A palaeogeomorphology restoration method and a storage medium

Abstract

The application discloses a palaeogeomorphology recovery method and a storage medium, and comprises the following steps: S1, acquiring data of a stratum top surface and a stratum bottom surface of a region to be recovered; S2, acquiring a convergence surface and performing flattening processing on the convergence surface to obtain data of the recovered stratum top surface and the stratum bottom surface; and S3, determining an erosion region range according to the data of the recovered stratum top surface and the stratum bottom surface, and completing palaeogeomorphology recovery according to the erosion region range. The flattening processing on the convergence surface makes the erosion region more accurate, the essential error of the palaeogeomorphology recovery is smaller, and the palaeogeomorphology recovery is more reasonable.

Description

Technical Field

[0001] This invention relates to the field of paleogeography technology, and in particular to a method for paleogeography restoration and a storage medium. Background Technology

[0002] Paleomorphological reconstruction can reproduce the surface landforms of a specific geological period. The constantly evolving paleomorphological forms play a crucial role in the accumulation of oil and gas. However, as oil and gas exploration continues to advance deeper, the current patterns of paleomorphological features are often incomplete or have even disappeared entirely. This hinders our intuitive and comprehensive understanding of their evolutionary process, becoming a major challenge in paleomorphological reconstruction. Accurate and reasonable reconstruction of paleomorphological features can effectively guide the exploration and development of oil and gas resources. Currently, Chinese scholars' research on paleomorphological features mainly focuses on the paleosedimentary features of sedimentary periods and their control over sedimentary systems and favorable reservoirs. They frequently use methods such as the overlying strata filling and completion method, the truncation point trend surface extension method, and the sequence stratigraphy base level determination to reconstruct the stratigraphic morphology of paleomorphological features. These methods differ in their principles and key focuses, resulting in varying applicable research environments. Currently, in areas of the Pearl River Estuary Basin with intense magmatic alteration, the factors that need to be considered in paleomorphological reconstruction have further increased, and existing technologies have significant errors in reconstructing paleomorphological features. Providing a feasible and scientifically sound method for paleogeographic restoration is a pressing technical challenge that urgently needs to be addressed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address at least one deficiency of the related technologies mentioned in the background: how to solve the problem of large errors in the restoration of ancient landforms by existing technologies, and to provide an ancient landform restoration method and storage medium.

[0004] The technical solution adopted by this invention to solve its technical problem is: to construct a method for ancient landform restoration, which includes the following steps:

[0005] S1: Obtain data on the top and bottom surfaces of the formation in the area to be restored;

[0006] S2: Obtain the convergence surface and flatten it to obtain the data of the recovered top and bottom surfaces of the formation;

[0007] S3: Determine the extent of the erosion zone based on the data from the restored top and bottom surfaces of the strata, and complete the paleomorphological restoration based on the extent of the erosion zone.

[0008] In some embodiments, the method further includes the following steps prior to step S1:

[0009] S01: Select areas that meet the conditions for magma uplift as the areas to be restored;

[0010] S02: Determine the geological period of the area to be restored; the geological period includes the Cenozoic era, and the top and bottom surfaces of the strata are the Cenozoic era interfaces.

[0011] Step S1 includes: obtaining data on the top and bottom surfaces of the strata in the area to be restored based on geological periods.

[0012] In some embodiments, step S1 includes:

[0013] Based on geological periods, a third-order sequence stratigraphic interpretation was performed on the area to be restored to obtain the interpretation depth of the top and bottom surfaces of the strata in the area to be restored.

[0014] In some embodiments, step S2 includes:

[0015] S21: Interpret the pre-existing faults beneath the basal interface during the Cenozoic era to obtain the convergence surface;

[0016] S22: Identify deep uplift reflections to determine fault morphology and flatten the convergence surface;

[0017] S23: Based on the convergence surface after flattening, obtain the interpretation level and interpretation depth of the restored top and bottom surfaces of the strata.

[0018] In some embodiments, step S3 includes:

[0019] S31: Based on the data of the restored top and bottom surfaces of the strata, the trend of the restored top and bottom surfaces of the strata is extended, and the extent of the erosion zone is determined based on the endpoint of the trend extension;

[0020] S32: Determine the ancient residual landforms and erosion thickness based on the extent of the erosion zone, and complete the ancient landform restoration based on the ancient residual landforms and erosion thickness.

[0021] In some embodiments, step S32 includes:

[0022] S321: The difference between the depth of the top surface of the strata below the unconformity and the depth of the bottom surface of the strata is used to obtain the ancient residual landform.

[0023] S322: The erosion thickness is obtained by subtracting the depth of the trend extension of the top and bottom surfaces of the strata above the unconformity.

[0024] S323: Overlay the ancient residual landforms and erosion thickness with the unconformity as the reference to obtain the eroded strata superposition zone;

[0025] S324: Perform depth numerical superposition of the residual area and the overlapping area of ​​eroded strata to complete the ancient landform restoration.

[0026] In some embodiments, the residual zone is the difference between the interpretation depths of the top and bottom surfaces of the formation.

[0027] In some embodiments, the method further includes:

[0028] The ridges of ancient landforms are identified as watersheds, and the areas between each watershed are designated as erosion zones. Ancient landform restoration is then completed for each erosion zone.

[0029] In some embodiments, the process of flattening the convergence surface further includes:

[0030] After flattening the convergence surface, the tilting tendency of the top and bottom surfaces of the strata is adjusted so that the volume difference between the extended portions of the top and bottom surfaces of the strata above the unconformity surface follows the law of conservation of mass.

[0031] The law of conservation of mass states that the total amount of material recovered in the eroded zone is equal to the total amount of sediment in the residual zone.

[0032] The present invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the paleomorphological restoration method described above.

[0033] By implementing this invention, the following beneficial effects are achieved:

[0034] This invention obtains data on the top and bottom surfaces of the strata in the area to be restored, then acquires the convergence surface and flattens it to obtain data on the restored top and bottom surfaces of the strata. Finally, the extent of the erosion zone is determined based on the restored data, and the paleomorphological restoration is completed based on the extent of the erosion zone. This reduces the error between the restored paleomorphological features and the actual features, making the restored paleomorphological features more reasonable. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0036] Figure 1 A flowchart of one embodiment of the paleomorphological restoration method of the present invention is shown;

[0037] Figure 2 A flowchart of analysis step S2 of an embodiment of the paleogeographic restoration method of the present invention is shown;

[0038] Figure 3-a An analysis diagram of an embodiment of the paleogeographic restoration method of the present invention using a traditional sedimentary layer restoration method is shown; Figure 3-b This diagram illustrates an embodiment of the paleogeographic restoration method of the present invention, using a method for paleogeographic restoration of sedimentary layers under magmatic uplift background.

[0039] Figure 4 A flowchart of analysis step S32 of an embodiment of the paleogeographic restoration method of the present invention is shown;

[0040] Figure 5 This paper shows a prototype basin distribution map after the restoration of the Wenwu Formation sedimentary layer in a certain work area, according to an embodiment of the paleogeographic restoration method of the present invention.

[0041] Figure 6 The diagram shows the paleogeographic features of a basin after the restoration of the Wenwu Formation sedimentary layer in a certain work area, according to an embodiment of the paleogeographic restoration method of the present invention. Detailed Implementation

[0042] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] It should be noted that the flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0044] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0045] like Figure 1 As shown, some embodiments of the present invention disclose a method for paleomorphological restoration, which includes the following steps:

[0046] S1: Obtain data on the top and bottom surfaces of the formation in the area to be restored;

[0047] S2: Obtain the convergence surface and flatten it to obtain the data of the recovered top and bottom surfaces of the formation;

[0048] S3: Determine the extent of the erosion zone based on the data from the restored top and bottom surfaces of the strata, and complete the paleomorphological restoration based on the extent of the erosion zone.

[0049] In some embodiments, before step S1, the following steps are included: S01: selecting an area that meets the conditions for magma uplift as the area to be restored; S02: determining the geological period of the area to be restored; the geological period includes the Cenozoic period, and the top surface and bottom surface of the strata are the Cenozoic period interface.

[0050] Step S1 includes: obtaining data on the top and bottom surfaces of the strata in the area to be restored based on geological periods.

[0051] In some embodiments, step S01 includes: selecting a metamorphic basin that meets the conditions for magmatic uplift as the area to be restored based on the tectonic evolution law of the work area;

[0052] Step S1 includes: collecting three-dimensional seismic data volumes covering the work area, and obtaining data on the top and bottom surfaces of the strata in the area to be restored based on geological periods.

[0053] Magmatic uplift conditions refer to conditions that clearly indicate the basin was affected by magmatic uplift at a certain period during its formation and evolution. These conditions are mainly based on magmatic rock samples discovered in the surrounding area, as well as structural analysis of the regional geological background and seismic geology. Metasource type refers to the change in the scale of the erosion zone over geological periods. The erosion zone refers to the material source area of ​​basin sediments in sedimentology.

[0054] Currently, the impact of magmatism on basin morphology and even the entire source-sink process has become a new focus. Existing techniques have two main problems: first, they lack detailed characterization of magmatic activity in uplifted areas, leading to unreasonable basin reconstructions where magmatism was intense but current stratigraphic remnants are insufficient; second, the source supply is unstable, making it difficult to accurately reconstruct early-stage basin boundaries and thus hindering the accurate characterization of the scale of latent source materials. Therefore, identifying the location and stages of magmatic uplift in source-rich uplifted areas has become a primary challenge.

[0055] However, identifying the location and timing of magmatic uplift in the source uplift zone remains challenging, resulting in a lack of effective methods for reconstructing the paleogeography of magmatically modified basins. The impact of magmatic uplift within depressions can be identified through abrupt changes in the sedimentary characteristics of the overlying strata. However, during periods of strong tectonic activity, the superposition effect of magmatic uplift and regional tectonic activity makes it difficult to distinguish and decouple the reconstruction factors, leading to significant errors between the reconstruction results and the actual situation.

[0056] In some embodiments, step S1 includes: performing a third-order sequence stratigraphic interpretation of the area to be restored according to geological period, and obtaining the interpretation depth of the top and bottom surfaces of the strata in the area to be restored.

[0057] Third-order sequence stratigraphy refers to the division of strata into different levels of sequence units based on sedimentary characteristics and the division of unconformities. Specifically, the third-order sequence strata in the area to be restored require interpretation using a high-density grid of at least 20m × 20m.

[0058] like Figure 2 As shown, in some embodiments, step S2 includes:

[0059] S21: Interpret the pre-existing faults beneath the basal interface during the Cenozoic era to obtain the convergence surface;

[0060] S22: Identify deep uplift reflections to determine fault morphology and flatten the convergence surface;

[0061] S23: Based on the convergence surface after flattening, obtain the interpretation level and interpretation depth of the restored top and bottom surfaces of the strata.

[0062] The basement interface of the Cenozoic era, also known as the Tg interface, indicates the lowest layer of the Cenozoic interface. Geological periods include the Cenozoic era, and the top and bottom surfaces of strata are the Cenozoic interfaces.

[0063] Interpreting pre-existing faults requires the formation of a high-density grid of 20m × 20m. Pre-existing faults are existing fractures that can connect to deep magma, meaning they extend very deep downwards and can directly connect to magma sources in the deep crust or upper mantle, allowing magma to rise along the fracture and potentially leading to volcanic eruptions or intrusions.

[0064] In some embodiments, step S3 includes:

[0065] S31: Based on the data of the restored top and bottom surfaces of the strata, the trend of the restored top and bottom surfaces of the strata is extended, and the extent of the erosion zone is determined based on the endpoint of the trend extension;

[0066] S32: Determine the ancient residual landforms and erosion thickness based on the extent of the erosion zone, and complete the ancient landform restoration based on the ancient residual landforms and erosion thickness.

[0067] like Figure 3-a As shown, traditional sedimentary layer reconstruction methods, without determining the fault plane morphology, only extend the existing stratigraphic interpretation. The intersection of the extensions of the top and bottom stratigraphic surfaces is directly affected by the stratigraphic interpretation and the dip angle of its extension lines.

[0068] like Figure 3-b As shown, flattening the convergence surface after determining the fault morphology can restore the top and bottom surfaces of the strata above the area affected by magma uplift, correct the intersection of the restored strata extension lines, and thus affect the calculation of subsequent erosion.

[0069] Sedimentary layers, also known as sedimentary strata, are defined by their top and bottom surfaces. Sedimentary layers are loose deposits or consolidated rock units with a distinct layered structure, formed on the Earth's surface or at the bottom of a body of water by the transportation and deposition of weathering and erosion products, biological remains, chemical deposits, or volcanic debris. Extending the top and bottom surfaces of the strata aims to more accurately reconstruct the sedimentary layers before erosion.

[0070] like Figure 4 As shown, in some embodiments, step S32 includes:

[0071] S321: The difference between the depth of the top surface of the strata below the unconformity and the depth of the bottom surface of the strata is used to obtain the ancient residual landform.

[0072] S322: The erosion thickness is obtained by subtracting the depth of the trend extension of the top and bottom surfaces of the strata above the unconformity.

[0073] S323: Overlay the ancient residual landforms and erosion thickness with the unconformity as the reference to obtain the eroded strata superposition zone;

[0074] S324: Perform depth numerical superposition of the residual area and the overlapping area of ​​eroded strata to complete the ancient landform restoration.

[0075] Among them, the obtained ancient residual landforms are those that have excluded the influence of magma uplift.

[0076] An unconformity is a recognizable interface between sedimentary layers from different periods, left behind after geological movements have caused erosion of the strata. It is usually distributed at the edge of a basin or other local areas and is the local top surface of the remaining sedimentary layers.

[0077] In some embodiments, the residual zone is the difference between the interpretation depths of the top and bottom surfaces of the formation.

[0078] The difference between the interpreted depth data of the top and bottom surfaces of strata marking geological periods is the unrecovered residual stratum thickness, i.e., the residual zone.

[0079] Identifying magmatic uplift presents another challenge, resulting in a lack of effective methods for reconstructing the paleomorphology of magmatically modified basins: In paleo-uplifted areas, erosion is more intense, and the remaining sedimentary layers are extremely limited. Reconstructing paleotectonic morphology through sedimentary characteristics often fails to account for the influence of magmatic uplift, making it difficult to predict the original basin boundaries. Table 1 shows the types of erosion intensity in the uplifted strata at basin boundaries.

[0080] Table 1 Types of erosion intensity of strata

[0081] In some embodiments, the method further includes: identifying the ridges of ancient landforms as watersheds, defining the areas between each watershed as erosion zones, and restoring the ancient landforms in the erosion zones.

[0082] Material distribution in accordance with the law of conservation of matter is carried out in the erosion zones to complete the paleogeographic restoration of all erosion zones within the erosion range.

[0083] The paleogeography is a metamorphic basin, meaning that the scale of the erosion zone changes with geological time; the erosion zone refers to the partitioning of the basin's sedimentary source area in sedimentology.

[0084] In some embodiments, after step S22, the method further includes: adjusting the tilting trend of the top and bottom surfaces of the formation after flattening the convergence surface, so that the volume difference between the extended portions of the top and bottom surfaces of the formation above the unconformity surface follows the law of conservation of mass.

[0085] The law of conservation of mass states that the total amount of material recovered in the eroded zone is equal to the total amount of sediment in the residual zone.

[0086] To supplement the integrity and usability of seismic data, if the convergence surface identification is incomplete due to missing parts of deep seismic data or limitations in seismic resolution, the tilting trend of the stratigraphic control interface can be appropriately adjusted after flattening the convergence surface. Since the erosion zone is a three-dimensional concept, the total amount of material recovered from the erosion zone must be equal to the total amount of material in the residual stratigraphic sedimentary body, that is, the volume recovered from the erosion zone is equal to the volume of the residual stratigraphic sedimentary body.

[0087] The law of conservation of matter also includes: when interpreting, the erosion amount of each two-dimensional profile in the 20m×20m high-density grid should follow the law of conservation of matter; the erosion amount is a numerical measurement in the two-dimensional profile, which can be obtained by calculating the difference between the erosion thickness of the top surface of the strata extending above the unconformity and the erosion thickness area of ​​the bottom surface of the strata.

[0088] The purpose of setting up erosion zones is to limit the material conservation of sediment volume within each erosion zone. The area between the top and bottom surfaces of the strata (two-dimensional profile) on a 20m×20m interpretation profile can be used as the basis for interpretation. It will be further extended to the entire area to be restored within the work area to form a three-dimensional concept.

[0089] Based on the mechanism of magmatic uplift through isostatic thinning of deep lithospheric strata, this study identifies key control boundaries reflecting magmatic uplift and comprehensively analyzes the complex processes of magmatic uplift, including their location and stages, thereby reconstructing the true high points under magmatic activity. Incorporating magmatic uplift reconstruction into the paleogeomorphological reconstruction process in basin margins expands the key control boundaries used as reconstruction benchmarks. This means that reconstruction not only utilizes the trend extension of the top surface of eroded residual strata but also considers the deformation reconstruction caused by magmatic activity, resulting in a more accurate reconstruction of the eroded zone's extent. Furthermore, as... Figures 5-6 As shown, erosion zoning can more accurately and reasonably restore paleomorphology, help clarify the dynamic evolution process of the source region, and refine the division of the source region's catchment units.

[0090] in, Figure 5 The fifth section of the Wenchang Formation refers to a section of the Wenchang Formation sedimentary strata formed by sedimentation during the Cenozoic rifting process in the basin. According to the third-order sequence stratigraphy interpretation, the Wenchang Formation sedimentary strata can be divided vertically into six sections, from bottom to top, namely the sixth section to the first section. Figure 6The NWW-trending faults are those that strike roughly in a Northwest-West (NWW) direction, while the NEE-trending faults are those that strike roughly in a Northeast-East (NEE) direction.

[0091] This invention addresses the inapplicability of existing paleogeographic reconstruction methods for prototype basins to source uplift zones with complex magmatic uplift processes. It applies magmatic uplift identification to the reconstruction of erosion interfaces, thereby improving the trend surface extension reconstruction method. This makes the paleogeographic reconstruction results of variable-source prototype basins caused by magmatic uplift more reasonable, thus effectively guiding the study of the evolution process of source-sink systems in oil and gas basins.

[0092] Some embodiments of the present invention disclose a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it implements the paleomorphological restoration method as described in any of the above embodiments, which will not be repeated here.

[0093] It is understood that the above embodiments only illustrate some implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above embodiments or technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. That is, the embodiments described "in some embodiments" can be freely combined with any of the preceding and following embodiments. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A method for ancient landform restoration, characterized in that, The method includes the following steps: S1: Obtain data on the top and bottom surfaces of the strata in the area to be restored; the area to be restored is a region that meets the conditions for magma uplift. S2: Obtain the convergence surface below the basement interface during the Cenozoic era and flatten it to obtain the data of the restored top and bottom surfaces of the strata; the convergence surface is a marker interface reflecting magma uplift obtained based on the mechanism of isostatic thinning of the deep lithosphere; the data of the restored top and bottom surfaces of the strata are the interpretation horizons and interpretation depths of the restored top and bottom surfaces of the strata; S3: Determine the extent of the erosion zone based on the interpretation horizon and interpretation depth of the restored top and bottom surfaces of the strata, and complete the paleomorphological restoration based on the extent of the erosion zone; Step S2 includes: S21: Interpret the pre-existing faults beneath the basal interface during the Cenozoic era to obtain the convergence surface; S22: Identify deep uplift reflections to determine fault morphology and flatten the convergence surface; S23: Based on the convergence surface after flattening, obtain the interpretation level and interpretation depth of the restored top and bottom surfaces of the strata.

2. The paleomorphological restoration method according to claim 1, characterized in that, The procedure preceding step S1 also includes: S01: Select areas that meet the conditions for magma uplift as the areas to be restored; S02: Determine the geological period of the area to be restored; the geological period includes the Cenozoic era, and the top and bottom surfaces of the strata are the Cenozoic era interfaces. Step S1 includes: obtaining data on the top and bottom surfaces of the strata in the area to be restored based on geological periods.

3. The paleomorphological restoration method according to claim 2, characterized in that, Step S1 includes: Based on geological periods, a third-order sequence stratigraphic interpretation was performed on the area to be restored to obtain the interpretation depth of the top and bottom surfaces of the strata in the area to be restored.

4. The paleomorphological restoration method according to claim 1, characterized in that, Step S3 includes: S31: Based on the data of the restored top and bottom surfaces of the strata, the trend of the restored top and bottom surfaces of the strata is extended, and the extent of the erosion zone is determined based on the endpoint of the trend extension; S32: Determine the ancient residual landforms and erosion thickness based on the extent of the erosion zone, and complete the ancient landform restoration based on the ancient residual landforms and erosion thickness.

5. The paleomorphological restoration method according to claim 4, characterized in that, Step S32 includes: S321: The difference between the depth of the top surface of the strata below the unconformity and the depth of the bottom surface of the strata is used to obtain the ancient residual landform. S322: The erosion thickness is obtained by subtracting the depth of the trend extension of the top and bottom surfaces of the strata above the unconformity. S323: Overlay the ancient residual landforms and erosion thickness with the unconformity as the reference to obtain the eroded strata superposition zone; S324: Perform depth numerical superposition of the residual area and the overlapping area of ​​eroded strata to complete the ancient landform restoration.

6. The paleogeographic restoration method according to claim 3 or 5, characterized in that, The residual zone is the difference between the interpretation depths of the top and bottom surfaces of the strata.

7. The method for paleomorphological restoration according to claim 1, characterized in that, The method further includes: The ridges of ancient landforms are identified as watersheds, and the areas between each watershed are designated as erosion zones. Ancient landform restoration is then completed for each erosion zone.

8. The method for paleomorphological restoration according to claim 7, characterized in that, The process of flattening the convergence surface also includes: After flattening the convergence surface, the tilting tendency of the top and bottom surfaces of the strata is adjusted so that the volume difference between the extended portions of the top and bottom surfaces of the strata above the unconformity surface follows the law of conservation of mass. The law of conservation of mass states that the total amount of material recovered in the eroded zone is equal to the total amount of sediment in the residual zone.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the paleomorphological restoration method as described in any one of claims 1-8.

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