A physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures

Abstract

The present invention discloses a physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures, comprising the following steps performed in sequence: based on the basic morphological characteristics of the seismic profile structure, after designing the physical boundary conditions of the sand box through the experimental model, the extrusion movement is parameterized and extruded according to geological knowledge, and slices are made after completing the physical simulation of all phases of non-detachment layers and detachment layers, and the slice results are interpreted and compared with the structural framework characteristics, stratigraphic distribution characteristics and fault style characteristics interpreted from the seismic data. The physical simulation analysis method provided by the present invention improves the matching problem with the actual geological movement, further reasonably and accurately explains the genetic mechanism of complex structures, and provides theoretical support for oil and gas exploration in the exploration area. The present invention is suitable for establishing a physical model of the genetic mechanism of multiple detachment-thrust structures, and provides important support for methods to improve the accuracy and rationality of seismic data interpretation schemes.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum and natural gas geological exploration, and relates to a geological exploration simulation analysis method, in particular to a physical simulation analysis method of the genetic mechanism of multiple slip-thrust structures. Background Art

[0002] Rich oil and gas resources have been discovered in the foreland thrust belt on the southern margin of the Junggar Basin, which has broad exploration prospects and is a hot research area both domestically and internationally. Therefore, studying the deformation mechanism of the southern margin of the Junggar Basin and its impact on the trap style is of great significance to oil and gas exploration and development in western my country. Among them, the detachment layer not only affects the structure and evolution of regional geology, but also affects the style and distribution of traps within the thrust belt. Previous studies on the detachment layer have also made important progress. Li Benliang and other scholars believe that the detachment layer not only controls the propagation of thrust structural deformation from the front of the mountain to the basin, but also controls the structural deformation above and below the detachment layer; Dong Chenqiang and other scholars believe that the existence of the detachment layer is not only a key factor affecting the formation and evolution of structural style, but also the main reason for the incoordination between deep and shallow structures.

[0003] The current kinematic models for the formation of the thrust belt (multiple detachment thrust structures) on the southern margin of the Junggar Basin can be summarized into the following three viewpoints:

[0004] (1) Late deformation model of a single detachment layer (Zhang Yulan, 2003; Liang Shuyi, 2019); (2) Late deformation model of two detachment layers (Fang Shihu, 2007; Yu Fusheng, 2012; Wang Xin, 2019); (3) Late deformation model of two detachment layers controlled by paleostructures (Chen Shuping, 2007; Zhang Xichen, 2020). Based on the above viewpoints, through the study of tectonic units such as the Tuoqi buried tectonic belt, the Dongwan tectonic belt, the Huomatu tectonic belt, the Hu'an tectonic belt, and the northern slope belt, three sets of detachment layer structural styles have been further proposed, but the necessary technical methods for analysis and verification are lacking.

[0005] The presence of multiple detachment layers leads to multi-layered detachment deformation during structural development, significantly complicating both structure and faulting. This influences poor seismic imaging and a high degree of variability in structural interpretation. Physical simulation is the most effective tool for improving the rationality and accuracy of seismic data interpretation.

[0006] Research has revealed that Chinese patents CN201710602401, CN201810603412, and CN202011379217 all propose a physical simulation method. The general approach is to analyze regional structural deformation to identify key factors influencing structural deformation, design and establish a sandbox physical model based on these key factors for experimental testing, and ultimately verify the rationality of the structural model through analysis of test results and perform iterative modifications. However, these methods all employ a single-layout, multiple-extrusion approach for sandbox physical simulation testing, which presents certain mismatches with geological movements and can lead to unreliable test results. Summary of the Invention

[0007] The purpose of the present invention is to provide a physical simulation analysis method for the genetic mechanism of multiple detachment thrust structures. By adopting the method of multi-stage paving and multi-stage extrusion of multiple sets of detachment layers under the control of ancient structures, the periodicity of detachment deformation is realized to solve the problem of matching the actual geological movement caused by one-time paving and multiple extrusion in the existing technology, further reasonably and accurately explain the genetic mechanism of complex structures, and provide theoretical support for oil and gas exploration in the exploration area.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures includes the following steps performed in sequence:

[0010] S1. Based on the basic morphological characteristics of the seismic profile structure, the physical boundary conditions of the sand box are designed through the experimental model;

[0011] S2. Lay out the first-phase structural morphology and the first-phase detachment layer, perform the first extrusion using a unidirectional extrusion mode, and complete the physical simulation of the first-phase non-detachment layer and detachment layer;

[0012] S3. Lay out the second-phase structural morphology and the second-phase detachment layer. Based on geological knowledge, set the parameters for the extrusion movement and perform a second extrusion to complete the physical simulation of the second-phase non-detachment layer and detachment layer.

[0013] S4. Repeat S3 based on geological knowledge to complete all phases of physical simulation of non-detachment layers and detachment layers;

[0014] S5. After completing the last simulation, the simulation results are sliced ​​into sandstone sections every 3 cm. The slice results are interpreted and compared with the structural framework characteristics, stratigraphic distribution characteristics, and fault pattern characteristics interpreted from the seismic data.

[0015] As a limitation, step S5 also includes modifying the interpretation scheme and performing simulation tests again to reduce the error of the physical simulation analysis.

[0016] As another limitation, in step S1, the basic morphological characteristics of the seismic section structure include section length, non-detachment layer formation parameters, detachment layer formation parameters, moving steel plate extrusion rate and moving distance;

[0017] The experimental model method is as follows: based on the basic morphological characteristics of the seismic profile structure, the boundary conditions of the physical model are composed of a bottom steel plate, a moving steel plate, a stationary steel plate and double-sided glass plates, and the lengths and widths of the bottom steel plate, the moving steel plate, the stationary steel plate and the double-sided glass plates are set respectively.

[0018] As a further limitation, the non-detachment layer formation parameters include thickness, internal friction angle of the sand body, and grain size;

[0019] The stratigraphic parameters of the detachment layer include thickness, lateral distribution range, paleo-tectonic morphology and relative position.

[0020] As a third limitation, in step S2, the first extrusion includes the following steps performed in sequence:

[0021] S21. Based on the seismic profile, with the moving steel plate as the origin and wet sand as the material, lay a corresponding number of paleo-tectonic models on the bottom steel plate according to the seismic profile position. The length, width, and height of the wet sand are all set to the same proportion based on the seismic profile;

[0022] S22. Silica gel was used as the material for paving to simulate the first stage of slip layer deposition, which together with the wet sand in S21 formed the base layer;

[0023] The thickness of the basement layer is set in the same proportion according to the structural morphology of the seismic section;

[0024] S23. Lay a dry sand layer to simulate a non-slip layer;

[0025] The thickness of the non-detachment layer is set in the same proportion according to the structural morphology of the seismic section;

[0026] S24 performs a unidirectional extrusion movement, and stops the movement after the extrusion movement of the steel plate;

[0027] The extrusion, rate and distance are based on the knowledge of structural deformation.

[0028] As a fourth limitation, in step S3, if there is no tectonic movement based on geological knowledge, no extrusion movement will be performed.

[0029] As a final limitation, in step S3, parameter setting includes the following steps performed in sequence:

[0030] S31. Lay a dry sand layer to simulate a non-slip layer;

[0031] The non-detachment layer strata are arranged in the same proportion according to the structural morphology of the seismic section;

[0032] S32. Lay silica gel as a slip layer simulation material to simulate the second stage of slip layer deposition;

[0033] S33. Lay a dry sand layer to simulate a non-slip layer;

[0034] The thickness of the non-detachment layer is set in the same proportion as the structural morphology of the seismic section;

[0035] S34 performs unidirectional extrusion movement, and stops after the extrusion movement of the steel plate;

[0036] The extrusion, rate and distance are based on the knowledge of structural deformation.

[0037] Due to the adoption of the above technical solution, the present invention has the following technical advancements compared with the prior art:

[0038] ① The physical simulation analysis method for the genetic mechanism of multiple slip-thrust structures provided by the present invention determines the key factors of structural genesis through comprehensive research of multiple information, and establishes a physical simulation model based on this. During the experimental stage, the physical model is repeatedly laid and squeezed to improve the matching problem with actual geological movement, further reasonably and accurately explain the genetic mechanism of complex structures, and provide theoretical support for oil and gas exploration in the exploration area.

[0039] ② The physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures provided by this invention focuses on controlling paleo-tectonic morphology and distribution. By analyzing the placement of multiple detachment layers and tectonic movements, the method aims to establish a sandbox model capable of analyzing the causal mechanisms of structural deformation. This sandbox physical model effectively analyzes the genetic mechanism of multiple detachment-thrust structures. This provides valuable insights into the control of deep paleo-tectonic morphology on present-day tectonic movements and provides guidance for developing interpretation schemes for buried piedmont structures.

[0040] ③ The physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures provided by the present invention improves the accuracy and rationality of seismic data interpretation schemes by using physical simulation analysis, providing a reasonable and reliable basis for geological exploration. The relevant ideas and implementation process specifically include the following aspects:

[0041] 1) Establish the boundary conditions and key control factors of the physical simulation model through comprehensive multi-information research;

[0042] 2) Using multiple laying and multiple extrusion methods to improve the matching with actual geological movement;

[0043] 3) Through comparative analysis of experimental results and seismic data interpretation schemes, mutual verification and iterative back-and-forth improvement of the accuracy and rationality of the interpretation schemes are carried out.

[0044] The present invention is applicable to establishing a physical model of the genetic mechanism of multiple slip-thrust structures, and provides important support for methods to improve the accuracy and rationality of seismic data interpretation schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a real seismic interpretation cross-section diagram in the embodiment;

[0046] Figure 2 1 is a cross-sectional view of the experimental sand body in the embodiment. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below by way of specific examples. It should be understood that the described examples are only used to illustrate the present invention and are not intended to limit the present invention.

[0048] Example A physical simulation analysis method for the genetic mechanism of multiple slip-thrust structures

[0049] This embodiment is a physical simulation analysis method for the mechanism of multiple slip-thrust structures. In order to illustrate the specific situation of this technology, it is now described based on an actual work area. The test area of ​​this invention is the southern edge of the Junggar Basin in Xinjiang. This area has multiple sets of slip layers, complex structural styles, and inheritance of vertical structures. Through the interpretation of previous seismic data, a north-south seismic interpretation section was selected as the comparison section of this experiment, and the section was interpreted. The actual seismic interpretation section is shown in the figure below. Figure 1 shown.

[0050] This embodiment includes the following steps performed in sequence:

[0051] S1. Based on the north-south seismic profile of the southern margin of the Junggar Basin ( Figure 1 ) basic morphological characteristics, and designed a structural physical model of similar scale through the experimental model. The specific method is as follows: the boundary conditions of the structural framework section of the southern margin of the Junggar Basin are composed of a bottom steel plate, a moving steel plate, a stationary steel plate, and double-sided glass plates;

[0052] Among them, the bottom steel plate is 2 meters long and 0.5 meters wide; the moving steel plate and the static steel plate are 0.5 meters long and 0.4 meters wide, with rubber gaskets on both wide edges, placed vertically on the bottom steel plate; the double-sided glass plates are 2 meters long and 0.4 meters wide; the compression motor is placed on the left.

[0053] S2. Based on the stratigraphic distribution and tectonic movement characteristics of the Second and Third Assemblage deposits and the Jurassic depositional period in the southern margin of the Junggar Basin, the first detachment layer was laid using a unidirectional extrusion mode. Specifically, the following steps were performed in sequence:

[0054] S21. Based on the seismic profile tectonic morphology, place two rectangular parallelepipeds of wet sand (A) and wet sand (B) on the bottom steel plate, 8 cm and 15 cm away from the moving steel plate, respectively. Wet sand A is 15 cm long, 3 cm wide, and 0.5 cm high; wet sand B is 15 cm long, 6 cm wide, and 0.3 cm high, representing the paleotectonic morphology.

[0055] S22. Lay silicone rubber over the entire surface, leveling and filling the top of the model. The silicone rubber and wet sand together form a uniform first slip layer, approximately 0.8 cm thick.

[0056] S23. A horizontal layer of approximately 1 cm thick white sand was laid, with a red marker layer placed in the middle to simulate Jurassic sedimentary stratigraphic characteristics. A wedge-shaped sand body, 1 cm high and 1 cm wide, was laid at the end of the moving steel plate, with a slope angle of approximately 45°, pointing in the direction of the moving steel plate's movement.

[0057] S24. The moving steel plate performs unidirectional extrusion motion at a rate of 0.005 mm / s and a distance of 15 cm, and then stops moving.

[0058] S3. Based on the strata distribution and fault characteristics of the Cretaceous sedimentary period in the southern margin of the Junggar Basin, the second phase of detachment layer was laid. Since no tectonic movement was believed to exist during this period, no moving steel plate extrusion was used. The specific steps included the following steps in sequence:

[0059] S31. Continue laying white sand, filling and leveling the entire area to make the top of the model flat. Lay four sets of red marking layers in the middle, bringing the overall thickness of the model to 4 cm.

[0060] S32. Lay the silicone gel horizontally and allow it to level, maintaining a thickness of 1 cm, to simulate Cretaceous detachment layer deposition.

[0061] S33. Lay 2.0cm white sand horizontally and place 2 sets of red marking layers in the middle.

[0062] S4. Repeat step S3 to lay the detachment layer based on the stratum distribution and fault characteristics of the Neogene sedimentary period in the southern margin of the Junggar Basin, completing the second compression movement simulation. Specifically, the following steps are performed in sequence:

[0063] S41. Lay 0.5cm white sand and a red marking layer in the middle;

[0064] S42. Lay silica gel horizontally and allow it to level, maintaining a thickness of 1 cm to simulate Paleogene detachment layer deposition.

[0065] S43. Lay 4cm of white sand horizontally, with 4 sets of red marking layers in the middle;

[0066] S44. The moving steel plate performs unidirectional extrusion motion at a rate of 0.005 mm / s and a distance of 20 cm, and then stops moving.

[0067] S5. Prepare sand body slices every 3 cm based on the above experimental results. The obtained slice results are interpreted and compared with the actual structural framework characteristics, stratigraphic distribution characteristics and fault pattern characteristics of the southern margin of the Junggar Basin, and the experimental parameters are adjusted.

[0068] The cross-section of the experimental sand body in this embodiment is as follows Figure 2 As shown, after comparison Figure 1 and Figure 2 It can be seen that the model constructed in this embodiment is highly similar to the real seismic interpretation section in terms of structural style and structural morphology.

Claims

1. A physical simulation analysis method for the genetic mechanism of multiple slip-thrust structures, characterized by: The process includes the following steps: S1. Based on the basic morphological characteristics of the seismic profile structure, the physical boundary conditions of the sand box are designed through the experimental model; S2. Lay out the first-phase structural morphology and the first-phase detachment layer, perform the first extrusion using a unidirectional extrusion mode, and complete the physical simulation of the first-phase non-detachment layer and detachment layer; S3. Lay out the second-phase structural morphology and the second-phase detachment layer. Based on geological knowledge, set the parameters for the extrusion movement and perform a second extrusion to complete the physical simulation of the second-phase non-detachment layer and detachment layer. S4. Repeat S3 based on geological knowledge to complete all phases of physical simulation of non-detachment layers and detachment layers; S5. After the final simulation is complete, the simulation results are sliced ​​into sandstone sections at 3 cm intervals. The resulting slices are interpreted and compared with the structural framework, stratigraphic distribution, and fault pattern characteristics interpreted from the seismic data. In step S2, the first extrusion includes the following steps performed in sequence: S21. Based on the seismic profile, with the moving steel plate as the origin and wet sand as the material, lay a corresponding number of paleo-tectonic models on the bottom steel plate according to the seismic profile position. The length, width, and height of the wet sand are all set to the same proportion based on the seismic profile; S22. Silica gel was used as the material for paving to simulate the first stage of slip layer deposition, which together with the wet sand in S21 formed the base layer; The thickness of the basement layer is set in the same proportion according to the structural morphology of the seismic section; S23. Lay a dry sand layer to simulate a non-slip layer; The thickness of the non-detachment layer is set in the same proportion according to the structural morphology of the seismic section; S24 performs a unidirectional extrusion movement, and stops the movement after the extrusion movement of the steel plate; The extrusion, rate and distance are based on the knowledge of structural deformation.

2. The physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures according to claim 1 is characterized in that: After step S5, the method further includes modifying the interpretation scheme and performing simulation tests again to reduce the error of the physical simulation analysis.

3. The physical simulation analysis method for the genetic mechanism of multiple detachment and thrust structures according to claim 1 is characterized in that: In step S1, the basic morphological characteristics of the seismic section structure include section length, non-detachment layer stratum parameters, detachment layer stratum parameters, moving steel plate extrusion rate and moving distance; The experimental model method is as follows: based on the basic morphological characteristics of the seismic profile structure, the boundary conditions of the physical model are composed of a bottom steel plate, a moving steel plate, a stationary steel plate and double-sided glass plates, and the lengths and widths of the bottom steel plate, the moving steel plate, the stationary steel plate and the double-sided glass plates are set respectively.

4. The physical simulation analysis method for the genetic mechanism of multiple detachment and thrust structures according to claim 1 is characterized in that: The non-slip layer formation parameters include thickness, internal friction angle of sand body and particle size; The stratigraphic parameters of the detachment layer include thickness, lateral distribution range, paleo-tectonic morphology and relative position.

5. The physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures according to any one of claims 1 to 4, characterized in that: In step S3, if there is no tectonic movement according to geological knowledge, no extrusion movement is performed.

6. The physical simulation analysis method for the genetic mechanism of multiple detachment-thrust structures according to any one of claims 1 to 4, characterized in that: In step S3, parameter setting includes the following steps performed in sequence: S31. Lay a dry sand layer to simulate a non-slip layer; The non-detachment layer strata are arranged in the same proportion according to the structural morphology of the seismic section; S32. Lay silica gel as a slip layer simulation material to simulate the second stage of slip layer deposition; S33. Lay a dry sand layer to simulate a non-slip layer; The thickness of the non-detachment layer is set in the same proportion as the structural morphology of the seismic section; S34 performs unidirectional extrusion movement, and stops after the extrusion movement of the steel plate; The extrusion, rate and distance are based on the knowledge of structural deformation.

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