Fracture sealing earthquake prediction method and system based on structural integrity constraints

Abstract

The present application discloses a fracture sealing seismic prediction method and system based on structural integrity constraints, which relates to the technical field of geological exploration. The method includes establishing a three-dimensional model of the fault zone based on the exploration data of the target area; calculating the information dimension of the fractal parameter and the chaos parameter within the fault zone based on the three-dimensional model; determining the critical value of the constraint condition for the internal structural integrity of the fault zone and the third-generation coherence value of the petroleum seismic exploration data; determining the characteristic parameters of the internal structural complexity degree of the fault zone based on the information dimension, the chaos parameter and the third-generation coherence value according to the critical value of the constraint condition; calculating the constraint closure index according to the characteristic parameters of the internal structural complexity degree of the fault zone in combination with the shale composition content of the fault zone filling and the fault deformation burial depth constant; and predicting the sealing performance of the fault zone based on the CSI lower limit threshold of the fault of the discovered oil and gas reservoir according to the constraint closure index. The present application can more accurately evaluate the sealing performance of the fault layer.

Description

Technical Field

[0001] The present application relates to the technical field of geological exploration, and particularly to a seismic prediction method and system for fracture sealing based on structural integrity constraints. Background Art

[0002] Fractures are a common geological structure. The oil and gas exploration and development targets related to fractures are rich and diverse, and the common ones mainly include fault block oil and gas reservoirs, fault dissolution body oil and gas reservoirs, fracture-type gas storage caverns, etc.; fracture sealing is an important evaluation item in the risk of oil exploration and development strategies. The influence of fracture sealing on the formation conditions such as oil and gas accumulation and preservation is profound, so it has always been a geological problem in the oil and gas industry. The traditional domestic and foreign research methods for fracture sealing evaluation are based on the statistics of many single geological parameters, such as the shale content of the formation, fault throw, shale gouge ratio (SGR), shale smear factor (SSF), etc. Most of these methods are limited by a small number of drilling data, and their lateral evaluation accuracy needs to be improved, and they are limited in industrial applications. In oil production, three-dimensional seismic data, due to its obvious lateral identification advantage, is the data used from the oil and gas exploration to the development stage, and it carries rich information of various types about the internal structure and sealing performance of the fault zone.

[0003] Currently, directly using seismic data to carry out research on the internal structure of the fault zone, evaluate the sealing performance, and then carry out the exploration and development of fault-related oil and gas reservoirs and the geological engineering evaluation of underground energy storage spaces has gradually become a new research hotspot with broad application scenarios. Summary of the Invention

[0004] The purpose of the present application is to provide a seismic prediction method and system for fracture sealing based on structural integrity constraints, which can improve the reliability of fracture sealing evaluation.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] In the first aspect, the present application provides a seismic prediction method for fracture sealing based on structural integrity constraints, including:

[0007] Obtain petroleum seismic exploration data of the target area; the petroleum seismic exploration data includes post-stack three-dimensional seismic data, target fault interpretation data, and target layer formation surface interpretation data.

[0008] According to the petroleum seismic exploration data, establish a three-dimensional model of the faults in the fracture zone of the target area.

[0009] Based on the three-dimensional model of the faults in the fracture zone, calculate the information dimension (DI) of the fractal parameter and the Lyapunov exponent (LYAP) of the chaotic parameter in the fracture zone.

[0010] Determine the critical value K of the constraint condition for the internal structural integrity of the fault zone and the third-generation coherence value C3 of the petroleum seismic exploration data; the value range of the critical value K of the constraint condition is 0.5 - 0.9, which is determined according to the expert system of the target area.

[0011] Based on the information dimension DI, the chaos parameter LYAP, and the third-generation coherence value C3, and based on the critical value K of the constraint condition, determine the characteristic parameter FI of the complexity of the internal structure of the fault zone.

[0012] According to the characteristic parameter FI of the complexity of the internal structure of the fault zone, combined with the shale component content of the fault zone filling and the fault deformation buried depth constant, calculate the constraint closure index CSI.

[0013] Based on the constraint closure index CSI and the lower limit threshold of CSI of the faults of the discovered oil and gas reservoirs, predict the sealing performance of the faults in the fault zone.

[0014] Optionally, based on the three-dimensional model of the faults in the fault zone, calculate the information dimension DI and the chaos parameter LYAP of the fractal parameters in the fault zone, specifically including:

[0015] According to the formula Calculate the information dimension DI of the fractal parameters in the fault zone.

[0016] In the formula, ε is the minimum scale unit used in the fractal measurement, and I is the information entropy.

[0017] Optionally, the calculation formula of the information entropy is:

[0018] I = ∑p i ln(1 / p i )

[0019] In the formula, p i is the probability that each measurement unit is observed.

[0020] Optionally, the formula expression of the third-generation coherence value C3 of the petroleum seismic exploration data is:

[0021]

[0022] Among them, λ max is the maximum eigenvalue, M is the total number of eigenvalues, and λ i is the eigenvalue of any seismic trace within the time window.

[0023] Optionally, based on the information dimension DI, the chaos parameter LYAP, and the third-generation coherence value C3, and based on the critical value K of the constraint condition, determine the characteristic parameter FI of the complexity of the internal structure of the fault zone, specifically including:

[0024] When C3 is greater than or equal to the constraint critical value K, the characteristic parameter FI of the internal structure complexity of the fault zone is calculated according to the formula FI = (LYAP + DI) / C3.

[0025] When C3 is less than the constraint critical value K, according to the formula Calculate the characteristic parameter FI of the internal structure complexity of the fault zone.

[0026] Optionally, according to the characteristic parameter FI of the internal structure complexity of the fault zone, combined with the shale component content of the fault zone filling and the fault deformation burial depth constant, the constraint sealing index CSI is calculated, specifically including:

[0027] According to the formula Calculate the constraint sealing index CSI; where SGR is the shale component content of the fault zone filling.

[0028] Optionally, the calculation formula for the shale component content of the fault zone filling is:

[0029]

[0030] where i is the i-th rock layer passing through the fault point, T i is the thickness of the i-th rock layer passing through the fault point, VSH i is the shale content of the i-th rock layer passing through the fault point, and D is the vertical fault throw of the fault.

[0031] Optionally, according to the constraint sealing index CSI, based on the CSI lower limit threshold of the faults of the discovered oil and gas reservoirs, the sealing performance of the faults in the fault zone is predicted, specifically including:

[0032] Compare the constraint sealing index CSI with the CSI lower limit threshold of the faults of the discovered oil and gas reservoirs.

[0033] If the constraint sealing index CSI is greater than the CSI lower limit threshold, it is predicted that the fault is laterally open.

[0034] If the constraint sealing index CSI is less than or equal to the CSI lower limit threshold, it is predicted that the fault is laterally sealed.

[0035] In a second aspect, the present application provides a seismic prediction system for fault sealing based on structural integrity constraints, including:

[0036] A data acquisition module for acquiring petroleum seismic exploration data of a target area.

[0037] A model construction module for establishing a three-dimensional model of the faults in the fault zone in the target area according to the petroleum seismic exploration data; the petroleum seismic exploration data includes post-stack three-dimensional seismic data, target fault interpretation data, and target layer formation surface interpretation data.

[0038] A parameter calculation module, configured to calculate the information dimension DI of the fractal parameter and the LYAP of the chaos parameter within the fracture zone based on the three-dimensional model of the fault in the fracture zone.

[0039] A parameter determination module, configured to determine the critical value K of the constraint condition for the internal structural integrity of the fracture zone and the third-generation coherence value C3 of the petroleum seismic exploration data; the value range of the critical value K of the constraint condition is 0.5 - 0.9, which is determined according to the expert system of the target area.

[0040] A complexity characteristic parameter calculation module, configured to determine the complexity characteristic parameter FI of the internal structure of the fracture zone based on the information dimension DI, the chaos parameter LYAP, and the third-generation coherence value C3, based on the critical value K of the constraint condition.

[0041] A constraint closure index calculation module, configured to calculate the constraint closure index CSI according to the complexity characteristic parameter FI of the internal structure of the fracture zone, in combination with the shale component content of the fracture zone filling and the fault deformation burial depth constant.

[0042] A prediction module, configured to predict the sealing performance of the fault in the fracture zone according to the constraint closure index CSI, based on the lower limit threshold of CSI of the faults of the discovered oil and gas reservoirs.

[0043] According to the specific embodiments provided in the present application, the following technical effects are disclosed in the present application:

[0044] The present application provides a seismic prediction method and system for fracture sealing based on structural integrity constraints. This method comprehensively considers the internal structure of the fracture zone and realizes a comprehensive analysis of the fracture development degree, structural complexity, integrity, shale content of the filling, and compaction effect caused by deformation burial depth within the fracture zone. By introducing the information dimension DI to describe the fracture development in the fault zone and using the research method of the chaotic system to characterize the chaotic characteristics reflecting the disordered reflection in the fault zone during the earthquake, which corresponds to the complexity of the fracture zone structure; using the seismic coherence attribute represented by the eigenvalue coherence C3 to effectively constrain the integrity of the internal structure of the fault slip surface; the fault deformation burial depth constant reflects the influence of the compaction degree on the sealing performance. Therefore, the method proposed in the present application can provide an evaluation effect that is more consistent with the actual geological laws. Description of the Drawings

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0046] Figure 1 Schematic flowchart of a fracture sealing earthquake prediction method based on structural integrity constraints provided by an embodiment of the present application.

[0047] Figure 2 Schematic diagram of functional modules of a fracture sealing earthquake prediction method system based on structural integrity constraints provided by an embodiment of the present application. Detailed implementation manners

[0048] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0049] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0050] Embodiment 1

[0051] As Figure 1 shown, this embodiment provides a fracture sealing earthquake prediction method based on structural integrity constraints, including:

[0052] Step 101: Obtain petroleum seismic exploration data of the target area; the petroleum seismic exploration data includes post-stack three-dimensional seismic data, target fault interpretation data, and target layer formation surface interpretation data.

[0053] Step 102: Establish a three-dimensional model of the fault zone faults in the target area according to the petroleum seismic exploration data.

[0054] Step 103: Calculate the information dimension DI of the fractal parameters and the LYAP of the chaos parameters in the fault zone based on the three-dimensional model of the fault zone faults.

[0055] Step 104: Determine the critical value K of the constraint conditions for the internal structural integrity of the fault zone and the third-generation coherence value C3 of the petroleum seismic exploration data; the value range of the critical value K of the constraint conditions is 0.5 - 0.9, which is determined according to the expert system of the target area.

[0056] Step 105: Determine the characteristic parameter FI of the internal structural complexity of the fault zone based on the information dimension DI, the chaos parameter LYAP, and the third-generation coherence value C3, based on the critical value K of the constraint conditions.

[0057] Step 106: Calculate the constrained sealing index CSI according to the characteristic parameter FI of the internal structure complexity of the fault zone, in combination with the shale component content of the fault zone filling and the fault deformation burial depth constant.

[0058] Step 107: Predict the sealing performance of the fault zone faults based on the constrained sealing index CSI and the CSI lower limit threshold of the discovered hydrocarbon reservoir faults.

[0059] Among them, in some embodiments, when performing steps 101-102, it may be specifically as follows:

[0060] Three-dimensional geometric modeling of the fault zone faults, using the interpretation results of 3D seismic data to establish the geometric model distribution of the faults in three-dimensional space, and at the same time calculating the fault throw distribution in three-dimensional space.

[0061] Among them, in some embodiments, when performing step 103, it may be specifically as follows:

[0062] Based on the three-dimensional model of the fault zone faults, calculate the information dimension DI and the chaos parameter LYAP of the fractal parameters in the fault zone, specifically including:

[0063] According to the formula Calculate the information dimension DI of the fractal parameters in the fault zone.

[0064] In the formula, ε is the minimum scale unit used in fractal measurement, and I is the information entropy.

[0065] Specifically, DI represents the information dimension, which is a dimension parameter for measuring the complexity in fractal geometry. It captures the irregularities and complexities inside the fractal structure.

[0066] The information dimension DI quantifies the information content and complexity of the fractal structure through this formula, and is an important concept in fractal geometry. In practical applications, the information dimension can be used as a tool to distinguish the characteristics of different fractal structures. It helps to identify and analyze the complex structures inside the fault zone and can be regarded as a response to the degree of fracture development inside the fault zone; it can be obtained by the box method.

[0067] In the process of obtaining DI, it no longer depends on the traditional fracture recognition results based on the structure map, but directly uses the algorithm based on the curvature of seismic data for obtaining. In this way, the complex structures in the fracture area will be processed more objectively and the details will be more obvious.

[0068] Specifically, the calculation formula of the information entropy is:

[0069] I = ∑p i ln(1 / p i )

[0070] In the formula, pi is the probability that each measurement unit is observed.

[0071] Among them, the chaotic parameter LYAP, which is short for Lyapunov exponent, is an important concept in the fields of chaos theory and dynamic systems. It is one of the numerical characteristics for identifying chaotic motion and is used in this embodiment to represent the chaotic characteristics in seismic data, which is a characterization of the chaotic characteristics of the complex structure inside the fault zone and is dimensionless.

[0072] Specifically, the Lyapunov exponent can be defined by the limit of the logarithm of the ratio of the distance between two trajectories changing with time. Specifically, it is expressed as:

[0073]

[0074] Among them, d(x(t), y(t)) represents the distance between two trajectories x(t) and y(t) at time t.

[0075] In the process of calculating the Lyapunov exponent, the basic steps involve determining the dynamic equation of the system, selecting an initial state of the system and calculating the distance between adjacent trajectories of the system, solving the Jacobian matrix, and solving the eigenvalues of the Jacobian matrix at each step of time evolution. Since petroleum seismic data is a record of the travel time of artificially excited seismic waves, it is applicable to the category characterized by the Lyapunov exponent.

[0076] Regarding the determination of chaos, if the largest Lyapunov exponent of a system is greater than zero, it indicates that the system exhibits chaotic characteristics, meaning the system is complex and nonlinear; conversely, if the largest Lyapunov exponent is less than or equal to zero, the system behaves simply and linearly.

[0077] In some embodiments, when performing step 104, it can be specifically as follows:

[0078] The value of K depends on the understanding or experience of the integrity of the internal structure of the fault in the seismic data of adjacent areas or this area. The value range is generally between 0.5 and 0.9, which is a critical segmentation of C3.

[0079] C3 represents the result of the operation of the eigenvalue feature algorithm in the third-generation coherence attribute of seismic data, which is dimensionless; C3 ranges from 0 to 1, and its definition is as follows:

[0080] The formula expression of the third-generation coherence value C3 of petroleum seismic exploration data is:

[0081]

[0082] Among them, λ max is the largest eigenvalue, M is the total number of eigenvalues, λi is the eigenvalue of any seismic trace within the time window.

[0083] Among them, in some embodiments, when performing step 105, it can be specifically as follows:

[0084] The step-by-step constraint on the internal structural integrity of the fault zone is carried out based on the third-generation coherence value C3 of seismic data. According to the information dimension DI, the chaos parameter LYAP, and the third-generation coherence value C3, based on the constraint condition critical value K, the characteristic parameter FI of the internal structural complexity of the fault zone is determined, which specifically includes:

[0085] When C3 is greater than or equal to the constraint condition critical value K, it represents high internal structural integrity, few fragments, high coherence of the corresponding seismic waveform, and strong waveform consistency. The characteristic parameter FI of the internal structural complexity of the fault zone is calculated according to the formula FI = (LYAP + DI) / C3.

[0086] When C3 is less than the constraint condition critical value K, it represents relatively low internal integrity of the fault zone, many fragments, low coherence of the corresponding seismic waveform, and poor waveform consistency. According to the formula Calculate the characteristic parameter FI of the internal structural complexity of the fault zone.

[0087] Among them, in some embodiments, when performing step 106, it can be specifically as follows:

[0088] The compaction effect reflects the influence of burial depth on formation porosity. The filling materials (fault rocks) inside the fault zone are also affected by the compaction effect, and it is evaluated by using the geological constant c related to the burial depth of fault deformation. c reflects the influence of the compaction degree of the rocks inside the fault zone on the constraint sealing index CSI, and the two are proportional. If the depth of the fault is less than 3000 meters, the corresponding c value is 0.5; if the depth of the fault is between 3000 meters and 3500 meters, the corresponding c value is 0.25; if the fault observation point exceeds a depth of 3500 meters, the corresponding value is 0.

[0089] According to the formula Calculate the constraint sealing index CSI; where SGR is the shale component content of the fault zone filling.

[0090] Among them, the calculation formula for the shale component content of the fault zone filling is:

[0091]

[0092] Among them, SGR is the shale component content of the fracture zone filling (fault rock), which is a commonly used parameter in the industry to evaluate fracture sealing. Based on petroleum seismic exploration data and vertical throw, the SGR value of the shale component content of the fracture zone filling at the calculation point is calculated. In the formula, SGR is the shale component content of the fracture zone filling, %; i is the i-th rock layer passing through the fault point; T i is the thickness of the i-th rock layer passing through the fault point, m; VSH i is the shale content of the i-th rock layer passing through the fault point, %; D is the vertical throw of the fault, m.

[0093] Specifically, when 0 < C3 < k, the calculation formula of CSI is as follows:

[0094]

[0095] When K < C3 < 1, the calculation formula of CSI is as follows:

[0096]

[0097] Among them, in some embodiments, when performing step 107, it can be specifically as follows:

[0098] Based on the constrained sealing index CSI and the CSI lower limit threshold of the faults of the discovered oil and gas reservoirs, predict the sealing performance of the faults in the fracture zone, specifically including:

[0099] Compare the constrained sealing index CSI with the CSI lower limit threshold of the faults of the discovered oil and gas reservoirs.

[0100] If the constrained sealing index CSI is greater than the CSI lower limit threshold, predict that the fault is laterally open.

[0101] If the constrained sealing index CSI is less than or equal to the CSI lower limit threshold, predict that the fault is laterally sealed.

[0102] Specifically, count the discovered oil reservoirs in the exploration area, calibrate the CSI lower limit threshold of their fault sealing, compare the CSI value of the fault to be evaluated with the sealing lower limit threshold, and quantitatively evaluate the sealing performance of the fault according to the comparison result, including:

[0103] Compare the CSI value of the fault to be predicted with the sealing lower limit threshold; among them, if CSI is greater than the sealing lower limit threshold, the fault is laterally open, and vice versa, the fault is laterally sealed.

[0104] The sealing ability of each measurement point in the fracture zone is characterized by the difference between the CSI value and the sealing lower limit threshold. If the difference is larger, the permeability of the fault is stronger, which means the sealing ability is weaker, and vice versa.

[0105] From the analysis of the above - mentioned constituent factors and parameters, the CSI index is composed of multiple parameter combinations that affect the permeability of the fault zone. The DI parameter is related to fractures, C3 is related to the integrity of the internal structure of the fault zone, LYAP is a characterization of the structural complexity, SGR is related to the properties of the fault - zone filling materials and the content of shale components, and c is related to the degree of compaction of the fault zone.

[0106] Example Two

[0107] As Figure 2 shown, this embodiment provides a seismic prediction system for fault sealing based on structural integrity constraints, including:

[0108] A data acquisition module 201 for acquiring petroleum seismic exploration data of the target area; the petroleum seismic exploration data includes post - stack three - dimensional seismic data, target fault interpretation data, and target layer formation surface interpretation data.

[0109] A model construction module 202 for establishing a three - dimensional model of the fault zone faults in the target area according to the petroleum seismic exploration data.

[0110] A parameter calculation module 203 for calculating the information dimension DI of the fractal parameter and the chaos parameter LYAP in the fault zone based on the three - dimensional model of the fault zone faults.

[0111] A parameter determination module 204 for determining the critical value K of the constraint condition for the integrity of the internal structure of the fault zone and the third - generation coherence value C3 of the petroleum seismic exploration data; the value range of the critical value K of the constraint condition is 0.5 - 0.9, which is determined according to the expert system of the target area.

[0112] A complexity characteristic parameter calculation module 205 for determining the characteristic parameter FI of the internal structure complexity of the fault zone based on the information dimension DI, the chaos parameter LYAP, and the third - generation coherence value C3, based on the critical value K of the constraint condition.

[0113] A constrained sealing index calculation module 206 for calculating the constrained sealing index CSI according to the characteristic parameter FI of the internal structure complexity of the fault zone, in combination with the shale component content of the fault - zone filling materials and the fault deformation burial depth constant.

[0114] A prediction module 207 for predicting the sealing performance of the fault zone faults according to the constrained sealing index CSI, based on the lower limit threshold of CSI of the faults of the discovered oil and gas reservoirs.

[0115] In summary, the present application has the following technical effects:

[0116] This application takes into account the factors of the internal structure of the fault zone and its seismic reflection characteristics, and realizes the coupling effect of the degree of fracture development, the complexity of the internal structure, the integrity of the structure, the shale content of the fault zone filling, and the compaction effect caused by the deformation burial depth. The fractal dimension parameter DI is introduced to describe the fracture development in the fault zone, and the parameter LYAP representing the chaotic characteristics is introduced to reflect the chaotic and disordered reflection characteristics of the fault zone in terms of seismicity, corresponding to the complexity of the fault zone structure; the seismic coherence attribute represented by the eigenvalue coherence C3 is used to realize the characterization and constraint of the integrity response of the internal structure of the fault slip surface; compared with the existing methods, this application also highlights the influence of the shale content SGR of the fault zone filling and the fault deformation burial depth constant c on the fault sealing property; the whole process reflects the coupling effect of various geological factors and realizes the quantitative seismic prediction of the fault sealing property; the invention proposes a constraint sealing index CSI that is closely related to the internal structure of the fault zone and the seismic reflection characteristics, reflecting the relatively objective sealing characteristics of the internal structure of the fault zone, and the evaluation effect brought by this method is more in line with the actual geological laws.

[0117] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0118] Specific examples are used in this article to elaborate on the principle and implementation mode of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A method for predicting fracture closure earthquakes based on structural integrity constraints, characterized in that: The fracture closure earthquake prediction method based on structural integrity constraints comprises: Acquiring petroleum seismic exploration data of the target area; the petroleum seismic exploration data includes post-stack three-dimensional seismic data, target fault interpretation data and target layer stratigraphic interpretation data; Based on the petroleum seismic exploration data, a three-dimensional model of the fault zone and faults in the target area is established; Based on the three-dimensional model of the fault zone, the information dimension DI and the chaos parameter LYAP of the fractal parameter in the fault zone are calculated; Determine the constraint condition critical value K of the internal structural integrity of the fault zone and the third-generation coherence value C3 of the petroleum seismic exploration data; the critical value K of the constraint condition has a value range of 0.5-0.9 and is determined according to the expert system of the target area; According to the information dimension DI, the chaos parameter LYAP and the third generation coherence value C3, based on the critical value K of the constraint condition, the characteristic parameter FI of the complexity of the internal structure of the fault zone is determined; The constraint closure index CSI is calculated based on the characteristic parameter FI of the internal structural complexity of the fault zone, combined with the mud content of the fault zone filling and the fault deformation depth constant. According to the constraint sealing index CSI, the sealing performance of faults in the fault zone is predicted based on the CSI lower limit threshold of the faults in the discovered oil and gas reservoirs; According to the information dimension DI, the chaos parameter LYAP and the third-generation coherence value C3, based on the critical value K of the constraint condition, the characteristic parameters FI of the complexity of the internal structure of the fault zone are determined, including: When C3 is greater than or equal to the critical value K of the constraint condition, the characteristic parameter FI of the internal structural complexity of the fault zone is calculated according to the formula FI = (LYAP + DI) / C3; When C3 is less than the critical value K of the constraint condition, according to the formula Calculate the characteristic parameter FI of the internal structural complexity of the fault zone; According to the characteristic parameter FI of the complexity of the internal structure of the fault zone, combined with the mud content of the fault zone filling and the fault deformation depth constant, the constraint closure index CSI is calculated, which includes: According to the formula Calculate the constraint closure index CSI; where SGR is the mud content of the fault zone filling, and c is the influence of the compaction degree of the rock inside the fault zone on the constraint closure index CSI.

2. A method for predicting fracture closure earthquakes based on structural integrity constraints according to claim 1, characterized in that: Based on the three-dimensional model of the fault zone, the information dimension DI and the chaos parameter LYAP of the fractal parameter in the fault zone are calculated, specifically including: According to the formula Calculate the information dimension DI of the fractal parameters in the fault zone; In the formula, ε is the minimum scale unit used in fractal measurement, and I is the information entropy.

3. A method for predicting fracture closure earthquakes based on structural integrity constraints according to claim 2, characterized in that: The calculation formula of the information entropy is: I=∑p i ln(1 / p i ); In the formula, p i is the probability of each measurement unit being observed.

4. A method for predicting fracture closure earthquakes based on structural integrity constraints according to claim 1, characterized in that: The formula expression of the third generation coherence value C3 of the petroleum seismic exploration data is: Among them, λ max is the maximum eigenvalue, M is the total number of eigenvalues, λ i is the characteristic value of any seismic trace in the time window.

5. A method for predicting fracture closure earthquakes based on structural integrity constraints according to claim 1, characterized in that: The calculation formula for the mud content of the fault zone filling is: Where i is the i-th rock layer that slides across the breakpoint, T i is the thickness of the i-th rock layer that slides across the fault point, VSH i is the mud content of the i-th rock layer that slides across the fault point, and D is the vertical fault throw of the fault.

6. A method for predicting fracture closure earthquakes based on structural integrity constraints according to claim 1, characterized in that: According to the constraint sealing index CSI, based on the CSI lower limit threshold of the discovered oil and gas reservoir faults, the sealing performance of the fault zone fault is predicted, including: The constraint closure index (CSI) is compared with the lower threshold of CSI of faults in discovered oil and gas reservoirs; If the constraint closure index CSI is greater than the CSI lower threshold, the fault is predicted to be lateral open; If the constraint closure index CSI is less than or equal to the CSI lower threshold, the fault is predicted to be laterally closed.

7. A fracture closure earthquake prediction system based on structural integrity constraints, characterized in that: include: A data acquisition module is used to acquire oil seismic exploration data of a target area; the oil seismic exploration data includes post-stack three-dimensional seismic data, target fault interpretation data and target layer stratigraphic interpretation data; A model building module, used to build a three-dimensional model of the fault zone and fault in the target area based on the petroleum seismic exploration data; A parameter calculation module, used for calculating the information dimension DI and the chaos parameter LYAP of the fractal parameter in the fault zone based on the three-dimensional model of the fault zone; A parameter determination module is used to determine a constraint condition critical value K of the internal structural integrity of the fault zone and a third-generation coherence value C3 of the petroleum seismic exploration data; the critical value K of the constraint condition has a value range of 0.5-0.9 and is determined according to an expert system of the target area; The complexity characteristic parameter calculation module is used to determine the complexity characteristic parameter FI of the internal structure of the fault zone based on the information dimension DI, the chaos parameter LYAP and the third-generation coherence value C3 and the critical value K of the constraint condition; According to the information dimension DI, the chaos parameter LYAP and the third-generation coherence value C3, based on the critical value K of the constraint condition, the characteristic parameters FI of the complexity of the internal structure of the fault zone are determined, including: When C3 is greater than or equal to the critical value K of the constraint condition, the characteristic parameter FI of the internal structural complexity of the fault zone is calculated according to the formula FI = (LYAP + DI) / C3; When C3 is less than the critical value K of the constraint condition, according to the formula Calculate the characteristic parameter FI of the internal structural complexity of the fault zone; The constraint closure index calculation module is used to calculate the constraint closure index CSI according to the characteristic parameter FI of the internal structural complexity of the fault zone, combined with the mud content of the fault zone filling and the fault deformation burial depth constant; According to the formula Calculate the constraint closure index CSI; where SGR is the mud content of the fault zone filling, and c is the impact of the compaction degree of the rock inside the fault zone on the constraint closure index CSI; The prediction module is used to predict the sealing performance of the fault zone fault according to the constraint sealing index CSI and based on the CSI lower limit threshold of the discovered oil and gas reservoir faults.

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