Quantitative evaluation method for development intensity of passive tectonic fracture

Abstract

The present application provides a kind of passive tectonic fracture development strength quantitative evaluation method, the passive tectonic fracture development strength quantitative evaluation method includes: step 1, obtains the structure diagram of target layer using seismic data interpretation result;Step 2, identify active fault, passive fault;Step 3, obtain the angle of active fault and passive fault in the target horizon, calculate the cosine value of angle;Step 4, calculate the horizontal fault throw and vertical fault throw of active fault;Step 5, calculate to obtain horizontal passive coefficient and vertical passive coefficient;Step 6, using horizontal passive coefficient and vertical passive coefficient, comprehensive evaluation the development strength of passive structure.The passive tectonic fracture development strength quantitative evaluation method starts from the active and passive angle of controlling structure development, evaluates the development influence degree of active fault to passive fault, provides the basis and basis of quantitative analysis for oil and gas exploration evaluation.

Description

Technical Field

[0001] This invention relates to the fields of structural geology and petroleum geology, and in particular to a quantitative evaluation method for the development intensity of passive tectonic fractures. Background Technology

[0002] Passive structures are a type of structure named based on the relative changes in the way stress is applied. They often develop in the context of multiple superimposed tectonic movements and the controlled development of large faults in basins (depressions). The release of tectonic stress is mainly through faulting. Boundary faults control the tectonic evolution process, stratigraphic distribution characteristics, erosion types, and sedimentary subsidence rates of the basin. Such boundary faults can be defined as active faults within the tectonic unit. "Passive structures" within a tectonic unit can be summarized as a series of structures formed by regulating the strain balance within the depression and controlled by boundary fault activity.

[0003] Currently, there are few quantitative evaluation studies on the development degree of passive structures. The evaluation methods mostly use conventional methods such as fracture activity rate and growth index, and there is no specific evaluation method applicable to the development intensity of passive structures.

[0004] Chinese patent application CN202010065612.4 discloses a method for predicting and evaluating fractured reservoirs. This method includes: determining the basic parameters of fracture development in fractured reservoirs based on geological data; conducting cross-analysis of well logging characteristics of fractured reservoirs to determine the geophysical identification basis; interpreting single-well fractured reservoirs to determine their vertical development characteristics and development patterns; combining well logging characteristics with DST testing to conduct single-well studies on the effectiveness of fractured reservoirs; using well logging characteristics to determine the predicted offset and azimuth of pre-stack five-dimensional fractures, and calculating the development intensity and orientation of fractured reservoirs; determining effective fracture development zones based on fracture effectiveness evaluation results; and completing a comprehensive reservoir evaluation and well location recommendations based on structural reservoir research results.

[0005] Chinese patent application CN201910280928.2 discloses a method and system for identifying strike-slip fault boundaries and main fault sections. The method includes: Step 1, preprocessing 3D seismic data of the area to be identified; Step 2, tracing marker layers of the strike-slip fault zone development area on a seismic profile formed based on the preprocessed 3D seismic data; Step 3, calculating the gradient structure tensor, coherence, and amplitude variation rate properties at the marker layers; and Step 4, comprehensively calculating the gradient structure tensor, coherence, and amplitude variation rate properties at the marker layers to determine the boundary of the strike-slip fault zone and the main fault section. This invention can evaluate the development scale of fault-soluble reservoirs within strike-slip fault zones, guide the selection of the most favorable drilling locations and horizontal well trajectories, and provide technical support for well site deployment in deep carbonate rock exploration and development.

[0006] Chinese patent application CN202010370953.2 discloses a method for evaluating the sealing performance of faults within carbonate rocks. The method includes: obtaining interpretation results of the target fault and its two sides using 3D seismic data and velocity field data; obtaining a fault planar distribution map, the thickness of the strata on both sides of the fault, the fault and strata attitude, and fluid inclusion samples; calculating the fault activity rate at different times, obtaining local stress field characteristics and fault properties, obtaining the attitude matching relationship between the strata and the fault, and obtaining fluid properties; establishing evaluation results for fault activity intensity, local stress field characteristics, fault properties, attitude matching, and fluid properties; and comprehensively evaluating the results of these five parameters to obtain the fault sealing performance evaluation result. The parameters used in this method for evaluating the sealing performance of faults within carbonate rocks are easily obtained, and the comprehensive evaluation method is simple and easy to implement. It effectively evaluates the effectiveness of fault-related traps developed within carbonate rocks and is worthy of widespread application in deep-exploration carbonate-type oil and gas fields.

[0007] The existing technologies described above are significantly different from the present invention and have failed to solve the technical problem we want to address. Therefore, we have invented a new quantitative evaluation method for the development strength of passive structural fractures. Summary of the Invention

[0008] The purpose of this invention is to provide a quantitative evaluation method that fully considers the kinematic and dynamic characteristics of active and passive fractures and reflects their correlation during development, thus truly reflecting the quantitative evaluation method of passive structural fracture development intensity using passive structural development intensity.

[0009] The objective of this invention can be achieved through the following technical measures: a quantitative evaluation method for the development strength of passive tectonic fractures, comprising:

[0010] Step 1: Obtain the structural map of the target layer using the seismic data interpretation results;

[0011] Step 2: Identify active fracture and passive fracture;

[0012] Step 3: Obtain the strike angle α between the active and passive fractures at the target stratum, and calculate the cosine value of the strike angle, cosα.

[0013] Step 4: Calculate the horizontal and vertical displacements of the active fracture.

[0014] Step 5: Calculate the horizontal passive coefficient and the vertical passive coefficient;

[0015] Step 6: Use the ratio expression of the horizontal passive coefficient and the vertical passive coefficient, i.e., horizontal passive coefficient / vertical passive coefficient, to comprehensively evaluate the development intensity of the passive structure.

[0016] The objective of this invention can also be achieved through the following technical measures:

[0017] In step 1, seismic data is used to perform isotactic interpretation of the target layer to form an iso-depth structural map of the target layer, wherein the target layer contains the target fault.

[0018] In step 2, passive and active fractures within the same structural region are identified through stress field analysis on the structural diagram.

[0019] In step 2, the location and distribution of active and passive fractures in the study area are determined by using regional tectonic dynamic analysis.

[0020] In step 3, the active fracture direction and the passive fracture direction are obtained by using the intersection lines of fractures at different locations on the target layer with the target layer, and the angle α between the two directions is obtained. The cosine value of this angle, cosα, is then calculated.

[0021] In step 4, the correspondence between the ascending and descending blocks of the active fracture is established, and the horizontal and vertical displacements of the active fracture are calculated.

[0022] In step 4, three-dimensional spatial models of active fracture and passive fracture are established respectively, the correspondence between the rising and falling blocks of active fracture is clarified, and the horizontal and vertical displacements of active fracture are obtained based on the projections in the horizontal and vertical directions.

[0023] In step 5, the component of the horizontal displacement of the passive fracture in the direction of the active fracture is obtained by using the ratio of the horizontal displacement of the passive fracture and the horizontal displacement of the active fracture, as well as the cosine of the angle between the two fractures. The horizontal passive coefficient is obtained as follows: horizontal displacement of passive fracture * cosα / horizontal displacement of active fracture.

[0024] In step 5, the component of the horizontal displacement of the passive fracture in the direction of the active fracture is obtained by using the ratio of the horizontal displacement of the passive fracture and the active fracture and the cosine value of the strike angle, thus obtaining the horizontal passive coefficient. The strike is the strike shown on the structural map of the same target layer; the cosine value is the cosine value of the strike angle of the same horizontal plane.

[0025] In step 5, the vertical passive coefficient is obtained by using the ratio of the vertical displacement of passive and active faults in the same target layer. The vertical passive coefficient = vertical displacement of passive structure * cosα / vertical displacement of active structure.

[0026] In step 6, the development intensity of passive structures is characterized by various correlation coefficients of horizontal and vertical passive coefficients, graphical displays, image displays, and digital displays.

[0027] The quantitative evaluation method for the development intensity of passive tectonic faults in this invention is applicable to the quantitative evaluation of the relative development intensity of active and passive faults in areas with complex fault development. It includes: obtaining a structural map of the target layer using seismic data interpretation results; identifying active and passive faults; obtaining the horizontal and vertical displacements of active and passive faults; obtaining the included angle between active and passive faults; and evaluating the control effect of active faults on the development intensity of passive faults using a passive tectonic adjustment coefficient.

[0028] This quantitative evaluation method for the development intensity of passive structural faults is the first to analyze the mechanical relationship between the development intensity of passive and active faults from the perspective of the active and passive mechanical genesis mechanisms controlling structural development. It ensures that the analysis can grasp the essence of the development of things through complex geological phenomena, evaluate the degree of development of passive faults by active faults from the genesis mechanism, quantitatively characterize the development intensity of passive and active structures at different stages, reconstruct the development and evolution history of passive structures, and understand the control of passive structures at different stages on sedimentary environment, reservoir, caprock, trap, and hydrocarbon charging. It provides a solution for clarifying the dynamic changes of hydrocarbon accumulation in passive structures and provides a quantitative analysis basis and evidence for hydrocarbon exploration and evaluation. Attached Figure Description

[0029] Figure 1 This is a flowchart of a specific embodiment of the method for quantitatively evaluating the development strength of passive structural fractures according to the present invention;

[0030] Figure 2 This is a contour map of the target layer structure in a specific embodiment of the present invention;

[0031] Figure 3 This is a plan view of a specific embodiment of the present invention;

[0032] Figure 4This is a three-dimensional view of the equivalent point displacement in a specific embodiment of the present invention;

[0033] Figure 5 This is a diagram illustrating the passive structural development intensity in a specific embodiment of the present invention;

[0034] Figure 6 This is a contour map of deep geological structures in a specific embodiment of the present invention;

[0035] Figure 7 This is a seismic profile of a region with passive fault development in a specific embodiment of the present invention;

[0036] Figure 8 This is a bar chart showing the statistical intensity of the horizontal development of passive faults in a certain region, as described in a specific embodiment of the present invention.

[0037] Figure 9 This is a statistical bar chart of the vertical development intensity of passive faults in a certain region, as shown in a specific embodiment of the present invention. Detailed Implementation

[0038] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0040] The quantitative evaluation method for the development intensity of passive tectonic faults in this invention is applicable to the quantitative evaluation of the relative development intensity of active and passive faults in areas with complex fault development. It includes: obtaining a structural map of the target layer using seismic data interpretation results; identifying active and passive faults; obtaining the horizontal and vertical displacements of active and passive faults; obtaining the included angle between active and passive faults; and evaluating the control effect of active faults on the development intensity of passive faults using a passive tectonic adjustment coefficient.

[0041] The following are several specific embodiments of the application of the present invention.

[0042] Example 1

[0043] In a specific embodiment 1 of the present invention, such as Figure 1 As shown, Figure 1This is a flowchart of a method for quantitatively evaluating the development strength of passive tectonic fractures according to the present invention. The method includes the following steps:

[0044] Step 1: Obtain the structural map of the target layer using seismic data;

[0045] Seismic data is used to interpret the target stratum using isotactic methods, resulting in an isotactic map of the target stratum, which includes the target fault.

[0046] Step 2: On the structural diagram, through stress field analysis, identify passive and active fractures within the same structural region;

[0047] By using regional tectonic dynamic analysis, the location and distribution of active and passive faults in the study area were determined.

[0048] Step 3: Obtain the strike angle between the active and passive fractures at the target stratum, and calculate the cosine value of the strike angle.

[0049] The active and passive fracture strikes are obtained by using the intersection lines of fractures at different locations on the target layer with the target layer, and the angle between the two strikes is obtained. The cosine value of this angle is then calculated.

[0050] Step 4: Establish the correspondence between the ascending and descending blocks of the active fracture, and calculate the horizontal and vertical displacements of the active fracture.

[0051] Three-dimensional spatial models of active and passive fractures were established respectively. The correspondence between the rising and falling blocks of the active fracture was clarified. The horizontal and vertical displacements of the active fracture were obtained based on the projections in the horizontal and vertical directions.

[0052] Step 5: Use the ratio of the horizontal displacement of the passive fracture to that of the active fracture and the cosine of the strike angle to obtain the component of the horizontal displacement of the passive fracture in the direction of the active fracture, and obtain the horizontal passive coefficient.

[0053] The component of the horizontal displacement of the passive fault in the direction of the active fault is obtained by using the ratio of the horizontal displacement of the passive fault and the cosine of the strike angle, thus obtaining the horizontal passive coefficient; the strike is the strike shown on the structural map of the same target layer; the cosine is the cosine of the strike angle of the same horizontal plane.

[0054] Step 6: Obtain the vertical passive coefficient by using the ratio of the vertical displacement of passive fracture and active fracture.

[0055] The vertical passive coefficient is obtained by using the ratio of the vertical displacement of passive and active faults in the same target layer.

[0056] Step 7: Use the horizontal passive coefficient and the vertical passive coefficient to comprehensively evaluate the development intensity of passive structures.

[0057] The development intensity of passive structures can be characterized by various correlation coefficients of horizontal and vertical passive coefficients, graphical displays, image displays, and digital displays.

[0058] Example 2

[0059] In a specific embodiment 2 of the present invention, the method for quantitatively evaluating the development strength of passive structural fractures includes the following steps:

[0060] Step 1: Obtain the structural map of the target layer using seismic data, such as... Figure 2 As shown, based on the regional tectonic background analysis and combined with the comprehensive analysis of geological data, a structural map of the target layer is produced using various interpretation software.

[0061] Step 2: On the structural diagram, through stress field analysis, identify passive and active fractures within the same structural region, such as... Figure 3 As shown, based on the regional tectonic stress analysis, the active fracture F and passive fractures F1, F2, F3, etc. in this region are determined;

[0062] Step 3: Obtain the strike angle between the active and passive faults at the target stratum, and calculate the cosine value of the strike angle, such as... Figure 3 As shown, the angle α between the strikes of the active fracture F and the passive fracture F1 is obtained;

[0063] Step 4: Establish the correspondence between the ascending and descending blocks of the active fracture, and calculate the horizontal and vertical displacements of the active fracture, such as... Figure 4 As shown, based on the three-dimensional display of the fracture, the horizontal displacement JK and vertical displacement AH of the passive and active fractures in the target layer are obtained;

[0064] Step 5: Using the ratio of the horizontal displacement of the passive fracture to that of the active fracture, and the cosine of the strike angle, obtain the component of the horizontal displacement of the passive fracture in the direction of the active fracture, and obtain the horizontal passive coefficient as shown below. Figure 4 As shown, based on the three-dimensional display of the fracture, the component of the passive fracture horizontal displacement in the direction of the active fracture is obtained by multiplying the passive fracture horizontal displacement by the cosine of the angle between the passive fracture and the active fracture.

[0065] Step 6: Using the ratio of the vertical displacement of passive fractures to that of active fractures, obtain the vertical passive coefficient, such as... Figure 4 As shown, based on the three-dimensional display of the fracture, the component of the vertical displacement of the passive fracture in the direction of the active fracture is obtained by multiplying the vertical displacement of the passive fracture with the cosine of the angle between the passive fracture and the active fracture.

[0066] Step 7: Use the horizontal passive coefficient and the vertical passive coefficient to comprehensively evaluate the development intensity of passive structures.

[0067] The development intensity of passive structures can be characterized by various correlation coefficients of horizontal and vertical passive coefficients, graphical displays, image displays, and digital displays.

[0068] Example 3:

[0069] In a specific embodiment 3 of the present invention, the method for quantitatively evaluating the development strength of passive structural fractures includes the following steps:

[0070] Step 1: Obtain the structural map of the target layer using seismic data, such as... Figure 6 As shown, based on the regional tectonic background analysis and combined with the comprehensive analysis of geological data, a structural map of the target layer is produced using various interpretation software.

[0071] Step 2: On the structural diagram, through stress field analysis, identify passive and active fractures within the same structural region, such as... Figure 6 As shown, based on the regional tectonic stress analysis, the active fault CN and the passive faults SC, W66, WG1, and WG7 in this area were identified.

[0072] Step 3: Obtain the strike angle between the active and passive faults at the target stratum, and calculate the cosine value of the strike angle, such as... Figure 6 As shown, the angle α between the strikes of the active fracture F and the passive fracture F1 is obtained;

[0073] Step 4: Establish the correspondence between the ascending and descending blocks of the active fracture, and calculate the horizontal and vertical displacements of the active fracture, such as... Figure 6 , Figure 7 As shown, based on the three-dimensional display of the fracture, the horizontal displacement JK and vertical displacement AH of the passive and active fractures in the target layer are obtained;

[0074] Step 5: Using the ratio of the horizontal displacement of the passive fracture to that of the active fracture, and the cosine of the strike angle, obtain the component of the horizontal displacement of the passive fracture in the direction of the active fracture, and obtain the horizontal passive coefficient as shown below. Figure 4 As shown, based on the three-dimensional display of the fracture, the component of the passive fracture horizontal displacement in the direction of the active fracture is obtained by multiplying the passive fracture horizontal displacement by the cosine of the angle between the passive fracture and the active fracture.

[0075] Step 6: Using the ratio of the vertical displacement of passive fractures to that of active fractures, obtain the vertical passive coefficient, such as... Figure 4 As shown, based on the three-dimensional display of the fracture, the component of the vertical displacement of the passive fracture in the direction of the active fracture is obtained by multiplying the vertical displacement of the passive fracture with the cosine of the angle between the passive fracture and the active fracture.

[0076] Step 7: Utilize the horizontal and vertical passive coefficients to comprehensively evaluate the development intensity of passive structures, such as... Figure 8 , Figure 9 As shown, the horizontal passive coefficient and the vertical passive coefficient are calculated respectively.

[0077] The development intensity of passive structures can be characterized by various correlation coefficients of horizontal and vertical passive coefficients, graphical displays, image displays, and digital displays.

[0078] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0079] Except for the technical features described in the specification, all other technologies are known to those skilled in the art.

Claims

1. A method for quantitatively evaluating the development strength of passive structural fractures, characterized by, The quantitative evaluation method of the development strength of the passive structure fault comprises: Step 1, obtaining the structure map of the target layer by using the seismic data interpretation result; Step 2, identifying the active fault and the passive fault; Step 3, obtaining the strike angle alpha of the active fault and the passive fault on the target layer, and calculating the cosine value of the strike angle; Step 4, calculating the horizontal fault throw and the vertical fault throw of the active fault; Step 5, calculating the horizontal passive coefficient and the vertical passive coefficient; Step 6, comprehensively evaluating the development strength of the passive structure by using the ratio expression of the horizontal passive coefficient and the vertical passive coefficient, i.e. horizontal passive coefficient / vertical passive coefficient.

2. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 1, characterized by, In step 1, the isodepth structure map of the target layer is formed by using the seismic data to perform isodepth interpretation on the target layer, and the target fault is contained in the target layer range.

3. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 1, characterized by, In step 2, the passive fault and the active fault in the same structure region are determined on the structure map by stress field analysis.

4. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 3, characterized by, In step 2, the positions and distributions of the active fault and the passive fault in the study area are determined by using regional structure dynamic analysis.

5. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 1, characterized by, In step 3, the strike of the active fault and the passive fault is obtained by using the intersection lines of the faults at different positions on the target layer and the target layer, and the strike angle between them is obtained, and the cosine value of the angle is calculated.

6. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 1, characterized by, In step 4, the corresponding relationship between the up-dip and the down-dip of the active fault is established, and the horizontal fault throw and the vertical fault throw of the active fault are calculated.

7. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 6, characterized by, In step 4, the three-dimensional space models of the active fault and the passive fault are respectively established, the corresponding relationship between the up-dip and the down-dip of the active fault is determined, and the horizontal fault throw and the vertical fault throw of the active fault are obtained according to the projections in the horizontal and vertical directions.

8. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 1, characterized by, In step 5, the horizontal fault throw component of the passive fault in the direction of the active fault is obtained by using the ratio of the horizontal fault throw of the passive fault and the active fault and the cosine value of the strike angle, and the horizontal passive coefficient is obtained, i.e. horizontal passive coefficient = passive fault horizontal fault throw*cos alpha / active fault horizontal fault throw.

9. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 8, characterized by, In step 5, the horizontal fault throw component of the passive fault in the direction of the active fault is obtained by using the ratio of the horizontal fault throw of the passive fault and the active fault and the cosine value of the strike angle, and the horizontal passive coefficient is obtained, i.e. horizontal passive coefficient = passive fault horizontal fault throw*cos alpha / active fault horizontal fault throw. In step 5, the vertical passive coefficient is obtained by using the ratio of the vertical fault throw of the passive structure and the active structure, i.e. vertical passive coefficient = passive structure vertical fault throw*cos alpha / active structure vertical fault throw.

10. The method for quantitatively evaluating the development strength of passive structural fractures according to claim 1, characterized in that, In step 6, the development strength of the passive structure is characterized by using various correlation coefficients, graphical display, image display and digital display of the horizontal passive coefficient and the vertical passive coefficient.

11. The method for quantitatively evaluating the development strength of a passive structural fracture according to claim 1, characterized by, ​

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