Novel fractured reservoir geologic cause modeling method

Abstract

The invention relates to the technical field of geologic modeling, in particular to a novel fractured reservoir geologic cause modeling method which comprises the following steps: dividing fractured carbonate reservoirs into matrixes and fractures according to the difference between reservoir spaces and seepage channels, and modeling step by step; the method comprises the following steps: dividing fractures into large-scale fractures and small-and medium-scale fractures according to scale differences, and establishing fracture models of different scales step by step; during crack modeling, different methods are adopted for classified modeling according to the difference of crack scales; according to the fractures with different scales, carrying out statistics on fracture elements, and carrying out classified assignment on the porosity, permeability and saturation of the fractures; and equivalently combining the matrix model and the crack model, and establishing a three-dimensional model. According to the method, the three-dimensional geologic model capable of accurately reflecting the real distribution condition of the underground cracks is established, the three-dimensional space distribution characteristics of the fractured carbonate oil and gas reservoir matrix and the cracks are accurately described, and the result can reflect the real underground geologic information.

Description

Technical Field

[0001] The invention relates to the technical field of geological modeling, and is a novel fracture reservoir geological genesis modeling method. Background Art

[0002] In recent years, a certain oil and gas field has made major breakthroughs in the exploration and development of Paleogene carbonate oil and gas. However, the Neogene carbonate reservoirs in this area have very developed fractures, and the distribution of fractures has a great impact on the production capacity of oil wells. The limited technical methods for modeling fractured carbonate reservoirs restrict oil and gas exploration and development, making it difficult for the oil and gas field to formulate an efficient well network deployment development plan, which seriously restricts the exploration and development process and development effect of carbonate oil and gas reservoirs in this area. It is necessary to form a set of applicable three-dimensional geological modeling methods for fractured carbonate oil and gas reservoirs, and establish a three-dimensional geological model with fracture characterization accuracy that can meet the design requirements of the oil and gas field development plan.

[0003] At present, the modeling of fractured carbonate oil and gas reservoirs mainly adopts the "two-step" fracture modeling idea based on the establishment of a matrix model. For large-scale fractures, these are usually fractures determined by seismic data. Their positions and shapes are basically determined and do not need to be randomly generated. They can be achieved through deterministic methods such as ant tracking. For small and medium-scale fractures, this type of fracture forms the main part of the reservoir fracture network. It is usually impossible to have detailed information on each fracture slice, but it is possible to obtain statistical information and prior knowledge about its distribution density, orientation, length, opening, etc. Using this information, it is possible to use geological statistical methods to randomly generate a fracture network system consisting of thousands of fracture slices to meet various prior statistics and knowledge.

[0004] At the same time, Dan Lingling, Ma Chao, Shi Changlin and others published a paper titled "Study on Dual-Media Three-Dimensional Geological Modeling of Carbonate Reservoirs in Iraq M Oilfield" in the journal "Complex Oil and Gas Reservoirs" (Complex Oil and Gas Reservoirs, Vol. 11, No. 2, June 2018). The main content of the paper is: Based on the characteristics of fractured carbonate reservoirs in the Middle East, a modeling method of "establishing a relationship between fault distance and fracture development intensity based on fracture parameter analysis, and using fracture development probability body as trend constraint" was proposed. Specifically, it includes: (1) Grid division: According to the actual area and well spacing of the study area, considering the needs of later numerical simulation and the requirements of development well network deployment, the plane grid is determined to be 100m×100m. By statistically analyzing the thickness of the reservoir in this area, it is found that there are many thin interbeds in the reservoir in this area, and the lateral distribution changes rapidly. In order to accurately simulate the vertical distribution of the reservoir, the vertical grid accuracy is determined to be 0.5m. (2) Structural model: The structure of the M oilfield is a fault anticline with a north-southwest-east trend, with a total of 7 reverse faults. The faults are developed along the two wings of the anticline, which are basically consistent with the long axis of the anticline, and most of them are NW-SE. With the single well layer data as the control and the four structural layers of seismic interpretation as the constraint, the structural model was established by the inter-well Kriging interpolation method. (3) Lithofacies model: In order to finely characterize the spatial distribution of the complex lithofacies in the area, the corresponding lithofacies parameters were applied in this modeling process. First, the lithofacies interpretation of all single wells was carried out and used as the hard data input for lithofacies modeling; on the basis of lithofacies data analysis, with comprehensive geological knowledge as the constraint, the lithofacies model of the oil field was established by using the sequential indicator simulation method. (4) Physical property model: The porosity of each layer of different lithofacies in the oil field was transformed normally one by one, and the permeability attribute was first transformed logarithmically and then transformed normally. The eigenvalues ​​of the distribution of physical property data were statistically analyzed for constrained random simulation. The sequential Gaussian simulation method was used to predict the matrix porosity and permeability distribution based on the variance function analysis. (5) Fracture modeling: The study area is close to the orogenic belt, with strong stratum deformation and folding, and a high degree of fracture development. Through the analysis of the main controlling factors of fracture development, it is found that the degree of fracture development is mostly controlled by faults. The closer to the fault, the higher the degree of fracture development; and the farther from the fault, the less developed the fracture. The fracture direction is mostly parallel to the main controlling fault, and vertical fault fractures are occasionally seen. Based on this, the relationship between the fault distance and the fracture development intensity is established to obtain a three-dimensional data body of fracture development probability. A fracture network model is established based on the parameters of the previous fracture characteristic analysis, and finally a fracture attribute model is obtained. (6) Model verification: The production wells show that the production capacity is basically positively correlated with the size of the dual medium permeability. From the numerical simulation results, in the historical fitting stage, the relative error between the fitted reserves and geological reserves of each reserve unit of the oil field is less than 3%, which meets the requirements of numerical simulation reserve fitting. In terms of production fitting, the main fitting is the development indicators of the oil field such as pressure and production. Through the overall adjustment of the oil field parameters, all indicators have achieved a good fitting effect.The oil field has 17 producing wells. The pressure, daily oil production, daily liquid production and water content of each well were fitted, and the fitting rate reached more than 90%.

[0005] In the existing technology, the available data include: Zhang Lan (2011) et al. used imaging logging data and conventional logging data to zon the metamorphic rock buried hills, and combined fault distance functions and seismic attribute predictions to carry out three-dimensional geological modeling of fracture reservoirs; Dan Lingling (2018) proposed a modeling method of "establishing a relationship between fault distance and fracture development intensity based on fracture parameter analysis, and using the fracture development probability body as a trend constraint"; Dong Shaoqun (2020) et al. used the method of coupling fractures of different scales to establish a three-dimensional geological model of tight sandstone fracture reservoirs.

[0006] The existing three-dimensional geological modeling methods and technologies for fractured carbonate reservoirs represented by the above-mentioned journal articles can well establish three-dimensional geological models for guiding early oil and gas resource exploration and evaluation. However, after the fractured carbonate oil and gas reservoirs enter the development period, especially in the middle and late stages of development, the three-dimensional geological models established by the above methods are difficult to meet the technical requirements of development plan well network deployment, development effect evaluation, etc. Its main shortcomings are: while using seismic attributes as constraints, the fault distance function is used to control the fracture strength, but the important factor of the difference in fracture development strength caused by the change of fault distance at different fault positions is not considered. The fracture simulation results in relatively weak tectonic areas such as the end of the fault and the position with small fault distance are often quite different from the actual development of the fracture. Summary of the invention

[0007] The present invention provides a novel method for modeling the geological genesis of fractured reservoirs, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem that after fractured carbonate oil and gas reservoirs enter the development period, especially in the middle and late stages of development, the three-dimensional geological model established by the existing method is difficult to meet the technical requirements of development plan well network deployment, development effect evaluation, etc.

[0008] The technical solution of the present invention is achieved by the following measures: A novel fracture reservoir geological genesis modeling method comprises the following steps:

[0009] Step A1: According to the differences in reservoir space and seepage channels, fractured carbonate reservoirs are divided into two categories: matrix and fracture, and modeling is performed step by step;

[0010] Step A2: Cracks are divided into large-scale and medium-scale types according to their size differences, and fracture models of different scales are established step by step;

[0011] Step A3: When modeling cracks, different methods are used to classify and model according to the differences in crack scales, and large-scale crack models and medium- and small-scale crack models are established;

[0012] Step A4: Count the fracture elements according to fractures of different scales, and classify and assign values ​​to fracture porosity, permeability, and saturation;

[0013] Step A5: Equivalently merge the matrix model and the fracture model to establish a three-dimensional model of porosity, permeability and saturation of fractured carbonate oil and gas reservoirs that meets the needs of numerical simulation.

[0014] The following are further optimizations and / or improvements to the above technical solutions:

[0015] The above may also include step A6, calculating geological reserves according to static method and dynamic method, and correcting the three-dimensional geological model in combination with historical matching conditions, so that the established three-dimensional geological model is more consistent with the actual geological conditions.

[0016] In the above step A3, a large-scale fracture model can be established first, and then a medium- and small-scale fracture model can be established based on the fractures identified by core, conventional logging, and imaging logging data, combined with the fault distance function with normalized fault distance and the seismic fracture prediction results, to accurately characterize the spatial distribution of fractures.

[0017] The modeling steps of the above-mentioned large-scale fracture model may include: smoothing and filtering the seismic data, and conducting fracture prediction, filtering out non-fracture responses such as faults from the fracture prediction results, obtaining a large-scale fracture data body for earthquake prediction, applying modeling software to automatically track and identify using a deterministic method, establishing an original large-scale fracture model, combining the results of regional stress analysis with a human-computer interactive editing function to group and edit large-scale fractures, and establishing a large-scale fracture model that conforms to geological characteristics.

[0018] The modeling steps of the above-mentioned small and medium-scale fracture model may include:

[0019] The fault throws at different positions of all faults are counted respectively, and the fault throws are normalized to obtain the normalized fault throw function of each fault;

[0020] Taking the normalized fault throw function of each fault as a constraint, a fault distance function based on fault throw is established;

[0021] Based on outcrop, core, logging and test data, study the fracture elements such as azimuth and dip angle, determine the fracture development stage and group system, and give the parameter value range of each group of fractures, length and opening. Combined with the results of earthquake fracture prediction and regional ground stress analysis, study the distribution law of each group of fractures;

[0022] The single-well fracture density data obtained from imaging logging statistics are used as hard data, the fault distance function based on fault throw statistics and seismic fracture prediction data are used as constraints, and sequential Gaussian simulation is applied to simulate fracture density, thus establishing a fracture density model that conforms to the structural origin.

[0023] Discrete fracture grid models of each group of fractures are established based on the orientation and length of each group of fractures.

[0024] When correcting the above three-dimensional geological model, the following steps may be specifically included:

[0025] Calculate the geological reserves of oil and gas reservoirs in fractured carbonate rock three-dimensional geological models, and compare them with the proven reserves and other geological research reserve results of oil and gas reservoirs to find out the problems in the three-dimensional geological model and correct the model until the error between the model reserves and the geological research reserve results is within the allowable range;

[0026] The corrected three-dimensional geological model is exported for numerical simulation, and historical fitting of single wells and blocks is carried out. The problems existing in the historical fitting of the three-dimensional geological model are analyzed, and the model is further modified. Finally, a three-dimensional geological model of fractured carbonate rocks that is consistent with the underground oil and gas reservoir information is established.

[0027] The present invention provides an effective three-dimensional geological modeling method for fractured carbonate reservoirs. The core of the method is to fully consider the key factor that fracture generation is affected by structure when modeling small and medium-scale fractures. On the basis of detailed analysis of fracture characteristics, single well fracture statistical parameters are used as hard data, and the fault distance function based on fault distance normalization and fracture prediction attribute body are used as common constraints to establish a three-dimensional geological model that can accurately reflect the real distribution of underground fractures, so as to meet the needs of development well deployment, scheme design and development dynamic analysis. The present invention mainly focuses on the characteristics of complex spatial distribution and great simulation difficulty of fractures, especially small and medium-scale fractures in fractured carbonate reservoirs. On the basis of fracture characteristic analysis, single well fracture data is used as hard data, and the fault distance function based on fault distance normalization and seismic attribute body are used as common constraints to realize three-dimensional geological modeling of fractured carbonate oil and gas reservoirs. The present invention overcomes the problem that the control effect of different parts of faults on fracture development is not considered in the current fracture reservoir modeling, and establishes a three-dimensional geological model that accurately reflects the real distribution of underground fractures. Compared with the prior art, the implementation process of the present invention has high professional requirements and is difficult to operate. After entering the market, it is not easy for competitors to imitate and use it. As a new means of three-dimensional geological modeling of fractured reservoirs, the present invention has a strong market competition pattern. The three-dimensional geological model established according to the present invention accurately depicts the three-dimensional spatial distribution characteristics of the matrix and fractures of fractured carbonate oil and gas reservoirs, especially the depiction of fractures at the end of the fault and at positions with smaller fault distances is more consistent with the actual development of underground fractures, and the results can reflect the real underground geological information. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Attached Figure 1 Schematic diagram of a flow chart of an embodiment of the present invention.

[0029] Attached Figure 2 It is a schematic diagram of the process of large-scale fracture three-dimensional geological modeling according to an embodiment of the present invention.

[0030] Attached Figure 3 It is a schematic diagram of the process of three-dimensional geological modeling of small and medium-scale fractures according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0032] In the present invention, for the convenience of description, the description of the relative position relationship of each component is described according to the layout of the drawings in the specification, such as: the position relationship of front, back, up, down, left, right, etc. is determined according to the layout direction of the drawings in the specification.

[0033] The present invention will be further described below in conjunction with embodiments and drawings:

[0034] Embodiment 1: As attached Figure 1 , 2 As shown in , 3, the novel fracture reservoir geological genesis modeling method includes the following steps:

[0035] Step A1: According to the differences in reservoir space and seepage channels, the fractured carbonate reservoir is divided into two categories: matrix and fracture, and modeling is performed step by step. The embodiment of the present invention is based on existing data, and is divided into major modeling categories based on fault modeling, structural modeling, stratigraphic modeling and lithofacies modeling. According to the dual medium classification of fractured carbonate reservoirs, the modeling categories are generally divided into two categories: matrix and fracture, and different methods are used for step-by-step modeling.

[0036] Step A2: Cracks are divided into large-scale and medium-scale cracks according to the difference in scale, and crack models of different scales are established step by step. In the embodiment of the present invention, large-scale cracks refer to cracks with large opening and large extension length that can be identified by seismic data; while cracks with relatively short extension distance and small opening that can only be identified by outcrops, cores, conventional logging or imaging logging are called medium-scale cracks.

[0037] Step A3: When modeling fractures, different methods are used for classification modeling according to the differences in fracture scales to establish large-scale fracture models and medium- and small-scale fracture models. In step A3, a large-scale fracture model is first established using deterministic modeling methods such as ant tracking using seismic data; then, a medium- and small-scale fracture model is established based on fractures identified by core, conventional logging, imaging logging and other data, combined with the fault distance function with normalized fault distance and seismic fracture prediction results, to accurately describe the spatial distribution of fractures.

[0038] Step A4: According to the fractures of different scales, the fracture elements are counted, and the fracture porosity, permeability, saturation, etc. are classified and assigned values.

[0039] Step A5: Equivalently merge the matrix model and the fracture model to establish a three-dimensional model of porosity, permeability and saturation of fractured carbonate oil and gas reservoirs that meets the needs of numerical simulation.

[0040] Step A6: Since fractured carbonate reservoirs have strong heterogeneity and complex fluid distribution patterns, after establishing a three-dimensional geological model, it is necessary to calculate geological reserves based on static and dynamic methods, and calibrate the three-dimensional geological model based on historical fitting conditions to make the established three-dimensional geological model more consistent with actual geological conditions.

[0041] In an embodiment of the present invention, the modeling steps of the large-scale fracture model are: first, the seismic data is smoothed and filtered, and fracture prediction is carried out, and non-fracture responses such as faults are filtered out from the fracture prediction results to obtain a large-scale fracture data body for earthquake prediction, and the modeling software is used to use a deterministic method for automatic tracking and identification to establish an original large-scale fracture model, and the human-computer interactive editing function is used in combination with the results of regional stress analysis to perform group classification, editing, and other processing on the large-scale fractures to establish a large-scale fracture model that conforms to geological characteristics.

[0042] In the embodiment of the present invention, the modeling step of the small and medium-scale fracture model is to first count the fault distances S at different positions of all faults respectively, and then use Normalize the fault distance S (where, is the normalized fault distance function of each sampling point on the fault, S_max is the maximum fault distance of the fault in the work area, and S_min is the minimum fault distance of the fault in the work area), and the normalized fault distance function of each fault is obtained. Taking into account the consistency of structural characteristics in a small range, the normalized fault distance function of each fault is used as a constraint to establish a fault distance function based on fault distance. According to the outcrop, core, logging and test data, the fracture elements such as azimuth and inclination are studied, the fracture development stage and group system are determined, and the range of values ​​of parameters such as azimuth, length, and opening of each group of fractures are given. Combined with the results of seismic fracture prediction and regional geostress analysis, the distribution law of each group of fractures is studied; then, the single well fracture density data of imaging logging statistics is used as hard data, and the fault distance function based on fault distance statistics and seismic fracture prediction data are used as constraints. The sequential Gaussian simulation is used to simulate the fracture density, and a fracture density model that conforms to the structural genesis is established; then, the discrete fracture grid model of each group of fractures is established in combination with the azimuth and length of each group of fractures.

[0043] Step B8: Modeling of small and medium-scale fractures. First, the fault distances S at different positions of all faults are counted, and the Normalize the fault distance S (where, =S_max is the normalized fault distance function of each sampling point on the fault, S_max is the maximum fault distance of the fault in the work area, and S_min is the minimum fault distance of the fault in the work area), and the normalized fault distance function of each fault is obtained. Considering the consistency of structural characteristics in a small range, the normalized fault distance function of each fault is used as a constraint to establish a fault distance function based on fault distance. According to the data of outcrops, cores, logging and testing, the fracture elements such as azimuth and inclination are studied, the fracture development period and group system are determined, and the range of parameters such as azimuth, length and opening of each group of fractures is given. Combined with the results of seismic fracture prediction and regional geostress analysis, the distribution law of each group of fractures is studied; then, the single well fracture density data of imaging logging statistics is used as hard data, and the fault distance function based on fault distance statistics and seismic fracture prediction data are used as constraints. The sequential Gaussian simulation is used to simulate the fracture density, and a fracture density model that conforms to the structural genesis is established; then, the discrete fracture grid model of each group of fractures is established respectively in combination with the azimuth and length of each group of fractures.

[0044] Step B9, fracture parameter modeling. Based on the established discrete fracture network model and fracture aperture data, fracture porosity, fracture conductivity and fracture permeability models are established, and the fracture permeability model is modified according to production characteristics and the interpretation results of well test fracture permeability; fracture saturation is established based on the fracture saturation analysis results, and the water layer below the oil-gas-water interface is directly assigned to establish a fracture saturation model.

[0045] Step B10, model merging: The three-dimensional geological models established for the matrix and the fractures are respectively combined by using the equivalent merging calculation method of each parameter, and an equivalent model is generated by merging through grid calculation to establish a three-dimensional geological model of fractured carbonate oil and gas reservoirs.

[0046] Step B11, model correction. The correction is divided into two parts: static correction and dynamic correction. When correcting the three-dimensional geological model, the following steps are specifically included: first, the geological reserves of the oil and gas reservoirs in the fractured carbonate rock three-dimensional geological model are calculated, and compared with the proven reserves and other geological research reserve results of the oil and gas reservoirs to find out the problems in the three-dimensional geological model, and correct the model until the error between the model reserves and the geological research reserve results is within the allowable range; then the corrected three-dimensional geological model is exported for numerical simulation, and single well and block historical fitting is carried out, the problems existing in the three-dimensional geological model in the historical fitting are analyzed, and the model is further modified to finally establish a fractured carbonate rock three-dimensional geological model that matches the underground oil and gas reservoir information.

[0047] The embodiment of the present invention has been applied to the fractured carbonate oil and gas reservoir of a certain oil and gas field. The three-dimensional geological model established according to the embodiment of the present invention accurately depicts the three-dimensional spatial distribution characteristics of the matrix and fractures of the fractured carbonate oil and gas reservoir, especially the depiction of the fractures at the end of the fault and the position with smaller fault distance is more consistent with the actual development of underground fractures. The result can reflect the real underground geological information and plays an important role in the well site deployment, well trajectory optimization design, and drilling tracking in a certain oil and gas field in Iraq. At present, 32 wells have been drilled and 29 wells have been completed, with a drilling success rate of 100% and a high yield rate of 72% for single well oil testing.

[0048] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A novel fracture reservoir geological genesis modeling method, characterized in that The following steps are involved: Step A1: According to the differences in reservoir space and seepage channels, fractured carbonate reservoirs are divided into two categories: matrix and fracture, and modeling is performed step by step; Step A2: Cracks are divided into large-scale and medium-scale types according to their size differences, and fracture models of different scales are established step by step; Step A3: When modeling the fractures, different methods are used to classify and model the fractures according to the differences in fracture scales, and large-scale fracture models and medium- and small-scale fracture models are established; Step A4: Count the fracture elements according to fractures of different scales, and classify and assign values ​​to fracture porosity, permeability, and saturation; Step A5: Equivalently merge the matrix model and the fracture model to establish a three-dimensional model of porosity, permeability and saturation of fractured carbonate oil and gas reservoirs that meets the needs of numerical simulation.

2. The novel fracture reservoir geological genesis modeling method according to claim 1, characterized in that The method further includes step A6, calculating geological reserves according to static method and dynamic method, and correcting the three-dimensional geological model in combination with historical matching conditions, so that the established three-dimensional geological model is more consistent with the actual geological conditions.

3. The novel fracture reservoir geological genesis modeling method according to claim 1 or 2, characterized in that In step A3, a large-scale fracture model is first established, and then a medium- and small-scale fracture model is established based on the fractures identified by core, conventional logging, and imaging logging data, combined with the fault distance function normalized by fault throw and the seismic fracture prediction results, to accurately characterize the spatial distribution of fractures.

4. The novel fracture reservoir geological genesis modeling method according to claim 1 or 2, characterized in that The modeling steps of the large-scale fracture model include: smoothing and filtering the seismic data, and conducting fracture prediction, filtering out non-fracture responses such as faults from the fracture prediction results, obtaining a large-scale fracture data body for earthquake prediction, applying the modeling software to use a deterministic method for automatic tracking and identification, establishing an original large-scale fracture model, combining the results of regional stress analysis with a human-computer interactive editing function to group and edit large-scale fractures, and establishing a large-scale fracture model that conforms to geological characteristics.

5. The novel fracture reservoir geological genesis modeling method according to claim 3, characterized in that The modeling steps of the large-scale fracture model include: smoothing and filtering the seismic data, and conducting fracture prediction, filtering out non-fracture responses such as faults from the fracture prediction results, obtaining a large-scale fracture data body for earthquake prediction, applying the modeling software to use a deterministic method for automatic tracking and identification, establishing an original large-scale fracture model, combining the results of regional stress analysis with a human-computer interactive editing function to group and edit large-scale fractures, and establishing a large-scale fracture model that conforms to geological characteristics.

6. The novel fracture reservoir geological genesis modeling method according to claim 1, 2 or 5, characterized in that The modeling steps of small and medium-scale fracture models include: The fault throws at different positions of all faults are counted respectively, and the fault throws are normalized to obtain the normalized fault throw function of each fault; Taking the normalized fault throw function of each fault as a constraint, a fault distance function based on fault throw is established; Based on outcrop, core, logging and test data, study the fracture elements such as azimuth and dip angle, determine the fracture development stage and group system, and give the parameter value range of each group of fractures, length and opening. Combined with the results of earthquake fracture prediction and regional ground stress analysis, study the distribution law of each group of fractures; The single-well fracture density data obtained from imaging logging statistics are used as hard data, the fault distance function based on fault throw statistics and seismic fracture prediction data are used as constraints, and sequential Gaussian simulation is applied to simulate fracture density, thus establishing a fracture density model that conforms to the structural origin. Discrete fracture grid models of each group of fractures are established based on the orientation and length of each group of fractures.

7. The novel fracture reservoir geological genesis modeling method according to claim 3, characterized in that The modeling steps of small and medium-scale fracture models include: The fault throws at different positions of all faults are counted respectively, and the fault throws are normalized to obtain the normalized fault throw function of each fault; Taking the normalized fault throw function of each fault as a constraint, a fault distance function based on fault throw is established; Based on outcrop, core, logging and test data, study the fracture elements such as azimuth and dip angle, determine the fracture development stage and group system, and give the parameter value range of each group of fractures, length and opening. Combined with the results of earthquake fracture prediction and regional ground stress analysis, study the distribution law of each group of fractures; The single-well fracture density data obtained from imaging logging statistics are used as hard data, the fault distance function based on fault throw statistics and seismic fracture prediction data are used as constraints, and sequential Gaussian simulation is applied to simulate fracture density, thus establishing a fracture density model that conforms to the structural origin. Discrete fracture grid models of each group of fractures are established based on the orientation and length of each group of fractures.

8. The novel fracture reservoir geological genesis modeling method according to claim 4, characterized in that The modeling steps of small and medium-scale fracture models include: The fault throws at different positions of all faults are counted respectively, and the fault throws are normalized to obtain the normalized fault throw function of each fault; Taking the normalized fault throw function of each fault as a constraint, a fault distance function based on fault throw is established; Based on outcrop, core, logging and test data, study the fracture elements such as azimuth and dip angle, determine the fracture development stage and group system, and give the parameter value range of each group of fractures, length and opening. Combined with the results of earthquake fracture prediction and regional ground stress analysis, study the distribution law of each group of fractures; The single-well fracture density data obtained from imaging logging statistics are used as hard data, the fault distance function based on fault throw statistics and seismic fracture prediction data are used as constraints, and sequential Gaussian simulation is applied to simulate fracture density, thus establishing a fracture density model that conforms to the structural origin. Discrete fracture grid models of each group of fractures are established based on the orientation and length of each group of fractures.

9. The novel fracture reservoir geological genesis modeling method according to claim 2, characterized in that When correcting the 3D geological model, the following steps are specifically included: Calculate the geological reserves of oil and gas reservoirs in fractured carbonate rock three-dimensional geological models, and compare them with the proven reserves and other geological research reserve results of oil and gas reservoirs to find out the problems in the three-dimensional geological model and correct the model until the error between the model reserves and the geological research reserve results is within the allowable range; The corrected three-dimensional geological model is exported for numerical simulation, and historical fitting of single wells and blocks is carried out. The problems existing in the historical fitting of the three-dimensional geological model are analyzed, and the model is further modified. Finally, a three-dimensional geological model of fractured carbonate rocks that is consistent with the underground oil and gas reservoir information is established.

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