A method for describing fracture surface geometric elements based on structural modeling

Abstract

The present invention provides a method for describing fracture surface geometry based on structural modeling, comprising: step 1, obtaining a structural map of the target layer segment and the seismic reflection layer of the boundary fracture surface; step 2, establishing a core profile of the seismic data interpretation results; step 3, constructing a three-dimensional model of the fracture slip along the fracture surface; step 4, obtaining parameters such as the inclination, strike, and dip of the fracture surface; step 5, modeling the geological structure using the target layer interface information and fracture surface data; step 6, obtaining the strike displacement along the fracture surface, as well as the vertical and horizontal displacement variables at different breakpoints on the fracture surface; and step 7, obtaining a plan view of the strike displacement of the fracture surface. This method for describing fracture surface geometry based on structural modeling can quantitatively obtain the displacement and slip trajectory of the geological body along the fracture surface, accurately calculate the displacement distance along the attitude direction, and accurately describe the horizontal and vertical slip changes, thereby achieving the purpose of breakpoint tracking and description and three-dimensional quantitative characterization of fault activity differences.

Description

Technical Field

[0001] The present invention relates to the fields of structural geology and petroleum exploration, and in particular to a method for describing fracture surface geometric elements based on structural modeling. Background Art

[0002] Faults are widely developed in petroliferous basins. Fault activity not only controls stratum sedimentation but also forms various trap types, such as fault noses, fault blocks, and fault anticlines. These traps play a significant, and potentially decisive, role in the migration, accumulation, and enrichment of oil and gas. The understanding of fault surfaces is crucial in both geological tectonic research and oil and gas exploration and development. A fault surface is a curved, deformed surface that separates geological bodies and slides along the dividing line; it is not an ideal straight surface. Under the influence of horizontal stress and gravity, strata developed in sedimentary basins undergo vertical dislocation, tilting, and sliding along fault surfaces, deforming in three dimensions along strike, dip, and vertical directions. In practice, many geologists focus their work primarily on describing structural layers, with the characterization of faults limited to planar configurations and fault systems. However, some researchers are able to infer geological information about fault surfaces based on their understanding of tectonic deformation patterns and cross-sections and planar structural maps. Therefore, fracture evaluation methods have primarily been conducted on a single plane, using single points and lines, primarily relying on two-dimensional geological profiles. The spatial characteristics of fractures have traditionally been characterized qualitatively based on researchers' experience, lacking quantitative characterization of three-dimensional displacements. Spatially, fracture surfaces exhibit undulating, dislocated, and deformed structures, with their occurrence determined by their strike, dip, and inclination. Accurate fracture surface descriptions constrain understanding of oil and gas geology and fracture structure, affecting not only the assessment of the hydrocarbon transport capacity of fault zones but also the study of fracture sealing properties after hydrocarbon accumulation. With increasing research, quantitative fracture surface characterization has become increasingly important in the study of structural and sedimentary matching, particularly in tracing provenance and tracking hydrocarbon migration and accumulation. Furthermore, high-quality and efficient oil and gas exploration and development urgently require detailed characterization of fracture surfaces. Currently, there are no suitable characterization and evaluation methods for fracture surfaces and fault slip characteristics, and there is a lack of technology to describe the geometric elements of fracture surfaces. Traditional evaluation methods for extensional, tension-torsional, and strike-slip faults still suffer from errors in their understanding and evaluation.

[0003] Chinese patent application number CN201310485186.X describes a 3D modeling method for fault structures. First, fault data is integrated into a 3D visualization system, from which fault control points are extracted and interpreted to form fault lines. Connectivity analysis is then performed for various scenarios, and fault lines and fault attributes are revised. The relationships between faults are calculated, and a fault network reflecting their topological structure is established. The fault plane is then intersected with the constructed initial stratigraphic model to obtain the initial intersection line between the stratigraphic layer and the fault. Displacement is calculated for each breakpoint on the initial intersection line, resulting in a 3D fault line including the upper and lower walls. Weights are then assigned to the various fault data generated, and fault planes are fitted to form a fault plane network, allowing stratigraphic model construction. This method effectively detects data and ensures the accuracy of fault models, and is suitable for applications in fields such as petroleum and geology.

[0004] Chinese patent application number CN201310571770.7 discloses a geophysical characterization method for oil and gas convergence conditions in channel sand reservoirs. This method includes: Step 1: structural ridge characterization; Step 2: delineating the oil-source fault network; Step 3: automated batch tracking of sand bodies; Step 4: fault-sand configuration analysis; and Step 5: comprehensive prediction of favorable oil-bearing zones. This geophysical characterization method utilizes advanced mathematical algorithms and signal processing techniques to perform rational characterization and comprehensive analysis, indicating macroscopic favorable oil and gas zones. Combined with geological analysis and comprehensive evaluation of oil and gas testing results, it can identify favorable exploration targets.

[0005] Chinese patent application number CN201710566937.9 describes a method for evaluating the vertical conductivity of reverse faults in volcanic rock areas in a piedmont nappe belt. The method includes establishing a structural geological model of the fault zone, a permeability-effective stress relationship model for the structural layers of the fault zone, a geometric relationship model for the structural layers of the fault zone, a component fault zone permeability evaluation model, a mathematical model for the permeability correction factor of the fault zone, selecting a profile for evaluating fault conductivity, establishing a quantitative evaluation model for vertical conductivity of the fault units, and determining threshold values ​​for the quantitative evaluation index of fault conductivity. The proposed quantitative evaluation method for the vertical conductivity of reverse faults enables a three-dimensional quantitative evaluation of the fault conductivity in volcanic rock brittle strata, enriching the quantitative evaluation methods for fault conductivity. The method can be widely applied to evaluating the conductivity of reverse faults in volcanic rock areas in the piedmont belt of compressional basins, and has important guiding significance for oil and gas exploration.

[0006] The above existing technologies are significantly different from the present invention and fail to solve the technical problem we want to solve. Therefore, we have invented a new method for describing the geometric elements of the fracture surface based on structural modeling. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for describing fracture surface geometric elements based on structural modeling, which truly reflects the spatial development characteristics of the fracture.

[0008] The object of the present invention can be achieved by the following technical measures: a fracture surface geometric element description method based on structural modeling, the fracture surface geometric element description method based on structural modeling comprising:

[0009] Step 1: Obtain the seismic reflection layer structure map of the target layer segment and boundary fault surface;

[0010] Step 2: Establish the core section of seismic data interpretation results;

[0011] Step 3, constructing a three-dimensional model diagram of the fault sliding along the fracture surface;

[0012] Step 4: Obtain parameters such as the fracture surface inclination, strike, and dip;

[0013] Step 5: Use the target layer interface information and fracture surface data to build geological structure model;

[0014] Step 6: Obtain the strike displacement along the fault surface, as well as the vertical and horizontal displacement variables at different breakpoints on the fault surface;

[0015] Step 7: Obtain a plan view of the displacement along the fracture surface.

[0016] The purpose of the present invention can also be achieved by the following technical measures:

[0017] In step 1, three-dimensional or two-dimensional seismic data and actual drilling data are used to perform structural interpretation on the target layer and boundary fault surface to form an iso-T0 seismic reflection layer structural map. Time-depth conversion is performed using logging data, time-depth conversion volume plate and velocity field data to form an iso-depth structural map of the target layer and fault surface. The target layer includes the boundary fault of the target layer, and the intersection line of the fault surface and the layer is used to obtain the strike and apparent length of the upper and lower walls of the fault on the plane.

[0018] In step 2, a basic section of the seismic interpretation results perpendicular to the fault line is established, and the apparent vertical fault throw, apparent horizontal dip displacement and apparent dip angle β of the target layer are obtained from the intersection of the fault and the horizon, and the corresponding geometric conversion relationship is established.

[0019] In step 3, the depth data of the upper and lower wall fault lines and fracture surfaces of the target layer segment are obtained, the three-dimensional geological structure model is built, a three-dimensional stereogram of the target layer and fracture surface is produced, and a three-dimensional model diagram of the fault sliding along the fracture surface is constructed; the geometric operation relationship between the target fracture breakpoint distance and the fracture surface contour line and the fault line space and plane is established, and the fault line and contour line are marked.

[0020] In step 4, the parameters such as the strike, dip and inclination of the fault surface are extracted. The spatial variation of the fault surface is analyzed using the seismic attributes of the target fault surface, and an attribute analysis diagram is drawn. The characteristics of the plane structural diagram and the three-dimensional stereogram of the fault surface are integrated. According to the variation of the fault lines in the upper and lower walls, the fault surface is divided into blocks and evaluated in sections according to the principle that the fault surface dip is relatively consistent and the fracture contour lines are relatively straight.

[0021] Step 5 includes:

[0022] Step 51, establishing a cutting reference surface along the fracture surface inclination direction and perpendicular to the fault line;

[0023] Step 52, obtaining the intersection line between the reference surface and the fracture surface along the fracture surface inclination, extracting the distance between the breakpoint curves, and calculating the horizontal fault distance and the vertical fault distance;

[0024] Step 53: Obtain the intersection line between the cutting reference surface perpendicular to the fault line and the fracture surface, extract the intersection distance, and calculate the plane projection distance and vertical displacement.

[0025] In step 51, a hanging wall fault line is selected, and a series of cutting reference surfaces RP are established along the dip direction of the fault surface at different breakpoints of the fault line, and a series of cutting reference surfaces SP are established along the strike direction of the footwall fault line at different breakpoints of the fault line.

[0026] In step 52, the intersection line IL of the cutting reference surface RP and the fault surface along the dip direction of the fault surface is obtained. The length of the spatial curved surface ΔL of the intersection line between the upper and lower plates is the dip displacement along the fault surface. The length of the intersection line on the horizontal projection plane is the horizontal fault distance ΔD. The vertical fault distance ΔH is calculated as: ΔH = ΔD*cotα; where α is the true dip angle of the fault surface, and ΔD is the horizontal fault distance, in meters.

[0027] In step 53, the intersection line AL between the cutting reference surface SP and the fault surface, which passes through the footwall breakpoint and is perpendicular to the strike direction of the fault line, is obtained. The spatial displacement length ΔAL of the intersection line between the upper and lower walls is the apparent inclination displacement along the fault surface. The projection distance of the intersection line AL on the horizontal plane is the horizontal apparent fault distance ΔD0. The conversion formula for the vertical apparent fault distance ΔH0 is: ΔH0 = ΔD*cotβ; where β is the apparent inclination angle of the fault surface, and ΔD is the horizontal apparent fault distance, in meters.

[0028] Step 6 includes:

[0029] Step 61, obtaining the displacement along the fracture surface;

[0030] Step 62: Obtain the vertical and horizontal displacement variables at different breakpoints on the fracture surface.

[0031] In step 61, a projection conversion relationship between corresponding geometric elements is established using a three-dimensional visualization of fault lines, fracture surface contour lines, and fracture surface intersection lines IL and AL, and the strike displacement ΔSD is obtained using a spatial modeling data volume.

[0032] In step 62, the calculation formula for the vertical displacement variable Δh of the fracture surface is: Δh = ΔH - ΔH0; the calculation formula for the horizontal displacement variable Δd of the fracture surface is: Δd = Δh / tanθ, unit, m; where θ is the angle between the fault line and the fracture surface contour line, unit, degree.

[0033] In step 7, the differences in horizontal and vertical displacements at different breakpoints of the fault are used to quantitatively characterize and trace the fault line to construct a differential trajectory of fault activity.

[0034] The method for describing fracture surface geometric elements based on structural modeling further includes, after step 7, step 8, performing differential characterization of fracture spatiotemporal activities.

[0035] In step 8, the geological time ΔT of the target layer segment is obtained based on the geological time scale. According to the strike displacement, dip displacement and vertical displacement of the fault, the strike slip rate, dip slip rate and vertical activity rate of the target fault along the fault surface are obtained to characterize the differential characteristics of the temporal and spatial activities of the fault and construct a differential fault slip trajectory.

[0036] The method for describing the geometric elements of the fracture surface based on structural modeling in the present invention performs structural modeling based on the reflection layer and fracture surface information obtained from three-dimensional (two-dimensional) seismic data, drilling data and geological data, establishes a corresponding conversion relationship between the geometric parameters of the fracture surface, and adopts the cutting intersection method to obtain the total slip distance and strike slip distance of the fracture surface, and then obtains the horizontal fault throw and vertical fault throw, as well as the horizontal and vertical displacement change components. It quantitatively and objectively characterizes the spatial activity characteristics of the fracture and the differences in its activities, and analyzes the activity mode of the fracture. The fracture activity evaluation system established by this method fully considers the continuity and spatiotemporal characteristics of the fracture evolution, and truly reflects the active displacement vector and change component of the fracture in different geological periods and at different structural positions, providing a research basis for the next step of analyzing the distribution characteristics and evolution laws of the fracture and the strata under its control, and understanding the control of the fracture on oil and gas accumulation.

[0037] This method of describing the geometric elements of the fracture surface based on structural modeling not only fully considers the geometric and kinematic characteristics of the vertical direction, strike and dip of the fracture surface plane, but also considers the geometric and kinematic characteristics of the downthrown plate (hanging plate), upthrown plate (footerly plate) and the entire fracture in the three-dimensional space domain, and also studies the spatial variation component of the fracture, which truly reflects the spatial development characteristics of the fracture. The present invention has good application effects and promotion prospects in geological research and oil and gas exploration in tensional, compressional and strike-slip basins. The restoration method provides an effective way to trace the provenance, oil and gas sealing and accumulation, and characterize the spatial displacement vector of the fracture, and lays the foundation for the differences in tectonic activity, paleo-geomorphological restoration, and its application in geology and oil and gas exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flow chart of a specific embodiment of the method for describing fracture surface geometric elements based on structural modeling of the present invention;

[0039] Figure 2 This is a structural diagram of the T6 structure + fracture surface in the Panhe area of ​​a specific embodiment 1 of the present invention;

[0040] Figure 3 This is a seismic cross-section diagram in a specific embodiment 1 of the present invention;

[0041] Figure 4 This is a three-dimensional schematic diagram of equivalent point displacement in a specific embodiment 1 of the present invention;

[0042] Figure 5 A three-dimensional diagram of the intersection of the fracture surface and the cutting surface in a specific embodiment 1 of the present invention;

[0043] Figure 6 A diagram of the total slip distance of a fracture in a specific embodiment 1 of the present invention;

[0044] Figure 7 A horizontal fault distance diagram of a fracture in a specific embodiment 1 of the present invention;

[0045] Figure 8 A vertical fault distance diagram of a fracture in a specific embodiment 1 of the present invention;

[0046] Figure 9 This is a diagram showing the displacement conversion model of the fracture strike in a specific embodiment 1 of the present invention;

[0047] Figure 10 This is a fracture strike displacement diagram in a specific embodiment 1 of the present invention.

[0048] Figure 11 This is a structural diagram of the T6 structure + fracture surface in the Linbei area in a specific embodiment 2 of the present invention;

[0049] Figure 12This is a seismic cross-section diagram in a specific embodiment 2 of the present invention;

[0050] Figure 13 A three-dimensional diagram of the intersection of the fracture surface and the cutting surface in a specific embodiment 2 of the present invention;

[0051] Figure 14 A diagram of the total slip distance of a fracture in a specific embodiment 2 of the present invention;

[0052] Figure 15 A horizontal fault distance diagram of a fracture in a specific embodiment 2 of the present invention;

[0053] Figure 16 A vertical fault distance diagram of a fracture in a specific embodiment 2 of the present invention;

[0054] Figure 17 A fracture strike displacement diagram in a specific embodiment 2 of the present invention;

[0055] Figure 18 This is a seismic cross-section diagram in a specific embodiment 3 of the present invention;

[0056] Figure 19 A three-dimensional diagram of the intersection of the fracture surface and the cutting surface in a specific embodiment 3 of the present invention;

[0057] Figure 20 A diagram of the total slip distance of a fracture in a specific embodiment 3 of the present invention;

[0058] Figure 21 A horizontal fault distance diagram of a fracture in a specific embodiment 3 of the present invention;

[0059] Figure 22 A vertical fault distance diagram of a fracture in a specific embodiment 3 of the present invention;

[0060] Figure 23 This is a fracture strike displacement diagram in a specific embodiment 3 of the present invention. DETAILED DESCRIPTION

[0061] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0062] 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 form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0063] The following are several specific embodiments of the present invention.

[0064] Example 1

[0065] In a specific embodiment 1 of the present invention, the fracture surface geometric element description method based on structural modeling includes the following steps:

[0066] Step 1: Use seismic data, actual drilling data and velocity field data to obtain the seismic reflection interface structure map of the target layer and fault surface;

[0067] Using three-dimensional (two-dimensional) seismic data, actual drilling data and other data, a detailed structural interpretation of the target layer, boundary fault surface, etc. is performed to form an iso-T0 seismic reflection layer structural map. Time-depth conversion is performed through logging data, time-depth conversion volume and velocity field data to form an iso-depth structural map of the target layer and fault surface. The target layer includes the boundary fault of the target layer. The intersection line of the fault surface and the layer is used to obtain the strike and apparent length of the upper and lower walls of the fault on the plane.

[0068] Step 2: Establish a core section of the seismic interpretation results perpendicular to the fault line to obtain the apparent vertical fault throw, apparent horizontal displacement and apparent dip angle of the fault surface of the target layer;

[0069] Establish a basic section of seismic interpretation results perpendicular (approximately perpendicular) to the fault line, determine the intersection of the target layer and the fault on the longitudinal section, obtain the apparent vertical fault throw, apparent horizontal dip displacement and apparent dip angle β of the target layer segment from the intersection, and clarify the corresponding geometric conversion relationship between them.

[0070] Step 3: Obtain the target layer and the upper and lower wall fault lines and fracture surface depth data to perform three-dimensional spatial structural modeling.

[0071] Seismic volumetric spatial sampling data is obtained for the target layer and the upper and lower wall fault lines and surfaces. Stereoscopic images of the target layer and fault surface are generated, and three-dimensional geological structural modeling is performed. A three-dimensional model of the fault slip along the fault surface is constructed, and spatial and planar conversion relationships between geometric elements such as the target fault breakpoints and the fault surface contour lines are established. The upper and lower wall fault lines are identified, and the fracture surface contour lines are drawn.

[0072] Step 4: Calculate the parameters of the fault surface, such as strike, dip and inclination, and extract the fault surface attributes from the seismic volume.

[0073] The seismic data volume is used to calculate the fault surface attitude parameters, and coherent slices, curvature, dip scan, amplitude and other attributes are extracted along the fault surface. The spatial changes of the fault surface are analyzed, and the change characteristics of the fracture surface structural map and three-dimensional stereogram are integrated. According to the direction of the fault line of the upper and lower walls, the fault surface is divided into blocks and evaluated in sections according to the principle that the fracture surface dip is relatively consistent and the fracture surface contour lines are relatively straight.

[0074] Step 5: Establish a cutting reference surface along the fracture surface and perpendicular to the fault line.

[0075] Establish geometric operation relationships between target fault breakpoints and between the fracture surface contour lines and the three-dimensional projection of the fault line. Select the hanging wall fault line and establish a series of cutting reference surfaces RP along the fracture surface dip direction and passing through different positions of the fault line breakpoints. Establish a series of cutting reference surfaces SP perpendicular to the footwall line strike and passing through different positions of the hanging wall fault line breakpoints.

[0076] Step 6: Obtain the intersection line between the fracture surface inclination reference surface and the fracture surface, extract the intersection line endpoint distance, and calculate the horizontal fault distance and vertical fault distance;

[0077] Obtain the intersection line IL between the cutting reference surface RP, which runs along the fault surface's dip direction and passes through the fault line breakpoint on the hanging wall, and the fault surface. The length of the spatial curved surface ΔL between the hanging wall and the hanging wall represents the total slip along the fault surface. The horizontal projection of the intersection line is the horizontal fault throw ΔD. The vertical fault throw ΔH is calculated as: ΔH = ΔD * cotα, where α is the true dip of the fault and ΔD is the horizontal fault throw (unit: m).

[0078] Step 7, obtaining the intersection line of the reference plane perpendicular to the fault line and the fracture plane and the distance between their endpoints, and calculating the plane projection distance and vertical displacement;

[0079] Obtain the intersection line AL between the cutting reference surface SP, which is perpendicular to the footwall fault line and passes through the hanging wall breakpoint, and the fault surface. The spatial length ΔAL of the intersection line between the hanging and footwalls is the total apparent slip along the fault surface. The horizontal projection of the intersection line AL is the horizontal apparent fault distance ΔD0. The vertical apparent fault distance ΔH0 is calculated as: ΔH0 = ΔD * cotβ. Where β is the apparent inclination angle, and ΔD0 is the horizontal apparent fault distance (unit: m).

[0080] Step 8, obtaining the displacement along the fault surface;

[0081] Using the three-dimensional visualization of the fault line, fracture surface contour line, and fracture surface intersection line IL and AL, the corresponding geometric projection relationship is constructed, and the strike displacement ΔSD is obtained using the spatial modeling data volume;

[0082] Step 9, obtaining vertical and horizontal displacement variables at different breakpoints on the fracture surface;

[0083] The calculation formula for the vertical displacement variable Δh of the fault surface is: Δh = ΔH - ΔH0; the calculation formula for the horizontal displacement variable Δd of the fault surface is: Δd = Δh / tanθ, unit, m; where θ is the angle between the fault line and the fracture surface contour line, unit, degree.

[0084] Step 10, obtaining the three-dimensional displacement variable of the fracture;

[0085] By utilizing the differences in horizontal and vertical displacements at different breakpoints of the fault, different positions of the fault line are quantitatively characterized and traced back to restore the source, and the differential trajectory of the fault activity is obtained.

[0086] Step 11: Characterization of spatiotemporal differences in fault activity;

[0087] 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 along the fault surface are obtained to characterize the spatiotemporal differences in fault activity and construct the spatiotemporal difference trajectory of the fault slip.

[0088] Specifically, it includes: obtaining the geological time ΔT of the target layer segment deposition based on the geological time scale, taking the ratio of the total horizontal dip fault distance to the deposition time of the target layer segment as the fault activity rate along the dip, which is used 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 layer segment as the fault strike activity rate, which is used 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 layer segment as the fault vertical activity rate, which is used to characterize the activity intensity of the fault along the vertical direction; and successively characterizing the differential characteristics of spatial activities at different positions and different layers of the fault line.

[0089] Example 2

[0090] In a specific embodiment 2 of the present invention, as Figure 1 As shown, Figure 1 This is a flow chart of the fracture surface geometric element description method based on structural modeling of the present invention.

[0091] Step 101: Obtain the target layer seismic reflection interface structure map through 3D seismic data and velocity field data. Figure 2 As shown in the figure, 3D seismic and velocity field data were used to interpret the isochronous structure of the T6 seismic reflection horizon in the Panhe area, generating an isochronous seismic reflection layer structural map. Simultaneously, the boundary faults of the target layer were interpreted. Time-depth conversion was performed using well logging data, a time-depth conversion plate, and velocity field data, generating an isochronous structural plan view of the target layer interface and its boundary fault surface.

[0092] In step 102, the structural map obtained in step 101 is used to obtain a core section of the seismic interpretation results perpendicular to the fault line. Figure 3 As shown, the intersection of the target layer and the fault is determined on the seismic section, the apparent vertical fault throw, apparent horizontal fault throw and apparent dip of the target layer are obtained, and the geometric conversion relationship between them is established.

[0093] In step 103, a three-dimensional diagram of the corresponding relationship between the upper and lower wall fault lines of the target layer and the fault points and the fracture surface contour lines in the three-dimensional space is constructed, such as Figure 4 In the figure, P is the fault point on the hanging wall, E is the intersection of the reference plane passing through point P along the dip direction of the fault plane and the footwall fault line; point F is the intersection of the reference plane passing through point P perpendicular to the footwall fault line and the footwall fault line; β is the angle between the horizontal plane and PF. The angle α between the fault plane and the horizontal plane is the true dip of the fault plane and can be expressed and converted using the following formula: tanα = ΔH / ΔD. α is the true dip, ΔH is the spacing between the normal contour lines on the fault plane structural map, and ΔD is the horizontal distance between the normal contour lines (unit: meters). The apparent dip angle is also calculated using the above formula.

[0094] In step 104, Figure 4 As shown in Figure 1, the fault line intersects the fracture surface contour line at point F along the contour line, intersecting EP at point G. Here, ∠GFE = ∠GPF = ∠θ, where θ is the angle between the footwall fault line and the contour line. EF is the strike displacement; EA is the horizontal fault throw; and PA is the vertical fault throw.

[0095] In step 105, the target layer interface information and fracture surface data are used to perform geological structure modeling. Figure 5 As shown, a cutting reference surface perpendicular to the footwall is established point by point from the breakpoint of the descending wall (hanging wall), and a cutting reference surface passing through the breakpoint and along the inclination direction of the fracture surface is established to obtain a series of intersection lines with the fracture surface.

[0096] In step 106, the length of the intersection line segment, i.e. the total slip distance, is extracted point by point and line by line. The result is as follows: Figure 6 The plane projection distance of the intersection endpoint is the horizontal displacement distance, and the plane diagram shown in Figure 7 is obtained; the depth difference of the intersection is the vertical displacement distance, and the plane diagram shown in Figure 7 is obtained. Figure 8 Floor plan shown.

[0097] In step 107, using the fracture surface structure diagram, according to Figure 9 As shown in the figure, the intersection point of the OPR surface of the vertical fault surface contour line and the uplifted plate is E, and the intersection point of the OPS surface of the vertical uplifted plate fault line and the uplifted plate is F. EF is the strike displacement ΔSD. Extract point by point and obtain the plane diagram of the strike displacement of the fault surface, as shown in the figure. Figure 10 shown.

[0098] Based on the geological time scale, the geological time of deposition of the target layer is ΔT; based on the fault strike displacement, total dip slip, and vertical displacement, the strike slip rate, dip slip rate, and vertical activity rate of the target layer along the fault surface can be obtained. Specifically, the ratio of the horizontal dip total slip distance to the target layer deposition time period is used as the fault dip activity rate, which is used to characterize the activity intensity of the fault along the fault surface; the ratio of the horizontal strike displacement distance to the target layer deposition time period is used as the fault strike activity rate, which is used to characterize the activity intensity of the fault along the strike; and the ratio of the vertical displacement distance to the target layer deposition time period is used as the fault vertical activity rate, which is used to characterize the activity intensity of the fault along the vertical direction.

[0099] Quantitative characterization and traceability restoration are carried out at different locations along the fault, and the differences in horizontal and vertical displacements at different breakpoints of the fault are used to construct differential fault slip trajectories; layering and segmentation can characterize the differential characteristics of the spatiotemporal activities of the fault.

[0100] Example 3:

[0101] In the third embodiment of the present invention, the method for describing the geometric elements of a fracture surface based on structural modeling includes the following steps:

[0102] Step 101: Obtain the target layer seismic reflection interface structure map through 3D seismic data and velocity field data. Figure 11 As shown in the figure, the structural interpretation of the T6 seismic reflection layer and the main fault in the layer in the Linbei area was carried out using 3D seismic data and velocity field data, and the isobath structural plan was obtained using well logging data, time-depth conversion plate and velocity field data.

[0103] In step 102, the structural map obtained in step 101 is used to obtain a core section of the seismic interpretation results perpendicular to the fault line. Figure 12 As shown in the figure, the intersection of the T6 layer and the fault is determined on the seismic section, the apparent vertical fault throw, apparent horizontal fault throw and apparent dip of the fault surface of the target layer are obtained, and the geometric conversion relationship between them is established.

[0104] In step 103, a three-dimensional diagram of the corresponding relationship between the upper and lower wall fault lines of the target layer and the fault points and the fracture surface contour lines in the three-dimensional space is constructed, such as Figure 4 In the figure, P is the fault point on the hanging wall, E is the intersection of the reference plane passing through point P along the dip direction of the fault plane and the footwall fault line; point F is the intersection of the reference plane passing through point P perpendicular to the footwall fault line and the footwall fault line; β is the angle between the horizontal plane and PF. The angle α between the fault plane and the horizontal plane is the true dip of the fault plane and can be expressed and converted using the following formula: tanα = ΔH / ΔD. α is the true dip, ΔH is the spacing between the normal contour lines on the fault plane structural map, and ΔD is the horizontal distance between the normal contour lines (unit: meters). The apparent dip angle is also calculated using the above formula.

[0105] In step 104, Figure 4 As shown in Figure 1, the fault line intersects the fracture surface contour line at point F along the contour line, intersecting EP at point G. Here, ∠GFE = ∠GPF = ∠θ, where θ is the angle between the footwall fault line and the contour line. EF is the strike displacement; EA is the horizontal fault throw; and PA is the vertical fault throw.

[0106] In step 105, the target layer interface information and the fracture surface data are used to build a geological structure model. Figure 13 As shown, a cutting reference surface perpendicular to the footwall is established point by point from the breakpoint of the descending wall (hanging wall), and a cutting reference surface passing through the breakpoint and along the inclination direction of the fracture surface is established to obtain a series of intersection lines with the fracture surface.

[0107] In step 106, the length of the intersection line segment, i.e. the total slip distance, is extracted point by point and line by line. The result is as follows: Figure 14 The plane projection distance of the intersection endpoints is the horizontal displacement distance, and the plane diagram shown in Figure 15 is obtained; the depth difference of the intersection is the vertical displacement distance, and the plane diagram shown in Figure 16 is obtained.

[0108] In step 107, using the fracture surface structure diagram, according to Figure 9 As shown in the figure, the intersection point of the OPR surface of the vertical fault surface contour line and the uplifted plate is E, and the intersection point of the OPS surface of the vertical uplifted plate fault line and the uplifted plate is F. EF is the strike displacement ΔSD. Extract point by point and obtain the plane diagram of the strike displacement of the fault surface, as shown in the figure. Figure 17 shown.

[0109] Example 4:

[0110] In the specific embodiment 4 of the present invention, Figure 1 This is a flow chart of the fracture surface geometric element description method based on structural modeling of the present invention.

[0111] Step 101: Obtain a seismic reflection interface structural map of the target layer using 3D seismic data and velocity field data. Using 3D seismic and velocity field data, a structural interpretation of the T6 seismic reflection horizon and main fault in the Tianjia area is performed. A structural iso-depth plan view is obtained using well logging data, time-depth conversion plates, and velocity field data.

[0112] In step 102, the structural map obtained in step 101 is used to obtain a core section of the seismic interpretation results perpendicular to the fault line. Figure 18 As shown in the figure, the intersection of the T6 layer and the fault is determined on the seismic section, the apparent vertical fault throw, apparent horizontal fault throw and apparent dip of the fault surface of the target layer are obtained, and the geometric conversion relationship between them is established.

[0113] In step 103, a three-dimensional diagram of the corresponding relationship between the upper and lower wall fault lines of the target layer and the fault points and the fracture surface contour lines in the three-dimensional space is constructed, such as Figure 4 In the figure, P is the fault point on the hanging wall, E is the intersection of the reference plane passing through point P along the dip direction of the fault plane and the footwall fault line; point F is the intersection of the reference plane passing through point P perpendicular to the footwall fault line and the footwall fault line; β is the angle between the horizontal plane and PF. The angle α between the fault plane and the horizontal plane is the true dip of the fault plane and can be expressed and converted using the following formula: tanα = ΔH / ΔD. α is the true dip, ΔH is the spacing between the normal contour lines on the fault plane structural map, and ΔD is the horizontal distance between the normal contour lines (unit: meters). The apparent dip angle is also calculated using the above formula.

[0114] In step 104, Figure 4 As shown in Figure 1, the fault line intersects the fracture surface contour line at point F along the contour line, intersecting EP at point G. Here, ∠GFE = ∠GPF = ∠θ, where θ is the angle between the footwall fault line and the contour line. EF is the strike displacement; EA is the horizontal fault throw; and PA is the vertical fault throw.

[0115] In step 105, the target layer interface information and the fracture surface data are used to build a geological structure model. Figure 19 As shown, a cutting reference surface perpendicular to the footwall is established point by point from the breakpoint of the descending wall (hanging wall), and a cutting reference surface passing through the breakpoint and along the inclination direction of the fracture surface is established to obtain a series of intersection lines with the fracture surface.

[0116] In step 106, the length of the intersection line segment, i.e. the total slip distance, is extracted point by point and line by line. The result is as follows: Figure 20 The plane projection distance of the intersection endpoints is the horizontal displacement distance, and the plane diagram shown in Figure 21 is obtained; the depth difference of the intersection is the vertical displacement distance, and the plane diagram shown in Figure 22 is obtained.

[0117] In step 107, using the fracture surface structure diagram, according to Figure 9 As shown in the figure, the intersection point of the OPR surface of the vertical fault surface contour line and the uplifted plate is E, and the intersection point of the OPS surface of the vertical uplifted plate fault line and the uplifted plate is F. EF is the strike displacement ΔSD. Extract point by point and obtain the plane diagram of the strike displacement of the fault surface, as shown in the figure. Figure 23 shown.

[0118] The present invention's fracture surface geometric element description method, based on structural modeling, can quantitatively obtain the displacement distance of geological bodies sliding along the fracture surface, accurately calculate the displacement along the strike direction, and finely describe the horizontal and vertical slip variables. This method can spatially locate the slip trajectory and digitally quantify the characteristics of the target fault activity differences. This restoration method provides an effective approach for provenance tracing, oil and gas sealing, and characterizing the spatial displacement vectors of the fracture. It also lays a foundation for the analysis of tectonic activity differences, paleogeomorphological restoration, and its application in geology and oil and gas exploration.

[0119] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0120] 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 fracture surface geometric element description method based on structural modeling, characterized by: The fracture surface geometric element description method based on structural modeling includes: Step 1: Obtain the seismic reflection layer structure map of the target layer segment and boundary fault surface; Step 2: Establish the core section of seismic data interpretation results; Step 3, constructing a three-dimensional model diagram of the fault sliding along the fracture surface; Step 4: Obtain geometric parameters such as the fracture surface inclination, strike, and dip; Step 5: Use the target layer interface information and fracture surface data to perform geological structure modeling; Step 6: Obtain the strike displacement along the fault surface, as well as the vertical and horizontal displacement variables at different breakpoints on the fault surface; Step 7, obtaining a plane diagram of displacement along the sliding direction of the fracture surface; Step 8: Characterization of spatiotemporal differences in fault activity; In step 1, a structural interpretation is performed on the target horizon and the boundary fault surface using three-dimensional or two-dimensional seismic data and actual drilling data to form an iso-T0 seismic reflection layer structural map. Time-depth conversion is performed using well logging data, time-depth conversion data, and velocity field data to form an iso-depth structural map of the target layer reflection interface and fault surface. The target horizon includes the boundary fault of the target layer, and the intersection line of the fault surface and the horizon is used to obtain the strike and apparent length of the upper and lower walls of the fault on the plane map. In step 3, the depth data of the upper and lower wall fault lines and fracture surfaces of the target layer are obtained, and a three-dimensional geological structure model is constructed to produce a three-dimensional stereogram of the target layer and fracture surface, and a three-dimensional model of the fault sliding along the fracture surface is constructed; the geometric operation relationship between the target fracture breakpoint distance and the fracture surface contour line and the fault line space and plane is established, and the fault line and contour line are marked; Step 5 includes: Step 51, establishing a cutting reference surface along the fracture surface inclination direction and perpendicular to the fault line; Step 52, obtaining the intersection line between the reference surface and the fracture surface along the fracture surface inclination, extracting the distance between the breakpoint curves, and calculating the horizontal fault distance and the vertical fault distance; Step 53, obtaining the intersection line between the cutting reference surface of the vertical fault line and the fracture surface, extracting the intersection distance, and calculating the plane projection distance and vertical displacement; In step 51, a hanging wall fault line is selected, and a series of cutting reference surfaces RP are established along the dip direction of the fault surface at different breakpoints of the fault line, and a series of cutting reference surfaces SP are established along the strike direction of the footwall fault line at different breakpoints of the fault line. Step 6 includes: Step 61, obtaining the displacement along the fracture surface; Step 62, obtaining vertical and horizontal displacement variables at different breakpoints on the fracture surface; In step 61, a projection conversion relationship between corresponding geometric elements is established using a three-dimensional visualization of fault lines, fracture surface contour lines, and fracture surface intersection lines IL and AL, and the strike displacement ΔSD is obtained using a spatial modeling data volume.

2. The method for describing fracture surface geometric elements based on structural modeling according to claim 1, characterized in that: In step 2, a basic section of the seismic interpretation results perpendicular to the fault line is established, and the apparent vertical fault throw, apparent horizontal dip displacement and apparent dip angle β of the target layer are obtained from the intersection of the fault and the horizon, and the corresponding geometric conversion relationship is established.

3. The method for describing fracture surface geometric elements based on structural modeling according to claim 1, characterized in that: In step 4, the parameters of the strike, dip and inclination of the fault surface are extracted, and the spatial changes of the fault surface are analyzed using the seismic attributes of the target fault surface. An attribute analysis diagram is drawn, and the characteristics of the plane structural diagram and the three-dimensional stereogram of the fault surface are integrated. According to the changes in the fault lines of the upper and lower walls, the fault surface is divided into blocks and evaluated in sections according to the principle that the fault surface dips are relatively consistent and the fracture contour lines are relatively straight.

4. The method for describing fracture surface geometric elements based on structural modeling according to claim 1, characterized in that: In step 52, the intersection line IL of the cutting reference surface RP and the fault surface along the dip direction of the fault surface is obtained. The length of the spatial curved surface ΔL of the intersection line between the upper and lower plates is the dip displacement along the fault surface. The length of the intersection line on the horizontal projection plane is the horizontal fault distance ΔD. The vertical fault distance ΔH is calculated as: ΔH = ΔD*cotα; where α is the true dip angle of the fault surface, and ΔD is the horizontal fault distance, in meters.

5. The method for describing fracture surface geometric elements based on structural modeling according to claim 1, characterized in that: In step 53, the intersection line AL of the cutting reference surface SP passing through the footwall breakpoint position and perpendicular to the fault line strike direction and the fracture surface is obtained. The spatial displacement length ΔAL of the intersection line between the footwall and the footwall is the apparent inclination displacement along the fracture surface. The projection distance of the intersection line AL on the horizontal plane is the horizontal apparent fracture distance ΔD0. The conversion formula for the vertical apparent fracture distance ΔH0 is: ΔH0 = ΔD*cotβ; where β is the apparent inclination angle of the fracture surface, and ΔD is the horizontal apparent fracture distance, in meters.

6. The fracture surface geometric element description method based on structural modeling according to claim 1 is characterized in that: In step 62, the calculation formula for the vertical displacement variable Δh of the fracture surface is: Δh = ΔH - ΔH0; the calculation formula for the horizontal displacement variable Δd of the fracture surface is: Δd = Δh / tanθ, unit, m; where θ is the angle between the fault line and the fracture surface contour line, unit, degree.

7. The method for describing fracture surface geometric elements based on structural modeling according to claim 1, characterized in that: In step 7, the differences in horizontal and vertical displacements at different breakpoints of the fault are used to quantitatively characterize and trace the fault line to construct a differential trajectory of fault activity.

8. The method for describing fracture surface geometric elements based on structural modeling according to claim 1, characterized in that: The method for describing fracture surface geometric elements based on structural modeling further includes, after step 7, performing differential characterization of fracture spatiotemporal activities.

9. The method for describing fracture surface geometric elements based on structural modeling according to claim 8, characterized in that: The geological time ΔT of the target layer is obtained based on the geological time scale. The sliding rate, sliding rate and vertical activity rate of the target fault along the fault surface are obtained according to the strike displacement, dip displacement and vertical displacement of the fault. The differential characteristics of the temporal and spatial activities of the fault are characterized and the differential slip trajectory of the fault is constructed.

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