Methods and apparatus for assessing the risk of fault activation

Abstract

The present invention provides a fault activation risk assessment method and device, which relates to the technical field of geological exploration, including: obtaining stress three-component data of multiple sampling points in a target study area, a set of fault strike data of all fault segments, geological stratigraphic structure data and gas-liquid injection and production construction data of the target study area; interpolating the stress three-component data of multiple sampling points using a preset interpolation algorithm to obtain an in-situ stress field of the target study area; determining the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area based on the geological stratigraphic structure data and the gas-liquid injection and production construction data; determining the fault activation probability of each fault segment based on the in-situ stress field, the fault strike data set and the pore-elastic stress disturbance field of the target study area; using the fault activation probability of all fault segments in the target study area as the fault activation risk assessment result of the target study area, thereby effectively improving the accuracy of the fault activation risk assessment result.

Description

Technical Field

[0001] The invention relates to the technical field of geological exploration, and in particular to a method and device for evaluating fault activation risk. Background Art

[0002] As human society transitions to clean energy, industrial activities such as hydraulic fracturing, geothermal resource development, CO2 geological storage, underground gas storage, and wastewater reinjection, which inject or extract gas or liquid into the earth's crust, are widely carried out around the world. However, while achieving production goals, the implementation of gas and liquid injection is often accompanied by significant seismic activity, among which destructive moderate to strong earthquakes also occur frequently. Therefore, assessing the risk of regional fault activation caused by industrial construction is of great significance to reducing the risk of induced earthquakes and guiding industrial construction design so as to ensure safe industrial production.

[0003] In the existing technology, the uncertainty of model parameters is taken into account. Based on the Monte Carlo random sampling principle, the FSP (Fault Slip Potential) method is proposed to calculate the probability of fault activation and slip after a certain pore pressure (such as ∆P=2MPa) disturbance caused by industrial activities on faults of different attitudes. This type of method has been widely used in many industrial development zones. However, with the continuous exploration of the mechanism of induced earthquakes, current research has realized that the above method only considers the impact of pore pressure changes caused by construction on the activation of pre-existing faults, and the activation assessment conditions are not considered comprehensively, resulting in poor accuracy of fault activation risk assessment results. Summary of the invention

[0004] The purpose of the present invention is to provide a fault activation risk assessment method and device to alleviate the technical problem of poor accuracy of fault activation risk assessment results in existing fault activation risk assessment methods.

[0005] In a first aspect, the present invention provides a fault activation risk assessment method, comprising: obtaining stress three-component data of multiple sampling points in a target study area, a set of fault strike data of all fault segments, geological stratigraphic structure data and gas-liquid injection and production construction data of the target study area; interpolating the stress three-component data of multiple sampling points using a preset interpolation algorithm to obtain an in-situ stress field of the target study area; determining the poroelastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area based on the geological stratigraphic structure data and the gas-liquid injection and production construction data; determining the fault activation probability of each fault segment based on the in-situ stress field, the fault strike data set and the poroelastic stress disturbance field of each fault segment in the target study area; and using the fault activation probability of all fault segments in the target study area as the fault activation risk assessment result of the target study area.

[0006] Optionally, based on the geological stratigraphic structure data and the gas-liquid injection and production construction data, the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area is determined, including: using the geological stratigraphic structure data and the gas-liquid injection and production construction data to construct the pore-elastic coupling control equation of the target study area; solving the pore-elastic coupling control equation using an analytical solution or a numerical solution to obtain the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area.

[0007] Optionally, based on the in-situ stress field, fault strike data set and pore-elastic stress disturbance field of each fault segment in the target study area, the fault activation probability of each fault segment is determined, including: for each type of data in the in-situ stress field and fault strike data set of the target fault segment, respectively constructing a corresponding truncated Gaussian distribution to obtain a truncated Gaussian distribution of stress three-component data and a truncated Gaussian distribution of fault strike data of the target fault segment; wherein the target fault segment represents any fault segment among all fault segments; the in-situ stress field and pore-elastic stress disturbance field of the target fault segment are respectively constructed into a truncated Gaussian distribution of stress three-component data and a truncated Gaussian distribution of fault strike data; The stress disturbance field is superimposed to obtain the superimposed stress field of the target fault segment; the truncated Gaussian distribution of the stress three-component data of the target fault segment, the truncated Gaussian distribution of the fault attitude data and the superimposed stress field are sampled to calculate the activation judgment result of the target fault segment according to the sampled target stress three-component data, target fault attitude data and target superimposed stress three-component data; wherein the activation judgment result includes one of the following: activation, non-activation; based on the activation judgment results of multiple samplings, the fault activation probability of the target fault segment is calculated.

[0008] Optionally, the activation judgment result of the target fault segment is calculated based on the sampled target stress three-component data, target fault strike data and target superimposed stress three-component data, including: determining the sliding trend and Coulomb stress disturbance of the target fault segment based on the target stress three-component data, target superimposed stress three-component data and target fault strike data; calculating the theoretical maximum sliding trend of the target fault segment under the in situ stress field of the target fault segment; determining the activation judgment result of the target fault segment based on the theoretical maximum sliding trend, the sliding trend and Coulomb stress disturbance of the target fault segment.

[0009] Optionally, based on the target stress three-component data, the target superimposed stress three-component data and the target fault strike data, the sliding trend and Coulomb stress disturbance of the target fault segment are determined, including: calculating the first normal stress and the first shear stress borne by the target fault segment under the in-situ stress field based on the target stress three-component data and the target fault strike data; calculating the second normal stress and the second shear stress borne by the target fault segment under the superimposed stress field based on the target superimposed stress three-component data and the target fault strike data; calculating the sliding trend of the target fault segment based on the first normal stress and the first shear stress; calculating the change in normal stress borne by the target fault segment after gas-liquid injection and production construction based on the second normal stress and the first normal stress; calculating the change in shear stress borne by the target fault segment after gas-liquid injection and production construction based on the second shear stress and the first shear stress; calculating the Coulomb stress disturbance of the target fault segment based on the change in normal stress and the change in shear stress.

[0010] Optionally, the theoretical maximum slip trend of the target fault segment under the in-situ stress field of the target fault segment is calculated, including: determining the three-component stress data of the target position point based on the in-situ stress field of the target fault segment; wherein the target position point represents any position point on the target fault segment; based on the three-component stress data of the target position point, calculating the slip trend corresponding to each theoretical optional fault strike data at the target position point; and taking the maximum slip trend among the slip trends corresponding to all theoretical optional fault strike data at all positions as the theoretical maximum slip trend of the target fault segment.

[0011] Optionally, based on the theoretical maximum slip trend, the slip trend of the target fault segment and the Coulomb stress disturbance, an activation judgment result of the target fault segment is determined, including: calculating the normalized slip trend of the target fault segment based on the theoretical maximum slip trend and the slip trend of the target fault segment; when it is determined that the normalized slip trend of the target fault segment is greater than a first threshold and the Coulomb stress disturbance of the target fault segment is greater than a second threshold, determining that the activation judgment result of the target fault segment is activated; otherwise, determining that the activation judgment result of the target fault segment is inactivated.

[0012] In a second aspect, the present invention provides a fault activation risk assessment device, comprising: an acquisition module, used to acquire stress three-component data of multiple sampling points in a target study area, a set of fault strike data of all fault segments, geological stratigraphic structure data and gas-liquid injection and production construction data of the target study area; an interpolation module, used to interpolate the stress three-component data of multiple sampling points using a preset interpolation algorithm to obtain an in-situ stress field of the target study area; a first determination module, used to determine the pore-elastic stress disturbance field caused by gas-liquid injection and production construction in the target study area based on the geological stratigraphic structure data and the gas-liquid injection and production construction data; a second determination module, used to determine the fault activation probability of each fault segment based on the in-situ stress field, fault strike data set and pore-elastic stress disturbance field of the target study area; and a third determination module, used to use the fault activation probability of all fault segments in the target study area as the fault activation risk assessment result of the target study area.

[0013] In a third aspect, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the fault activation risk assessment method of any one of the aforementioned embodiments is implemented.

[0014] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer instructions, which, when executed by a processor, implements the fault activation risk assessment method of any one of the aforementioned embodiments.

[0015] When evaluating the fault activation risk of the target study area, the present invention takes into account the geological stratigraphic conditions, fault conditions and gas-liquid injection and production construction conditions of the target study area, and jointly determines the fault activation probability of each fault segment in the target study area based on the fault occurrence data set, the in-situ stress field and the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction. That is, the method simultaneously considers the two physical mechanisms of fault activation, namely fluid diffusion and pore-elastic coupling effect, to evaluate the fault activation risk caused by gas-liquid injection and production construction, thereby effectively alleviating the technical problem of poor accuracy of fault activation risk assessment results in existing fault activation risk assessment methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A flow chart of a fault activation risk assessment method provided by an embodiment of the present invention;

[0018] Figure 2 A flow chart for determining the probability of fault activation of each fault segment based on the in situ stress field, fault occurrence data set and pore-elastic stress disturbance field of the target study area provided in an embodiment of the present invention;

[0019] Figure 3 A functional module diagram of a fault activation risk assessment device provided by an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0024] Embodiment 1

[0025] Figure 1 A flow chart of a fault activation risk assessment method provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method specifically comprises the following steps:

[0026] Step S102, obtaining stress three-component data of multiple sampling points in the target study area, a set of fault strike data of all fault segments, geological stratigraphic structure data of the target study area, and gas-liquid injection and production construction data.

[0027] Through the exploration of the mechanism of induced earthquakes, it is found that in addition to the changes in pore pressure caused by fluid diffusion, the changes in pore-elastic stress caused by the pore-elastic coupling effect may also induce earthquakes. Therefore, the changes in pore-elastic stress caused by the pore-elastic coupling effect during gas-liquid injection and production cannot be ignored. In order to accurately evaluate the risk of fault activation in the target study area, the embodiment of the present invention needs to obtain the three-component stress data (vertical principal stress perpendicular to the surface, maximum horizontal principal stress and minimum horizontal principal stress perpendicular to each other in the horizontal plane) of multiple sampling points in the target study area and the fault occurrence data set of all fault segments in the target study area. On the other hand, it is also necessary to collect the geological stratigraphic structure data of the target study area and the gas-liquid injection and production construction data in the area.

[0028] Among them, the stress three-component data (that is, stress tensor) of multiple sampling points are obtained after actual measurement using the equipment. The embodiment of the present invention does not specifically limit the number of sampling points in the current step. The user needs to adaptively configure the corresponding number of sampling points according to the size of the study area. Obviously, the larger the study area, the more sampling points should be.

[0029] By collecting or using high-precision seismic reflection three-dimensional data, the three-dimensional fault distribution (including fault strike data) of the target study area can be interpreted, and then the faults in the target study area are discretized according to preset discrete conditions to obtain multiple fault segments, and the fault strike data of all fault segments constitute a fault strike data set; wherein, the above-mentioned preset discrete conditions can be to discretize the fault into fault segments of about 200 meters along the strike, or to discretize the fault into multiple fault segments according to multiple specified strike angle value ranges. The embodiment of the present invention does not specifically limit the fault discretization method; the fault strike data at least includes: strike angle and dip angle.

[0030] In order to accurately simulate the pore-elastic stress disturbance field of the target study area after gas-liquid injection and production construction, in an embodiment of the present invention, the geological stratigraphic structure data of the target study area include: stratigraphic structure data, lithology data, Young's modulus data, Poisson's ratio data, permeability data and porosity data, etc.; the gas-liquid injection and production construction data include: single well injection rate, single well construction time, injection volume and injection pressure, etc.

[0031] Step S104, using a preset interpolation algorithm to interpolate the stress three-component data of multiple sampling points to obtain the in-situ stress field of the target study area.

[0032] In view of the limited number of sampling points measured in the target study area, in order to evaluate the fault activation of the entire study area, it is necessary to interpolate the stress three-component data of multiple sampling points through a preset interpolation algorithm, and use the interpolated result as the in-situ stress field of the target study area. The embodiment of the present invention does not specifically limit the preset interpolation algorithm, and the user can select it according to actual needs, for example, bilinear interpolation, cubic interpolation, Lagrange interpolation, etc.

[0033] Step S106, based on the geological stratigraphic structure data and the gas-liquid injection and production construction data, determine the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area.

[0034] Optionally, an embodiment of the present invention determines the borehole-elastic stress disturbance field by solving the borehole-elastic coupling control equation, wherein some parameters in the borehole-elastic coupling control equation need to adaptively adopt the geological stratigraphic structure data of the target study area, and set the boundary conditions and time step of the borehole-elastic coupling control equation based on the gas-liquid injection and production construction data.

[0035] Step S108, determining the fault activation probability of each fault segment based on the in situ stress field, fault occurrence data set and pore-elastic stress disturbance field of each fault segment in the target study area.

[0036] The embodiment of the present invention combines the in-situ stress field of each fault segment in the target study area, the pore-elastic stress disturbance field caused by simulated construction, and the fault occurrence data set to analyze the impact of gas-liquid injection and production on the fault stress, and calculates the fault activation probability of each fault segment after construction based on the preset criteria for judging fault activation.

[0037] Step S110: taking the fault activation probability of all fault segments in the target study area as the fault activation risk assessment result of the target study area.

[0038] After obtaining the fault activation risk assessment results of the target study area, the fault activation risk assessment results of the target study area and the positions, strike angles and dip angles of each fault segment in the study area can be integrated to obtain the fault activation probability distribution data of the target study area.

[0039] When evaluating the fault activation risk in the target study area, the embodiment of the present invention takes into account the geological stratigraphic conditions, fault conditions and gas-liquid injection and production construction conditions in the target study area, and jointly determines the fault activation probability of each fault segment in the target study area based on the fault occurrence data set, the in-situ stress field and the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction. That is, the method simultaneously considers the two physical mechanisms of fault activation, fluid diffusion and pore-elastic coupling effect, to evaluate the fault activation risk caused by gas-liquid injection and production construction, thereby effectively alleviating the technical problem of poor accuracy of fault activation risk assessment results in existing fault activation risk assessment methods. The method is helpful to guide the well site selection and construction parameter design in the gas-liquid injection and production area, reduce the risk of induced earthquakes, and ensure safe production.

[0040] In an optional implementation, the above step S106, based on the geological stratigraphic structure data and the gas-liquid injection and production construction data, determines the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area, and specifically includes the following steps:

[0041] Step S1061, using geological stratum structure data and gas-liquid injection and production construction data, construct the pore-elastic coupling control equation of the target study area.

[0042] Step S1062, using analytical solution or numerical solution to solve the borehole-elastic coupling control equation, to obtain the borehole-elastic stress disturbance field caused by gas-liquid injection and production in the target study area.

[0043] Based on the above description, it can be known that according to the definition of the pore-bullet coupling control equation, it is necessary to bring part of the geological stratigraphic structure data of the target study area into the equation, and the boundary conditions of the equation are determined by the gas-liquid injection and production construction data. In other words, the embodiment of the present invention uses the gas-liquid injection and production construction data as the load of the pore-bullet coupling finite element model of the target study area to set the boundary conditions of the equation. For example, the time step of the calculation is set according to the duration and cycle of the gas-liquid injection and production construction.

[0044] Among them, the construction method of the pore-elastic coupling finite element model of the target study area is: according to the geological stratigraphic structure data of the target study area, the geometric structure of the model is set and the corresponding physical parameters are assigned. In addition, the radius of the fracturing zone can also be set according to the fracture information near the horizontal wells in the target study area and the range of small earthquake activities related to fracturing. Furthermore, the above-mentioned constructed geometric model is divided into grids to provide a data basis for solving the subsequent pore-elastic coupling control equation. After constructing the pore-elastic coupling control equation of the target study area, the embodiment of the present invention selects an analytical solution or a numerical solution to solve the equation, and then obtains the pore-elastic stress disturbance field caused by gas-liquid injection and production construction in the study area. The numerical solution includes: finite element method, finite difference method, etc.

[0045] In an optional embodiment, if Figure 2As shown, the above step S108 determines the fault activation probability of each fault segment based on the in situ stress field, fault occurrence data set and pore-elastic stress disturbance field of each fault segment in the target study area, and specifically includes the following steps:

[0046] Step S1081, for each type of data in the in-situ stress field and fault attitude data set of the target fault segment, a corresponding truncated Gaussian distribution is constructed to obtain the truncated Gaussian distribution of the stress three-component data and the truncated Gaussian distribution of the fault attitude data of the target fault segment.

[0047] The target fault segment refers to any fault segment among all fault segments.

[0048] Specifically, the three-component stress data of each position point in the in-situ stress field include: vertical principal stress, maximum horizontal principal stress and minimum horizontal principal stress, and the fault attitude data include: strike angle and dip angle. In order to avoid the influence of data errors on the accuracy of fault activation risk assessment results, the embodiment of the present invention constructs corresponding truncated Gaussian distributions for each type of data in the in-situ stress field and fault attitude data set of the target fault segment, that is, this step needs to construct truncated Gaussian distributions of the following five types of data for each fault segment: truncated Gaussian distribution of vertical principal stress, truncated Gaussian distribution of maximum horizontal principal stress, truncated Gaussian distribution of minimum horizontal principal stress, truncated Gaussian distribution of strike angle and truncated Gaussian distribution of dip angle. The fault attitude data and three-component stress data of each fault segment in the study area can be obtained from the above five truncated Gaussian distributions corresponding to the fault segment.

[0049] Step S1082, superimposing the in-situ stress field and the perturbation field of the pore-elastic stress of the target fault segment to obtain the superimposed stress field of the target fault segment.

[0050] That is, according to the location of the target fault segment, the perturbation field of the borehole elastic stress caused by the construction is superimposed with its original stress field according to the location, so as to obtain the superimposed stress field of the target fault segment after the construction.

[0051] Step S1083, sampling the truncated Gaussian distribution of the stress three-component data of the target fault segment, the truncated Gaussian distribution of the fault attitude data and the superimposed stress field, so as to calculate the activation judgment result of the target fault segment based on the sampled target stress three-component data, target fault attitude data and target superimposed stress three-component data.

[0052] The activation judgment result includes one of the following: activated, non-activated.

[0053] Step S1084, based on the activation judgment results of multiple samplings, the fault activation probability of the target fault segment is calculated.

[0054] Taking into account the uncertainty of stress and fault strike data, the embodiment of the present invention calculates the conditional probability of fault activation after the superposition of two stress fields through sampling, so as to perform a relatively objective and quantitative fault activation risk assessment. Specifically, for the target fault segment, a sample point is respectively extracted from the truncated Gaussian distribution of its stress three-component data, the truncated Gaussian distribution of fault strike data and the superimposed stress field. At this time, the sampling point represents the target fault segment, and then the activation judgment result of the target fault segment under this sampling can be calculated based on the target stress three-component data sampled from the truncated Gaussian distribution of the stress three-component data, the target fault strike data sampled from the truncated Gaussian distribution of the fault strike data, and the target superimposed stress three-component data sampled from the superimposed stress field.

[0055] In order to obtain the fault activation probability of the target fault segment, it is necessary to repeatedly sample the truncated Gaussian distribution of the stress three-component data, the truncated Gaussian distribution of the fault attitude data and the superimposed stress field of the target fault segment, and then calculate the fault activation probability based on the activation judgment results of multiple samplings. For example, the target fault segment is sampled 100 times, of which 90 activation judgment results are activation and 10 activation judgment results are non-activation, then the fault activation probability of the target fault segment is determined to be 90%.

[0056] In an optional implementation, in the above step S1083, the activation judgment result of the target fault segment is calculated according to the sampled target stress three-component data, the target fault strike data and the target superimposed stress three-component data, which specifically includes the following steps:

[0057] Step S10831, based on the target stress three-component data, the target superimposed stress three-component data and the target fault strike data, determine the slip trend and Coulomb stress disturbance of the target fault segment.

[0058] According to the sampled target stress three-component data and target fault strike data, the embodiment of the present invention can calculate the normal stress and shear stress borne by the target fault segment under the in-situ stress field, and then calculate the sliding trend of the target fault segment. Similarly, according to the sampled target superimposed stress three-component data and target fault strike data, the normal stress and shear stress borne by the target fault segment under the superimposed stress field can be calculated. Finally, according to the changes in the normal stress and shear stress borne by the target fault segment before and after the gas-liquid injection and production construction, the Coulomb stress disturbance of the target fault segment is calculated.

[0059] Step S10832, calculating the theoretical maximum slip trend of the target fault segment under the in situ stress field of the target fault segment.

[0060] Step S10833, based on the theoretical maximum slip trend, the slip trend of the target fault segment and the Coulomb stress disturbance, determine the activation judgment result of the target fault segment.

[0061] Specifically, the theoretical maximum sliding trend of the target fault segment can be calculated based on the in-situ stress field of the target fault segment, and then the normalized sliding trend of the target fault segment can be calculated based on the sliding trend of the target fault segment and the theoretical maximum sliding trend of the target fault segment. The embodiment of the present invention specifically judges the activation judgment result of the target fault segment through the values ​​of the two indicators of normalized sliding trend and Coulomb stress disturbance. Specifically, the larger the normalized sliding trend and Coulomb stress disturbance, the greater the possibility of fault activation.

[0062] In an optional implementation, the above step S10831, based on the target stress three-component data, the target superimposed stress three-component data and the target fault strike data, determines the sliding trend and Coulomb stress disturbance of the target fault segment, specifically comprising the following steps:

[0063] Step S108311, based on the target stress three-component data and the target fault strike data, calculate the first normal stress and the first shear stress borne by the target fault segment under the in situ stress field.

[0064] Specifically, according to the target fault strike data currently sampled, the normal vector of the fault plane of the target fault segment can be determined. ,in, Indicates the strike angle corresponding to the current sampling point, Represents the dip angle corresponding to the current sampling point. After the normal vector is determined, the three-component data of the target stress obtained by the current sampling is decomposed based on the normal vector to determine the normal stress perpendicular to the fault plane and the shear stress parallel to the fault plane, that is, the first normal stress borne by the target fault segment under the in situ stress field. and the first shear stress .in, , , Represents the above target stress three-component data.

[0065] Step S108312, based on the target superimposed stress three-component data and the target fault strike data, calculate the second normal stress and the second shear stress borne by the target fault segment under the superimposed stress field.

[0066] Referring to the above-mentioned determination method of the first normal stress and the first shear stress, the three-component data of the target superimposed stress currently sampled are decomposed based on the normal vector to obtain the second normal stress borne by the target fault segment under the superimposed stress field. and the second shear stress . , , Represents the above target superimposed stress three-component data.

[0067] Step S108313, based on the first normal stress and the first shear stress, calculate the sliding trend of the target fault segment. The sliding trend is calculated as: .

[0068] Step S108314, based on the second normal stress and the first normal stress, calculate the change in normal stress borne by the target fault segment after the gas-liquid injection and production operation. That is, .

[0069] Step S108315, based on the second shear stress and the first shear stress, calculate the shear stress change of the target fault segment after the gas-liquid injection and production operation. .

[0070] Step S108316, based on the normal stress change and the shear stress change, calculate the Coulomb stress disturbance of the target fault segment. The formula for the Coulomb stress disturbance is: ,in, Represents the friction coefficient of the target fault segment.

[0071] In an optional implementation, the above step S10832, calculating the theoretical maximum slip trend of the target fault segment under the in situ stress field of the target fault segment, specifically includes the following steps:

[0072] Step S108321, determining the stress three-component data of the target position point based on the in-situ stress field of the target fault segment; wherein the target position point represents any position point on the target fault segment.

[0073] Step S108322, based on the stress three-component data of the target location point, calculate the sliding trend corresponding to each theoretical optional fault strike data at the target location point.

[0074] Step S108323, taking the maximum sliding trend among the sliding trends corresponding to all theoretical optional fault attitude data at all position points as the theoretical maximum sliding trend of the target fault segment.

[0075] That is to say, although the fault attitude data of the target fault segment has been determined, in order to effectively normalize the sliding trend of the target fault segment, the embodiment of the present invention needs to calculate the theoretical maximum sliding trend of the target fault segment under the in situ stress field of the target fault segment.

[0076] Take a location point as an example. The stress three-component data of the location point is determined and known according to the formula , , , based on the current fault strike data ( ) determines the sliding trend corresponding to the normal vector n, then in this step, the actual fault attitude data of the position point is ignored, and when the three-component data of the calculated stress are determined, all theoretical optional fault attitude data ( ) to obtain the sliding trend corresponding to the position point and obtain multiple sliding trends corresponding to the position point.

[0077] Similarly, the various sliding trends corresponding to all theoretically optional fault attitude data at each position point of the target fault segment are calculated when the three-component stress data of each point are determined. Finally, the maximum value is selected from all calculated sliding trends as the theoretical maximum sliding trend of the target fault segment. .

[0078] For example, assuming that the three-component stress data of a location point are determined, the theoretically optional fault attitude data ( ) There are M groups, then referring to the above method, M sliding trends can be calculated at this position point. If there are N position points in the target fault segment, a total of N*M sliding trends should be calculated, and the maximum value of the N*M sliding trends is taken as the theoretical maximum sliding trend of the target fault segment.

[0079] In an optional implementation, the above step S10833, based on the theoretical maximum slip trend, the slip trend of the target fault segment and the Coulomb stress disturbance, determines the activation judgment result of the target fault segment, specifically including the following steps:

[0080] Step S108331, based on the theoretical maximum sliding trend and the sliding trend of the target fault segment, the normalized sliding trend of the target fault segment is calculated. Specifically, the formula for the normalized sliding trend is: .

[0081] Step S108332: when it is determined that the normalized slip trend of the target fault segment is greater than the first threshold value, and the Coulomb stress disturbance of the target fault segment is greater than the second threshold value, the activation judgment result of the target fault segment is determined to be activated.

[0082] Step S108333: otherwise, determine that the activation judgment result of the target fault segment is inactive.

[0083] For example, if the activation criteria for a fault segment are: >0.5, and >0.01 MPa. And the fault segment =0.7, =0.02 MPa, which means that under this sampling, the activation judgment result of the target fault segment is activation.

[0084] Embodiment 2

[0085] The embodiment of the present invention further provides a fault activation risk assessment device, which is mainly used to execute the fault activation risk assessment method provided in the above-mentioned embodiment 1. The fault activation risk assessment device provided in the embodiment of the present invention is specifically introduced below.

[0086] Figure 3 A functional module diagram of a fault activation risk assessment device provided by an embodiment of the present invention, such as Figure 3 As shown, the device mainly includes: an acquisition module 10, an interpolation module 20, a first determination module 30, a second determination module 40, and a third determination module 50, wherein:

[0087] The acquisition module 10 is used to obtain stress three-component data of multiple sampling points in the target study area, a set of fault strike data of all fault segments, geological stratigraphic structure data of the target study area, and gas-liquid injection and production construction data.

[0088] The interpolation module 20 is used to perform interpolation processing on the stress three-component data of multiple sampling points using a preset interpolation algorithm to obtain the in-situ stress field of the target study area.

[0089] The first determination module 30 is used to determine the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area based on the geological stratum structure data and the gas-liquid injection and production construction data.

[0090] The second determination module 40 is used to determine the fault activation probability of each fault segment based on the in situ stress field, fault occurrence data set and pore-elastic stress disturbance field of each fault segment in the target study area.

[0091] The third determination module 50 is used to use the fault activation probability of all fault segments in the target study area as the fault activation risk assessment result of the target study area.

[0092] When evaluating the fault activation risk of the target study area, the embodiment of the present invention takes into account the geological stratigraphic conditions, fault conditions and gas-liquid injection and production construction conditions of the target study area, and jointly determines the fault activation probability of each fault segment in the target study area based on the fault occurrence data set, the in-situ stress field and the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction. That is, the device simultaneously considers the two physical mechanisms of fault activation, namely fluid diffusion and pore-elastic coupling effect, to evaluate the fault activation risk caused by gas-liquid injection and production construction, thereby effectively alleviating the technical problem of poor accuracy of fault activation risk assessment results in existing fault activation risk assessment methods.

[0093] Optionally, the first determining module 30 is specifically configured to:

[0094] The pore-elastic coupling control equation of the target study area is constructed using geological stratigraphic structure data and gas-liquid injection and production construction data.

[0095] The pore-elastic coupling control equation is solved by analytical or numerical methods to obtain the pore-elastic stress disturbance field caused by gas-liquid injection and production in the target study area.

[0096] Optionally, the second determining module 40 includes:

[0097] A construction unit is used to construct corresponding truncated Gaussian distributions for each type of data in the in-situ stress field and fault attitude data set of the target fault segment, so as to obtain the truncated Gaussian distribution of the stress three-component data and the truncated Gaussian distribution of the fault attitude data of the target fault segment; wherein the target fault segment represents any fault segment among all fault segments.

[0098] The superposition unit is used to superimpose the in-situ stress field and the perturbation field of the pore-bomb stress of the target fault segment to obtain the superimposed stress field of the target fault segment.

[0099] The sampling calculation unit is used to sample the truncated Gaussian distribution of the stress three-component data of the target fault segment, the truncated Gaussian distribution of the fault attitude data and the superimposed stress field, so as to calculate the activation judgment result of the target fault segment according to the sampled target stress three-component data, target fault attitude data and target superimposed stress three-component data; wherein the activation judgment result includes one of the following: activation, non-activation.

[0100] The calculation unit is used to calculate the fault activation probability of the target fault segment based on the activation judgment results of multiple samplings.

[0101] Optionally, the sampling calculation unit includes:

[0102] The first determination subunit is used to determine the sliding trend and Coulomb stress disturbance of the target fault segment based on the target stress three-component data, the target superimposed stress three-component data and the target fault strike data.

[0103] The calculation subunit is used to calculate the theoretical maximum slip trend of the target fault segment under the in situ stress field of the target fault segment.

[0104] The second determination subunit is used to determine the activation judgment result of the target fault segment based on the theoretical maximum slip trend, the slip trend of the target fault segment and the Coulomb stress disturbance.

[0105] Optionally, the first determining subunit is specifically configured to:

[0106] Based on the three-component data of target stress and the strike data of target fault, the first normal stress and the first shear stress borne by the target fault segment under the in situ stress field are calculated.

[0107] Based on the three-component data of target superimposed stress and the strike data of target fault, the second normal stress and second shear stress borne by the target fault segment under the superimposed stress field are calculated.

[0108] Based on the first normal stress and the first shear stress, the slip tendency of the target fault segment is calculated.

[0109] Based on the second normal stress and the first normal stress, the change in normal stress borne by the target fault section after gas-liquid injection and production construction is calculated.

[0110] Based on the second shear stress and the first shear stress, the change in shear stress borne by the target fault section after gas-liquid injection and production construction is calculated.

[0111] Based on the normal stress change and the shear stress change, the Coulomb stress disturbance of the target fault segment is calculated.

[0112] Optionally, the computing subunit is specifically used for:

[0113] The target stress three-component data of the target position point are determined based on the in-situ stress field of the target fault segment; wherein the target position point represents any position point on the target fault segment.

[0114] Based on the stress three-component data at the target location point, the sliding trend corresponding to each theoretical optional fault strike data at the target location point is calculated.

[0115] The maximum sliding trend among the sliding trends corresponding to all theoretical optional fault attitude data at all positions is taken as the theoretical maximum sliding trend of the target fault segment.

[0116] Optionally, the second determining subunit is specifically configured to:

[0117] Based on the theoretical maximum slip tendency and the slip tendency of the target fault segment, the normalized slip tendency of the target fault segment is calculated.

[0118] When it is determined that the normalized slip trend of the target fault segment is greater than the first threshold value, and the Coulomb stress disturbance of the target fault segment is greater than the second threshold value, the activation judgment result of the target fault segment is determined to be activation.

[0119] Otherwise, the activation judgment result of the target fault segment is determined to be inactive.

[0120] Embodiment 3

[0121] See also Figure 4 An embodiment of the present invention provides an electronic device, which includes: a processor 60, a memory 61, a bus 62 and a communication interface 63, the processor 60, the communication interface 63 and the memory 61 are connected through the bus 62; the processor 60 is used to execute an executable module stored in the memory 61, such as a computer program.

[0122] The memory 61 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 63 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used.

[0123] The bus 62 may be an ISA bus, a PCI bus, or an EISA bus. The bus may be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, Figure 4 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0124] Among them, the memory 61 is used to store programs, and the processor 60 executes the program after receiving the execution instruction. The method executed by the device defined by the process disclosed in any embodiment of the above-mentioned embodiment of the present invention can be applied to the processor 60 or implemented by the processor 60.

[0125] The processor 60 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 60. The above processor 60 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiments of the present invention can be directly embodied as a hardware decoding processor to be executed, or the hardware and software modules in the decoding processor can be executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 61, and the processor 60 reads the information in the memory 61 and completes the steps of the above method in combination with its hardware.

[0126] A computer program product of a fault activation risk assessment method and apparatus provided in an embodiment of the present invention includes a computer-readable storage medium storing a non-volatile program code executable by a processor. The instructions included in the program code can be used to execute the method in the previous method embodiment. The specific implementation can be found in the method embodiment and will not be repeated here.

[0127] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0128] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0129] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0130] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0131] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0132] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fault activation risk assessment method, characterized in that: include: Acquire stress three-component data of multiple sampling points in the target study area, a set of fault strike data of all fault segments, geological stratigraphic structure data and gas-liquid injection and production construction data of the target study area; Using a preset interpolation algorithm to interpolate the stress three-component data of the multiple sampling points to obtain the in-situ stress field of the target study area; Based on the geological stratigraphic structure data and the gas-liquid injection and production construction data, determining the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area; Determine the fault activation probability of each fault segment based on the in situ stress field, fault occurrence data set and pore-elastic stress disturbance field of each fault segment in the target study area; Taking the fault activation probability of all fault segments in the target study area as the fault activation risk assessment result of the target study area; Wherein, based on the in situ stress field, fault occurrence data set and pore-elastic stress disturbance field of each fault segment in the target study area, the fault activation probability of each fault segment is determined, including: For each type of data in the in-situ stress field and fault attitude data set of the target fault segment, a corresponding truncated Gaussian distribution is constructed to obtain a truncated Gaussian distribution of stress three-component data and a truncated Gaussian distribution of fault attitude data of the target fault segment; wherein the target fault segment represents any fault segment among all the fault segments; Superimposing the in-situ stress field and the perturbation field of the pore bomb stress of the target fault segment to obtain the superimposed stress field of the target fault segment; Sampling the truncated Gaussian distribution of the stress three-component data, the truncated Gaussian distribution of the fault attitude data and the superimposed stress field of the target fault segment, so as to calculate the activation judgment result of the target fault segment according to the sampled target stress three-component data, target fault attitude data and target superimposed stress three-component data; wherein the activation judgment result includes one of the following: activation, non-activation; Based on the activation judgment results of multiple samplings, the fault activation probability of the target fault segment is calculated.

2. The fault activation risk assessment method according to claim 1, characterized in that: Based on the geological stratigraphic structure data and the gas-liquid injection and production construction data, determining the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area, including: Using the geological stratigraphic structure data and the gas-liquid injection and production construction data, constructing the pore-elastic coupling control equation of the target study area; The pore-elastic coupling control equation is solved by using an analytical solution or a numerical solution to obtain the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area.

3. The fault activation risk assessment method according to claim 1, characterized in that: The activation judgment result of the target fault segment is calculated based on the sampled target stress three-component data, target fault strike data and target superimposed stress three-component data, including: Determine the slip trend and Coulomb stress disturbance of the target fault segment based on the target stress three-component data, the target superimposed stress three-component data and the target fault strike data; calculating a theoretical maximum slip trend of the target fault segment under an in situ stress field of the target fault segment; Based on the theoretical maximum slip trend, the slip trend of the target fault segment and the Coulomb stress disturbance, an activation judgment result of the target fault segment is determined.

4. The fault activation risk assessment method according to claim 3, characterized in that: Determining the sliding trend and Coulomb stress disturbance of the target fault segment based on the target stress three-component data, the target superimposed stress three-component data and the target fault strike data includes: Based on the target stress three-component data and the target fault strike data, calculating the first normal stress and the first shear stress borne by the target fault segment under the in situ stress field; Based on the target superimposed stress three-component data and the target fault attitude data, calculating the second normal stress and the second shear stress borne by the target fault segment under the superimposed stress field; calculating a slip trend of the target fault segment based on the first normal stress and the first shear stress; Calculating the change in normal stress borne by the target fault segment after gas-liquid injection and production based on the second normal stress and the first normal stress; Based on the second shear stress and the first shear stress, calculating the shear stress change of the target fault segment after the gas-liquid injection and production operation; Based on the normal stress change and the shear stress change, the Coulomb stress disturbance of the target fault segment is calculated.

5. The fault activation risk assessment method according to claim 3, characterized in that: Calculating the theoretical maximum slip trend of the target fault segment under the in situ stress field of the target fault segment, including: Determine the stress three-component data of the target position point based on the in-situ stress field of the target fault segment; wherein the target position point represents any position point on the target fault segment; Based on the stress three-component data of the target location point, calculating the sliding trend corresponding to each theoretical optional fault strike data at the target location point; The maximum sliding trend among the sliding trends corresponding to all theoretical optional fault attitude data at all position points is taken as the theoretical maximum sliding trend of the target fault segment.

6. The fault activation risk assessment method according to claim 3, characterized in that: Based on the theoretical maximum slip trend, the slip trend of the target fault segment and the Coulomb stress disturbance, determining the activation judgment result of the target fault segment, including: Calculating a normalized slip trend of the target fault segment based on the theoretical maximum slip trend and the slip trend of the target fault segment; When it is determined that the normalized slip trend of the target fault segment is greater than a first threshold value, and the Coulomb stress disturbance of the target fault segment is greater than a second threshold value, determining that the activation judgment result of the target fault segment is activation; Otherwise, the activation judgment result of the target fault segment is determined to be inactive.

7. A fault activation risk assessment device, characterized in that: include: An acquisition module is used to acquire stress three-component data of multiple sampling points in the target study area, a set of fault occurrence data of all fault segments, geological stratigraphic structure data of the target study area, and gas-liquid injection and production construction data; An interpolation module is used to perform interpolation processing on the stress three-component data of the plurality of sampling points using a preset interpolation algorithm to obtain the in-situ stress field of the target study area; A first determination module is used to determine the pore-elastic stress disturbance field caused by the gas-liquid injection and production construction in the target study area based on the geological stratum structure data and the gas-liquid injection and production construction data; A second determination module is used to determine the fault activation probability of each fault segment in the target study area based on the in situ stress field, fault occurrence data set and pore-elastic stress disturbance field of each fault segment; A third determination module is used to use the fault activation probability of all fault segments in the target study area as the fault activation risk assessment result of the target study area; Wherein, the second determination module includes: A construction unit is used to construct corresponding truncated Gaussian distributions for each type of data in the in-situ stress field and fault attitude data set of the target fault segment, so as to obtain the truncated Gaussian distribution of the stress three-component data and the truncated Gaussian distribution of the fault attitude data of the target fault segment; wherein the target fault segment represents any fault segment among all the fault segments; A superposition unit, used for superimposing the in-situ stress field and the perturbation field of the pore bomb stress of the target fault segment to obtain the superimposed stress field of the target fault segment; A sampling calculation unit is used to sample the truncated Gaussian distribution of the stress three-component data, the truncated Gaussian distribution of the fault attitude data and the superimposed stress field of the target fault segment, so as to calculate the activation judgment result of the target fault segment according to the sampled target stress three-component data, target fault attitude data and target superimposed stress three-component data; wherein the activation judgment result includes one of the following: activation, non-activation; The calculation unit is used to calculate the fault activation probability of the target fault segment based on the activation judgment results of multiple samplings.

8. An electronic device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor executes the computer program, the fault activation risk assessment method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the fault activation risk assessment method according to any one of claims 1 to 6 is implemented.

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