Method for balancing and recovering ancient landform based on three-dimensional structure

Abstract

The invention discloses a method for balancing and recovering an ancient landform based on a three-dimensional structure, which belongs to the technical field of petroleum geophysical exploration and is characterized by comprising the following steps of: a, establishing a three-dimensional structure model through three-dimensional seismic interpretation; b, determining the deformation period and evolution of the regional structure; c, determining a deformation kinematics mechanism of the research target area; d, according to the determined deformation kinematics mechanism, performing three-dimensional structure balance recovery on the structure in the area; and e, obtaining the ancient landform of the target strata series. According to the method, all the faults are subjected to structure recovery processing in the recovery process, recovery distortion caused by superposition of upper and lower wall stratums of the faults is effectively removed, and the ancient landform morphology can be accurately recovered.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum geophysical prospecting, and in particular to a method for restoring ancient landforms based on three-dimensional structural balance. Background Art

[0002] Since paleo-geomorphology is affected by the combined effects of tectonic deformation, differential compaction, sedimentary filling, and weathering and erosion, most of the current paleo-geomorphology restoration methods are still qualitative or semi-quantitative, mainly in the following aspects: 1. The residual thickness method and the impression method based on the interpretation of the significant marker layer and target layer of the seismic profile (Bai Wenhua et al., 2002; Liu Xiaoping et al., 2007; Hong Yugang et al., 2007; Li Zhenhong et al., 2010; Hu Xiuquan et al., 2014). Both methods use the residual thickness of the target layer and the thickness of the overlying layer to characterize the karst paleo-geomorphology based on the determination of a marker layer underlying and overlying the target layer as the isochronous datum. However, they are mainly limited to the relatively harsh conditions for the selection of the isochronous datum: that is, the distribution within a large area; the influence of tectonic activities between the datum and the denudation surface of the target layer is small; the marker layer is easy to identify in drilling, logging and seismic profiles.

[0003] 2. Qualitative karst paleo-geomorphology restoration method based on sequence stratigraphy (Song Guoqi et al., 2000; Zhao Junxing et al., 2003; Shen Zhaojun, 2012). That is, on the basis of analyzing and comparing the sequence stratigraphic sections of single wells in the region, a sequence framework is established and the relative thickness between the two regional isochronous surfaces closest to the target layer is selected to characterize the paleo-karst landform. However, the selection of the two regional isochronous surfaces has a great influence on the paleo-geomorphological characteristics restored by this method.

[0004] 3. Comprehensively utilize core observation, logging, seismic data attribute enhancement and rock physical property analysis to characterize the paleokarst system (Dai Jinyou et al., 2005; Jiang Hua et al., 2011; Dou et al., 2011; Shen Zhaojun, 2012). This method mainly establishes a semi-quantitative model for identifying karst paleo-geomorphological features based on seismic attribute enhancement. In the identification process, drilling logging and rock physical property data are used to continuously constrain and verify the identification model, so as to relatively accurately characterize the paleokarst landform.

[0005] A Chinese patent document with publication number CN116299669A and publication date June 23, 2023 discloses a method for restoring the micro-paleomorphic evolution process of a wellless delta sedimentary area, characterized in that it includes the following steps: Setting a plan range that completely covers the deltaic deposition target area where drilling is planned; Prepare the target layer thickness map for the planned drilling within the plane range; Determine the main source direction of the target layer during the deposition period of the expected drilling; In the 3D seismic work area, take the center of the plane range as the origin, draw a straight line along the main source direction, and extract the seismic sections with different angles to the main source direction; In the extracted seismic profile, starting from the bottom of the target layer, from bottom to top, the seismic reflection characteristics unique to deltaic sedimentation are observed to identify and track the progradational complex lobe; For each progradational composite lobe, a series of seismic sections are extracted using seismic section grid density, parallel to the provenance direction and perpendicular to the provenance direction. Track the top and bottom interfaces of the pre-accumulated composite lobes; According to the obtained top and bottom interfaces of the pre-depositional composite lobe, a thickness map of the pre-depositional composite lobe is compiled; Based on the thickness map of the target layer section to be drilled, the thickness map of the progradational composite lobe is superimposed from bottom to top to compile the micro-paleomorphology map after the deposition of the progradational composite lobe; The micro-paleomorphological maps are arranged in order to restore the micro-paleomorphological evolution process of the wellless delta deposition target area.

[0006] The patent document discloses a method for restoring the micro-paleomorphological evolution process in a wellless delta sedimentary area, which can avoid dependence on drilling data, improve the thickness accuracy of the micro-paleomorphological evolution process, and achieve the purpose of rapid restoration of the micro-paleomorphological evolution process in an undrilled area. However, it cannot remove the restoration distortion caused by the superposition of the stratigraphic layers on the upper and lower walls of the fault, which affects the accurate restoration of the paleomorphological morphology. Summary of the invention

[0007] In order to overcome the defects of the above-mentioned prior art, the present invention provides a method for restoring ancient landforms based on three-dimensional structural balance. During the restoration process, the present invention performs structural restoration processing on all faults, effectively removes the restoration distortion caused by the superposition of strata on the upper and lower plates of the faults, and can accurately restore the ancient landform morphology.

[0008] The present invention is achieved through the following technical solutions: A method for restoring ancient landforms based on three-dimensional structural balance, characterized by comprising the following steps: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

[0009] In step a, the three-dimensional seismic interpretation refers to the interpretation of the geological layers involved in the deformation and all faults.

[0010] The step b specifically refers to determining the time and phase of structural deformation of the target stratum by combining the regional tectonic background, structural evolution, and growth strata and unconformity analysis in seismic data.

[0011] The step c specifically refers to identifying the characteristics of regional deformation through quantitative geometric analysis of different structures in the region and establishing a kinematic model of all fault-related folds in the study area.

[0012] In the step d, the three-dimensional structural balance restoration includes removing faults and wrinkles.

[0013] The fault removal specifically refers to moving the strata above the fault in the opposite direction through a kinematic mechanism, removing the fault throw of the existing fault, connecting the corresponding strata above and below the fault, and removing the vertical structural superposition.

[0014] The de-folding specifically refers to removing the fold morphology of the overlying strata to remove the structural deformation after the overlying strata are deposited.

[0015] The step e specifically refers to removing all structural deformations after the top of the target stratum is deposited through three-dimensional equilibrium restoration, and stripping all the strata above to obtain the paleo-geomorphology of the target stratum during its deposition period.

[0016] The growth stratum refers to the deformation process of the stratum under high sedimentation rate.

[0017] The unconformity refers to structural deformation at a low sedimentation rate.

[0018] The beneficial effects of the present invention are mainly manifested in the following aspects: 1. The present invention, a. establishes a three-dimensional structural model through three-dimensional seismic interpretation; b. determines the period and evolution of regional structural deformation; c. determines the deformation kinematic mechanism of the research target area; d. performs three-dimensional structural balance restoration of the structure in the area according to the determined deformation kinematic mechanism; e. obtains the paleo-geomorphology of the target stratum system. Compared with the prior art, all faults are subjected to structural restoration processing during the restoration process, effectively removing the restoration distortion caused by the superposition of the strata on the upper and lower plates of the faults, and can accurately restore the paleo-geomorphology.

[0019] 2. The present invention establishes a regional three-dimensional structural model through a detailed interpretation of three-dimensional seismic data, removes faults and folds on the structural model, removes the later fold and fault deformation effects, and restores the paleo-geomorphology before the deposition of the overlying strata, effectively overcoming the defects of the existing layer leveling technology and greatly improving the reliability of paleo-geomorphology restoration.

[0020] 3. The present invention, based on 3D seismic detailed interpretation and 3D structural modeling, establishes the accurate form of the present structure, lays a foundation for the accurate restoration of ancient landforms, and is suitable for structural evolution analysis and oil and gas accumulation evaluation.

[0021] 4. In the present invention, since all faults are subjected to structural restoration during the restoration process, the restoration distortion caused by the superposition of the strata between the upper and lower plates of the fault is effectively removed.

[0022] 5. The present invention selects fault parallel flow for de-folding operation according to regional structural deformation, which has greater advantages than the simple shearing and flattening method widely used nowadays.

[0023] 6. The present invention adopts three-dimensional fault removal and fold removal operations, thereby avoiding the distortion caused by restoring paleo-geomorphology by superimposing the reverse fault structure, effectively overcoming the defects of the prior art, and obtaining a more accurate paleo-geomorphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 It is a flowchart of the present invention; Figure 2 The three-dimensional seismic profile interpretation of the study area of ​​the present invention shows the structural deformation pattern of the Permian system; Figure 3 A three-dimensional structural model diagram of the three-dimensional seismic data of the present invention; Figure 4 It is a target layer pattern map after removing faults and folds in the three-dimensional structural balance restoration of the present invention; Figure 5 This is a schematic diagram of paleo-geomorphology restored based on three-dimensional structural balance according to the present invention. DETAILED DESCRIPTION

[0025] Example 1 See also Figure 1 , a method for restoring ancient landforms based on three-dimensional structural balance, comprising the following steps: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

[0026] This embodiment is the most basic implementation method, which includes: a. establishing a three-dimensional structural model through three-dimensional seismic interpretation; b. determining the period and evolution of regional structural deformation; c. determining the deformation kinematic mechanism of the target area; d. restoring the three-dimensional structural balance of the structure in the area according to the determined deformation kinematic mechanism; and e. obtaining the paleo-geomorphology of the target stratum system. Compared with the prior art, all faults are structurally restored during the restoration process, which effectively removes the restoration distortion caused by the superposition of the upper and lower plates of the fault, and can accurately restore the paleo-geomorphology.

[0027] Example 2 See also Figure 1 , a method for restoring ancient landforms based on three-dimensional structural balance, comprising the following steps: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

[0028] Preferably, in step a, the three-dimensional seismic interpretation refers to the interpretation of the geological layers involved in the deformation and all faults.

[0029] The step b specifically refers to determining the time and phase of structural deformation of the target stratum by combining the regional tectonic background, structural evolution, and growth strata and unconformity analysis in seismic data.

[0030] This embodiment is a preferred implementation method. By finely interpreting the three-dimensional seismic data, a regional three-dimensional structural model is established, and fault and fold removal operations are performed on the structural model to remove the later fold and fault deformation effects, and restore the paleo-geomorphology before the deposition of the overlying strata. This effectively overcomes the defects of the existing layer leveling technology and greatly improves the reliability of paleo-geomorphology restoration.

[0031] Example 3 See also Figure 1 , a method for restoring ancient landforms based on three-dimensional structural balance, comprising the following steps: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

[0032] In step a, the three-dimensional seismic interpretation refers to the interpretation of the geological layers involved in the deformation and all faults.

[0033] Further preferably, the step b specifically refers to determining the time and phase of tectonic deformation of the target stratum by combining the regional tectonic background, tectonic evolution, and growth strata and unconformity analysis in seismic data.

[0034] The step c specifically refers to identifying the characteristics of regional deformation through quantitative geometric analysis of different structures in the region and establishing a kinematic model of all fault-related folds in the study area.

[0035] This embodiment is another preferred implementation method. Based on the detailed interpretation of 3D seismic data and 3D structural modeling, the accurate form of the current structure is established, which lays a foundation for the accurate restoration of ancient landforms and is suitable for structural evolution analysis and oil and gas accumulation evaluation.

[0036] Example 4 See also Figure 1 , a method for restoring ancient landforms based on three-dimensional structural balance, comprising the following steps: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

[0037] In step a, the three-dimensional seismic interpretation refers to the interpretation of the geological layers involved in the deformation and all faults.

[0038] The step b specifically refers to determining the time and phase of structural deformation of the target stratum by combining the regional tectonic background, structural evolution, and growth strata and unconformity analysis in seismic data.

[0039] The step c specifically refers to identifying the characteristics of regional deformation through quantitative geometric analysis of different structures in the region and establishing a kinematic model of all fault-related folds in the study area.

[0040] In the step d, the three-dimensional structural balance restoration includes removing faults and wrinkles.

[0041] The fault removal specifically refers to moving the strata above the fault in the opposite direction through a kinematic mechanism, removing the fault throw of the existing fault, connecting the corresponding strata above and below the fault, and removing the vertical structural superposition.

[0042] The de-folding specifically refers to removing the fold morphology of the overlying strata to remove the structural deformation after the overlying strata are deposited.

[0043] This embodiment is another preferred implementation method. Since all faults are subjected to structural restoration during the restoration process, the restoration distortion caused by the superposition of the strata between the upper and lower plates of the fault is effectively removed.

[0044] Example 5 See also Figure 1 , a method for restoring ancient landforms based on three-dimensional structural balance, comprising the following steps: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

[0045] In step a, the three-dimensional seismic interpretation refers to the interpretation of the geological layers involved in the deformation and all faults.

[0046] The step b specifically refers to determining the time and phase of structural deformation of the target stratum by combining the regional tectonic background, structural evolution, and growth strata and unconformity analysis in seismic data.

[0047] The step c specifically refers to identifying the characteristics of regional deformation through quantitative geometric analysis of different structures in the region and establishing a kinematic model of all fault-related folds in the study area.

[0048] In the step d, the three-dimensional structural balance restoration includes removing faults and wrinkles.

[0049] The fault removal specifically refers to moving the strata above the fault in the opposite direction through a kinematic mechanism, removing the fault throw of the existing fault, connecting the corresponding strata above and below the fault, and removing the vertical structural superposition.

[0050] The de-folding specifically refers to removing the fold morphology of the overlying strata to remove the structural deformation after the overlying strata are deposited.

[0051] More preferably, the step e specifically refers to removing all structural deformations after the top of the target stratum system is deposited through three-dimensional equilibrium restoration, and stripping all the strata above to obtain the paleo-geomorphology of the target stratum deposition period.

[0052] This embodiment is another preferred implementation method. According to the regional structural deformation, the fault parallel flow is selected to perform the de-wrinkling operation, which has a greater advantage than the simple shearing and flattening method widely used nowadays.

[0053] Example 6 See also Figure 1-Figure 5 , a method for restoring ancient landforms based on three-dimensional structural balance, comprising the following steps: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

[0054] In step a, the three-dimensional seismic interpretation refers to the interpretation of the geological layers involved in the deformation and all faults.

[0055] The step b specifically refers to determining the time and phase of structural deformation of the target stratum by combining the regional tectonic background, structural evolution, and growth strata and unconformity analysis in seismic data.

[0056] The step c specifically refers to identifying the characteristics of regional deformation through quantitative geometric analysis of different structures in the region and establishing a kinematic model of all fault-related folds in the study area.

[0057] In the step d, the three-dimensional structural balance restoration includes removing faults and wrinkles.

[0058] The fault removal specifically refers to moving the strata above the fault in the opposite direction through a kinematic mechanism, removing the fault throw of the existing fault, connecting the corresponding strata above and below the fault, and removing the vertical structural superposition.

[0059] The de-folding specifically refers to removing the fold morphology of the overlying strata to remove the structural deformation after the overlying strata are deposited.

[0060] The step e specifically refers to removing all structural deformations after the top of the target stratum is deposited through three-dimensional equilibrium restoration, and stripping all the strata above to obtain the paleo-geomorphology of the target stratum during its deposition period.

[0061] The growth stratum refers to the deformation process of the stratum under high sedimentation rate.

[0062] The unconformity refers to structural deformation at a low sedimentation rate.

[0063] This embodiment is the best implementation method. Since it adopts three-dimensional fault removal and wrinkle removal operations, it avoids the distortion caused by restoring the ancient landform by superimposing the reverse fault structure, effectively overcomes the defects of the existing technology, and obtains a more accurate ancient landform morphology.

[0064] The principle of the present invention is as follows: Comprehensive 3D seismic interpretation, structural geometry analysis, 3D structural modeling and structural balance restoration, through the detailed interpretation of 3D seismic data to establish a regional 3D structural model, the structural evolution analysis and 3D structural balance restoration are organically combined, the structural model is de-faulted and de-folded, the later fold and fault deformation effects are removed, and the paleo-geomorphology before the deposition of the overlying strata is restored.

[0065] Due to the use of three-dimensional fault removal and fold removal operations, the distortion caused by restoring paleo-geomorphology by superimposing the reverse fault structure is effectively avoided, the defects of the existing technology are overcome, and a more accurate paleo-geomorphology can be obtained.

Claims

1. A method for restoring ancient landforms based on three-dimensional structural balance, characterized in that: The following steps are involved: a. Establish a 3D structural model through 3D seismic interpretation; b. Determine the period and evolution of regional tectonic deformation; c. Determine the kinematic mechanism of deformation in the target area; d. Perform three-dimensional structural balance restoration on the structures in the region based on the determined deformation kinematic mechanism; e. Obtain the paleo-geomorphology of the target stratum.

2. A method for restoring ancient landforms based on three-dimensional structural balance according to claim 1, characterized in that: In step a, the three-dimensional seismic interpretation refers to the interpretation of the geological layers involved in the deformation and all faults.

3. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 1, characterized in that: The step b specifically refers to determining the time and phase of structural deformation of the target stratum by combining the regional tectonic background, structural evolution, and growth strata and unconformity analysis in seismic data.

4. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 1, characterized in that: The step c specifically refers to identifying the characteristics of regional deformation through quantitative geometric analysis of different structures in the region and establishing a kinematic model of all fault-related folds in the study area.

5. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 1, characterized in that: In the step d, the three-dimensional structural balance restoration includes removing faults and wrinkles.

6. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 5, characterized in that: The fault removal specifically refers to moving the strata above the fault in the opposite direction through a kinematic mechanism, removing the fault throw of the existing fault, connecting the corresponding strata above and below the fault, and removing the vertical structural superposition.

7. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 5, characterized in that: The de-folding specifically refers to removing the fold morphology of the overlying strata to remove the structural deformation after the overlying strata are deposited.

8. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 1, characterized in that: The step e specifically refers to removing all structural deformations after the top of the target stratum is deposited through three-dimensional equilibrium restoration, and stripping all the strata above to obtain the paleo-geomorphology of the target stratum during its deposition period.

9. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 3, characterized in that: The growth stratum refers to the deformation process of the stratum under high sedimentation rate.

10. The method for restoring ancient landforms based on three-dimensional structural balance according to claim 3, characterized in that: The unconformity refers to structural deformation at a low sedimentation rate.

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