A method, device and storage medium for quantitatively characterizing paleogeomorphology

Abstract

The present application relates to shale oil and gas exploration and development technical field, disclose a kind of palaeogeomorphology quantitative characterization method, equipment and storage medium, method comprising the following steps: determining palaeogeomorphology study area, and obtaining study area basic parameters and address data, obtain palaeogeomorphology recovery key parameters;Palaeogeomorphology recovery key parameters are calculated and analyzed, restore ancient topography;According to the restored ancient topography, quantitative recovery ancient river system, obtain ancient river system prototype;According to the restored ancient topography, quantitative depict ancient slope, obtain ancient slope plane distribution;According to ancient river system prototype, establish the relationship between sedimentation noise and water depth change, qualitative characterization ancient water depth;According to qualitative ancient water depth, calculate relative water depth D, to predict ancient water depth H.The present application has beneficial effects: establish palaeogeomorphology three-dimensional space configuration relationship, reveal the evolution of micro-palaeogeomorphology of the same sedimentary basin, to effectively guide shale oil and gas exploration and development, provide more reliable model for its evaluation.

Description

Technical Field

[0001] This invention relates to the field of shale oil and gas exploration and development technology, and in particular to a method, equipment and storage medium for quantitative characterization of paleogeography. Background Technology

[0002] Paleomorphological reconstruction analysis is of great guiding significance for oil and gas exploration, including paleoenvironmental reconstruction, basin analysis, sedimentary facies type and distribution, sequence stratigraphy research, distribution of high-quality reservoirs and oil reservoirs, restoration of pre-depositional paleomorphology, and detailed paleomorphological research.

[0003] Paleomorphological restoration generally includes tectonic restoration and thickness restoration. This paper analyzes the tectonic restoration process and thickness restoration methods. Currently, the mainstream methods include sedimentology, high-resolution sequence stratigraphy, stripping and filling methods, tectonic sedimentary simulation methods, sedimentary period micro-amplitude paleomorphological extrapolation methods, well-seismic combined methods, and the newer "dual-interface" paleomorphological restoration method. Each method has its own advantages and disadvantages, and each has its own advantages under specific geological conditions.

[0004] However, current paleomorphological restoration mainly focuses on the restoration of relative paleomorphological features, failing to achieve a comprehensive restoration of paleomorphological features through both qualitative and quantitative methods. Summary of the Invention

[0005] The purpose of this invention is to propose a method, device, and storage medium for quantitative characterization of ancient landforms, thereby solving the technical problem that existing technologies have failed to comprehensively restore ancient landforms through qualitative and quantitative methods.

[0006] A quantitative characterization method for paleogeography includes the following steps:

[0007] S1: Determine the paleogeographic study area, obtain the basic parameters and geological data of the study area, and obtain the key parameters for paleogeographic reconstruction;

[0008] S2: Calculate and analyze key parameters for ancient landform restoration to reconstruct ancient topography;

[0009] S3: Based on the restored ancient topography, quantitatively reconstruct the ancient water system to obtain the prototype of the ancient water system;

[0010] S4: Based on the restored paleotopography, the paleoslope is quantitatively characterized to obtain the planar distribution of the paleoslope;

[0011] S5: Based on the ancient river system prototype, establish the relationship between sedimentary noise and water depth changes, and qualitatively characterize the ancient water depth;

[0012] S6: Based on the qualitative paleowater depth, establish the relationship between natural gamma logging and water depth variation, and fit the natural gamma logging with U to calculate the relative water depth D, thereby predicting the paleowater depth H.

[0013] A storage medium that stores instructions and data for implementing a method for quantitative characterization of paleogeography.

[0014] A quantitative paleogeographic characterization device includes: a processor and a storage medium; the processor loads and executes instructions and data in the storage medium to implement a quantitative paleogeographic characterization method.

[0015] The beneficial effects provided by this invention are as follows: This invention combines the "new four ancient" characteristics, such as ancient topography, ancient water system, ancient slope, and ancient water depth, to qualitatively and quantitatively restore the ancient geomorphological features, establish the three-dimensional spatial configuration relationship of ancient geomorphology, and reveal the evolution of micro-paleomorphology in syn-sedimentary basins, thereby effectively guiding shale oil and gas exploration and development and providing a more reliable model for its evaluation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0017] Figure 2 This is a map showing the distribution of the prototype paleogeography and sedimentary facies in an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram illustrating the identification and tracking of key interfaces of the research target layer using Landmark in this invention;

[0019] Figure 4 This invention utilizes time-domain and depth-domain fitting analysis graphs;

[0020] Figure 5 This is a reconstruction diagram of an ancient water system according to an embodiment of the present invention;

[0021] Figure 6 This is a reconstruction diagram of the ancient slope according to an embodiment of the present invention;

[0022] Figure 7 This is a schematic diagram of the qualitative and quantitative reconstruction of ancient water depth according to an embodiment of the present invention;

[0023] Figure 8 This is an overall schematic diagram of the method described above in this invention;

[0024] Figure 9 This is a schematic diagram of the hardware device of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0026] Before formally describing the present invention, a general description of the solution of the present invention will be given first to facilitate understanding.

[0027] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating the method of the present invention;

[0028] This invention provides a method for quantitative characterization of paleogeography, comprising the following steps:

[0029] S1: Determine the paleogeographic study area, obtain the basic parameters and geological data of the study area, and obtain the key parameters for paleogeographic reconstruction;

[0030] It should be noted that step S1 is as follows: determine the study area, select basic parameters and geological data of the study area for analysis, clarify the division of the stratigraphic sequence, and at the same time, collect and quantify the parameters of the study area, select key parameters, including the thickness of the participating strata, the thickness of strata erosion, the sediment compaction coefficient, the paleo-river system of the same period, the paleo-slope of the same period, and the paleo-water depth of the same depositional period.

[0031] S2: Calculate and analyze key parameters for ancient landform restoration to reconstruct ancient topography;

[0032] It should be noted that the key parameters selected for paleogeographic restoration will be calculated and analyzed, including residual basin boundaries, residual thickness analysis, erosion calculation and restoration, and sediment compaction correction, in order to restore its paleotopography.

[0033] Specifically, the process of paleogeographic parameter restoration technology in step S2 is as follows:

[0034] S21: Residual stratum thickness analysis first requires obtaining layered data and seismic interface data from multiple single wells. Through the geological stratification of single wells, the seismic profile data is compared and calibrated using Landmark to obtain the basic formula for time-depth conversion. The basic formula is: D = 0.0002 * Tw 2 +0.5905*Tw+94.022, where Tw is the unit for explaining two-way transmission at different strata, in milliseconds (ms). The basic formula may vary depending on the region.

[0035] Please refer to Figure 4 , Figure 4 This invention utilizes time-domain and depth-domain fitting analysis graphs;

[0036] Based on this, the key interfaces of the target layer were identified and tracked using the whole basin seismic profile data of the study area.

[0037] Please refer to Figure 3 , Figure 3 This invention utilizes Landmark to identify and track key interfaces of the research target layer;

[0038] Meanwhile, by using the data exported from the Geoframe system to generate maps in Petrel, residual stratigraphic thickness maps of different strata can be obtained.

[0039] It should be noted that the Geoframe system is a well logging data processing system. The Geoframe system can realize functions such as interactive interpretation of conventional well logging curves, dip angle processing, processing and interpretation of imaging data, and engineering applications, providing oilfields with some key parameters for oil, gas and water layer evaluation, reserve calculation, drilling and fracturing engineering applications, etc.

[0040] It should be noted that Petrel is an exploration and development platform developed by Schlumberger, centered on a 3D geological model, and belongs to the category of geophysical software.

[0041] S22: Erosion Calculation and Recovery. A comprehensive analysis of single wells and seismic profiles in the study area was conducted, and the erosion thickness was recovered using the stratigraphic correlation method.

[0042] Please refer to Figure 2 , Figure 2 This is a map showing the distribution of paleogeography and sedimentary facies of the prototype of this invention.

[0043] S23: Sediment compaction correction. The recovery of compaction volume mainly relies on the EBM basin simulation system to obtain simulation parameter points and collect data to recover the total subsidence of the target stratum in the study area. Based on the recovered total subsidence, a grid subtraction operation is performed between it and the residual stratum thickness to obtain a planar distribution map of compaction volume in the study area.

[0044] S24: Based on the restoration of residual stratum thickness, stratum erosion thickness, and sediment compaction coefficient, three-dimensional spatial visualization technology is used to model the prototype basin, thereby obtaining the paleogeomorphic representation of key interfaces and revealing the evolution of micro-paleogeomorphism in the syn-sedimentary basin.

[0045] S3: Based on the restored ancient topography, quantitatively reconstruct the ancient water system to obtain the prototype of the ancient water system;

[0046] Please refer to Figure 5 , Figure 5 This is a reconstruction diagram of an ancient water system according to an embodiment of the present invention; Figure 5 (a) represents the paleogeographic projection quantification map; (b) represents the paleoflow direction analysis map; (c) represents the flow calculation map; and (d) represents the paleo-river system prototype map.

[0047] It should be noted that the quantitative characterization of the paleoriver system process in step S3 is as follows:

[0048] S31: Based on the restoration of micro-paleomorphology, paleomorphology is projected and quantified in Petrel, and paleomorphology is automatically picked up in a quantitative manner.

[0049] S32: Import the grid data file of the quantitatively reconstructed paleogeography into ArcMap. Perform depression filling in the hydrological analysis module and check against the original grid data to eliminate false depressions caused by errors and ensure the accuracy of the paleo-river flow direction.

[0050] S33: The D8 algorithm is used to analyze the flow direction and flow rate of the ancient drainage system, outputting FLOAT data. The Con function in the raster calculator is used to filter out outlier values ​​in the raster data to obtain the final ancient drainage system model.

[0051] It should be noted that the D8 algorithm is a commonly used algorithm in Digital Elevation Model (DEM) analysis, primarily used to determine the direction of surface water flow. This algorithm is based on the steepest slope method, assuming the surface is impermeable and rainfall is uniform, meaning water always flows to the lowest point. In the D8 algorithm, water flow in a single grid cell can only flow into the eight adjacent grid cells.

[0052] S4: Based on the restored paleotopography, the paleoslope is quantitatively characterized to obtain the planar distribution of the paleoslope;

[0053] Please refer to Figure 6 , Figure 6 This is a reconstruction diagram of the ancient slope according to an embodiment of the present invention; Figure 6 (a) represents the paleogeographic raster vector map; (b) represents the paleogeographic slope extraction map; (c) represents the paleogeographic slope data quantification map; and (d) represents the paleogeographic profile distribution reconstruction map.

[0054] It should be noted that the quantitative restoration process of ancient slope in step S4 is as follows:

[0055] S41: Based on the restoration of paleogeography, seismic stratigraphic data is extracted using GlobalMapper software, and paleogeography is rasterized and vectorized. The converted raster elevation surface is used as input, and the restored slope aspect is represented by positive degrees between 0 and 360 degrees. Measurements are performed clockwise with north as the reference direction.

[0056] It should be noted that Global Mapper is a map-making software that can display data (such as SRTM data) as raster maps, elevation maps, and vector maps. It can also edit, convert, print, record GPS data, and utilize GIS (Geographic Information System) functions.

[0057] S42: After rasterizing the paleogeomorphology, the stratigraphic data is quantified according to the surface data to establish the elevation difference. The slope break zones of different landforms in the study area are qualitatively and quantitatively restored using the principle of the plane method or the principle of the geodesic method. The profile / line data are then distributed in a plane to restore the plane paleoslope distribution of the study area.

[0058] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the qualitative and quantitative reconstruction of ancient water depth according to an embodiment of the present invention. Figure 7 (a) Qualitative characterization of paleowater depth - sedimentary noise method; (b) Semi-quantitative characterization of paleowater depth - GR-U fitting method; (c) Comprehensive bar chart of qualitative and quantitative paleowater depth in the study area; S5: Based on the paleoriver prototype, establish the relationship between sedimentary noise and water depth changes, and qualitatively characterize paleowater depth;

[0059] S6: Based on the qualitative paleowater depth, establish the relationship between natural gamma-ray logging and water depth variation, and fit the natural gamma-ray logging with U to calculate the relative water depth D, thereby predicting the paleowater depth H. The natural gamma-ray logging-U fitting formula is W(U). i =aGr i +b, relative ancient water depth D=sum[W(U)] i ] 2 / (n-1), the predicted water depth is calculated as H=D*H max / D max .

[0060] Finally, refer to Figure 8 , Figure 8 This is an overall schematic diagram of the method described above in this invention. This invention quantitatively characterizes paleomorphology through four aspects: paleotopography, paleowater systems, paleoslope, and paleowater depth.

[0061] Please see Figure 9 , Figure 9 This is a schematic diagram of the hardware device in operation according to an embodiment of the present invention. The hardware device specifically includes: a quantitative paleomorphological characterization device 401, a processor 402, and a storage medium 403.

[0062] A quantitative paleogeographic characterization device 401: The quantitative paleogeographic characterization device 401 implements the quantitative paleogeographic characterization method.

[0063] Processor 402: The processor 402 loads and executes the instructions and data in the storage medium 403 to implement the method for quantitative characterization of ancient landforms.

[0064] Storage medium 403: The storage medium 403 stores instructions and data; the storage medium 403 is used to implement the above-mentioned method for quantitative characterization of ancient landforms.

[0065] The beneficial effects of this invention are as follows: This invention combines the "new four ancient" characteristics, such as paleotopography, paleowater system, paleoslope, and paleowater depth, to qualitatively and quantitatively restore the paleomorphological features, establish the three-dimensional spatial configuration relationship of paleomorphology, and reveal the evolution of micro-paleomorphology in syn-sedimentary basins, thereby effectively guiding shale oil and gas exploration and development and providing a more reliable model for its evaluation.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for quantitative characterization of paleotopography, characterized in that: The method comprises the following steps: S1: determining a palaeogeomorphology research area, and acquiring basic parameters and address data of the research area to obtain palaeogeomorphology recovery key parameters; S2: performing calculation and analysis on the palaeogeomorphology recovery key parameters to recover a palaeotopography; S3: quantitatively recovering a palaeowatershed according to the recovered palaeotopography to obtain a palaeowatershed prototype; S4: quantitatively depicting a palaeoslope according to the recovered palaeotopography to obtain a palaeoslope planar distribution; S5: establishing a relationship between sediment noise and water depth variation according to the palaeowatershed prototype to qualitatively represent a palaeowater depth; S6: establishing a relationship between a natural gamma logging and water depth variation according to the qualitative palaeowater depth, fitting the natural gamma logging and U, calculating a relative water depth D, and thus predicting a palaeowater depth H; Step S4 specifically comprises: S41: on the basis of palaeogeomorphology recovery, extracting seismic horizon data by using a Global Mapper software, performing grid vectorization on the palaeogeomorphology, taking the converted grid elevation surface as input, and representing the recovered slope direction by a positive number between 0 and 360 degrees, with north as a benchmark direction and measurement in a clockwise direction; S42: after performing grid vectorization on the palaeogeomorphology, establishing a height difference value according to the cell data, performing qualitative-quantitative recovery on slope break zones in different geomorphologies in the research area by using a planar method principle or a geodesic line method principle, performing planar distribution on profile / line-of-sight data, and recovering a planar palaeoslope distribution of the research area; The qualitative representation process of the palaeowater depth in step S5 is as follows: S51: on the basis of analysis on basic data and geological data, inferring an overall sedimentary environment; S52: on the basis of analysis on the sedimentary environment, performing correlation analysis on logging curves of multiple wells, clearly selecting a natural gamma logging curve, filtering out a Milankovitch orbital parameter signal in an astronomical cycle, analyzing a La04 theoretical period and superimposed noise signals, establishing a relationship between strength of the remaining noise signals and change of a lake level, and thus qualitatively representing a palaeowater depth; The quantitative prediction process of the palaeowater depth in step S6 is as follows: S61: on the basis of a sequence and a sedimentary environment, reading Th, U and K element contents according to analysis on spectral logging data, and analyzing redox conditions of the research area; on the basis of a sequence framework, clearly determining migration characteristics of geochemical elements, and establishing a correlation between the redox conditions and the water depth; S62: by using analysis on the sedimentary environment, redox evaluation and palaeowater depth calculation, establishing a relationship between a natural gamma logging and water depth variation, fitting the natural gamma curve and the element U, quantitatively calculating and predicting a palaeowater depth.

2. The method for quantitative characterization of paleogeomorphology according to claim 1, wherein: The calculation and analysis in step S2 comprise residual basin boundary analysis, residual thickness analysis, denudation amount calculation and recovery, and sediment compaction correction.

3. The method for quantitative characterization of paleogeomorphology according to claim 1, wherein: The quantitative representation process of the palaeowatershed in step S3 is as follows: S31: on the basis of palaeogeomorphology recovery, performing projection quantization on the palaeogeomorphology in petrel, and performing quantitative automatic picking on the palaeogeomorphology; S32: The grid data file of quantitative palaeogeomorphology restoration is rasterized and imported into ArcMap; the depression filling processing is conducted in the hydrological analysis module, and the original grid data is checked to eliminate the pseudo-depression formed by errors and ensure the accuracy of the palaeo-drainage flow direction; S33: The D8 algorithm is used to analyze the palaeo-drainage flow direction and flow, FLOAT data is output, and the Con function in the grid calculator is used to screen out the abnormal values in the grid data to obtain the final palaeo-drainage model.

4. A storage medium characterized by: The storage medium stores instructions and data for implementing the method for quantitatively representing palaeogeomorphology according to any one of claims 1-3.

5. A device for quantitative palaeogeomorphic characterization, characterized in that: The method comprises: A processor and a storage medium; the processor loads and executes the instructions and data in the storage medium to implement the method for quantitatively representing palaeogeomorphology according to any one of claims 1-3.

Images