A method and apparatus for reconstructing a subsidence prototype

Abstract

This invention discloses a method for prototyping and reconstructing modified depressions, comprising the following steps: dissecting and analyzing the depression structure in the study area to identify its structural characteristics; identifying the substratigraphic framework of the main depositional periods in the study area; identifying and statistically analyzing the fault points and displacements within the depression structure, and reconstructing the vertical displacements of the faults; identifying the vertical uplift of the depression structure and reconstructing the amount of vertical uplift; identifying the horizontal extension of the depression structure and reconstructing the amount of horizontal extension; tracing and characterizing the residual stratigraphic boundaries within the study area, and extracting key occurrence information of the residual strata; and based on the extracted key occurrence information of the residual strata, reconstructing and reconstructing the original distribution morphology of the target strata within the depression structure. This invention can fully utilize the sedimentary and structural information of the basin's residual stratigraphy, and through detailed characterization and constraint of sedimentary boundaries, accurately and conveniently reconstruct and reconstruct modified depressions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas resource exploration and development, in particular to a reconstruction type depression prototype recovery and reconstruction method based on high-precision sedimentary boundary constraint. BACKGROUND

[0002] The prototype basin structure and evolution control the development of sedimentary systems, the distribution of source rocks and the process of oil and gas migration and enrichment in important historical periods. Its recovery and reconstruction have very important petroleum geological significance. In-depth development of prototype basin recovery and reconstruction is of great significance for sedimentary system analysis, clear understanding of the distribution range of high-quality source rocks and prediction of favorable reservoirs, and is the basis and important basis for oil and gas exploration well deployment. In recent years, the exploration and development of China's offshore oil and gas basins has gradually expanded to new depressions and new zones. The depression formation process often goes through multiple tectonic uplifts and magmatic activities. The depression structure is highly reconstructed, the strata are severely eroded, and the unclear understanding of the depression structure and the unclear understanding of the distribution range of high-quality source rocks seriously restrict the exploration prospects of new depressions.

[0003] The traditional prototype basin recovery method is mainly based on the paleogeomorphology research method of balanced section, but the recovery method under the condition of strong erosion of strata and strong reconstruction is not very suitable. In this case, the previous method is mainly based on the acoustic travel time method, the porosity method and the paleogeothermal method, but the above methods are based on single well data, and the accuracy and human subjective influence are large, the applicability is limited, and the operability is not high, so the original basin shape cannot be accurately recovered.

[0004] For the recovery of the prototype basin with strong tectonic activity and severe erosion and reconstruction, there is no good solution in the industry at present. The existing method is difficult to obtain ideal prototype basin recovery effect, and the accuracy and precision of the recovery of the prototype structure and the eroded strata of the basin cannot be guaranteed, so a quantitative recovery and reconstruction method with high operability and accurate recovery effect is needed. SUMMARY

[0005] The present application aims to solve at least one of the technical problems in the prior art. To this end, the present application provides a reconstruction type depression prototype recovery and reconstruction method based on high-precision sedimentary boundary constraint, which aims to make full use of the sedimentary and structural information of the residual strata of the basin, accurately and conveniently recover and reconstruct the prototype of the reconstruction type depression by finely depicting and constraining the sedimentary boundary.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a reconstruction type depression prototype recovery and reconstruction method, comprising the following steps:

[0008] Anatomizing and analyzing the sag structure of the study area, identifying the sag structure characteristics of the study area;

[0009] Identifying the main sedimentary period stratigraphic framework of the study area;

[0010] Identifying and counting the fault points and fault throw of the faults in the sag structure, and restoring the vertical fault throw of the faults;

[0011] Identifying the vertical uplift of the sag structure and restoring the vertical uplift amount;

[0012] Identifying the horizontal extension of the sag structure and restoring the horizontal extension amount;

[0013] Tracking and describing the residual strata sedimentary boundary in the study area, and extracting the key attitude information of the residual strata;

[0014] Based on the extracted key attitude information of the residual strata, the original distribution pattern of the target strata in the sag structure is restored and reconstructed.

[0015] As preferred: the "anatomizing and analyzing the sag structure of the study area, identifying the sag structure characteristics of the study area" is specifically:

[0016] Based on the seismic data and geological stratification data of the study area, the sag structure is anatomized and analyzed, and the main controlling faults, secondary associated faults and angular unconformity surfaces in the sag structure are identified.

[0017] As preferred: the "identifying the main sedimentary period stratigraphic framework of the study area" is specifically:

[0018] Based on the seismic data and geological stratification data of the study area, the main sedimentary period stratigraphic framework of the study area is identified, and the main stratum interface distribution range and stratum distribution pattern in the whole area are determined through the seismic reflection characteristics and interface reflection characteristics.

[0019] As preferred: the "based on the identified sag structure characteristics and the identified stratum interface distribution range and stratum distribution pattern, identifying and counting the fault points and fault throw of the main controlling faults and secondary associated faults in the sag structure, and restoring the vertical fault throw of the faults.

[0020] As preferred: the "identifying the vertical uplift of the sag structure and restoring the vertical uplift amount" is specifically:

[0021] For the sag structure with vertical uplift of faults, appropriate reference surface is selected, and the vertical uplift amount is calculated through the elevation difference of the same set of continuous traceable strata in flat area and uplift area, and the vertical restoration is carried out.

[0022] As preferred: the "identifying the horizontal extension of the sag structure and restoring the horizontal extension amount" is specifically:

[0023] For the depression structure with horizontal extension of faults, the horizontal extension amount is calculated by the displacement amount of the same set of continuous traceable strata in the horizontal direction, and the horizontal restoration is performed.

[0024] As preferred: the "tracking and depicting the residual strata sedimentary boundary in the research area, and extracting the key occurrence information of the residual strata" specifically refers to:

[0025] After the vertical fault throw recovery, the vertical uplift amount recovery and the horizontal extension amount recovery of the depression structure are completed, the residual strata distribution range of the target strata in the research area in the depression structure is finely tracked, and the key occurrence information of the residual strata is extracted.

[0026] As preferred: the "restoring and reconstructing the original distribution form of the target strata in the depression structure" specifically refers to:

[0027] The key occurrence information of the extracted residual strata is used as a constraint and test condition of a deep learning model based on knowledge enhancement, and at the same time, based on the vertical recovery of the depression structure and the horizontal recovery of the depression structure, the original distribution form of the source rock sedimentary strata before the reconstruction of the depression structure is restored and reconstructed, and the stratum distribution form of the prototype basin during the source rock deposition period in the research area is obtained.

[0028] As preferred: it further includes the step of obtaining the key characteristic parameters of the prototype basin during the source rock deposition period in the research area, specifically:

[0029] The key characteristic parameters of the prototype basin during the source rock deposition period in the research area are obtained according to the stratum distribution form of the prototype basin during the source rock deposition period in the research area, including the area, volume and maximum denudation thickness of the prototype basin source area.

[0030] In the second aspect, the present application provides a reconstruction type depression prototype restoration and reconstruction device, comprising:

[0031] The first processing unit is used for dissecting and analyzing the depression structure in the research area, identifying the depression structure characteristics in the research area;

[0032] The second processing unit is used for identifying the main sedimentary period stratum framework in the research area;

[0033] The third processing unit is used for identifying and counting the breakpoints and throws of the faults in the depression structure, and restoring the vertical throw of the faults;

[0034] The fourth processing unit is used for identifying the vertical uplift of the depression structure and restoring the vertical uplift amount;

[0035] The fifth processing unit is used for identifying the horizontal extension of the depression structure and restoring the horizontal extension amount;

[0036] The sixth processing unit is used for tracking residual stratum sedimentary boundary in the delineation research area and extracting key occurrence information of the residual stratum;

[0037] The seventh processing unit is used for recovering and reconstructing the original distribution form of the target stratum in the depression structure based on the extracted key occurrence information of the residual stratum.

[0038] The present application has the following advantages due to the above technical solutions:

[0039] The present application takes high-precision sedimentary boundary and sedimentary thickness as constraints, comprehensively considers the structural style and the depositional system, maximally recovers and reconstructs the structural style and the depositional filling features of the reformed depression, correctly recognizes the depression structure and the resource potential, lays a foundation for the depositional system analysis in the basin, the distribution range of the high-quality hydrocarbon source rock and the favorable reservoir prediction, provides an important basis for the oil and gas exploration deployment, and improves the success rate of the reformed depression oil and gas exploration. BRIEF DESCRIPTION OF DRAWINGS

[0040] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the present application. Throughout the drawings, like reference numerals will be used to refer to like components. In the drawings:

[0041] Figure 1 A flow chart of the reformed depression prototype recovery and reconstruction method provided for the embodiments of the present application;

[0042] Figure 2 A base structure map after the prototype basin recovery of the research area in the embodiments of the present application. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present application clearer, the specific embodiments of the present application are further described below in combination with the drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0044] The method for prototyping and reconstructing modified depressions provided by this invention includes the following steps: dissecting and analyzing the depression structure in the study area to identify its structural characteristics; identifying the stratigraphic framework of the main depositional periods in the study area; identifying and statistically analyzing the fault points and displacements within the depression structure, and reconstructing the vertical displacements of the faults; identifying the vertical uplift of the depression structure and reconstructing the amount of vertical uplift; identifying the horizontal extension of the depression structure and reconstructing the amount of horizontal extension; tracing and characterizing the residual stratigraphic boundaries within the study area, and extracting key occurrence information of the residual strata; and based on the extracted key occurrence information of the residual strata, reconstructing and reconstructing the original distribution morphology of the target strata in the depression structure. This invention can fully utilize the sedimentary and structural information of the basin's residual stratigraphy, and through detailed characterization and constraint of sedimentary boundaries, accurately and conveniently reconstruct and reconstruct modified depressions.

[0045] The modified depression prototype restoration and reconstruction method and apparatus provided in the embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0046] Example 1:

[0047] This embodiment selects a small residual depression in a depression in the Pearl River Estuary Basin as the study area. The strata in this depression were severely eroded above the uplift area during the key depositional period. The exploration potential of the depression is unclear, and the distribution range and effective volume of the source rocks are unknown. The method of this invention is used to reconstruct the prototype basin of the source rocks during a specific depositional period and to calculate the key information of the source area during that period.

[0048] Please see Figure 1 This embodiment provides a method for restoring and reconstructing a modified depression prototype, which includes the following steps:

[0049] S1. Dissect and analyze the depression structure in the study area to identify its structural characteristics:

[0050] Based on seismic data and geological stratification data of the study area, the depression structure was dissected and analyzed to identify the main controlling fault, secondary associated faults and angular unconformities within the depression structure.

[0051] S2. Identify the substratigraphic framework of the main sedimentary periods in the study area:

[0052] Based on seismic data and geological stratification data of the study area, the stratigraphic framework of the main sedimentary periods in the study area was identified. The distribution range and stratigraphic distribution morphology of the main stratigraphic interfaces in the whole area were delineated by seismic reflection characteristics and interface reflection characteristics, including seismic reflection layers T4, T5, T6 and T7.

[0053] S3. Identify and statistically analyze the fault points and displacements within the depression structure, and reconstruct the vertical displacements of the faults:

[0054] Based on the depression structure features identified in step S1 and the stratigraphic interface distribution range and stratigraphic distribution morphology delineated in step S2, the fault points and fault displacements of the main control faults and secondary associated faults within the depression structure are identified and statistically analyzed, and the vertical fault displacements are recovered.

[0055] S4. Identify the vertical uplift of the depression structure and recover the amount of vertical uplift:

[0056] For depression structures with vertical uplift due to faults, an appropriate reference surface is selected, and the vertical uplift is calculated by the elevation difference between the same set of continuous traceable strata in flat and uplifted areas, and then vertically restored.

[0057] S5. Identify the horizontal extension of the depression structure and recover the amount of horizontal extension:

[0058] For depression structures with horizontal fault extension, the horizontal extension is calculated by measuring the horizontal displacement of the same set of continuously traceable strata, and then horizontally restored.

[0059] S6. Tracing and characterizing the residual stratigraphic boundaries within the study area:

[0060] The distribution range of the target strata (i.e. source rock sedimentary strata) in the depression structure after the restoration of vertical fault displacement, vertical uplift and horizontal extension was completed was finely tracked in the study area. The sedimentary boundaries were finely delineated and key occurrence information of the residual strata was extracted, including the dip angle and dip direction of the residual strata.

[0061] S7. Restore and reconstruct the original distribution morphology of the target strata in the depression structure:

[0062] Using a knowledge-enhanced deep learning model, the key occurrence information of the residual strata extracted in step S6 is used as constraints and validation conditions for the deep learning model to restore and reconstruct the original distribution morphology of the target strata before the depression structure modification, thus obtaining the stratigraphic distribution morphology of the prototype basin during the hydrocarbon source rock deposition period in the study area (e.g., Figure 2 (As shown).

[0063] In the above embodiments, preferably, the modified depression prototype restoration and reconstruction method provided by the present invention further includes the following steps:

[0064] S8. Calculate the key characteristic parameters of the prototype basin during the hydrocarbon source rock deposition period in the study area:

[0065] Based on the restoration and reconstruction results in step S7, key characteristic parameters of the prototype basin during the hydrocarbon source rock deposition period in the study area were obtained, including the area, volume, and maximum erosion thickness of the prototype basin source area. The restoration and reconstruction results show that the source area of ​​the prototype basin during the hydrocarbon source rock deposition period exceeded 300 square kilometers, the maximum erosion thickness reached 275 meters, and the comprehensive calculation showed that the depression resource volume exceeded 100 million cubic meters, which can provide an important basis for oil and gas exploration deployment.

[0066] Example 2:

[0067] Embodiment 1 above provides a method for restoring and reconstructing a modified depression prototype. Correspondingly, this embodiment provides a device for restoring and reconstructing a modified depression prototype. The device provided in this embodiment can implement the method for restoring and reconstructing a modified depression prototype in Embodiment 1. This device can be implemented through software, hardware, or a combination of both. For example, the device may include integrated or separate functional modules or units to perform the corresponding steps in the methods of Embodiment 1. Since the device for restoring and reconstructing a modified depression prototype in this embodiment is basically similar to the method embodiment, the description process in this embodiment is relatively simple. For relevant details, please refer to the description in Embodiment 1. The device for restoring and reconstructing a modified depression prototype in this embodiment is merely illustrative.

[0068] The modified depression prototype restoration and reconstruction device provided in this embodiment includes:

[0069] The first processing unit is used to dissect and analyze the depression structure in the study area and identify the characteristics of the depression structure in the study area.

[0070] The second processing unit is used to identify the substratigraphic framework of the main sedimentary periods in the study area;

[0071] The third processing unit is used to identify and count the fault points and displacements of faults within the depression structure, and to recover the vertical displacements of the faults.

[0072] The fourth processing unit is used to identify the vertical uplift of the depression structure and recover the amount of vertical uplift.

[0073] The fifth processing unit is used to identify the horizontal extension of the depression structure and recover the amount of horizontal extension;

[0074] The sixth processing unit is used to trace and characterize the sedimentary boundaries of residual strata within the study area and extract key occurrence information of the residual strata.

[0075] The seventh processing unit is used to restore and reconstruct the original distribution morphology of the target strata in the depression structure based on the key occurrence information of the extracted residual strata.

[0076] Example 3:

[0077] This embodiment provides a processing device for implementing the modified depression prototype restoration and reconstruction method provided in Embodiment 1. The processing device can be a client-side processing device, such as a mobile phone, laptop, tablet computer, desktop computer, etc., to execute the method of Embodiment 1.

[0078] The processing device includes a processor, a memory, a communication interface, and a bus. The processor, memory, and communication interface are connected via the bus to enable communication between them. The memory stores a computer program that can run on the processor. When the processor runs the computer program, it executes the modified depression prototype restoration and reconstruction method provided in Embodiment 1.

[0079] Preferably, the memory may be high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device.

[0080] Preferably, the processor can be any type of general-purpose processor such as a central processing unit (CPU) or a digital signal processor (DSP), and there is no limitation herein.

[0081] Example 4:

[0082] The modified depression prototype restoration and reconstruction method of Embodiment 1 can be specifically implemented as a computer program product. The computer program product may include a computer-readable storage medium on which computer-readable program instructions for executing the method described in Embodiment 1 are loaded.

[0083] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any combination thereof.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for restoring and reconstructing a modified depression prototype, characterized in that, Includes the following steps: The depression structure in the study area was dissected and analyzed to identify its structural characteristics. Identify the substratigraphic framework of the main sedimentary periods in the study area; Identify and statistically analyze the fault points and displacements within the depression structure, and reconstruct the vertical displacements of the faults, specifically as follows: Based on the identified depression structure features and the delineated stratigraphic interface distribution range and stratigraphic distribution morphology, the fault points and fault displacements of the main controlling faults and secondary associated faults within the depression structure are identified and statistically analyzed, and the vertical fault displacements are recovered. Identify the vertical uplift of the depression structure and recover the amount of vertical uplift, specifically as follows: A reference surface was selected, and the vertical uplift was calculated using the elevation difference between the same set of continuously traceable strata in flat and uplifted areas, and then vertically restored. Identify the horizontal extension of the depression structure and recover the amount of horizontal extension, specifically: The horizontal extension is calculated by measuring the horizontal displacement of the same set of continuously traceable strata, and then horizontally restored. Tracing and characterizing the residual stratigraphic boundaries within the study area, and extracting key occurrence information of the residual strata, specifically: The distribution range of the target strata in the depression structure after the restoration of vertical fault displacement, vertical uplift and horizontal extension was carried out in detail, and its sedimentary boundary was finely delineated to extract key occurrence information of the residual strata. Based on the key attitude information of the extracted residual strata, the original distribution morphology of the target strata in the depression structure is restored and reconstructed, specifically as follows: Using a knowledge-enhanced deep learning model, the key occurrence information of the extracted residual strata is used as the constraint and test condition of the deep learning model. At the same time, based on the vertical restoration and horizontal restoration of the depression structure, the original distribution morphology of the source rock sedimentary strata before the depression structure was modified is restored and reconstructed, so as to obtain the stratigraphic distribution morphology of the prototype basin during the deposition of source rocks in the study area.

2. The method for restoring and reconstructing the modified depression prototype according to claim 1, characterized in that, The aforementioned "dissection and analysis of the depression structure in the study area to identify its structural characteristics" specifically refers to: Based on seismic data and geological stratification data of the study area, the depression structure was dissected and analyzed to identify the main controlling fault, secondary associated faults, and angular unconformities within the depression structure.

3. The method for restoring and reconstructing the prototype of the modified depression according to claim 2, characterized in that, The aforementioned "identification of the substratigraphic framework of the main sedimentary periods in the study area" specifically refers to: Based on seismic data and geological stratification data of the study area, the stratigraphic framework of the main sedimentary periods in the study area was identified, and the distribution range and stratigraphic distribution morphology of the main stratigraphic interfaces throughout the area were delineated by seismic reflection characteristics and interface reflection characteristics.

4. The method for restoring and reconstructing the modified depression prototype according to claim 3, characterized in that, It also includes the step of obtaining key characteristic parameters of the prototype basin during the hydrocarbon source rock deposition period in the study area, specifically: Based on the stratigraphic distribution morphology of the prototype basin during the hydrocarbon source rock deposition period in the study area, key characteristic parameters of the prototype basin during the hydrocarbon source rock deposition period were obtained, including the area, volume, and maximum erosion thickness of the prototype basin source area.

5. A modified depression prototype restoration and reconstruction apparatus, used to implement the modified depression prototype restoration and reconstruction method as described in any one of claims 1 to 4, characterized in that, The device includes: The first processing unit is used to dissect and analyze the depression structure in the study area and identify the characteristics of the depression structure in the study area. The second processing unit is used to identify the substratigraphic framework of the main sedimentary periods in the study area; The third processing unit is used to identify and count the fault points and displacements of faults within the depression structure, and to recover the vertical displacements of the faults. The fourth processing unit is used to identify the vertical uplift of the depression structure and recover the amount of vertical uplift. The fifth processing unit is used to identify the horizontal extension of the depression structure and recover the amount of horizontal extension; The sixth processing unit is used to trace and characterize the sedimentary boundaries of residual strata within the study area and extract key occurrence information of the residual strata. The seventh processing unit is used to restore and reconstruct the original distribution morphology of the target strata in the depression structure based on the key occurrence information of the extracted residual strata.

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