Method for determining the geological age of thrust tectonic compression of paleo-buried hill in rifted basin

Abstract

The present application belongs to the technical field of petroleum exploration. The present application discloses a method for determining the geological age of the thrust structure extrusion revival of the buried hill in a faulted basin, comprising: determining the trend of the top surface of the buried hill and the regional normal fault on the three-dimensional seismic data volume of the faulted basin after three-dimensional median dip filter processing. Determining the thrust fault on the seismic profile which is basically parallel to the trend of the regional normal fault. Identifying the thrust fault anticline structure according to the morphological characteristics of the top surface of the buried hill. Identifying the slope edge seismic facies, the onlap unconformity seismic reflection interface and the seismic reflection interface corresponding to the fault throw disappearance point of the thrust fault on the overlying strata of the footwall of the thrust fault. Determining the starting time and the ending time of the extrusion revival of the thrust fault, and determining the geological time stage between the starting time and the ending time as the geological age of the thrust structure extrusion revival of the buried hill in the faulted basin. Through the above method, the thrust structure of the buried hill in the faulted basin and the geological age of the extrusion revival thereof can be accurately identified.

Description

Technical Field

[0001] This invention belongs to the field of petroleum exploration technology. More specifically, this invention relates to a method for determining the geological age of the compressional reactivation of ancient buried hill thrust structures in rift basins. Background Technology

[0002] A rift basin is a basin formed primarily by extensional forces under the combined action of regional extensional and shearing processes. Normal faults, also known as extensional faults, specifically refer to large-scale, low-angle normal faults formed by regional extension. Most normal faults form in horizontal extensional regions and are the main identifying structural feature and most prominent structural characteristic of extensional basins.

[0003] During geological evolution, rift basins frequently experience extensional strike-slip deformation. In this stress field stage, due to the decomposition of the shear stress field, both extensional and compressive stress components should develop simultaneously. While undergoing extension, the strata 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 forming paleoburied hills in the later stages of basin evolution.

[0004] Ancient buried hills are trap structures formed by the overburden of impermeable rock layers after long-term weathering and erosion of paleotopic uplifts. An ancient buried hill consists of two parts separated by an unconformity: below the unconformity is the core of the buried hill, composed of older strata and rock masses, and above the unconformity is a slab structure composed of younger strata. Bedrock buried hill traps and overlying anticline traps formed by late compression since the Cenozoic era are favorable hydrocarbon-bearing traps. Localized fold structures formed by compression in the Paleogene period are important anticline traps and can also serve as promising exploration targets.

[0005] In existing technologies, due to the extensional stress characteristics of rift basins, reverse faults in ancient buried hills are usually attributed to the compressional paleotectonic processes that preceded the development of the rift basin, neglecting the thrusting action of reverse faults in the later stages of rifting. This is detrimental to the accurate identification of valuable anticline traps. Furthermore, normal faults are particularly well-developed on seismic profiles within rift basins. The tectonic movements and erosion during the rift basin's evolution make the characteristics of thrust faults within ancient buried hills relatively vague and often difficult to identify. Moreover, even if the problem of identifying thrust faults is solved, the geological age of their compressional reactivation remains difficult to determine, hindering the identification of valuable hydrocarbon traps.

[0006] Therefore, given that extensional and local compressional forces may coexist in the rift basin stage, how to interpret 3D seismic data to identify the specific age of the ancient buried hill thrust-compression structure in the rift basin evolution stage, and thus accurately predict the formation age of the ancient buried hill oil and gas reservoir, is an urgent problem to be solved. Summary of the Invention

[0007] To address at least one or more of the technical problems mentioned above, embodiments of the present invention provide a method for determining the geological age of the compressional reactivation of thrust structures in a rift basin, comprising: a first step, determining the summit of the ancient buried hill and the strike of regional normal faults on a 3D seismic data volume of the rift basin after three-dimensional dip median filtering; 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 based on the morphological characteristics of the summit of the ancient buried hill; and a fourth step, in the thrust... The fifth step involves identifying the overlying strata of the footwall of the fault, the seismic facies at the slope edge, the overlying irregular seismic reflection interface located below the slope edge seismic facies, and the seismic reflection interface corresponding to the point where the fault displacement disappears. The geological age of the overlying irregular seismic reflection interface is taken as the starting time of the compressional reactivation of the thrust fault, and the geological age of the seismic reflection interface corresponding to the point where the fault displacement disappears is taken as the ending time of the compressional reactivation of the thrust fault. The geological time stage between the starting time and the ending time is determined as the geological age of the compressional reactivation of the ancient buried hill thrust structure in the rift basin.

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

[0009] According to one embodiment of the present invention, in the second step, the reverse fault is determined by identifying the seismic reflection fault point, the rupture wave, and the seismic velocity reversal.

[0010] According to one embodiment of the present invention, in the second step, multiple parallel seismic profiles are taken to identify reverse faults.

[0011] According to one embodiment of the present invention, in the third step, the thrust fault anticline structure is identified on the seismic profile and three-dimensional seismic isochronous slice. The thrust fault anticline structure includes: the top surface of the ancient buried mountain, the hanging wall of the thrust fault, and the cross section of the thrust fault.

[0012] According to one embodiment of the present invention, in the fourth step, the seismic facies at the edge of the slope zone, the overlying irregular seismic reflection interface, and the seismic reflection interface corresponding to the point where the fault displacement of the thrust fault disappears 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: a seismic phase with a disordered reflection structure, a seismic phase with a blank reflection structure, and a seismic phase with a wedge-shaped structure; the overlying inhomogeneous seismic reflection interface refers to: a seismic inhomogeneous interface with an overlying contact relationship.

[0014] According to one embodiment of the invention, in the fourth step, the step of identifying the slope margin seismic facies in the overlying strata of the hanging wall of the thrust fault precedes the identification of the overlying irregular seismic reflection interface located below the slope margin seismic facies.

[0015] Using the methods provided above, embodiments of the present invention can accurately identify thrust structures formed by late-stage compressional reactivation of ancient buried hills in rift basins.

[0016] In this invention, by taking multiple seismic profiles in a direction that is basically parallel to the strike of the regional normal fault, thrust faults formed by the tectonic compression of the rift basin stage can be effectively identified on these seismic profiles, overcoming the problem that thrust faults inside the ancient buried hills of the rift basin are difficult to identify.

[0017] In this invention, by identifying the superconformity seismic reflection interface in the overlying strata of the footwall of a thrust fault, the initiation time of the compressional reactivation of the paleoburied hill thrust structure during the rift basin depositional stage can be determined. By using the seismic reflection interface corresponding to the fault point of the thrust fault, the termination time of the compressional reactivation of the paleoburied hill thrust structure during the rift basin depositional stage can be determined, thus accurately determining the geological age of the compressional reactivation of the paleoburied hill thrust structure in the rift basin. This method eliminates the drawback of conventionally classifying thrust structures within paleoburied hills in rift basins as early compressional tectonic products prior to rift basin deposition, providing a basis for identifying valuable hydrocarbon traps. Attached Figure Description

[0018] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

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

[0020] Figure 2 A schematic diagram illustrating the steps involved in determining the geological age of the compressional reactivation of ancient buried hill thrust structures in a rift basin is shown.

[0021] Figure 3 A schematic diagram is shown for identifying the super-inorganic seismic reflection interface on a seismic profile of a thrust fault;

[0022] Figure 4 A schematic diagram is shown for identifying the seismic reflection interface corresponding to the fault point on another seismic profile of the thrust fault. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be understood that the terms "comprising" and "including" as used in the specification and claims of this invention indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

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

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

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

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

[0029] like Figure 1As shown, in the system 100, multiple geophones 110, spaced apart from each other, are arranged on the surface 101 of the exploration target area to form a geophone array covering the target area on a plane. These geophones 110 are connected to the seismic information processing equipment via wired or wireless connections. Multiple seismic sources 120 are also provided. The seismic information processing equipment can perform preliminary processing on the seismic data. The working process of the three-dimensional seismic exploration system is as follows: seismic sources 120 located at multiple locations are artificially excited to generate seismic waves. The seismic waves are reflected from the boundaries of the strata 102 and received by the geophone array, forming seismic information that varies over time and is collected on a plane. The seismic information received by the geophone array represents certain measures of seismic wave energy as a function of time, such as displacement, velocity, wave impedance, and pressure. This information can be grouped in different ways, such as traces and sets, and then processed or converted according to the correspondence between time and space to form a three-dimensional seismic data volume in the form of a three-dimensional array, thus obtaining high-quality three-dimensional seismic fine imaging data. This three-dimensional seismic data volume is formed by the spatial stacking of interface points. Interpreting three-dimensional seismic data volumes allows for observation of geological interfaces from different directions, and the study of geological volume variations in three-dimensional space can be achieved by cutting cross sections, longitudinal sections, and horizontal slices.

[0030] Figure 2 A schematic diagram illustrating the steps involved in determining the geological age of the compressional reactivation of ancient buried hill thrust structures in a rift basin is shown.

[0031] like Figure 2 As shown, a method 200 for determining the geological age of the compressional reactivation of a thrust structure in a rift basin includes: Step S201: Determining the summit of the ancient buried hill and the strike of the regional normal fault on a 3D seismic data volume of the rift basin after median dip filtering. Step S202: Identifying the thrust fault on a seismic profile substantially parallel to the strike of the regional normal fault. Step S203: Identifying the thrust anticline structure on the hanging wall of the thrust fault based on the morphological characteristics of the summit of the ancient buried hill. Step S204: Identifying the slope edge seismic facies, the overlying uneven seismic reflection interface located below the slope edge seismic facies, and the seismic reflection interface corresponding to the point where the thrust fault displacement disappears in the overlying strata of the hanging wall of the thrust fault. In the fifth step S205, the geological age of the overlying uneven seismic reflection interface is taken as the starting time of the reactivation of the thrust fault compression, and the geological age of the seismic reflection interface corresponding to the point where the fault displacement disappears is taken as the ending time of the reactivation of the thrust fault compression. The geological time period between the starting time and the ending time is determined as the geological age of the reactivation of the ancient buried hill thrust structure in the rift basin. In this invention, steps one through five are executed progressively.

[0032] In the 3D seismic data volume, normal faults in the paleoburied hill area of ​​the rift basin are a prominent representative structure. Regional normal faults refer to large-scale, low-angle normal faults formed by regional extension, whose strike is generally consistent with the overall extension direction of the rift basin. The overall extension direction refers to the main extension direction of the rift basin, ignoring the influence of local bends and shape variations. The overlying strata refer to the impermeable rock layers overlying the paleoburied hill, which can be directly interpreted from the longitudinal seismic profile. The top surface of the paleoburied hill can be directly read from the profile.

[0033] In the first step S201, the 3D seismic data volume of the rift basin can be obtained through... Figure 1 The data is acquired through a system and can be preprocessed using three-dimensional dip median filtering to obtain high signal-to-noise ratio data. The three-dimensional dip median filtering preprocessing method is existing technology and will not be elaborated upon here. By interpreting the stratigraphy and faults of the three-dimensional seismic data volume, regional normal faults and overlying strata can be identified. For example, after preprocessing the three-dimensional seismic data volume to eliminate high-frequency noise, improve fault identification capabilities, and enhance fault interpretation accuracy, and after seismic coherence processing, stratigraphy and fault interpretation are performed. Dip-slip faults that slide downwards from the hanging wall relative to the footwall are identified in the seismic profile, obtaining information such as the shape, dip, and distribution range of normal faults. Strata above the top surface of the bedrock unconformity in the three-dimensional seismic data volume are classified as overlying strata. As another example, the three-dimensional seismic data volume can be imported into existing seismic data identification software, such as Landmark software, which automatically outputs the results after stratigraphy and fault interpretation, and based on these results, regional normal faults and overlying strata can be identified.

[0034] Optionally, the top of a paleoburied hilltop can be identified by at least one of the following characteristics: seismic inhomogeneity, differences in seismic reflection characteristics, and vertical variations in seismic velocity. That is, a paleoburied hilltop is related to seismic inhomogeneity; the presence of an overlap at the bottom interface of the upper strata and / or erosion at the top interface of the lower strata indicates the existence of a paleoburied hilltop. Alternatively, there can be significant differences in seismic reflection characteristics (frequency, amplitude, structure) above and below the paleoburied hilltop; structure refers to the direction, continuity, and length of the phase axis. Alternatively, there can be abrupt changes in the seismic velocity spectrum above and below the paleoburied hilltop. These three factors can be used in combination or individually.

[0035] Late-stage tectonic compression in the basin has led to a more complex structural pattern, significantly influencing hydrocarbon accumulation conditions and models. Late-stage compression since the Cenozoic has formed ancient buried hill traps and anticline traps in the overlying strata. Local fold structures formed by compression in the Paleogene have become important anticline traps, serving as promising exploration targets. Pre-existing faults in the ancient buried hill bedrock have been reactivated under late-stage Paleogene compression, improving the physical properties of the bedrock reservoir. While bedrock reservoirs are inherently dense with relatively underdeveloped reservoir properties, late-stage thrust faulting generates numerous fractures and cracks, significantly improving porosity and permeability, potentially transforming them into high-quality reservoirs.

[0036] During the Late Paleogene, the source rocks in the basin began to reach the hydrocarbon generation threshold, and oil and gas began to be generated in large quantities. This was due to the activation of thrust faults formed by tectonic compression, which facilitated the vertical migration of oil and gas. This is because the conductivity of a fault is greater during its active phase than during its static phase, which is more conducive to the accumulation and formation of oil and gas reservoirs.

[0037] The compressional action in the late stage of the rift basin altered the conditions for hydrocarbon accumulation, enriched the hydrocarbon accumulation model, and had a significant impact on the basin's hydrocarbon accumulation process.

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

[0039] In seismic profiles parallel or substantially parallel to the strike of a regional normal fault, thrust faults cannot be effectively identified. This is because such thrust faults are formed by late-stage compression, where the compressive stress component is perpendicular to the tensile stress component, and the tensile stress component is aligned with the strike of the normal fault. In this invention, the inventors identified thrust faults in the bedrock of buried hills by selecting a direction substantially parallel to the strike of the regional normal fault. "Substantially parallel" means that the angle between the direction of the selected seismic profile and the strike of the regional normal fault is no greater than 10 degrees, including any value between 0 and 10 degrees, or any range of two values.

[0040] By identifying thrust faults in the bedrock of ancient buried hills along directions substantially parallel to the strike of regional normal faults, it is possible to effectively identify thrust faults formed by strike-slip or compressional processes. Furthermore, the intersection between the top of the ancient buried hill and the fault surface can help determine if the fault strike is a thrust strike. Such thrust fault structures improve and increase porosity and permeability, which is conducive to hydrocarbon accumulation; their specific identification is beneficial for finding effective hydrocarbon traps.

[0041] According to one embodiment of the present invention, in the process of identifying thrust faults, multiple seismic profiles are selected, and thrust faults are identified on each seismic profile to determine their strike, location, morphology, and distribution range. Preferably, the multiple seismic profiles are parallel to each other.

[0042] By selecting multiple seismic profiles, thrust faults can be identified on seismic profiles at different locations, reducing the omission of related thrust faults. When selecting seismic profiles, the selection range depends on the distribution and extent of regional normal faults, which can identify mutually restrictive and interconnected hydrocarbon-forming structures.

[0043] According to one embodiment of the present invention, reverse faults are identified based on at least one of the following features: seismic reflection phase axis fault points in ancient buried hills, sectional waves, seismic velocity reversal characteristics, and three-dimensional seismic isochronous slice fault identification criteria.

[0044] In this invention, different features that represent thrust faults are combined to identify thrust faults, which greatly improves the identification of difficult-to-identify cases and increases the success rate and accuracy of identification.

[0045] In the third step S203, after identifying the thrust fault, the structure of the thrust anticline is further determined. This structure is a typical reservoir-friendly structure. Since the ancient buried mountain top 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 on the hanging wall of the thrust fault based on the morphological characteristics of the ancient buried mountain top.

[0046] Identifying thrust-fault anticlines at a specific angle on a seismic profile is challenging due to factors such as extension and strike-slip. To identify thrust-fault anticlines, a rotation axis is pre-set in the overlying strata above the thrust fault. Multiple seismic profiles are selected around this pre-set axis to identify the thrust-fault anticline structure. Preferably, the angle between adjacent seismic profiles is 2°–15°, and can be uniformly or non-uniformly distributed. For example, angles of 3° and 6° are used.

[0047] In this invention, a rotation axis is preset, and a seismic profile is selected by rotation. The reverse fault anticline structure is comprehensively identified on seismic profiles at multiple angles, which can effectively identify and reduce omissions.

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

[0049] Preferably, different rotation axes can be selected multiple times within the distribution range of the thrust fault, and seismic profiles can be selected for each.

[0050] Using rotating seismic profile scanning in the overlying strata within the distribution range of thrust faults can improve the accuracy of identification.

[0051] In the fourth step S204, the compression reactivation time of the thrust fault is identified, and the markers of the start and end times of the compression reactivation of the thrust fault are located respectively: namely, the overlying irregular seismic reflection interface located below the seismic phase at the slope edge and the seismic reflection interface corresponding to the point where the fault displacement of the thrust fault disappears.

[0052] Figure 3 A schematic diagram is shown for identifying the super-inorganic seismic reflection interface on a seismic profile of a thrust fault.

[0053] To locate the overlying heterogeneous seismic reflection interface representing this onset time, firstly, characteristic seismic phases A at the slope edge formed by the thrust fault S are identified; these include seismic phases exhibiting chaotic reflection structures, seismic phases with blank reflection structures, and seismic phases with wedge-shaped structures. The overlying strata located in the footwall are then identified. The footwall includes bedrock and overlying strata. The overlying strata contain the characteristic seismic phases. Secondly, after locating these slope edge seismic phases, the overlying heterogeneous seismic reflection interface B can be located below these seismic phases as a marker of the onset time.

[0054] Figure 4 A schematic diagram is shown for identifying the seismic reflection interface corresponding to the fault point on another seismic profile of the thrust fault.

[0055] To locate the seismic reflection interface that represents the termination time, firstly, the fault point C at the highest position of the thrust fault S at the end of the compression is identified. Then, the seismic phase axis D corresponding to the fault point is located as a marker of the termination time.

[0056] Perform step S205 to determine the geological time stage between the start and end times as the geological age of the compression and reactivation of the ancient buried hill thrust structure in the rift basin.

[0057] Using the methods provided above, embodiments of the present invention can accurately identify thrust structures formed by late-stage compressional reactivation of ancient buried hills in rift basins.

[0058] In this invention, by taking multiple seismic profiles in a direction that is basically parallel to the strike of the regional normal fault, thrust faults formed by the tectonic compression of the rift basin stage can be effectively identified on these seismic profiles, overcoming the problem that thrust faults inside the ancient buried hills of the rift basin are difficult to identify.

[0059] In this invention, by identifying the superconformity seismic reflection interface in the overlying strata of the footwall of a thrust fault, the initiation time of the compressional reactivation of the paleoburied hill thrust structure during the rift basin depositional stage can be determined. By using the seismic reflection interface corresponding to the fault point of the thrust fault, the termination time of the compressional reactivation of the paleoburied hill thrust structure during the rift basin depositional stage can be determined, thus accurately determining the geological age of the compressional reactivation of the paleoburied hill thrust structure in the rift basin. This method eliminates the drawback of conventionally classifying thrust structures within paleoburied hills in rift basins as early compressional tectonic products prior to rift basin deposition, providing a basis for identifying valuable hydrocarbon traps.

[0060] While numerous embodiments of the 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. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of protection of the invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for determining the geological age of the reactivation of ancient buried hill thrust structures in a rift basin, characterized in that, include: The first step is to determine the top surface of the ancient buried mountain and the strike of the regional normal fault on the three-dimensional seismic data volume of the rift basin after three-dimensional dip median filtering. The second step is to identify the reverse fault on a seismic profile that is substantially parallel to the strike of the normal fault in the region. The third step is to identify the reverse fault anticline structure in the hanging wall of the reverse fault based on the morphological characteristics of the ancient buried mountain top. The fourth step involves identifying the slope edge seismic facies, the overlying irregular seismic reflection interface located below the slope edge seismic facies, and the seismic reflection interface corresponding to the point where the fault displacement of the thrust fault disappears in the overlying strata of the footwall of the thrust fault. The fifth step is to take the geological age of the supercontinuous seismic reflection interface as the starting time of the compressional reactivation of the thrust fault, and the geological age of the seismic reflection interface corresponding to the point where the fault displacement of the thrust fault disappears as the ending time of the compressional reactivation of the thrust fault. The geological time period between the starting time and the ending time is determined as the geological age of the compressional reactivation of the ancient buried hill thrust structure in the rift basin.

2. The method according to claim 1, characterized in that, In the first step, the ancient buried mountain top surface is determined by at least one of the following characteristics: seismic inhomogeneity, differences in seismic reflection characteristics, and vertical variation of seismic velocity; The strike of the normal fault in the region corresponds to the overall extension direction of the rift basin.

3. The method according to claim 1, characterized in that, In the second step, the reverse fault is determined by identifying the seismic reflection fault point, the rupture wave, and the seismic velocity reversal.

4. The method according to claim 1, characterized in that, In the second step, multiple parallel seismic profiles are taken to identify reverse faults.

5. The method according to claim 4, characterized in that, In the third step, the thrust fault anticline structure is identified on seismic profiles and 3D seismic isochronous slices. The thrust fault anticline structure includes: the top surface 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 facies at the slope edge, the overlying irregular seismic reflection interface, and the seismic reflection interface corresponding to the point where the fault displacement of the thrust fault disappears 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: seismic phases with chaotic reflection structures, seismic phases with blank reflection structures, and seismic phases with wedge-shaped structures; The aforementioned superimposed inhomogeneous seismic reflection interface refers to a seismic inhomogeneous interface that has a superimposed contact relationship.

8. The method according to claim 1, characterized in that, In the fourth step, the step of identifying the slope edge seismic facies in the overlying strata of the footwall of the thrust fault precedes the identification of the overlying irregular seismic reflection interface located below the slope edge seismic facies.

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