the crack development degree is poor; when the crack development index is 0.005 to 0.20, the crack development degree is average; when the crack development index is 0.20 to 0.55, the crack development degree is good; when the crack development index is ≥0.55, the crack development degree is very good.

2. The method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors according to claim 1, characterized in that, Crack linear density is the ratio of the total length of cracks to the area per unit area. The formula for calculating crack linear density is: In the formula F m Let L be the linear density of cracks, and L be the total length of cracks per unit area, where L = L1 + L2 + L3 + ... + L n Ln is the length of the nth crack, and A is the unit area.

3. The method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors according to claim 2, characterized in that, The method for determining the crack length is as follows: three-dimensional seismic exploration is carried out in the study area to obtain seismic data, the seismic data is processed and analyzed, and geological features are identified to obtain the crack length.

4. The method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors according to claim 1, characterized in that, The method for calculating Poisson's ratio is as follows: In the formula V p V is the longitudinal wave velocity. s The velocity is the transverse wave velocity.

5. The method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors according to claim 1, characterized in that, The methods for obtaining shear wave velocity and longitudinal wave velocity are as follows: geological and well logging analysis is performed on the shale reservoir in the study area to collect relevant geological parameters and obtain shear wave velocity and longitudinal wave velocity data; if there is no shear wave data in conventional well logging, it can be obtained by converting the relationship between longitudinal wave and shear wave data.

6. The method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors according to claim 1, characterized in that, Brittle mineral components include feldspar, quartz, carbonate minerals, and pyrite. The formula for calculating the content of brittle mineral components is as follows: A = (m1 / m2) × 100% In the formula, m1 is the weight of the brittle mineral components, and m2 is the total weight of the rock.

7. The method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors according to claim 6, characterized in that, The method for obtaining the weight of brittle mineral components is as follows: rock cores are obtained through drilling, the obtained rock cores are made into thin sections, the thin sections are observed using a polarizing microscope to identify the brittle mineral components in the rock, the proportion of brittle minerals in the rock is determined by the point count under the microscope or image analysis software, and the thin section samples are subjected to X-ray diffraction analysis to determine the types and relative contents of brittle mineral components, and to determine the proportion and weight of different brittle mineral components.

8. The method for evaluating the degree of development of non-tectonic fractures in shale under multiple coupling factors according to claim 1, characterized in that, The formula for calculating organic carbon content is: B = TC-IC In the formula, TC is the total carbon concentration; IC is the inorganic carbon concentration.

9. An evaluation system for the development degree of non-tectonic fractures in shale under multiple coupling factors, characterized in that, The system is used to implement the evaluation method for the development degree of non-tectonic fractures in shale under multiple coupled factors as described in any one of claims 1-8, including: The first data module is used to obtain the crack development index; The second data module is used to obtain the Poisson ratio and to normalize it. The third data module is used to obtain the content of brittle mineral components and to homogenize the content of brittle mineral components. The fourth data module is used to obtain the organic carbon content and homogenize it. The calculation module is used to calculate the fracture development index of non-structural fractures in mudstone and shale; The evaluation module is used to calculate the fracture development index of non-tectonic fractures in shale. When the fracture development index is ≤0.005, the fracture development degree is poor; when the fracture development index is 0.005 to 0.20, the fracture development degree is average; when the fracture development index is 0.20 to 0.55, the fracture development degree is good; and when the fracture development index is ≥0.55, the fracture development degree is very good.

10. An electronic device comprising at least one processor and a memory communicatively connected to said at least one processor; said memory storing instructions executable by said at least one processor, characterized in that, The instructions are executed by the at least one processor to enable the at least one processor to perform the evaluation method for the degree of development of non-tectonic fractures in shale under multiple coupling factors as described in any one of claims 1-8.

Images