Method for recovering slip trajectory of dip-slip fault

Abstract

The present invention provides a method for restoring the slip trajectory of dip-slip faults, including: Step 1, obtaining the structural map of the bottom interface of the target interval, the structural map of the boundary fault plane, and their combined mosaic; Step 2, establishing a profile of the basic interpretation results along the survey line direction; Step 3, obtaining the true dip angle of the fault plane; Step 4, obtaining the spatial position and true length of the fault; Step 5, obtaining the vertical displacement and dip displacement of the fault breakpoint in space; Step 6, obtaining the strike displacement of the fault breakpoint along the fault plane; Step 7, constructing the fault slip trajectory; Step 8, conducting a spatio-temporal displacement difference evaluation. This method for restoring the slip trajectory of dip-slip faults can quantitatively obtain the three-dimensional displacement components of the hanging wall's dip-slip activity along the fault plane, accurately describe the slip trajectory and locate the initial breakpoint position, realize the quantitative characterization of the activity difference characteristics of the spatial target fault, and lay a foundation for the restoration of the prototype basin and its application in oil and gas exploration.

Description

Technical Field

[0001] The present invention relates to the fields of geology and petroleum geology, and particularly to a method for restoring the slip trajectory of dip-slip faults. Background Art

[0002] Dip-slip faults are widely developed in the fault-depressed basins in eastern China. The restoration of the activity trajectory of dip-slip faults plays an important role in the study of the matching relationship between structures and sediments, especially in stratigraphic correlation and provenance direction tracing, occupies an extremely important position in the quantitative characterization of faults and tectonic restoration evaluation, and is widely applied in aspects such as hydrocarbon migration, accumulation and reservoir formation in the oil and gas exploration field. In continental sedimentary basins, normal faults develop in a tensional extensional environment, and the strata undergo vertical offset and horizontal displacement; as the horizontal stress changes, under the action of gravity, the faults dip-slip; the strata tilt and undergo slip movement in a three-dimensional space domain along the strike, dip and vertical directions. The evaluation methods of tensional faults are generally analyzed in the plane and section, lacking the description of spatial displacement, and the conventional technical methods for characterizing the activity of extensional faults are no longer suitable for such fault development models. Similarly, there are still certain errors in using the evaluation methods of strike-slip faults to understand and evaluate. In the area covered by 3D seismic data, due to the advantages of the data, the understanding of fault activity is relatively reliable, but in the vast new oil and gas exploration areas, there is a lack of 3D seismic data volume and more effective targeted technical means. In the basin, depression and sag edge zones, in the geological structure conversion zones, especially in the areas where dip-slip and detachment faults are developed, it is necessary to restore the boundary of the prototype basin, especially to restore the original stratigraphic sedimentary boundary, that is, the initial development position of the fault, to determine the sediment provenance and the hydrocarbon enrichment route, all of which involve the accurate positioning and restoration of the fault. At present, there is no suitable characterization and evaluation method for the slip trace of faults.

[0003] In the Chinese patent application with the application number: CN201910308488.7, a method for carving a fault zone is involved, including: determining the boundary of the fault zone in the area to be analyzed, and then obtaining the contour of the fault zone in the area to be analyzed; determining the cave data in the area to be analyzed through wave impedance inversion; using the fault automatic extraction technology to extract the fault plane in the area to be analyzed, and determining the fault data and fracture data in the area to be analyzed; intersecting the cave data, fault data and fracture data with the fault zone contour and taking the intersection to obtain the cave data volume, fault data volume and fracture data volume within the fault zone contour respectively; re-scaling the cave data volume, fault data volume and fracture data volume within the fault zone contour according to their respective value ranges and fusing them into a data volume to obtain the three-dimensional space carving of the fault zone in the area to be analyzed.

[0004] In the Chinese patent application with the application number: CN201410641309.9, a method for studying the fracture zone by coring wells in the fracture zone is involved. This method includes: using a method combining logging formation correlation and seismic interpretation to preliminarily determine the depth of the fracture zone in the coring well; designing the planar position of the coring well target according to the need to study the fracture zone; predicting the width range of the fracture zone on the well trajectory based on the regional tectonic characteristics, the nature of the fault, the fault throw, and the lithology of the hanging wall and footwall of the fracture zone, so as to design and determine the coring well section; drilling and coring, analyzing and judging the change of the fracture zone depth based on the actual drilling data, and timely and moderately adjusting the coring well section to ensure the integrity of the fracture zone coring; and using the obtained core data to carry out a series of related studies on the fracture zone structure and sealing property.

[0005] In the Chinese patent application with the application number: CN201910280928.2, a method and system for discriminating the strike-slip fault boundary and the main fault plane are involved. This method includes: Step 1, preprocessing the three-dimensional seismic data of the area to be discriminated; Step 2, tracing the marker horizon in the strike-slip fault zone development area on the seismic section formed based on the preprocessed three-dimensional seismic data; Step 3, calculating the gradient structure tensor, coherence, and amplitude change rate attributes at the marker horizon; Step 4, determining the boundary of the strike-slip fault zone and the main strike-slip fault plane by comprehensively calculating the gradient structure tensor, coherence, and amplitude change rate attributes at the marker horizon.

[0006] The above prior arts are all quite different from the present invention and fail to solve the technical problems we want to solve. Therefore, we have invented a new method for restoring the slip trajectory of dip-slip faults. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for restoring the slip trajectory of dip-slip faults that truly reflects the dip-slip activity characteristics of fault blocks at different geological times and different tectonic positions.

[0008] The purpose of the present invention can be achieved by the following technical measures: A method for restoring the slip trajectory of dip-slip faults, which includes:

[0009] Step 1, obtaining the bottom interface structure map of the target interval, the boundary fault plane structure map, and their combined mosaic;

[0010] Step 2, establishing a basic interpretation result profile along the survey line direction;

[0011] Step 3, obtaining the true dip angle of the fault plane;

[0012] Step 4, obtaining the spatial position and true length of the fault;

[0013] Step 5, obtaining the vertical displacement and dip displacement amounts of the fault breakpoints in space;

[0014] Step 6, obtain the displacement of the fault break point along the sliding direction of the fault plane;

[0015] Step 7, construct the fault slip trajectory;

[0016] Step 8, conduct the spatio-temporal displacement difference evaluation.

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

[0018] In Step 1, using 3D (2D) seismic data, actual well drilling data and velocity field data, conduct isochronous T0 structural interpretation on the bottom interface of the target interval and the boundary fault plane to form an isochronous T0 structure map.

[0019] In Step 1, through well logging data, time-depth conversion template and velocity field data, conduct time-depth conversion to form a planar mosaic of the isodepth structure map of the bottom interface of the target interval and its boundary fault plane. The target interval boundary fault is included within the target horizon range. Use the intersection line of the fault plane and the horizon to obtain the strike and horizontal projection length of the fault on the target horizon.

[0020] In Step 2, establish a basic interpretation result profile in the survey line direction, determine the intersection points of the target horizon and the fault on the longitudinal profile, obtain the apparent vertical fault throw, apparent horizontal dip displacement and apparent dip angle of the fault plane in the target interval, and clarify their geometric relationships.

[0021] In Step 3, set up top and bottom reference planes, sketch the corresponding points of the fault in the target interval and the three-dimensional corresponding relationship stereogram of the fault plane within the three-dimensional space range, and obtain the true dip angle of the fault plane.

[0022] In Step 3, set up the bottom reference plane at the intersection point of the fault line and the fault plane contour line, and set up the top reference plane along the corresponding break points on the hanging wall of the target interval; design and establish a three-dimensional visibility stereogram of the relevant line segments such as the survey line, hanging wall break points, projection, fault plane contour line and its normal line, reference plane and the intersection line of the fault plane, and mark the positional relationship of the target fault and the fault plane contour line on the horizontal projection map; use the fault plane structure map to obtain the isodepth line interval value and horizontal displacement distance along the normal line direction of the fault plane contour line, and obtain the true dip angle of the fault plane according to the trigonometric function relationship.

[0023] In Step 3, the true dip angle of the fault plane is represented and converted by the following formula:

[0024] tanα = ΔHn / ΔLn

[0025] where α is the true dip angle, ΔHn is the normal isodepth line spacing on the fault plane structure map, ΔLn is the horizontal distance of the normal isodepth line, unit: m.

[0026] In step 4, along the bottom reference plane at the intersection of the fault endpoint and the contour line of the cross-section, a three-dimensional geometric correspondence between the fault and the plane projection is constructed to obtain the true spatial length of the fault.

[0027] In step 4, the calculation formula for the true spatial length of the fault is:

[0028] FL = √(Δh * Δh + Δl * Δl);

[0029] Where FL is the true length of the fault, Δh is the spacing between the isobaths of the two endpoints of the fault on the cross-section structure diagram, and Δl is the projected view length on the fault plane diagram, with the unit of m.

[0030] In step 5, a spatial triangular geometric operation relationship between the true breakpoints of the fault in the target formation and the contour line of the cross-section is constructed; along the top reference plane, the vertical displacement distance ΔH of the fault breakpoint in space is obtained, where ΔH = the isobath value of the top reference plane - the isobath value of the spatial breakpoint; using the true dip angle of the fault plane, the horizontal dip displacement ΔL is obtained.

[0031] In step 6, the fault breakpoints are spatially repositioned along the fault plane to the true breakpoint positions; along the normal of the contour line of the cross-section where the true fault breakpoints are located, they intersect with the bottom reference plane along the fault breakpoint and the top reference plane of the restored target position respectively. The projected distance between the two intersection points on the horizontal plane can be obtained from the conversion relationship between the right-angle side and the hypotenuse of the triangle where they are located, and the projected distance is the horizontal strike displacement amount ΔD of the fault along the cross-section.

[0032] In step 7, using the horizontal dip displacement amount ΔL, the strike displacement amount ΔD, and the vertical displacement distance ΔH, the total slip distance of the breakpoints on the dip-slip fault is calculated; the positions of the fault breakpoints are marked on the reference plane, and they are connected and extended along the normal direction of the contour line of the cross-section to the projection of the hanging-wall breakpoint on the contour line to obtain the slip trajectory of the fault along the cross-section.

[0033] In step 7, using the differences in the horizontal and vertical displacement amounts at different breakpoints of the fault, quantitative characterization and traceability restoration are carried out for different positions of the fault line to construct the differential slip trajectory of the fault.

[0034] In step 8, based on the geological time scale, the geological time ΔT of the deposition of the target interval is obtained. According to the strike displacement amount, dip displacement amount, and vertical displacement amount of the fault, the strike slip rate, dip slip rate, and vertical activity rate of the target fault along the fault plane are obtained to characterize the differential characteristics of the activity of the dip-slip fault.

[0035] In step 8, the ratio of the horizontal dip displacement distance to the sedimentation time of the target interval is used as the dip activity rate of the fault to characterize the activity intensity of the fault along the dip; the ratio of the horizontal strike displacement distance to the sedimentation time of the target interval is used as the strike activity rate of the fault to characterize the activity intensity of the fault along the strike; the ratio of the vertical displacement distance to the sedimentation time of the target interval is used as the vertical activity rate of the fault to characterize the activity intensity of the fault along the vertical direction; to characterize the differential characteristics of the spatial activity of dip-slip faults; quantitative characterization and source tracing restoration are carried out at different positions along the fault line, and the differential trajectory of fault slip is constructed by using the differences in horizontal and vertical displacement amounts at different breakpoints of the fault.

[0036] The method for restoring the slip trajectory of dip-slip faults in the present invention not only fully considers the geometric and kinematic characteristics of the fault plane and section along the strike and dip, considers the geometric and kinematic characteristics of the hanging wall (footwall) and the footwall (hanging wall) and the entire fault on the three-dimensional space displacement surface, but also considers the initial position and the current real space position of the fault development, and quantitatively and objectively reflects the spatial activity characteristics of dip-slip faults. The method for restoring the slip trajectory of dip-slip faults calculates the differences in dip-slip fault activities based on the data such as the real length of the fault space, the fault strike, the true dip angle of the fault plane, and the fault activity time obtained from three-dimensional (two-dimensional) seismic data, drilling data and geological data, including the strike displacement amount, dip displacement amount and vertical throw at different parts of the fault, as well as the activity rates of each component, to analyze the activity mode of dip-slip faults. The evaluation system for dip-slip fault activity established by this method fully considers the continuity and spatio-temporal characteristics of the evolution of dip-slip fault blocks, and truly reflects the dip-slip activity characteristics of fault blocks at different geological times and different structural positions, providing a research basis for further analyzing the dip-slip faults and the stratigraphic distribution characteristics and tectonic evolution laws controlled by them, and understanding the control effect of dip-slip faults on hydrocarbon accumulation. This method has good application effects and broad prospects for promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of a specific embodiment of the method for restoring the slip trajectory of dip-slip faults of the present invention;

[0038] Figure 2 It is the + section structure diagram of T7 structure in Yangxin area in a specific embodiment of the present invention;

[0039] Figure 3 It is a cross-sectional view in a specific embodiment 1 of the present invention;

[0040] Figure 4 It is a three-dimensional diagram of corresponding point displacement in a specific embodiment 1 of the present invention;

[0041] Figure 5 It is a bar chart of the activities of each component of dip-slip faults in a specific embodiment 1 of the present invention;

[0042] Figure 6 This is the + cross-section structure diagram of the T8 structure in the Weibei area in Specific Embodiment 2 of the present invention;

[0043] Figure 7 This is the cross-sectional view in Specific Embodiment 2 of the present invention;

[0044] Figure 8 This is the stereogram of the displacement of corresponding points in Specific Embodiment 2 of the present invention;

[0045] Figure 9 This is the + cross-section structure diagram of the T7 structure in the Shanghe area in Specific Embodiment 3 of the present invention;

[0046] Figure 10 This is the cross-sectional view in Specific Embodiment 3 of the present invention;

[0047] Figure 11 This is the stereogram of the displacement of corresponding points in Specific Embodiment 3 of the present invention. Specific Embodiments

[0048] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, 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.

[0050] The method for restoring the slip trajectory of dip-slip faults of the present invention includes the following steps:

[0051] Step 1, obtaining the bottom interface structure diagram of the target interval, the boundary fault cross-section structure diagram and their combined mosaic diagram by using three-dimensional (two-dimensional) seismic data, actual well drilling data and velocity field data;

[0052] Using two-dimensional and three-dimensional seismic data, actual well drilling data and velocity field data, performing isochronous T0 structure interpretation on the bottom interface of the target interval and the boundary fault cross-section to form an isochronous T0 structure diagram, and performing time-depth conversion through well logging data, time-depth conversion templates and velocity field data, etc. to form a plane mosaic diagram of the isodepth structure diagram of the bottom interface of the target interval and its boundary fault cross-section. The target horizon range includes the boundary faults of the target horizon, and the strike and horizontal projection length of the fault on the target horizon are obtained by using the intersection line of the cross-section and the horizon.

[0053] Step 2: Establish a backbone interpretation result profile along the survey line direction, and obtain the apparent vertical throw, apparent horizontal dip displacement distance, and apparent dip angle of the fault plane in the target interval.

[0054] Establish a survey line interpretation result profile, determine the intersection points of the target horizon and the fault on the longitudinal profile, obtain the apparent vertical throw, apparent horizontal dip displacement distance, and apparent dip angle of the fault plane in the target interval, and clarify their geometric relationships.

[0055] Step 3: Set up top and bottom reference planes, draw the corresponding stereogram of the equivalent points of the fault in the target interval and the fault plane within the three-dimensional space range, and obtain the true dip angle of the fault plane.

[0056] Set up the bottom reference plane at the intersection of the fault line and the fault plane contour line, and set up the top reference plane along the equivalent breakpoint on the hanging wall side of the target interval; construct the corresponding stereogram of the equivalent points on the hanging wall and footwall sides of the target interval within the three-dimensional space range, and mark the positional relationship between the target fault and the fault plane contour line on the horizontal projection map; use the fault plane structure map to obtain the interval between isobaths and the horizontal displacement distance along the normal direction of the fault plane contour line, and obtain the true dip angle of the fault plane according to the trigonometric function relationship.

[0057] The true dip angle of the fault plane can be expressed and converted by the following formula: tanα = ΔHn / ΔLn. Where α is the true dip angle, ΔHn is the interval between normal isobaths on the fault plane structure map, ΔLn is the horizontal distance of the normal isobaths, unit: m.

[0058] Step 4: Along the bottom reference plane at the intersection of the fault endpoint and the fault plane contour line, construct the three-dimensional geometric correspondence between the fault and the plane projection, and obtain the spatial position and true length of the fault.

[0059] Along the bottom reference plane at the intersection of the fault endpoint and the fault plane contour line, construct the three-dimensional geometric correspondence between the fault and the plane projection, and obtain the true spatial length of the fault. FL = √(Δh*Δh + Δl*Δl); where FL is the true length of the fault, Δh is the interval between isobaths at both ends of the fault on the fault plane structure map, Δl is the projected view length on the fault plane map, unit: m.

[0060] Step 5: Select the top reference plane, construct the geometric operation relationship between the fault breakpoints of the target fault and the fault plane contour line, and obtain the vertical displacement and dip displacement of the fault breakpoints in space.

[0061] Construct the spatial triangular geometric operation relationship between the true breakpoints of the target formation fault and the fault plane contour line; along the top reference plane, obtain the vertical displacement distance ΔH of the fault breakpoint in space, where ΔH = the isobath value of the top reference plane - the isobath value of the spatial breakpoint; use the true dip angle of the fault plane to obtain the horizontal dip displacement ΔL.

[0062] Step 6: Obtain the sliding strike displacement of the fault breakpoint along the fault plane.

[0063] Along the normal line of the contour line on the section where the true fault break is located, it intersects with the bottom reference plane of the fault break and the top reference plane of the restored target position respectively. The projection distance between the two intersection points on the horizontal plane can be obtained from the conversion relationship between the right-angled side and the hypotenuse of the triangle where they are located. The projection distance is the horizontal strike displacement ΔD of the fault along the section.

[0064] Step 7: Utilize the differences in horizontal and vertical displacement amounts at different fault breaks to construct the fault slip trajectory.

[0065] Utilize the horizontal dip displacement amount ΔL, strike displacement amount ΔD, and vertical displacement distance ΔH to calibrate the restored position of the fault break on the top reference plane. Connect it with the true fault break along the normal direction of the section contour line, and the fault slip trajectory along the section can be obtained.

[0066] Utilize the differences in horizontal and vertical displacement amounts at different fault breaks to quantitatively characterize and trace the restoration of different positions on the fault line, and the differential fault slip trajectory can be constructed.

[0067] Step 8: Obtain the geological time ΔT of the deposition of the target interval based on the geological time scale. According to the strike displacement amount, dip displacement amount, and vertical displacement amount of the fault, obtain the strike sliding rate, dip sliding rate, and vertical activity rate of the target fault along the fault plane to characterize the differential characteristics of the dip-slip fault activity.

[0068] Specifically, it includes: taking the ratio of the horizontal dip displacement distance to the deposition time of the target interval as the dip activity rate of the fault to characterize the activity intensity of the fault along the dip; taking the ratio of the horizontal strike displacement distance to the deposition time of the target interval as the strike activity rate of the fault to characterize the activity intensity of the fault along the strike; taking the ratio of the vertical displacement distance to the deposition time of the target interval as the vertical activity rate of the fault to characterize the activity intensity of the fault along the vertical direction; and characterizing the differential characteristics of the spatial activity of the dip-slip fault.

[0069] Quantitatively characterize and trace the restoration along different positions on the fault line, and utilize the differences in horizontal and vertical displacement amounts at different fault breaks to construct the differential fault slip trajectory.

[0070] In a specific embodiment 1 of applying the present invention, as Figure 1 shown, Figure 1 is the flow chart of the method for restoring the slip trajectory of the dip-slip fault of the present invention.

[0071] In step 102, utilize the structural map obtained in step 101 to obtain the interpreted result profile in the survey line direction. As Figure 3 shown, determine the intersection position of the target horizon and the fault on the seismic profile, obtain the apparent vertical fault throw, apparent horizontal dip displacement distance, and apparent dip angle of the section, and clarify their geometric relationships.

[0072] In step 103, a three-dimensional corresponding relationship stereogram between the fault breakpoints of the target layer and the top reference plane (the upthrown block is selected in the example) within the three-dimensional space range is constructed. As Figure 4 shown, O is the projection of the fault point H on the top reference plane; EO and KP are the survey line directions; GH is the spatial fault; GP is the projection of the fault along the fault point G on the bottom reference plane; GM and AF are the intersection lines of the section plane and the reference plane; α is the true dip angle of the section plane; β is the apparent dip angle of the section plane. Mark the positional relationship between the target fault and the isoline of the fault plane on the top horizontal projection map; the true dip angle of the fault plane can be expressed and converted by the following formula: tanα = ΔHn / ΔLn. Where α is the true dip angle, ΔHn is the spacing of the normal isobaths on the section structure map, ΔLn is the horizontal distance of the normal isobaths, unit, m.

[0073] In step 104, a bottom reference interface is set up at the intersection of the fault line of the downthrown block and the isoline of the section plane. According to the three-dimensional geometric corresponding relationship between the fault and the plane projection, the true spatial length Lf of the fault is obtained. As Figure 4 shown, GH is Lf; PH is Δh; PK is Δl; using Lf*Lf = Δh*Δh + Δl*Δl, the true length Lf of the fault is obtained. Δh is the spacing of the isobaths at both ends on the section structure map, Δl is the projected view length on the fault plane map, unit, m.

[0074] In step 105, the intersection points of the target formation fault line and the isoline of the fault plane are selected to construct a spatial triangular geometric operation relationship with the isoline of the section plane; along the top reference plane, the vertical displacement distance H of the fault breakpoint in space is obtained, where H = the isobath value of the breakpoint - the depth value of the restored reference plane; using the true dip angle of the fault plane, the horizontal dip displacement ΔL is obtained. As Figure 4 shown, in △FOH, OP is ΔH; OF is ΔL, which is expressed and converted by the following formula: ΔL = ΔH / tanα, to obtain ΔL.

[0075] In step 106, using the section structure map of the fault plane, according to Figure 4 , EO is obtained in △EOH; in △EOF, the horizontal strike displacement distance ΔD is obtained.

[0076] In step 107, using the horizontal dip displacement ΔL, the strike displacement ΔD and the vertical displacement distance ΔH, the restored position of the breakpoint on the top reference plane is calibrated. Along the normal direction of the isoline of the section plane, connecting to the true fault breakpoint, the slip trajectory of the fault along the section plane can be obtained. As Figure 5As shown in the figure, A, B, C, D, E, F, and G are the inflection points where the fault trend of the fault downthrow side changes; the total slip distance is the spatial slip distance from the starting breakpoint to the final breakpoint; the horizontal dip displacement ΔL, the horizontal strike displacement ΔD, and the vertical displacement ΔH are compared at the same breakpoint. The numbers represent the displacement values at different breakpoints, and the unit is: kilometer. This fault is the boundary fault of the depression, with strong vertical activity, showing a relatively large vertical displacement, and horizontal strike and dip sliding are shown at different breakpoints. Figure 5 The moving trend line shows the change trend of the displacement at each breakpoint.

[0077] In step 108, based on the geological time scale, the geological time of the formation deposition in the target interval is ΔT; according to the strike displacement, dip displacement, and vertical displacement of the fault, the strike sliding rate, dip sliding rate, and vertical activity rate of the target fault point along the fault plane can be obtained, specifically including: taking the ratio of the horizontal dip displacement to the deposition time of the target interval as the dip activity rate of the fault, which is used to characterize the activity intensity of the fault along the dip; taking the ratio of the horizontal strike displacement to the deposition time of the target interval as the strike activity rate of the fault, which is used to characterize the activity intensity of the fault along the strike; taking the ratio of the vertical displacement to the deposition time of the target interval as the vertical activity rate of the fault, which is used to characterize the activity intensity of the fault along the vertical; and characterizing the differential characteristics of the spatial activity of the dip-slip fault.

[0078] In the specific embodiment 2 of applying the present invention, as Figure 1 shown, Figure 1 is the flow chart of the method for restoring the slip trajectory of the dip-slip fault of the present invention.

[0079] Step 101, obtain the bottom interface structure map of the target interval through 3D seismic data and 3D velocity field data. As Figure 6 shown, using 3D seismic data and velocity field data, perform isochronous structural interpretation on the T8 horizon in the Weibe area to form an isochronous structure map; at the same time, interpret its boundary faults and perform plane combination and mosaic to form the T8 structure + fault plane isochronous map in the Weibe area. Through well logging data, time-depth conversion templates, velocity field and other data, perform time-depth conversion to form the plan view of the bottom interface of the target interval and its boundary fault section isodepth structure map.

[0080] In step 102, using the structure map obtained in step 101, obtain the interpretation result profile in the direction of the vertical hanging wall. As Figure 7 shown, determine the intersection position of T8 and the fault on the seismic profile, obtain the apparent vertical fault throw, apparent horizontal dip displacement, and apparent dip angle of the fault plane in the target interval, and clarify the profile geometric relationship among them.

[0081] In step 103, construct a three-dimensional corresponding relationship stereo map between the fault breakpoints of the target interval and the top reference plane (the hanging wall is selected in the example) within the three-dimensional space range. As Figure 4As shown in the figure, O is the projection of the breakpoint H on the top reference plane; EO and KP are the survey line directions; GH is the spatial fault; GP is the projection of the fault along the breakpoint G on the bottom reference plane; GM and AF are the intersection lines of the section plane and the reference plane; α is the true dip angle of the section plane; β is the apparent dip angle of the section plane. Identify the positional relationship between the target fault and the contour lines of the fault plane on the top horizontal projection map; the true dip angle of the fault plane can be expressed and converted by the following formula: tanα = ΔHn / ΔLn. Where α is the true dip angle, ΔHn is the spacing of the normal isobaths on the section structure map, ΔLn is the horizontal distance of the normal isobaths, unit: m.

[0082] In step 104, a bottom reference interface is established at the intersection of the fault line on the downthrown side and the contour lines of the section plane. According to the three-dimensional geometric correspondence between the fault and the plane projection, the true spatial length Lf of the fault is obtained. As Figure 4 shown, GH is Lf; PH is Δh; PK is Δl; using Lf*Lf = Δh*Δh + Δl*Δl, the true length Lf of the fault is obtained. Δh is the spacing of the isobaths at both ends on the section structure map, Δl is the projected visual length on the fault plane map, unit: m.

[0083] In step 105, select the breakpoints on the downthrown side and construct the spatial triangular geometric operation relationship with the contour lines of the section plane; along the top reference plane, obtain the vertical displacement distance H of the fault breakpoints in space, where H = the isobath value of the breakpoint - the depth value of the restored reference plane; using the true dip angle of the fault plane, obtain the horizontal dip displacement ΔL. As Figure 4 shown, in △FOH, OP is ΔH; OF is ΔL, which is expressed and converted by the following formula: ΔL = ΔH / tanα, to obtain ΔL.

[0084] In step 106, using the section structure map, according to Figure 4 , obtain EO in △EOH; in △EOF, obtain the horizontal strike displacement distance ΔD.

[0085] Figure 8 shown Figure 6 in the total slip distance, horizontal dip displacement ΔL, horizontal strike displacement ΔD and vertical displacement distance ΔH at breakpoints 1 - 9. The numbers in the figure represent the displacement values at different breakpoints, unit: m.

[0086] In step 107, using the horizontal dip displacement ΔL, strike displacement ΔD and vertical displacement distance ΔH, calibrate the position of the breakpoints on the upthrown side, and connect them along the normal direction of the contour lines of the section plane to the true breakpoints on the downthrown side of the fault, and the slip trajectory of the fault along the section plane can be obtained, Figure 6 the position indicated by the arrow.

[0087] In the specific embodiment 3 of applying the present invention, as Figure 1 shown, Figure 1Flow chart of the method for restoring the slip track of dip-slip fault in the present invention.

[0088] Step 101: Obtain the structural map of the bottom interface of the target interval through 3D seismic data and 3D velocity field data. As Figure 9 shown, using 3D seismic data and velocity field data, perform isochronous structural interpretation on the T7 horizon in the Shanghe area to form an isochronous structural map; at the same time, interpret its boundary faults and perform planar combination and mosaicking to form the T7 structure + section isochronous map in the Shanghe area. Through well logging data, time-depth conversion templates, velocity field and other data, perform time-depth conversion to form the plan view of the isodepth structural map of the bottom interface of the target interval and its boundary fault section.

[0089] In step 102, use the structural map obtained in step 101 to obtain the interpreted result profile in the direction of the survey line. As Figure 10 shown, determine the intersection positions of the target horizon and the fault on the seismic profile, and obtain the apparent vertical throw, apparent horizontal dip displacement distance and fault section of the target interval.

[0090] In step 103, construct a three-dimensional stereo map of the corresponding relationship between the fault breakpoints of the target horizon and the reference plane of the hanging wall within the three-dimensional space. As Figure 4 shown, O is the projection of the breakpoint H on the top reference plane; EO and KP are in the direction of the survey line; GH is the spatial fault; GP is the projection of the fault along the breakpoint G on the bottom reference plane; GM and AF are the intersection lines of the fault section and the reference plane; α is the true dip angle of the fault section; β is the apparent dip angle of the fault section. Mark the positional relationship between the target fault and the contour line of the fault section on the top horizontal projection map; the true dip angle of the fault section can be expressed and converted by the following formula: tanα = ΔHn / ΔLn. Where α is the true dip angle, ΔHn is the spacing of the normal isodepth lines on the structural map of the fault section, ΔLn is the horizontal distance of the normal isodepth lines, unit, m.

[0091] In step 104, set up the bottom reference interface at the intersection of the fault line of the hanging wall and the contour line of the fault section, and obtain the true spatial length Lf of the fault according to the three-dimensional geometric correspondence between the fault and the plane projection. As Figure 4 shown, GH is Lf; PH is Δh; PK is Δl; use Lf*Lf = Δh*Δh + Δl*Δl to obtain the true length Lf of the fault, Δh is the spacing of the isodepth lines at both ends on the structural map of the fault section, Δl is the projected view length on the fault plan view, unit, m.

[0092] In step 105, select the inflection points of the target formation fault, construct the spatial triangular geometric operation relationship with the contour line of the fault section; along the top reference plane, obtain the vertical displacement distance H of the fault breakpoint in space, where H = the isodepth value of the breakpoint - the depth value of the restoration reference plane; use the true dip angle of the fault section to obtain the horizontal dip displacement ΔL. As Figure 4As shown, in △FOH, OP is ΔH; OF is ΔL, which is expressed and converted by the following formula: ΔL = ΔH / tanα to obtain ΔL.

[0093] In step 106, using the fault plane structure map, according to Figure 4 , obtain EO in △EOH; in △EOF, obtain the horizontal strike displacement ΔD.

[0094] Figure 11 Shown Figure 9 The total slip distance, horizontal dip displacement ΔL, horizontal strike displacement ΔD, and vertical displacement ΔH at the A - H breakpoints in the figure. The numbers in the figure represent the displacement values at different breakpoints, unit: m.

[0095] In step 107, using the horizontal dip displacement ΔL, strike displacement ΔD, and vertical displacement ΔH, calibrate the restored position of the breakpoint on the top reference plane, connect it to the true fault breakpoint along the normal direction of the section contour line, and the slip trajectory of the fault along the section can be obtained. Figure 9 As indicated by the arrow on the section.

[0096] The present invention provides a method for restoring the slip trajectory of dip - slip faults, including: using three - dimensional (two - dimensional) seismic data and velocity field data to obtain the structure maps of the bottom interface of the target interval and the boundary fault planes of the target interval; obtaining the interpretation result profile in the survey network direction, setting up top and bottom reference planes, establishing a three - dimensional model diagram of the fault slipping along the section, building the spatial geometric correspondence relationship between the hanging wall of the target interval, the section, and the reference plane, and obtaining the true dip angle of the section within the range of the moving trajectory along the fault plane; according to the relationship between the spatial fault and its planar projection, obtaining the breakpoint position and vertical distance, and calculating the true length of the fault in the three - dimensional domain; projecting the spatial true breakpoints onto the top and bottom reference planes respectively to obtain their vertical displacement amounts; using the spatial geometric transformation relationship to obtain the displacement amounts of the fault breakpoints along the strike and dip directions. This method can quantitatively obtain the three - dimensional displacement components of the hanging wall's dip - slip activity along the fault plane, accurately describe the slip trajectory and locate the initial breakpoint position, and realize the quantitative characterization of the activity difference characteristics of the spatial target fault. This restoration method provides an effective way for tensional detachment, horizontal displacement of dip - slip faults, and quantitative characterization of activity differences, and lays a foundation for the restoration of the prototype basin and its application in oil and gas exploration.

[0097] Finally, it should be noted that: The above - mentioned are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0098] Except for the technical features described in the specification, the rest are well-known technologies to those skilled in the art.

Claims

1. Method for restoring slip trajectory of dip-slip fault Characterized in that The method for restoring the slip trajectory of the dip-slip fault includes Step 1: Obtain the structural map of the bottom interface of the target interval, the structural map of the boundary fault plane, and their combined mosaic Step 2: Establish a profile of the basic interpretation results along the survey line direction Step 3: Obtain the true dip angle of the fault plane Step 4: Obtain the spatial position and true length of the fault Step 5: Obtain the vertical displacement and dip displacement of the fault breakpoint in space Step 6: Obtain the sliding strike displacement of the fault breakpoint along the fault plane Step 7: Construct the fault slip trajectory Step 8: Conduct spatio-temporal displacement difference evaluation In Step 3, set up top and bottom reference planes, draw the corresponding relationship stereogram of the equivalent points of the fault in the target interval and the fault plane within the three-dimensional space range, and obtain the true dip angle of the fault plane In Step 3, set up the bottom reference plane at the intersection of the fault line and the fault plane contour line, and set up the top reference plane along the equivalent breakpoint of the hanging wall of the target interval; design and establish a three-dimensional visibility stereogram of the relevant line segments such as the survey line, the hanging wall breakpoint, the projection, the fault plane contour line and its normal line, and the intersection line of the reference plane and the fault plane, and mark the positional relationship between the target fault and the fault plane contour line on the horizontal projection map; use the structural map of the fault plane to obtain the equal-depth line interval value and the horizontal displacement distance along the normal direction of the fault plane contour line, and obtain the true dip angle of the fault plane according to the trigonometric function relationship In Step 3, the true dip angle of the fault plane is represented and converted by the following formula tanα = ΔHn / ΔLn Where α is the true dip angle, ΔHn is the normal equal-depth line spacing on the fault plane structural map, ΔLn is the horizontal distance of the normal equal-depth line, unit: m In Step 7, use the horizontal dip displacement ΔL, the strike displacement ΔD and the vertical displacement ΔH to calculate the total slip distance of the breakpoint on the dip-slip fault; mark the position of the fault breakpoint on the reference plane, and connect and extend along the normal direction of the fault plane contour line to the projection of the hanging wall breakpoint on the contour line to obtain the slip trajectory of the fault along the fault plane In Step 7, use the differences in horizontal and vertical displacement amounts at different breakpoints of the fault to quantitatively characterize and trace back and restore different positions of the fault line, and construct the differential trajectory of the fault slip 2. The method for restoring the slip trajectory of the dip-slip fault according to claim 1 Characterized in that In Step 1, use 3D seismic data, actual well drilling data and velocity field data to conduct isochronous T0 structural interpretation of the bottom interface of the target interval and the boundary fault plane to form an isochronous T0 structural map 3. The method for restoring the slip trajectory of the dip-slip fault according to claim 2 Characterized in that In Step 1, conduct time-depth conversion through well logging data, time-depth conversion template and velocity field data to form a planar mosaic of the equal-depth structural maps of the bottom interface of the target interval and its boundary fault plane. The target layer boundary fault is included within the target horizon range, and the strike and horizontal projection length of the fault on the target horizon are obtained using the intersection line of the fault plane and the horizon 4. The method for restoring the slip trajectory of the dip-slip fault according to claim 1 Characterized in that In step 2, establish the basic interpretation result profile in the survey line direction, determine the intersection points of the target horizon and the fault on the longitudinal profile, obtain the apparent vertical throw, apparent horizontal dip displacement distance and apparent dip angle of the fault plane in the target interval, and clarify their geometric relationships.

5. The method for restoring the slip trajectory of a dip-slip fault according to claim 1, wherein, in step 4, along the bottom reference plane at the intersection of the fault end point and the fault plane contour line, construct the three-dimensional geometric correspondence between the fault and the plane projection, and obtain the true spatial length of the fault.

6. The method for restoring the slip trajectory of a dip-slip fault according to claim 5, wherein, in step 4, the calculation formula for the true spatial length of the fault is: FL = √(Δh * Δh + Δl * Δl); where FL is the true length of the fault, Δh is the distance between the isobath lines at both ends of the fault on the structural map of the fault plane, Δl is the projected view length on the fault plane plan, and the unit is m.

7. The method for restoring the slip trajectory of a dip-slip fault according to claim 1, wherein, in step 5, construct the spatial triangular geometric operation relationship between the true fault break points of the target formation and the fault plane contour line; along the top reference plane, obtain the vertical displacement distance ΔH of the fault break point in space, where ΔH = the isobath value of the top reference plane - the isobath value of the spatial break point; use the true dip angle of the fault plane to obtain the horizontal dip displacement ΔL.

8. The method for restoring the slip trajectory of a dip-slip fault according to claim 1, wherein, in step 6, relocate the fault break point along the fault plane in space to the true break point position; along the normal line of the fault plane contour line where the true fault break point is located, intersect with the bottom reference plane along the fault break point and the top reference plane of the restored target position respectively. The projection distance between the two intersection points on the horizontal plane can be obtained from the conversion relationship between the right-angle side and the hypotenuse of the triangle where they are located. The projection distance is the horizontal strike displacement amount ΔD of the fault along the fault plane.

9. The method for restoring the slip trajectory of a dip-slip fault according to claim 1, wherein, in step 8, obtain the geological time ΔT of the deposition of the target interval based on the geological time scale. According to the strike displacement amount, dip displacement amount and vertical displacement amount of the fault, obtain the strike sliding rate, dip sliding rate and vertical activity rate of the target fault along the fault plane, and characterize the differential characteristics of the dip-slip fault activity.

10. The method for restoring the slip trajectory of a dip-slip fault according to claim 1, wherein, in step 8, take the ratio of the horizontal dip displacement distance to the deposition time of the target interval as the dip activity rate of the fault, which is used to characterize the activity intensity of the fault along the dip; take the ratio of the horizontal strike displacement distance to the deposition time of the target interval as the strike activity rate of the fault, which is used to characterize the activity intensity of the fault along the strike; take the ratio of the vertical displacement distance to the deposition time of the target interval as the vertical activity rate of the fault, which is used to characterize the activity intensity of the fault along the vertical direction; characterize the differential characteristics of the spatial activity of the dip-slip fault; Quantitatively characterize and trace back the restoration along different positions of the fault line, and use the differences in the horizontal and vertical displacement amounts at different fault break points to construct the differential slip trajectory of the fault.

Images