Method for identifying fault structural attributes of different groups of compressional-torsion fault zones

Abstract

The present invention provides a method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone, comprising: step 1, conducting a standard reflection axis interpretation of a target layer in a three-dimensional seismic acquisition area; step 2, conducting a coherent volume processing of three-dimensional seismic post-stack data for the target layer; step 3, extracting coherent slices of the target layer along the standard reflection axis; step 4, performing a three-dimensional seismic volume equal time slice scanning; step 5, marking the fault combination patterns and strike-slip orientations of different groups of faults in the target layer of the compression-torsion fault zone; step 6, drawing an approximate finite strain characteristic map of the target layer; and step 7, semi-quantitatively identifying the structural attributes of different groups of faults. The method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone realizes the scientific identification of the structural attributes of different groups of faults corresponding to the target layer in a complex compression-torsion fault zone, thereby serving the evaluation of the activity characteristics of fluid mineral resources along the compression-torsion fault zone.

Description

Technical Field

[0001] The invention relates to the technical field of compressional-torsion oil and gas basin structural analysis and oil and gas exploration and development, and in particular to a method for identifying structural attributes of different groups of faults in a compressional-torsion fault zone. Background Art

[0002] Many oil and gas basins in western China generally have the characteristics of non-coaxial compressional structural deformation, and the structural interpretation is highly multi-solution and difficult to analyze. The existence of angular shear components causes faults to generally have a certain strike-slip component, and multi-strike and multi-group faults are combined to form a very complex large-scale compression-torsion fault zone. Referring to the Riedel shear model analysis and the characterization of a large number of fault zones, it is revealed that multiple groups of faults with greatly different structural properties have developed in the same period in the strong compression-torsion structural deformation zone. The strike-slip orientations of these faults are greatly different, and the compression and extension properties are not the same. This has become a difficult problem in the fine characterization and analysis of the compression-torsion fault zone.

[0003] The current analysis method of fault structural attributes mainly uses the reflection characteristics of seismic profiles to identify compressional-torsion faults or tensional-torsion faults based on the vertical uplift and downlift relationship of the two plates of the fault. The dip angle of strike-slip faults in the western oil and gas basins is generally greater than 85°, and they tend to be vertical faults, and the fault dip is difficult to accurately calibrate. In theory, high-angle strike-slip faults need to be marked as left-running or right-running plates, and it is unscientific and inaccurate to mark the ascending or descending plates. This has caused the problem of multiple solutions and inaccuracy in judging the compressional or extensional structural attributes based on the uplift and downlift relationship of the two plates of the fault. In addition, the strike-slip fault zone in the western compressional-torsion basin is a deformation structure that causes vertical uplift and downlift activities by large-scale horizontal azimuth dislocation of rock strata. This also determines that the identification method of the structural attributes of compressional-torsion faults must have the content of plane structural analysis. With the large-scale acquisition and application of three-dimensional seismic data, especially high-density three-dimensional seismic data in oil and gas basins, the accuracy of interpretation and analysis of compressional-torsion structures has been continuously improved. It is necessary to continuously improve and improve the structural attribute analysis technology and methods of compressional-torsion faults to meet the current needs of mineral resource exploration.

[0004] In the Chinese patent application with application number: CN202010188216.0, a three-attribute fusion fault identification method based on the dominant frequency of seismic data is involved, which includes: the first step, frequency division processing of the full-band seismic data of the target area; the second step, the selection of the dominant frequency data body; the third step, the production of coherence, dip and azimuth attribute bodies; the fourth step, the three attributes of coherence, dip and azimuth are superimposed and displayed using HIS to obtain the final three-attribute fusion body, and the attribute slices of the target structural layer are produced to interpret the fault plane element characteristics, and the fault plane element characteristics will be clearly displayed.

[0005] In the Chinese patent application with application number: CN201810821511.8, a fault zone identification method is involved, which includes the following steps: Step 1: prepare the original seismic data body; Step 2: perform fine preprocessing; Step 3: calculate the structural guide body; Step 4: calculate the edge detection data body; Step 5: obtain the fault enhancement data body; Step 6: calculate the seismic gradient structure tensor eigenvalue data body and obtain the eigenvalue data body characterizing the chaotic reflection characteristics of the fault zone; Step 7: obtain the fault zone structure data body; Step 8: perform data body fusion processing on the fault enhancement data body and the fault zone structure data body to obtain the fault zone prediction result.

[0006] In the Chinese patent application with application number: CN201910831798.7, a fault interpretation method based on the combination of profile interaction and structural style guidance is involved, which includes the following steps: 1) interpretative processing of seismic data used for fault interpretation; 2) using variance body and ant body technology to produce attribute slices near the interpretation target layer; 3) analyzing the tectonic stress field of the work area and the typical structural style of the profile, and establishing a structural style library; 4) conducting fault interpretation on the profile perpendicular to the fault based on profile interaction and section gridding technology; 5) using three-dimensional visualization technology to control the quality of fault interpretation; 6) after completing the interpretation of a single fault, using the established structural style library as prior information, and using the classic structural style template to constrain and guide the combination relationship between faults on the profile; 7) repeating the above steps 4) to 6) until the interpretation of all faults in the entire work area is completed; 8) establishing a fault framework model of the work area to complete the fault interpretation work.

[0007] The existing technologies are significantly different from the present invention and fail to solve the technical problems we want to solve. To this end, we have invented a method for identifying the structural properties of faults of different groups in a compression-torsion fault zone under the guidance of modern compression-torsion structural deformation theory, which solves the above technical problems. Summary of the invention

[0008] The purpose of the present invention is to provide a method for identifying the structural properties of different groups of faults in a compression-torsion fault zone in a compression-torsion oil and gas basin, which is key to the analysis of the plane deformation characteristics of the compression-torsion structure.

[0009] The purpose of the present invention can be achieved by the following technical measures: a method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone, the method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone comprising:

[0010] Step 1: Conduct standard reflection axis interpretation of target horizons in the 3D seismic acquisition area;

[0011] Step 2: Carry out coherent volume processing of 3D seismic post-stack data for the target layer;

[0012] Step 3, extracting the coherent slices of the target layer along the standard reflection axis;

[0013] Step 4, performing equal time slice scanning of the three-dimensional seismic volume;

[0014] Step 5, identifying the fault combination patterns and strike-slip orientations of different groups of target layers in the compression-slip fault zone;

[0015] Step 6, drawing an approximate finite strain characteristic map of the target layer;

[0016] Step 7: Semi-quantitatively identify the structural properties of different fault systems.

[0017] The purpose of the present invention can also be achieved by the following technical measures:

[0018] In step 1, the superimposed 3D seismic processing results data are used to complete the standard reflection axis tracking interpretation of the target layer in the seismic interpretation system. The standard reflection axis is required to have medium-strong and medium-strong continuity to facilitate human-computer interactive tracking description, and the interpretation grid is not less than 5×5; encryption processing is completed in the 3D seismic data interpretation system.

[0019] In step 2, the coherence volume processing of the target layer corresponding to the time window is completed in the 3D seismic interpretation system; the coherence volume processing effect is tested on the profile and isochronous slice, and the fault is required to be identifiable.

[0020] In step 3, relevant slice extraction of the standard reflection axis is completed in the 3D seismic interpretation system, requiring that the extraction time window is within 10 ms above and below the standard reflection axis and the fault is clearly visible.

[0021] In step 4, equal time slicing is performed on the stacked post-processed 3D seismic data volume around the standard reflection axis in the 3D seismic interpretation system, and the standard reflection axis is projected on the horizontal slices to encrypt the interpretation results and analyze the formation twist and shear azimuth characteristics.

[0022] In step 4, equal time slice scanning is performed around the standard reflection axis at intervals of 2-5 ms to ensure that the strike-slip features of faults with different strike directions are fully identified and marked.

[0023] In step 4, multiple equal-time slices with clear stratum twisting characteristics, breakpoints, and shearing orientations are selected, and the corresponding time values ​​of the slices are marked to establish an equal-time slice library.

[0024] In step 5, the drawings completed in steps 3 and 4 are used as the data basis for the geometric, kinematic and dynamic analysis of the compression-torsion fault zone of the present invention, and the combination patterns and strike-slip orientations of different groups of faults in the target layer of the compression-torsion fault zone are identified; the strikes of different groups of faults and the combination pattern diagrams of multiple groups of faults are drawn according to the slices along the standard axis to achieve geometric feature analysis; the torsional characteristics and strike-slip orientations of different groups of faults are identified according to the equal-time slices to achieve kinematic feature analysis.

[0025] In step 5, the CS and anti-CS structures of the combined styles of faults of different groups in the compression-torsion fault zone are identified as the iconic features for identifying the slip orientation and faults of different structural attributes in the compression-torsion fault zone.

[0026] In step 5, faults with strike angle differences of less than 5° are regarded as the same group of faults, and their left- or right-slip characteristics are marked according to equal time slices.

[0027] In step 6, referring to modern compression-torsion deformation theory and simple shear model, the main shear slip zone and P symmetric shear orientation are calibrated according to the SC fabric; the Riedel R shear orientation is calibrated according to the anti-SC fabric; the R' shear fault orientation is calibrated by the fault that intersects the main shear slip zone at the maximum angle and strikes in the opposite direction; based on the above calibration results, an approximate finite strain ellipse is drawn for compression-torsion structural attribute analysis.

[0028] In step 7, the seismic profile reflection characteristics are combined to identify the structural properties of different fault systems; the major and minor axes of the approximate finite strain ellipse are drawn to indicate the orientations of the maximum compression and maximum extension characteristics; the azimuth angle ψ between the strike of different fault systems and the major axis of the approximate finite strain ellipse is calculated, and the compression-torsion or tension-torsion structural properties of different fault systems are qualitatively identified using the quantitative ψ value.

[0029] In step 7, ψ is between 0° and 90°. As ψ increases, the compression and twisting degree of the corresponding group of faults gradually weakens, while the tension and twisting degree gradually increases.

[0030] In step 7, different groups of faults and their ψ are numbered in order to form a statistical analysis table of the fault trends and ψ of different groups of faults in the compression-torsion fault zone, and the structural attributes of strong compression-torsion, compression-torsion, tension and strong tension-torsion are further identified based on ψ.

[0031] In step 7, the seismic reflection profile characteristics of the target layer and field geological surveys are combined to further support the identification results of different groups of faults to ensure accurate identification of the structural attributes of different groups of faults in the compression-torsion fault zone.

[0032] The method for identifying the structural properties of different groups of faults in a compression-torsion fault zone in the present invention is suitable for the field of applied science and is generally applicable to three-dimensional seismic acquisition areas in compression-torsion oil and gas basins. It can identify the structural properties and distribution characteristics of different groups of faults formed in the same period in a complex compression-torsion fault zone, and serve the evaluation of fluid mineral resources.

[0033] Compared with the existing technology, the method of the present invention has the following advantages: the method is more in line with the theoretical basis of modern compression-torsion structural deformation, is not limited to identifying the structural properties of the fault mainly based on the vertical geometry and kinematic characteristics of the rock layers on both sides of the fault, strengthens the plane strain analysis technology and the systematic identification of the structural properties of multiple fault systems, and solves the problems of multi-solution and inaccuracy of previous identification methods.

[0034] The method of the present invention has been verified in the Fudong area, Cainan area, Mosuowan and Wuerhe area of ​​the Junggar Basin, and the qualitative conclusions formed have been further confirmed by field surveys and drilling coring data. The approximate finite strain ellipse formed by the method of the present invention is a large-scale approximation based on the regional compression-torsion structural deformation characteristics. Although the accuracy is limited, multiple embodiments have confirmed that it does not affect the implementation effect and identification conclusion of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a specific embodiment of the method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone of the present invention;

[0036] Figure 2 It is a cross-sectional diagram of the development characteristics of the compression-torsion faults in the Luliang area and the fine interpretation and tracking of the coal seams of the Badaowan Formation of the Lower Jurassic in a specific embodiment of the present invention;

[0037] Figure 3 It is an isochronous slice diagram of the post-stack 3D seismic around the coal seam of the Badaowan Formation of the Lower Jurassic in the Luliang area in a specific embodiment of the present invention;

[0038] Figure 4 It is a combined pattern diagram of different groups of faults in the compression-torsion fault zone of the Badaowan Formation coal seam of the Lower Jurassic in Luliang area in a specific embodiment of the present invention;

[0039] Figure 5 This is an approximate strain characteristic diagram of the coal seams of the Badaowan Formation of the Lower Jurassic in the Luliang area in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0042] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0043] The method for identifying the structural properties of different groups of faults in a compression-torsion fault zone of the present invention comprises the following steps:

[0044] In step 1, the standard reflection axis interpretation of the target layer in the 3D seismic acquisition area is carried out. The superimposed 3D seismic processing results data that meet industry standards are selected to complete the tracking and interpretation of the standard reflection axis of the target layer in the seismic interpretation system. The standard reflection axis is required to have medium-strong and medium-strong continuity to facilitate human-computer interactive tracking description, and the interpretation grid is not less than 5×5; encryption processing is completed in the 3D seismic data interpretation system.

[0045] Preferably, a landmark seismic interpretation system may be used.

[0046] In step 2, coherence volume processing of post-stack 3D seismic data for the target layer is carried out. The coherence volume processing of the corresponding time window of the target layer is completed in the 3D seismic interpretation system; the coherence volume processing effect is tested on the profile and isochronous slice, and the fault is required to be identifiable.

[0047] Preferably, the structure cube processing module of the landmark seismic interpretation system can be used.

[0048] In step 3, extract the coherent slices of the target horizon along the standard reflection axis. The relevant slice extraction of the standard reflection axis is completed in the 3D seismic interpretation system, requiring the extraction time window to be within 10ms above and below the standard reflection axis, and the fault to be clearly visible.

[0049] In step 4, the 3D seismic volume is scanned by equal time slices. In the 3D seismic interpretation system, equal time slices are performed on the stacked post-processed 3D seismic data volume around the standard reflection axis, and the standard reflection axis is placed on the horizontal slices to encrypt the interpretation results and analyze the twist and shear azimuth characteristics of the formation.

[0050] Preferably, equal time slice scanning is performed around the standard reflection axis at intervals of 2-5 ms to ensure that the strike-slip features of faults with different strike directions are fully identified and marked.

[0051] Preferably, multiple isochronous slices with clear stratum twisting characteristics, breakpoints, and shearing orientations are screened, and the corresponding time values ​​of the slices are marked to establish an isochronous slice library.

[0052] In step 5, the drawings completed in steps 3 and 4 are used as the data basis for the geometric, kinematic and dynamic analysis of the compression-torsion fault zone of the present invention, and the combination patterns and strike-slip orientations of different groups of faults in the target layer of the compression-torsion fault zone are identified. According to the slices along the standard axis, the strikes of different groups of faults and the combination pattern diagrams of multiple groups of faults are drawn to achieve geometric feature analysis. According to the equal time slices, the torsional characteristics and strike-slip orientations of different groups of faults are identified to achieve kinematic feature analysis.

[0053] Preferably, the "CS" and anti-"CS" structures of the combination styles of different groups of faults in the compression-torsion fault zone are highlighted as the iconic features for identifying the slip orientation and faults of different structural attributes in the compression-torsion fault zone.

[0054] Preferably, faults with fault strike azimuth angle differences of less than 5° are regarded as the same group of faults, and the left- or right-slip characteristics are indicated according to equal time slices.

[0055] In step 6, draw an approximate finite strain characteristic map of the target horizon. Referring to modern compression-torsion deformation theory and simple shear mode, the main shear slip zone (PDZ) and P symmetric shear orientation are calibrated according to the "SC" fabric; the Riedel R shear orientation is calibrated according to the reverse "SC" fabric; the R' shear fault orientation is calibrated by the reverse strike-slip fault that intersects the main shear slip zone (PDZ) at the maximum angle; based on the above calibration results, draw an approximate finite strain ellipse for compression-torsion structural attribute analysis.

[0056] In step 7, the seismic profile reflection characteristics are combined to identify the structural properties of different fault systems. The major and minor axes of the approximate finite strain ellipse are drawn to indicate the orientations of the maximum compression and maximum extension characteristics; the azimuth angle ψ between the strike of different fault systems and the major axis of the approximate finite strain ellipse is calculated, and the compression-torsion or tension-torsion structural properties of different fault systems are qualitatively identified using the quantitative ψ value.

[0057] Preferably, ψ is between 0° and 90°. As ψ increases, the compression and twisting degree of the corresponding group of faults gradually weakens, and the tension and twisting degree gradually increases.

[0058] Preferably, different groups of faults and their ψ are numbered in order to form a statistical analysis table of the fault trends and ψ of different groups of faults in the compression-torsion fault zone, and the structural properties of strong compression-torsion, compression-torsion, tension and strong tension-torsion are further identified based on ψ.

[0059] Preferably, the seismic reflection profile characteristics of the target strata are combined to further support the identification results of different groups of faults, so as to ensure the accurate identification of the structural attributes of different groups of faults in the compression-torsion fault zone.

[0060] The method for identifying the structural properties of different groups of faults in a compression-torsion fault zone of the present invention is suitable for the field of applied science and is generally applicable to three-dimensional seismic acquisition areas of compression-torsion oil and gas basins. It mainly solves the current problems of multi-solution and inaccuracy in identifying the structural properties of high-angle strike-slip faults based on the vertical fault throw of seismic profiles, and realizes the scientific identification of the structural properties of different groups of faults corresponding to target layers in complex compression-torsion fault zones, thereby serving the evaluation of the activity characteristics of fluid mineral resources along the compression-torsion fault zone.

[0061] The following are several specific embodiments of the present invention.

[0062] Embodiment 1:

[0063] In a specific embodiment 1 of the present invention, Figure 1 As shown, Figure 1 This is a flow chart of a method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone in the Luliang area of ​​the Junggar Basin of the present invention. It includes the following steps:

[0064] In step 101, the human-computer interactive tracking interpretation of the standard reflection axis corresponding to the Lower Jurassic coal seam in a certain 3D seismic acquisition area in Luliang area is completed in the landmark seismic interpretation system, such as Figure 2 As shown, Figure 2 The profile diagram is a detailed interpretation and tracking diagram of the development characteristics of the compression-torsion faults in the Luliang area and the coal seams of the Lower Jurassic Badaowan Formation. The seismic standard reflection axis has medium-strong amplitude and medium-strong continuous reflection characteristics, and the human-computer interactive interpretation grid is 5×5; the encryption processing and interpretation of the standard reflection axis is completed in the three-dimensional seismic data interpretation system to form an encrypted interpretation file. The process enters step 102.

[0065] In step 102, the structurecube processing module of the landmark seismic interpretation system is used to perform coherent volume processing on the post-stack 3D seismic data of the Lower Jurassic Badaowan Formation. The coherent volume processing effect is checked using longitudinal and transverse sections and isochronous slices, and the faults are intuitively identifiable. The process enters step 103.

[0066] In step 103, the coherent slices along the coal seam of the Badaowan Formation of the Lower Jurassic are extracted, and the extraction time window is 20ms, which is placed within 10ms above and below the interpreted standard reflection axis; the slices along the layer can identify four groups of faults with different strikes, and the faults are clear and describable, which can be used for subsequent fault combination pattern analysis. The process enters step 104.

[0067] In step 104, an equal time slice scan is performed around the post-stack processed 3D seismic data volume corresponding to the coal seam of the Badaowan Formation of the Lower Jurassic in the 3D seismic interpretation system, and the standard reflection axis encryption interpretation results are placed on the horizontal slices, such as Figure 3 As shown, Figure 3This is a specific embodiment of the present invention. The isochronous slice diagram of the post-stack 3D seismic around the coal seams of the Lower Jurassic Badaowan Formation in Luliang area; according to the difference in the twist and shear orientation of the strata, the coal seams of the Lower Jurassic Badaowan Formation in Luliang area have 3 groups of left-hand strike-slip faults and 1 group of right-hand strike-slip faults; the isochronous slices with clear twist and shear orientation characteristics are selected, the seismic reflection time corresponding to the slices is marked, and the isochronous slice library corresponding to the coal seams of the Lower Jurassic in a certain 3D seismic acquisition area in Luliang area is established. The process enters step 105.

[0068] In step 105, four groups of faults in the compression-slip fault zone are drawn based on the coherent slices along the layer, and the plane combination analysis of the four groups of faults is carried out; three groups of left-hand strike-slip faults and one group of right-hand strike-slip faults are identified by combining the equal-time horizontal slice library; the geometric and kinematic analysis diagram of the compression-slip fault zone of the Lower Jurassic in a certain 3D seismic acquisition area in Luliang area is formed, as shown in FIG. Figure 4 As shown, Figure 4 This is a combined pattern diagram of different groups of faults in the compression-torsion fault zone of the Badaowan Formation coal seam in the Lower Jurassic in Luliang area according to a specific embodiment of the present invention. The process enters step 105.

[0069] In step 106, referring to modern compression-torsion deformation theory and simple shear mode, the main shear slip zone (PDZ) and P symmetric shear orientation are calibrated according to the "SC" fabric, with the PDZ trending at NW301° and the P symmetric shear fault trending at NW322°; the Riedel R shear orientation is calibrated according to the anti-"SC" fabric, with the R shear fault trending at NE70°; the R' shear fault orientation is calibrated by the fault that intersects the main shear slip zone (PDZ) at the maximum angle and strikes in the opposite direction, with the R' reverse shear fault trending at NE25°; based on the above calibration results, an approximate finite strain ellipse is drawn, as shown in FIG. Figure 5 As shown, Figure 5 This is an approximate strain characteristic diagram of the coal seam of the Badaowan Formation of the Lower Jurassic in Luliang area according to a specific embodiment of the present invention. The process enters step 107.

[0070] In step 107, the major and minor axes of the approximate finite strain ellipse are drawn, and the characteristic orientations of maximum compression and maximum extension are marked; the angle ψ between the orientation of the faults of different groups and the major axis of the approximate finite strain ellipse is calculated; the faults of different groups and their ψ are numbered in sequence to form a statistical analysis table of the orientation of the faults of different groups in the compression-twist fault zone and their ψ, as shown in Table 1, the P symmetric shear fault corresponds to ψ1=5°, the main shear slip zone (PDZ) corresponds to ψ2=26°, the Riedel R shear fault corresponds to ψ3=70°, and the R' reverse shear fault corresponds to ψ4=58°. It is required to divide the ψ value range into 4 parts at intervals of 22.5°, wherein the intervals of 0°-22.5°, 22.5°-45°, 45°-67.5° and 67.5°-90° correspond to the structural attributes of strong compression-twist, compression-twist, tension-twist and strong tension-twist in turn. According to the ψ values ​​of the four groups of faults in the target strata in Luliang area, the structural attributes of the P symmetric shear fault with strong compression and torsion, the main shear slip zone (PDZ) with compression and torsion, the Riedel R shear fault with strong tension and torsion, and the R' reverse shear fault with tension and torsion were identified. Combined with the seismic reflection profile characteristics of the target strata, the identification results of the faults of different groups were further confirmed, and it was clear that the structural attributes of the four groups of faults in the compression-twist fault zone in Luliang area were accurately identified.

[0071] Table 1 Identification of structural attributes of four groups of faults in the Badaowan Formation transverse fault zone in Luliang area

[0072] Fault system serial number Direction ψ angle Construction properties P 1 NW322° 5° Strong pressure twist PDZ 2 NW301° 26° Compression R 3 NE77° 70° Strong tension and twist R' 4 NE25° 58° Zhang Niu

[0073] Embodiment 2:

[0074] In a specific embodiment 2 of the present invention, as Figure 1 As shown, Figure 1 This is a flow chart of the method for identifying the structural attributes of different groups of faults in the compression-torsion fault zone of the present invention. It includes the following steps:

[0075] In step 101, the human-computer interactive tracking interpretation of the standard reflection axis corresponding to the Xishanyao Formation of the Middle Jurassic in a certain 3D seismic acquisition area in Cainan area is completed in the landmark seismic interpretation system. The seismic standard reflection axis has medium-strong amplitude and medium-strong continuous reflection characteristics, and the human-computer interactive interpretation grid is 5×5; the encryption processing interpretation of the standard reflection axis is completed in the 3D seismic data interpretation system to form an encrypted interpretation file. The process enters step 102.

[0076] In step 102, the structurecube processing module of the landmark seismic interpretation system is used to perform coherent volume processing on the post-stack 3D seismic data for the Xishanyao Formation of the Middle Jurassic. The coherent volume processing effect is checked using longitudinal and transverse sections and isochronous slices, and the faults are intuitively identifiable. The process proceeds to step 103.

[0077] In step 103, the coherent slices along the layer of the Xishanyao Formation of the Middle Jurassic are extracted, and the extraction time window is 30ms, which is placed within 15ms above and below the interpreted standard reflection axis; four groups of faults with different strikes can be identified along the layer slices, and the faults are clear and describable, which can be used for subsequent fault combination pattern analysis. The process enters step 104.

[0078] In step 104, an equal-time slice scan is performed around the corresponding post-stack processed 3D seismic data volume of the Middle Jurassic Xishanyao Formation in the 3D seismic interpretation system, and the standard reflection axis is placed on the horizontal slice to encrypt the interpretation results; according to the difference in the twist and shear orientation of the strata, 3 groups of left-slip faults and 1 group of right-slip faults are developed in the Middle Jurassic Xishanyao Formation in Cainan area; the equal-time slices with clear twist and shear orientation characteristics are selected, the corresponding seismic reflection time of the slices is marked, and the equal-time slice library corresponding to the Middle Jurassic Xishanyao Formation in a certain 3D seismic acquisition area in Cainan area is established. The process enters step 105.

[0079] In step 105, four groups of faults in the transpressional fault zone are drawn based on the coherent slices along the layer, and the plane combination analysis of the four groups of faults is carried out; three groups of left-hand strike-slip faults and one group of right-hand strike-slip faults are identified in combination with the equal-time horizontal slice library; and the geometric and kinematic analysis diagram of the transpressional fault zone of the Xishanyao Formation in the Middle Jurassic in a certain 3D seismic acquisition area in the Cainan area is formed. The process enters step 105.

[0080] In step 106, referring to modern compression-torsion deformation theory and simple shear mode, the main shear slip zone (PDZ), Riedel R shear and P syn-shear orientations are calibrated according to the anti-SC fabric, with the PDZ strike of NEE65°, the R shear fault strike of NE44° and the P syn-shear fault strike of NWW277°; the reverse strike-slip fault that intersects the main shear slip zone (PDZ) at the maximum angle is calibrated as the R' shear fault orientation, and the R' reverse shear fault strikes NNE12°; based on the above calibration results, an approximate finite strain ellipse is drawn. The process enters step 107.

[0081] In step 107, the major and minor axes of the approximate finite strain ellipse are drawn, and the characteristic orientations of maximum compression and maximum extension are marked; the angle ψ between the orientation of the faults of different groups and the major axis of the approximate finite strain ellipse is calculated; the faults of different groups and their ψ are numbered in sequence to form a statistical analysis table of the orientation of the faults of different groups in the compression-twist fault zone and their ψ, as shown in Table 2, the P symmetric shear fault corresponds to ψ1 = 9°, the main shear slip zone (PDZ) corresponds to ψ2 = 41°, the Riedel R shear fault corresponds to ψ3 = 62°, and the R' reverse shear fault corresponds to ψ4 = 86°. It is required to divide the ψ value range into 4 parts at intervals of 22.5°, wherein the intervals of 0°-22.5°, 22.5°-45°, 45°-67.5° and 67.5°-90° correspond to the structural attributes of strong compression-twist, compression-twist, tension-twist and strong tension-twist in turn. According to the ψ values ​​of the four groups of faults in the target strata in Cainan area, the structural attributes of the P symmetric shear fault with strong compression and torsion, the main shear slip zone (PDZ) with compression and torsion, the Riedel R shear fault with strong tension and torsion, and the R' reverse shear fault with tension and torsion were identified. Combined with the seismic reflection profile characteristics of the target strata, the identification results of faults in different groups were further confirmed, and it was confirmed that the structural attributes of the four groups of faults in the compression and torsion fault zone of the Middle Jurassic Xishanyao Formation in Cainan area were accurately identified.

[0082] Table 2 Identification of structural attributes of four groups of faults in the compression-torsion fault zone of the Xishanyao Formation in Cainan area

[0083] Fault system serial number Direction ψ angle Construction properties P 1 NWW277° 9° Strong pressure twist PDZ 2 NEE65° 41° Compression R 3 NE44° 62° Zhang Niu R' 4 NNE12° 86° Strong tension and twist

[0084] Embodiment 3:

[0085] In a specific embodiment 3 of the present invention, as Figure 1 As shown, Figure 1 This is a flow chart of the method for identifying the structural attributes of different groups of faults in the compression-torsion fault zone of the present invention. It includes the following steps:

[0086] In step 101, the human-computer interactive tracking interpretation of the standard reflection axis of the Cretaceous Tugulu Group in a certain 3D seismic acquisition area around the Wuerhe Asphalt Village in the northwest edge of the Quasi-northwest is completed in the landmark seismic interpretation system. The seismic standard reflection axis has medium-strong amplitude and medium-strong continuous reflection characteristics, and the human-computer interactive interpretation grid is 5×5; the encryption processing interpretation of the standard reflection axis is completed in the 3D seismic data interpretation system to form an encrypted interpretation file. The process enters step 102.

[0087] In step 102, the structurecube processing module of the landmark seismic interpretation system is used to perform coherent volume processing on the post-stack 3D seismic data for the Cretaceous Tugulu Group. The coherent volume processing effect is checked using longitudinal and transverse sections and isochronous slices, and the faults are visually identifiable. The process proceeds to step 103.

[0088] In step 103, the Cretaceous Tugulu Group coherent slices along the layer are extracted, and the extraction time window is 16ms, which is placed within 8ms above and below the interpreted standard reflection axis; four groups of faults with different strikes can be identified along the layer slices, and the faults are clear and describable, which can be used for subsequent fault combination pattern analysis. The process enters step 104.

[0089] In step 104, an equal-time slice scan is performed around the corresponding post-stack processed 3D seismic data volume of the Cretaceous Tugulu Group in the 3D seismic interpretation system, and the standard reflection axis is placed on the horizontal slice to encrypt the interpretation results; according to the difference in the twist and shear orientation of the strata, the Cretaceous Tugulu Group around the Wuerhe Asphalt Village has developed 3 groups of left-slip faults and 1 group of right-slip faults; select the equal-time slices with clear twist and shear orientation characteristics, mark the seismic reflection time corresponding to the slices, and establish the equal-time slice library corresponding to the Cretaceous Tugulu Group. The process enters step 105.

[0090] In step 105, four groups of faults in the compression-torsion fault zone are drawn based on the coherent slices along the layer, and the plane combination analysis of the four groups of faults is carried out; three groups of left-hand strike-slip faults and one group of right-hand strike-slip faults are identified in combination with the equal-time horizontal slice library; and the geometric and kinematic analysis diagram of the compression-torsion fault zone of the Cretaceous Tugulu Group is formed. The process enters step 105.

[0091] In step 106, referring to modern compression-torsion deformation theory and simple shear mode, the main shear slip zone (PDZ) and P syn-direction shear orientation are calibrated according to the "SC" structure, with the PDZ trending at NW283° and the P syn-direction shear fault trending at NW327°; the Riedel R shear orientation is calibrated according to the anti-"SC" structure, with the R shear fault trending at NE72°; the R' shear fault orientation is calibrated by the reverse strike-slip fault that intersects the main shear slip zone (PDZ) at the maximum angle, with the R' reverse shear fault trending at NE30°; based on the above calibration results, an approximate finite strain ellipse is drawn. The process enters step 107.

[0092] In step 107, the major and minor axes of the approximate finite strain ellipse are drawn, and the characteristic orientations of maximum compression and maximum extension are marked; the angle ψ between the strike of different faults and the major axis of the approximate finite strain ellipse is calculated; the faults of different groups and their ψ are numbered in sequence to form a statistical analysis table of the strike of different faults in the compression-twist fault zone and their ψ, as shown in Table 3. The P symmetric shear fault corresponds to ψ1=9°, the main shear slip zone (PDZ) corresponds to ψ2=35°, the Riedel R shear fault corresponds to ψ3=66°, and the R' reverse shear fault corresponds to ψ4=72°. It is required to divide the ψ value range into 4 parts at intervals of 22.5°, wherein the intervals of 0°-22.5°, 22.5°-45°, 45°-67.5° and 67.5°-90° correspond to the structural attributes of strong compression-twist, compression-twist, tension-twist and strong tension-twist in turn. According to the ψ values ​​of the four groups of faults in the target strata in Cainan area, the P symmetric shear faults have strong compression and torsion, the main shear slip zone (PDZ) has compression and torsion, the Riddle R shear faults have strong tension and torsion, and the R' reverse shear faults have tension and torsion. The field survey of the Wuerhe Asphalt Village has confirmed that the structural attributes of the faults of different groups are accurately identified, and the asphalt veins are mainly distributed along the NE-trending tension and torsion faults and the NEE-trending strong tension and torsion faults.

[0093] Table 3 Identification of structural attributes of four groups of faults in the Tugulu Group transverse fault zone in the northwestern margin of the Quaternary

[0094] Fault system serial number Direction ψ angle Construction properties P 1 NW327° 9° Strong pressure twist PDZ 2 NWW283° 35° Compression R 3 NE72° 66° Zhang Niu R' 4 NNE30° 72° Strong tension and twist

[0095] The method for identifying the structural properties of different groups of faults in a compression-torsion fault zone of the present invention has been applied to multiple structural units, solving the problem of identifying the structural properties of multiple groups of faults in a complex compression-torsion structural zone, forming a structural geological basis for evaluating the activity of fluid minerals along faults with different properties, and effectively guiding oil and gas exploration practices. The method of the present invention is generally applicable to three-dimensional seismic acquisition areas of compression-torsion oil and gas basins, and is mainly used for the analysis of complex compression-torsion fault zones in areas of medium and strong compression-torsion structural deformation. Compared with the prior art, the method of the present invention is more in line with the theoretical basis of modern compression-torsion structural deformation, and is not limited to identifying the structural properties of the fault mainly based on the vertical geometry and kinematic characteristics of the rock layers on both sides of the fault. It strengthens the plane strain analysis technology and the systematic identification of the structural properties of multiple groups of faults, and solves the problems of multiple solutions and inaccuracy of previous identification methods. The implementation effect of the present invention is related to the quality of three-dimensional seismic data. The three-dimensional seismic data currently collected in oil-bearing basins can ensure the smooth implementation of the method of the present invention.

[0096] Finally, it should be noted that the above is only 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 aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0097] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone, characterized in that: The methods for identifying the fault structural attributes of different groups of the compression-torsion fault zone include: Step 1: Conduct standard reflection axis interpretation of target horizons in the 3D seismic acquisition area; Step 2: Carry out coherent volume processing of 3D seismic post-stack data for the target layer; Step 3, extracting the coherent slices of the target layer along the standard reflection axis; Step 4, performing equal-time slice scanning of a three-dimensional seismic volume; Step 5, identifying the fault combination patterns and strike-slip orientations of different groups of target layers in the compression-slip fault zone; Step 6, drawing an approximate finite strain characteristic map of the target layer; Step 7, semi-quantitatively identify the structural attributes of different fault systems; In step 5, the maps completed in steps 3 and 4 are used as the data basis for the geometric, kinematic and dynamic analysis of the compression-torsion fault zone, and the combination patterns and strike-slip orientations of different groups of faults in the target layer of the compression-torsion fault zone are identified; the strikes of different groups of faults and the combination pattern diagrams of multiple groups of faults are drawn according to the slices along the standard axis to achieve the geometric feature analysis; the torsional characteristics and strike-slip orientations of different groups of faults are identified according to the equal time slices to achieve the kinematic feature analysis; In step 5, the SC and anti-SC structures of the combined styles of different groups of faults in the compression-transduction fault zone are highlighted as the iconic features for identifying the slip orientation and faults of different structural attributes in the compression-transduction fault zone; In step 6, referring to modern compression-torsion deformation theory and simple shear model, the main shear slip zone and P symmetric shear orientation are calibrated according to the SC fabric; the Riedel R shear orientation is calibrated according to the anti-SC fabric; the R' shear fault orientation is calibrated by the fault that intersects the main shear slip zone at the maximum angle and strikes in the opposite direction; based on the above calibration results, an approximate finite strain ellipse is drawn for compression-torsion structural attribute analysis.

2. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 1 is characterized in that: In step 1, the superimposed 3D seismic processing results data is used to complete the standard reflection axis tracking interpretation of the target layer in the seismic interpretation system. The standard reflection axis is required to have medium-strong amplitude and medium-strong continuity to facilitate human-computer interactive tracking description, and the interpretation grid is not less than 5×5. The encryption process is completed in the 3D seismic data interpretation system.

3. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 1 is characterized in that: In step 2, the coherence volume processing of the target layer corresponding to the time window is completed in the 3D seismic interpretation system; the coherence volume processing effect is tested on the profile and isochronous slice, and the fault is required to be identifiable.

4. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 1 is characterized in that: In step 3, relevant slice extraction of the standard reflection axis is completed in the 3D seismic interpretation system, requiring that the extraction time window is within 10 ms above and below the standard reflection axis and the fault is clearly visible.

5. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 1 is characterized in that: In step 4, equal time slicing is performed on the stacked post-processed 3D seismic data volume around the standard reflection axis in the 3D seismic interpretation system, and the standard reflection axis is projected on the horizontal slices to encrypt the interpretation results and analyze the formation twist and shear azimuth characteristics.

6. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 5 is characterized in that: In step 4, equal time slice scanning is performed around the standard reflection axis at intervals of 2-5 ms to ensure that the strike-slip features of faults with different strike directions are fully identified and marked.

7. The method for identifying the structural attributes of different groups of faults in a compression-torsion fault zone according to claim 5 is characterized in that: In step 4, multiple equal-time slices with clear stratum twisting characteristics, breakpoints, and shearing orientations are selected, and the corresponding time values ​​of the slices are marked to establish an equal-time slice library.

8. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 7 is characterized in that: In step 5, faults with strike angle differences of less than 5° are regarded as the same group of faults, and their left- or right-slip characteristics are marked according to equal time slices.

9. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 1, characterized in that: In step 7, the structural attributes of faults of different groups are identified by combining the reflection characteristics of the seismic profile; the major axis and minor axis of the approximate finite strain ellipse are drawn, and the orientations of the maximum compression and maximum extension characteristics are marked; The angle ψ between the strike of different fault systems and the major axis of the approximate finite strain ellipse is calculated, and the compression-torsion or tension-torsion structural attributes of different fault systems are qualitatively identified using quantitative ψ values.

10. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 9, characterized in that: In step 7, ψ is between 0° and 90°. As ψ increases, the compression and twisting degree of the corresponding group of faults gradually weakens, while the tension and twisting degree gradually increases.

11. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 9, characterized in that: In step 7, different groups of faults and their ψ are numbered in order to form a statistical analysis table of the fault trends and ψ of different groups of faults in the compression-torsion fault zone, and the structural attributes of strong compression-torsion, compression-torsion, tension and strong tension-torsion are further identified based on ψ.

12. The method for identifying structural attributes of different groups of faults in a compression-torsion fault zone according to claim 9, characterized in that: In step 7, the seismic reflection profile characteristics of the target layer and field geological surveys are combined to further support the identification results of different groups of faults to ensure accurate identification of the structural attributes of different groups of faults in the compression-torsion fault zone.

Images