Method for determining fracture basin ancient buried hill recoil structure extrusion resurgence geological age

Abstract

The invention belongs to the technical field of oil exploration. The invention discloses a method for determining the age of extrusion resurgence geology of a backlash structure of an ancient and buried hill in a broken basin, and the method comprises the steps: determining the top surface of the ancient and buried hill and the trend of a regional normal fault on a three-dimensional seismic data body of the broken basin subjected to three-dimensional inclination median filtering processing. And determining a thrust fault on a seismic section basically parallel to the trend of the regional normal fault. And recognizing the reverse thrusting anticline structure according to the morphological characteristics of the top surface of the ancient diving mountain. And identifying a slope edge seismic facies, an upper super-irregular seismic reflection interface and a seismic reflection interface corresponding to a fault displacement vanishing point of the thrust fault on an overlying stratum of a footwall of the thrust fault. And determining the starting time and the ending time of the extrusion resurgence of the thrust fault, and determining the geological time stage between the starting time and the ending time as the geological age of the extrusion resurgence of the ancient buried hill thrust structure of the fault basin. By means of the method, the ancient buried hill recoil structure of the broken basin and the geological age of extrusion resurgence of the ancient buried hill recoil structure can be accurately recognized.

Description

Technical Field

[0001] The present invention belongs to the technical field of petroleum exploration, and more specifically, to a method for determining the geological age of the compression and resurrection of the thrust structure of an ancient buried hill in a fault basin. Background Art

[0002] A fault basin is a basin formed by extension under the combined action of regional extension and shear. Normal faults are also called extensional faults, specifically large-scale low-angle normal faults formed by regional extension. Most normal faults are formed in horizontal extension. Normal faults are the main identification structure and the most obvious structural feature of extensional basins.

[0003] During the geological evolution, fault basins often experience extensional strike-slip deformation. During this stress field stage, due to the decomposition of the shear stress field, extensional stress components and compressional stress components should develop simultaneously. While the strata are experiencing extension, they are also locally subjected to compression. Therefore, during the extensional strike-slip deformation stage, normal faults and thrust faults may coexist in the basin, resulting in compressional structures in the ancient buried hills in the late stage of basin evolution.

[0004] The buried hill is a trap structure formed by an ancient topographic protrusion that has been weathered and eroded for a long time and is covered by an overlying impermeable rock layer. The buried hill consists of two parts of the structure divided by an unconformity surface. Below the unconformity surface is the buried hill core composed of old rock layers and rock bodies, and above the unconformity surface is a drape structure composed of newer strata. The bedrock buried hill traps and the anticline traps of the overlying strata formed by late compression since the Cenozoic have become favorable oil and gas traps. The local fold structure formed by compression in the Paleogene has become an important anticline trap and can also be used as a favorable exploration target.

[0005] In the prior art, due to the extensional stress genesis of the fault basin, the reverse faults in the ancient buried hills of the fault basin are usually attributed to the compression paleo-tectonic stage before the development of the fault basin, ignoring the thrust effect of the reverse faults in the late fault stage, which is not conducive to the accurate determination of valuable anticline traps. Moreover, in the fault basin, normal faults are particularly developed on the seismic profile, and the tectonic changes and erosion and transformation during the evolution of the fault basin make the characteristics of the thrust faults inside the ancient buried hills relatively vague and usually difficult to identify. Furthermore, even if the problem of the difficulty in identifying the thrust faults is solved, there is still the problem that the geological age of their compression revival is difficult to determine, which is not conducive to the determination of valuable oil and gas traps.

[0006] Based on this, it is an urgent problem to be solved how to identify the specific age of the ancient buried hill thrust compression structure in the evolution stage of the fault basin through the interpretation of three-dimensional seismic data, considering that extension and local compression may exist simultaneously in the fault basin stage, so as to accurately predict the formation age of the ancient buried hill oil and gas reservoir. Summary of the invention

[0007] In order to at least solve one or more of the technical problems mentioned above, an embodiment of the present invention provides a method for determining the geological age of compression and resurrection of the ancient buried hill thrust structure in a fault basin, comprising: a first step, determining the top of the ancient buried hill and the strike of the regional normal fault on a three-dimensional seismic data volume of the fault basin processed by a three-dimensional dip median filter; a second step, determining the thrust fault on a seismic profile substantially parallel to the strike of the regional normal fault; a third step, identifying the thrust anticline structure on the hanging wall of the thrust fault according to the morphological characteristics of the top of the ancient buried hill; a fourth step, determining the thrust anticline structure on the hanging wall of the thrust fault; and a fifth step, determining the thrust anticline structure on the hanging wall of the thrust fault. The overlying strata of the footwall of the fault identify the slope edge seismic phase, the onlapping discontinuous seismic reflection interface located below the slope edge seismic phase, and the seismic reflection interface corresponding to the vanishing point of the fault throw of the thrust fault; the fifth step is to use the geological age of the onlapping discontinuous seismic reflection interface as the starting time of the compression resurrection of the thrust fault, and the geological age of the seismic reflection interface corresponding to the vanishing point of the fault throw of the thrust fault as the ending time of the compression resurrection of the thrust fault, and determine the geological time stage between the starting time and the ending time as the geological age of the compression resurrection of the ancient buried hill thrust structure in the fault basin.

[0008] According to one embodiment of the present invention, in the first step, the top of the ancient buried mountain is determined by at least one of the following characteristics: seismic inhomogeneity relationship, difference in seismic reflection characteristics and vertical change of seismic velocity; the strike of the regional normal fault is the overall extension direction of the fault basin.

[0009] According to one embodiment of the present invention, in the second step, thrust faults are determined by identifying seismic reflection discontinuities, surface waves and seismic velocity inversions.

[0010] According to one embodiment of the present invention, in the second step, a plurality of mutually parallel seismic sections are taken to identify thrust faults.

[0011] According to one embodiment of the present invention, in the third step, the thrust anticline structure is identified on the seismic profile and the 3D seismic isochronal slice, and the thrust anticline structure includes: the top of the ancient buried mountain, the hanging wall of the thrust fault, and the section of the thrust fault.

[0012] According to one embodiment of the present invention, in the fourth step, the seismic phase of the slope edge, the onlapping discontinuity seismic reflection interface, and the seismic reflection interface corresponding to the displacement vanishing point of the thrust fault are identified on the seismic profile of the overlying strata.

[0013] According to one embodiment of the present invention, in the fourth step, the slope edge seismic phase refers to: the seismic phase with a chaotic reflection structure, the seismic phase with a blank reflection structure, and the seismic phase with a wedge-shaped structure; the onlap inhomogeneous seismic reflection interface refers to: the seismic inhomogeneous interface with an onlap contact relationship.

[0014] According to one embodiment of the present invention, in the fourth step, in the overlying strata of the footwall of the thrust fault, the step of identifying the slope edge seismic phase precedes the step of identifying the onlapping inhomogeneous seismic reflection interface located below the slope edge seismic phase.

[0015] Through the method provided above, the embodiment of the present invention can accurately identify the thrust structure formed by the late compression and resurrection of the ancient buried hill in the fault basin.

[0016] In the present invention, by intercepting multiple seismic sections in a direction basically parallel to the strike of the regional normal fault, the thrust faults formed by tectonic compression in the fault basin stage can be effectively identified on these seismic sections, thus overcoming the problem of difficult identification of thrust faults inside the ancient buried hills in the fault basin.

[0017] In the present invention, the on-lapping inhomogeneous seismic reflection interface is identified in the overlying strata of the footwall of the thrust fault, and the starting time of the compression and resurrection of the ancient buried hill thrust structure in the fault depression deposition stage can be determined. The end time of the compression and resurrection of the ancient buried hill thrust structure in the fault depression deposition stage can be determined by the seismic reflection interface corresponding to the fault point of the thrust fault, so as to accurately determine the geological age of the compression and resurrection of the ancient buried hill thrust structure in the fault depression basin. The above method eliminates the drawback of conventionally determining the internal thrust structure of the ancient buried hill in the fault depression basin as the product of the early compression structure before the fault depression deposition, and provides a basis for determining valuable oil and gas traps. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0019] Figure 1 A schematic diagram of a three-dimensional seismic survey system is shown;

[0020] Figure 2 A schematic diagram showing the steps for determining the geological age of the compressional resurrection of the ancient buried hill thrust structure in the fault basin is shown;

[0021] Figure 3 A schematic diagram showing the identification of an onlapping seismic reflection interface on a seismic section of a thrust fault is shown;

[0022] Figure 4 A schematic diagram showing the identification of the seismic reflection interface corresponding to the breakpoint on another seismic section of the thrust fault. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] It should be understood that the terms "include" and "comprising" used in the description and claims of the present invention indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0025] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the claims, the singular forms of "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in the specification of the present invention and the claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0026] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0027] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] Figure 1 A schematic diagram of a three-dimensional seismic survey system is shown.

[0029] like Figure 1As shown, in the system 100, a plurality of mutually spaced detectors 110 for detecting seismic waves are arranged on the surface 101 of the exploration target area, forming a detector array covering the target area on a plane, and these detectors 110 are connected to the seismic information processing device by wired or wireless connection, and a plurality of seismic sources 120 are also arranged. The seismic information processing device can perform preliminary processing on the seismic data. The working process of the three-dimensional seismic exploration system is: artificially excite the seismic sources 120 located at multiple positions to generate seismic waves, which are reflected from the boundary of the stratum 102 and received by the detector array to form seismic information collected on a plane and changing with time. The seismic information received by the detector array represents certain measurements of seismic wave energy as a function of time, such as displacement, velocity, wave impedance, pressure, etc. This information can be grouped in different ways, such as traces, sets, etc., and then processed or format converted according to the corresponding relationship between time and space to form a three-dimensional seismic data body in the form of a three-dimensional array, that is, high-quality three-dimensional seismic fine imaging data is obtained, and the three-dimensional seismic data body is formed by spatial stacking of interface points. The interpretation of three-dimensional seismic data can observe the morphology of geological interfaces from different directions and study the changes of geological bodies in three-dimensional space by cutting cross sections, longitudinal sections and horizontal slices.

[0030] Figure 2 A schematic diagram of the steps for determining the geological age of compressional resurrection of ancient buried hill thrust structures in fault basins is shown.

[0031] like Figure 2 As shown, a method 200 for determining the geological age of compression and resurrection of the thrust structure of the ancient buried hill in the fault basin comprises: a first step S201, determining the top of the ancient buried hill and the strike of the regional normal fault on the three-dimensional seismic data volume of the fault basin processed by the three-dimensional dip median filter. A second step S202, determining the thrust fault on the seismic profile substantially parallel to the strike of the regional normal fault. A third step S203, identifying the thrust anticline structure in the upper plate of the thrust fault according to the morphological characteristics of the top of the ancient buried hill. A fourth step S204, identifying the slope edge seismic phase, the upper overlapped inhomogeneous seismic reflection interface located below the slope edge seismic phase, and the seismic reflection interface corresponding to the displacement vanishing point of the thrust fault in the overlying strata of the footwall of the thrust fault. The fifth step S205, takes the geological age of the onlapping uneven seismic reflection interface as the starting time of the thrust fault compression resurrection, takes the geological age of the seismic reflection interface corresponding to the displacement vanishing point of the thrust fault as the ending time of the thrust fault compression resurrection, and determines the geological time stage between the starting time and the ending time as the geological age of the compression resurrection of the ancient buried hill thrust structure in the fault basin. In the present invention, the first step to the fifth step are performed progressively.

[0032] In the three-dimensional seismic data volume, the normal faults in the ancient buried hill area of ​​the fault basin are more prominent representative structures. Regional normal faults refer to large-scale low-angle normal faults formed by regional extension, and their strike is basically consistent with the overall extension direction of the fault basin. The overall extension direction refers to the main extension direction of the fault basin, ignoring the influence of its local bending and shape changes. The overlying strata refer to the impermeable rock layers overlying the ancient buried hill, which can be directly interpreted from the seismic longitudinal section. The top of the ancient buried hill can be read directly on the section.

[0033] In the first step S201, the 3D seismic data volume of the fault basin can be obtained by Figure 1 The system acquisition in the 3D seismic data can be obtained, and the data with high signal-to-noise ratio can be obtained by preprocessing with the 3D dip median filter. The 3D dip median filter preprocessing method belongs to the prior art and will not be described in detail in the present invention. By interpreting the strata and faults of the 3D seismic data body, the regional normal faults and overlying strata can be identified. For example, the 3D seismic data body is preprocessed to eliminate high-frequency noise, improve the fault identification ability, improve the fault interpretation accuracy, and perform seismic coherence processing, and then interpret the strata and faults, and identify the sliding faults with the downward sliding tendency of the upper plate relative to the lower plate in the seismic profile, and obtain the shape, dip, distribution range and other information of the normal faults. The strata above the top surface of the bedrock unconformity in the 3D seismic data body are classified as overlying strata. For another example, the 3D seismic data body can be imported into the existing seismic data recognition software, such as Landmark software, to automatically output the results of the strata and fault interpretation, and identify the regional normal faults and overlying strata based on the results.

[0034] Optionally, the top of the ancient buried mountain is determined by at least one of the following characteristics: seismic inhomogeneity, difference in seismic reflection characteristics, and vertical change in seismic velocity. That is, the top of the ancient buried mountain is related to the seismic inhomogeneity, and the top of the ancient buried mountain exists when there is an onlap of the bottom interface of the upper stratum and / or there is erosion of the top interface of the lower stratum. Alternatively, there are obvious differences in seismic reflection characteristics (frequency, amplitude, structure) above and below the top of the ancient buried mountain, and the structure refers to the direction, continuity, length of the axis, etc. of the event axis. Alternatively, there is a velocity mutation in the seismic velocity spectrum above and below the top of the ancient buried mountain. These three elements can be used in combination or separately.

[0035] The late structural compression of the basin makes the structural style of the fault basin more complex, which has an important impact on the oil and gas accumulation conditions and patterns. The late compression since the Cenozoic formed the ancient buried hill trap and the anticline trap of the overlying strata. The local fold structure formed by compression in the Paleogene has become an important anticline trap, which can be used as a favorable exploration target. The pre-formed faults in the bedrock of the ancient buried hill were revived again under the compression in the late Paleogene, which can improve the physical properties of the bedrock reservoir. The bedrock reservoir itself is relatively dense and the reservoir properties are relatively underdeveloped, but under the late action of the thrust fault, a large number of fractures and cracks will be generated, which greatly improves and increases the porosity and permeability of the bedrock reservoir and has the potential to become a high-quality reservoir.

[0036] In the late Paleogene, the source rocks in the basin began to enter the hydrocarbon generation threshold, and oil and gas began to be generated in large quantities. This is because the thrust faults formed by tectonic compression began to become active, which is conducive to the vertical migration of oil and gas. Because the transport capacity of faults in the active period is greater than that in the static period, it is more conducive to the migration and accumulation of oil and gas.

[0037] Due to the late compression effect of the fault basin, the oil and gas accumulation conditions in the basin have changed, the oil and gas accumulation pattern has been enriched, and a relatively important impact has been exerted on the basin's accumulation effect.

[0038] Based on this, in the second step S202, thrust faults are identified in a local area, where the local area is defined by a regional normal fault. Specifically, thrust faults are identified along a seismic section in a direction substantially parallel to the strike of the regional normal fault.

[0039] In the seismic profile that is parallel or substantially parallel to the dip of the regional normal fault, the thrust fault cannot be effectively identified. This is because the formation of this thrust fault is caused by late compression, and its compression stress component is perpendicular to the tensile stress component, and the tensile stress component is consistent with the dip of the normal fault. In the present invention, the inventors have adopted a direction that is substantially parallel to the strike of the regional normal fault to identify the thrust fault in the bedrock of the ancient buried hill. Substantially parallel means that the angle between the direction of the seismic profile and the strike of the regional normal fault is not greater than 10 degrees, including every value between 0 degrees and 10 degrees or a numerical interval consisting of any two values.

[0040] By identifying thrust faults in the bedrock of the ancient buried hill in a direction that is basically parallel to the strike of the regional normal fault, thrust faults formed by strike-slip or compression can be effectively identified. In addition, the intersection between the top of the ancient buried hill and the cross section can assist in determining that the strike of the fault is a thrust strike. This thrust fault structure has the effect of improving and increasing porosity and permeability, which is conducive to reservoir formation. Specific identification of it is conducive to finding effective oil and gas traps.

[0041] According to one embodiment of the present invention, in the process of identifying thrust faults, multiple seismic sections are selected, and thrust faults are identified on each seismic section to determine the direction, position, shape and distribution range of the thrust faults. Preferably, the multiple seismic sections are parallel to each other.

[0042] By selecting multiple seismic sections, thrust faults can be identified separately on seismic sections at different locations, which can reduce the omission of related thrust faults. When selecting seismic sections, the selection range depends on the distribution form and range of regional normal faults, and can identify mutually constrained and interrelated reservoir-forming structures.

[0043] According to one embodiment of the present invention, thrust faults are identified based on at least one of the following characteristics: ancient buried hill seismic reflection event breakpoints, fault waves, seismic velocity reversal characteristics, and three-dimensional seismic isochronal slice fault identification basis.

[0044] In the present invention, different characteristics of thrust faults are combined to identify thrust faults, which can greatly improve the situation that is difficult to identify and increase the success rate and accuracy of identification.

[0045] In the third step S203, after the thrust fault is determined, the structure of the thrust anticline is further determined, which is a typical structure that benefits oil reservoirs. Since the top of the ancient buried mountain has been located in the first step and the thrust fault has been located in the second step, the thrust anticline structure can be identified in the hanging wall of the thrust fault according to the morphological characteristics of the top of the ancient buried mountain.

[0046] Due to the influence of multiple factors such as extension and strike-slip, it is difficult to identify the thrust anticline structure on a seismic section at a certain angle. When identifying the thrust anticline structure, a rotation axis is set in advance in the overlying strata above the thrust fault, and multiple seismic sections are selected to identify the thrust anticline structure by rotating around the preset rotation axis. Preferably, the angle between adjacent seismic sections is 2°-15°, which can be evenly distributed or unevenly distributed. For example, the angles are 3° and 6° respectively.

[0047] In the present invention, the rotation axis is pre-set, the seismic section is selected by rotation, and the thrust anticline structure is comprehensively identified on the seismic sections at multiple angles, which can effectively identify and reduce omissions.

[0048] Preferably, the preset rotation axis is set within the distribution range of the thrust fault, which can narrow the identification range.

[0049] Preferably, different rotation axes may be selected multiple times within the distribution range of the thrust faults, and seismic profiles may be selected respectively.

[0050] The accuracy of identification can be improved by scanning and identifying the overlying strata within the distribution range of the thrust fault using rotating seismic profiles.

[0051] In the fourth step S204, the compression resurrection time of the thrust fault is identified, and the marks of the start time and the end time of the compression resurrection of the thrust fault are located respectively: that is, the onlapping discontinuous seismic reflection interface located below the slope edge seismic phase and the seismic reflection interface corresponding to the displacement vanishing point of the thrust fault.

[0052] Figure 3 A schematic diagram showing the identification of an onlapping seismic reflection interface on a seismic section of a thrust fault is shown.

[0053] In order to locate the upper-overlapping inhomogeneous seismic reflection interface that can represent the starting time, first, identify the characteristic seismic phase A of the slope edge formed by the compression of the thrust fault S, that is, the seismic phase with a chaotic reflection structure, the seismic phase with a blank reflection structure, and the seismic phase with a wedge structure. Identify the overlying strata located in the footwall. The footwall includes bedrock and overlying strata. The overlying strata contain characteristic seismic phases. Secondly, after locating these slope edge seismic phases, the upper-overlapping inhomogeneous seismic reflection interface B can be located below the seismic phase as a marker of the starting time.

[0054] Figure 4 A schematic diagram showing the identification of the seismic reflection interface corresponding to the breakpoint on another seismic section of the thrust fault.

[0055] In order to locate the seismic reflection interface that can represent the end time, first, the breakpoint C at the highest position of the thrust fault S when the compression ends is identified, and then the seismic phase axis D corresponding to the breakpoint is located as a mark of the end time.

[0056] The fifth step S205 is executed to determine the geological time period between the start time and the end time as the geological age of compression and resurrection of the ancient buried hill thrust structure in the fault basin.

[0057] Through the method provided above, the embodiment of the present invention can accurately identify the thrust structure formed by the late compression and resurrection of the ancient buried hill in the fault basin.

[0058] In the present invention, by intercepting multiple seismic sections in a direction basically parallel to the strike of the regional normal fault, the thrust faults formed by tectonic compression in the fault basin stage can be effectively identified on these seismic sections, thus overcoming the problem of difficult identification of thrust faults inside the ancient buried hills in the fault basin.

[0059] In the present invention, the on-lapping inhomogeneous seismic reflection interface is identified in the overlying strata of the footwall of the thrust fault, and the starting time of the compression and resurrection of the ancient buried hill thrust structure in the fault depression deposition stage can be determined. The end time of the compression and resurrection of the ancient buried hill thrust structure in the fault depression deposition stage can be determined by the seismic reflection interface corresponding to the fault point of the thrust fault, so as to accurately determine the geological age of the compression and resurrection of the ancient buried hill thrust structure in the fault depression basin. The above method eliminates the drawback of conventionally determining the internal thrust structure of the ancient buried hill in the fault depression basin as the product of the early compression structure before the fault depression deposition, and provides a basis for determining valuable oil and gas traps.

[0060] Although multiple embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may conceive of many changes, modifications, and alternatives without departing from the thought and spirit of the present invention. It should be understood that in the process of practicing the present invention, various alternatives to the embodiments of the present invention described herein may be adopted. The appended claims are intended to define the scope of protection of the present invention, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for determining the geological age of the compression resurrection of the ancient buried hill thrust structure in the fault basin, characterized in that: include: The first step is to determine the top of the ancient buried mountain and the strike of the regional normal fault on the 3D seismic data volume of the fault basin after 3D dip median filtering; The second step is to identify thrust faults on a seismic section substantially parallel to the strike of normal faults in the region; The third step is to identify the thrust anticline structure in the hanging wall of the thrust fault according to the morphological characteristics of the top of the ancient buried mountain; The fourth step is to identify the slope edge seismic phase, the onlapping discontinuity seismic reflection interface below the slope edge seismic phase, and the seismic reflection interface corresponding to the throw vanishing point of the thrust fault in the overlying strata of the footwall of the thrust fault; The fifth step is to use the geological age of the onlapping uneven seismic reflection interface as the starting time of the compression resurrection of the thrust fault, and the geological age of the seismic reflection interface corresponding to the vanishing point of the thrust fault as the ending time of the compression resurrection of the thrust fault, and determine the geological time period between the starting time and the ending time as the geological age of the compression resurrection of the ancient buried hill thrust structure in the fault basin.

2. The method according to claim 1, characterized in that In the first step, the top of the ancient buried mountain is determined by at least one of the following characteristics: seismic inhomogeneity relationship, seismic reflection characteristic difference and vertical change of seismic velocity; The strike direction of the normal faults in the region is the general extension direction of the fault basin.

3. The method according to claim 1, characterized in that In the second step, the thrust faults are determined by identifying seismic reflection discontinuities, surface waves and seismic velocity reversals.

4. The method according to claim 1, characterized in that: In the second step, a plurality of mutually parallel seismic sections are taken to identify thrust faults.

5. The method according to claim 4, characterized in that In the third step, the thrust anticline structure is identified on a seismic section and a 3D seismic isochronal slice. The thrust anticline structure includes: the top of the ancient buried mountain, the hanging wall of the thrust fault, and the cross section of the thrust fault.

6. The method according to claim 4, characterized in that In the fourth step, the seismic phase of the slope zone edge, the onlapping discontinuity seismic reflection interface, and the seismic reflection interface corresponding to the displacement vanishing point of the thrust fault are identified on the seismic profile of the overlying strata.

7. The method according to claim 1, characterized in that In the fourth step, the slope edge seismic phase refers to: a seismic phase with a chaotic reflection structure, a seismic phase with a blank reflection structure, and a seismic phase with a wedge structure; The onlapping inhomogeneous seismic reflection interface refers to a seismic inhomogeneous interface with an onlapping contact relationship.

8. The method according to claim 1, characterized in that In the fourth step, in the overlying strata of the footwall of the thrust fault, the step of identifying the slope edge seismic phase is prior to identifying the onlapping inhomogeneous seismic reflection interface located below the slope edge seismic phase.

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