A lithology-based palaeogeomorphology slope calculation method and device

Abstract

This paper relates to the field of oil and gas exploration, and particularly to a method and apparatus for calculating paleogeographic slope based on lithology. The method includes determining the overlying strata reference surface and the underlying strata reference surface of a target stratum in a preset area; correcting the overlying strata reference surface based on the maximum thickness between the overlying and underlying strata reference surfaces to obtain paleotectonic relative height data; correcting the paleotectonic relative height data based on standard lithology within the preset area to obtain paleogeographic relative height data; and determining a paleogeographic slope map based on the paleogeographic relative height data. The embodiments described in this paper correct the overlying strata reference surface, resulting in good paleogeographic reconstruction and easy identification; furthermore, the paleogeographic depth data is converted into slope data to establish a high-precision paleogeographic slope map, providing analytical basis for karst paleogeographic prediction and sedimentary pattern analysis, thus meeting the needs of oil and gas exploration.

Description

Technical Field

[0001] This article relates to the field of oil and gas exploration, and in particular to a method, apparatus, computer equipment and storage medium for calculating paleogeographic slope based on lithology. Background Technology

[0002] As oil and gas exploration in my country continues to deepen, stratigraphic studies of ancient landforms are becoming increasingly common.

[0003] Current technologies for analyzing paleogeography typically focus only on slope break zones, analyzing sedimentary paleogeography through sedimentary structure analysis. This approach lacks systematicity and predictive capability. Furthermore, existing technologies rarely study paleogeographic slope, making it impossible to intuitively understand the steepness of stratigraphic slopes based on paleogeographic slope data, thus hindering further guidance for oil and gas exploration. Moreover, current paleogeographic research is generally based on individual seismic identification and is limited to specific regions, lacking a systematic and holistic perspective. Additionally, the lack of quantitative methods restricts scientific research and exploration deployment.

[0004] Given the lack of research on the slope of paleogeomorphology in existing technologies, there is an urgent need to develop a method for calculating the slope of paleogeomorphology based on lithology. Summary of the Invention

[0005] To address the problems of the prior art, this paper provides a paleogeographic slope calculation method based on lithology.

[0006] According to one aspect of the embodiments herein, the method includes: determining the overlying strata reference surface and the underlying strata reference surface of the target stratum in a preset area; correcting the overlying strata reference surface based on the maximum thickness value between the overlying strata reference surface and the underlying strata reference surface to obtain paleotectonic relative height data; correcting the paleotectonic relative height data based on the standard lithology in the preset area to obtain paleogeographic relative height data; and determining a paleogeographic slope map based on the paleogeographic relative height data.

[0007] According to one aspect of the embodiments herein, the process of determining the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface includes: calculating a first thickness value and a second thickness value for a plurality of wells in a preset area based on the overlying stratum reference surface and the underlying stratum reference surface, wherein the first thickness value is the distance between the destination layer of each well and the overlying stratum reference surface, and the second thickness value is the distance between the destination layer of each well and the underlying stratum reference surface; calculating the thickness value of the plurality of wells between the overlying stratum reference surface and the underlying stratum reference surface based on the first thickness value and the second thickness value of the plurality of wells; selecting the maximum thickness value from the thickness values ​​of the plurality of wells between the overlying stratum reference surface and the underlying stratum reference surface; and using the selected maximum thickness value as the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface.

[0008] According to one aspect of the embodiments herein, correcting the overlying stratum reference surface based on the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface to obtain the paleotectonic relative height data further includes: correcting the overlying stratum reference surface of the plurality of wells based on the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface and a correction coefficient to obtain the paleotectonic relative height data; wherein the correction coefficient is calculated using a first thickness value and a second thickness value of the plurality of wells in the preset region.

[0009] According to one aspect of the embodiments herein, correcting the overlying strata reference surface based on the maximum thickness value between the overlying strata reference surface and the underlying strata reference surface and the correction coefficient to obtain the paleotectonic relative height data includes: obtaining the paleotectonic relative height data according to the following formula: y(i)=[H max -h(i)]×G; where y(i) is the relative height data of the paleotectonic structure, h(i) represents the second thickness value of the i-th well, and H max G is the maximum thickness value, and G is the correction coefficient.

[0010] According to one aspect of the embodiments herein, the standard lithology determination process within the preset area includes: calculating the fine-seam ratio of multiple wells in the preset area, wherein the fine-seam ratio is the ratio of the sum of the thicknesses of mudstone and siltstone in the overlying strata to the first thickness value; determining a reference well based on the arithmetic mean of the fine-seam ratios of the multiple wells; and using the fine-seam ratio of the reference well as the standard lithology of the preset area.

[0011] According to one aspect of the embodiments herein, correcting the paleotectonic relative height data based on the standard lithology within the preset area to obtain paleogeographic relative height data includes: determining the paleogeographic relative height data according to the following formula: X(i)=y(i)×{1-(j(i)-j p); where X(i) represents the relative height data of the paleogeography, y(i) represents the relative height data of the paleotectonic structure, j(i) represents the fineness ratio of multiple wells, and j p The fineness ratio of the reference well P.

[0012] According to one aspect of the embodiments herein, determining an ancient landform slope map based on the ancient landform relative height data includes: determining the ancient landform depth data based on the difference between the ancient landform relative height data and the maximum thickness value; converting the ancient landform depth data into ancient landform slope data; and determining the ancient landform slope map based on the ancient landform slope data.

[0013] This embodiment also provides a paleogeographic slope calculation device based on lithology, including: a first determining unit, used to determine the overlying stratum reference surface and the underlying stratum reference surface of the target stratum in a preset area;

[0014] The first acquisition unit is used to correct the overlying stratum reference surface based on the maximum thickness values ​​of the overlying stratum reference surface and the underlying stratum reference surface, so as to obtain paleotectonic relative height data.

[0015] The second acquisition unit is used to correct the paleotectonic relative height data according to the standard lithology within the preset area, so as to obtain the paleogeographic relative height data.

[0016] The third acquisition unit is used to correct the paleotectonic relative height data according to the standard lithology within the preset area, and obtain the paleogeographic relative height data.

[0017] The second determining unit is used to determine the ancient landform slope map based on the ancient landform relative height data.

[0018] This embodiment also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method.

[0019] This embodiment also provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the above-described method.

[0020] Using the embodiments described in this paper, the overlying strata reference surface is corrected to obtain more accurate paleogeographic depth data, making the topographic features of paleogeography more prominent, the paleogeographic reconstruction effect better, and easier to identify. Furthermore, the paleogeographic depth data is converted into slope data to establish a high-precision paleogeographic slope map, providing an analytical basis for karst paleogeographic prediction and sedimentary pattern analysis, and meeting the needs of oil and gas exploration. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments or prior art described herein, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this article. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The diagram shown is a flowchart of a paleogeographic slope calculation method based on lithology, as described in this embodiment.

[0023] Figure 2 The diagram shown is a flowchart of a method for determining the maximum thickness between the overlying strata reference surface and the underlying strata reference surface, as provided in this embodiment.

[0024] Figure 3 The diagram shown is a flowchart of a method for determining standard lithology within a preset area, according to an embodiment of this paper.

[0025] Figure 4 The diagram shown is a flowchart of a method for determining paleomorphological slope in an embodiment of this paper.

[0026] Figure 5 The diagram shown is a structural schematic of a paleogeographic slope calculation device based on lithology, as described in this embodiment.

[0027] Figure 6 The diagram shown is a schematic representation of a paleogeographic slope calculation device based on lithology, as described in this embodiment.

[0028] Figure 7 The image shown is a schematic diagram of an ancient landform profile according to an embodiment of this paper.

[0029] Figure 8 The image shown is a schematic diagram of the depth of an ancient landform as described in this embodiment.

[0030] Figure 9 The diagram shown is a schematic representation of the relationship between a central unit and adjacent units in an embodiment of this paper.

[0031] Figure 10 The diagram shown is a schematic representation of an ancient landform slope in an embodiment of this paper.

[0032] Figure 11 The diagram shown is a structural schematic of a computer device according to an embodiment of this article.

[0033] Explanation of symbols in the attached drawings:

[0034] 501. First Determined Unit;

[0035] 502. First Acquisition Unit;

[0036] 5021, Thickness value first calculation module;

[0037] 5022, Second Calculation Module for Thickness Value;

[0038] 5023, Maximum Thickness Value Filtering Module;

[0039] 5024, Overlying strata reference surface correction module;

[0040] 503. Second Acquisition Unit;

[0041] 5031, Detailed area ratio calculation module;

[0042] 5032, Benchmark Well Determination Module;

[0043] 504. Third Acquisition Unit;

[0044] 5041. Paleostructural relative height data correction module;

[0045] 505. Second Determined Unit;

[0046] 5051, Depth Data Determination Module;

[0047] 5052, Slope Data Determination Module;

[0048] 1102. Computer equipment;

[0049] 1104. Processor;

[0050] 1106. Memory;

[0051] 1108. Drive mechanism;

[0052] 1110. Input / output module;

[0053] 1112. Input devices;

[0054] 1114. Output devices;

[0055] 1116. Presentation device;

[0056] 1118. Graphical User Interface;

[0057] 1120. Network interface;

[0058] 1122. Communication link;

[0059] 1124. Communication bus. Detailed Implementation

[0060] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments herein will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments herein, and not all of the embodiments. Based on the embodiments herein, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this document.

[0061] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings herein are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0062] This specification provides the operational steps of the methods described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel.

[0063] It should be noted that the lithology-based paleogeographic slope calculation method and device presented in this paper can be used in the fields of geological exploration and oil and gas field exploration. This paper does not limit the application scenarios of the lithology-based paleogeographic slope calculation method and device.

[0064] like Figure 1 The diagram shows a flowchart of a paleogeographic slope calculation method based on lithology, as described in this embodiment. The method specifically includes the following steps:

[0065] Step 101: Determine the overlying and underlying strata reference surfaces of the target stratum in the preset area. In this step, the overlying and underlying strata reference surfaces are determined above and below the target stratum, respectively. In some embodiments of this specification, the overlying and underlying strata reference surfaces are determined according to the principle of regional isochronism. For reference surfaces with isochronism, they are not a horizontal plane throughout the preset area, but a continuous smooth curved surface, and the curvature of the reference surface varies at different locations of sedimentary system development. The overlying strata reference surface can be used as a comparative reference surface to reconstruct the original paleogeographic morphology of the underlying strata before deposition.

[0066] In some embodiments of this specification, the overlying strata reference surface of a preset area can be determined according to certain rules. For example, the residual thickness method can be used to reconstruct paleomorphology. The residual thickness method uses the point where the overlying strata begin deposition after the erosion of the landform to be reconstructed is taken as an isochronous surface. A specific segment of the sedimentary strata is selected as the reference surface, and this segment is flattened. The magnitude of the residual thickness above this surface represents the paleomorphology. In some embodiments of this specification, the paleomorphology of the target stratum can be reconstructed on an isochronous surface reference. The overlying strata reference surface of the target stratum is not a physical interface, but rather an abstract potential energy surface equivalent to a river equilibrium profile. For the Earth's surface to reach equilibrium with the reference surface, it needs to change its shape through deposition or erosion and move towards the reference surface.

[0067] In some embodiments of this specification, the curvature of the overlying strata base surface is not significantly different, and the overlying strata base surface is parallel to the lake level of the same period. The overlying sedimentary strata of the overlying strata base surface can fill in and complete the underlying paleogeography. The overlying strata base surface is relatively close to the unconformity of the weathering crust. This application can also use methods such as the impression method, sedimentological methods, sequence stratigraphy, and stripping method to determine the overlying strata base surface. This application does not limit the methods for determining the overlying strata base surface and the underlying strata base surface.

[0068] In some embodiments of this specification, the overlying strata reference surface and the underlying strata reference surface can be lithological and lithofacies transition surfaces, with stable interfaces, basically consistent lithological types, and small erosion ranges. Furthermore, the overlying strata reference surface and the underlying strata reference surface are easier to identify geologically and seismically, and are more stable within the region. Figure 7 shows an isobathographic paleogeomorphism according to an embodiment of this paper. In the figure, the area between the overlying strata reference surface and the underlying strata reference surface includes coal-based rocks, carbonate rocks, mudstone, dolomite, and a basement. There is a certain thickness between the overlying strata reference surface and the underlying strata reference surface.

[0069] Step 102: Based on the maximum thickness between the overlying strata reference surface and the underlying strata reference surface, correct the overlying strata reference surface to obtain paleotectonic relative height data. This step, by obtaining the maximum thickness between the overlying strata reference surface and the underlying strata reference surface of a preset area, corrects the overlying strata reference surface and further simulates the paleomorphology corresponding to that preset area.

[0070] In this step, the overlying stratum reference surface undergoes weathering, erosion, and other stratigraphic changes, accumulating over time. Within the preset area, the overlying stratum reference surface is a continuous, smooth curved surface. Therefore, at different surface locations within the preset area, the thickness between the overlying and underlying stratum reference surfaces varies with the surface location. Thus, multiple wells are installed within the preset area, corresponding to the target stratum, the overlying stratum reference surface, and the underlying stratum reference surface. Each well in the preset area can vertically penetrate the target stratum, the overlying stratum reference surface, and the underlying stratum reference surface. Based on the thickness value between the overlying and underlying stratum reference surfaces corresponding to each well, the maximum thickness value between the overlying and underlying stratum reference surfaces within the preset area is determined. This is used to correct the overlying stratum reference surface of the preset area.

[0071] The thickness between the overlying stratum reference surface and the underlying stratum reference surface is composed of the distance between the target stratum in the preset area and the overlying stratum reference surface, and the distance between the target stratum in the preset area and the underlying stratum geoid.

[0072] By acquiring thickness values ​​corresponding to multiple wells within a preset area, and selecting the thickness with the largest value from among these values, the maximum thickness value is determined. This maximum thickness value represents the maximum thickness between the overlying strata reference surface and the underlying strata reference surface within the preset area. A detailed description of this step can be found here. Figure 2 .

[0073] Step 103: Correct the paleotectonic relative height data based on the standard lithology within the preset area to obtain paleogeographic relative height data. In this step, a well with relatively stable lithology within the preset area is selected as a standard well. The paleotectonic relative height data obtained in step 102 is corrected using this standard well to further obtain the paleogeographic relative height data.

[0074] Step 104: Determine the paleomorphic slope map based on the paleomorphic relative height data. In this step, the paleomorphic height data is converted into a paleomorphic isobath, and the slope is calculated from the depth data in the paleomorphic isobath to obtain the paleomorphic slope map.

[0075] Figure 2This document provides a flowchart of a method for determining the maximum thickness between an overlying stratum reference surface and an underlying stratum reference surface, as illustrated in this embodiment. The method includes the following steps:

[0076] Step 201: Based on the overlying stratum reference surface and the underlying stratum reference surface, calculate the first thickness value and the second thickness value of multiple wells in the preset area. The first thickness value is the distance between the target stratum of each well and the overlying stratum reference surface, and the second thickness value is the distance between the target stratum of each well and the underlying stratum reference surface.

[0077] As per the steps

[0078] As described in step 102, multiple wells are set between the overlying stratum reference surface and the underlying stratum reference surface in a preset area. Each well extends downwards from the stratum, passing through the overlying stratum reference surface, the target layer, and the underlying stratum reference surface. Therefore, based on each well in the preset area, the distance between the target layer and the overlying stratum reference surface, and the distance between the target layer and the underlying stratum reference surface for each well, can be determined. In this step, the well can be an actual drilled well or a virtual well. A well can be set at 1-kilometer intervals within the preset area. Therefore, a preset area can obtain the first and second thickness values ​​for multiple wells. For example, if the surface length of the preset area is 50 kilometers, and a well is set at 1-kilometer intervals within this area, then 50 wells can be set in this preset area. Each of the 50 wells in this preset area has its own corresponding first and second thickness values ​​between the overlying stratum reference surface and the underlying stratum reference surface. Figure 7 In the image, you can see that wells B, A, and P are set on the surface of the preset area. Figure 7 The upper and lower reference surfaces in the text correspond to the overlying strata reference surface and the underlying strata reference surface described herein, respectively. Wells B, A, and P in the preset area each have their own corresponding first thickness value *m* and second thickness value *h*. The first thickness value represents the distance between the target stratum and the upper reference surface, including the thickness of the coal base, carbonate rock, and mudstone; the second thickness value represents the distance between the target stratum and the underlying strata reference surface, including the thickness of the dolomite and basement. Because the target stratum, the overlying strata reference surface, and the underlying strata reference surface in the preset area are not on the same horizontal plane, but rather on continuous smooth curved surfaces, wells A, B, and P each have different first and second thickness values.

[0079] Step 202: Calculate the thickness values ​​of the multiple wells between the overlying formation reference surface and the underlying formation reference surface based on the first thickness value and the second thickness value of the multiple wells.

[0080] In this step, the thickness value of multiple wells between the overlying formation reference surface and the underlying formation reference surface includes the sum of the distance between the target formation of each well and the overlying formation reference surface, and the distance between the target formation of each well and the underlying formation reference surface. As described in step 201, the distance between the target formation of each well and the overlying formation reference surface is the first thickness value, and the distance between the target formation of each well and the underlying formation reference surface is the second thickness value. Therefore, the thickness value of each well between the overlying formation reference surface and the underlying formation reference surface is the sum of the first thickness value and the second thickness value. Furthermore, multiple wells in this area have their own corresponding thickness values ​​between the overlying formation reference surface and the underlying formation reference surface, and there are multiple thickness values ​​in this area. For example, if the length of the preset area is 5 kilometers, and a well is set at a distance of 1 kilometer in this area, then 5 wells can be set in the preset area, namely well A, well B, well C, well E, and well D. Among them, the first thickness of well A is 120 meters, and the second thickness is 200 meters; the first thickness of well B is 122 meters, and the second thickness is 209 meters; the first thickness of well C is 109 meters, and the second thickness is 201 meters; the first thickness of well D is 121 meters, and the second thickness is 202 meters; and the first thickness of well E is 124 meters, and the second thickness is 208 meters. Therefore, the thickness between the overlying stratum reference surface and the underlying stratum reference surface in well A is 320 meters; in well B, it is 331 meters; in well C, it is 320 meters; in well D, it is 323 meters; and in well E, it is 332 meters.

[0081] Step 203: Select the maximum thickness value from the thickness values ​​of the multiple wells between the overlying stratum reference surface and the underlying stratum reference surface. Based on the thickness values ​​of the multiple wells between the overlying stratum reference surface and the underlying stratum reference surface determined in step 202, the maximum thickness value can be selected from multiple thickness values. For example, five wells set in a preset area: Well A, Well B, Well C, Well E, and Well D. Among these five wells, the thickness values ​​between the overlying stratum reference surface and the underlying stratum reference surface of Well A are 320 meters, 331 meters, 320 meters, 323 meters, and 332 meters, respectively. The maximum thickness value among these five wells is selected as the thickness value between the overlying stratum reference surface and the underlying stratum reference surface of Well B.

[0082] Step 204: The maximum thickness value selected is used as the maximum thickness value between the overlying strata reference surface and the underlying strata reference surface. The maximum thickness value among the multiple wells determined in step 203 is used as the maximum thickness value between the overlying strata reference surface and the underlying strata reference surface in the preset area.

[0083] According to one embodiment of this document, the overlying strata reference surface of the plurality of wells is corrected based on the maximum thickness value between the overlying strata reference surface and the underlying strata reference surface, and a correction coefficient, to obtain the paleotectonic relative height data; wherein, the correction coefficient is calculated using the first thickness value and the second thickness value of the plurality of wells in the preset region. In this step, the correction coefficient can be determined based on the average of the first thickness value and the second thickness value of the plurality of wells in the preset region. Specifically, the correction coefficient can be determined according to the following formula:

[0084] Where h represents the second thickness value for each well. This represents the average of the first thickness values ​​of multiple wells within a preset area; This represents the average of the second thickness values ​​of multiple wells in a preset area.

[0085] In this step, other methods can also be used to obtain the correction coefficient, which are not limited to this application.

[0086] According to one embodiment of this document, the step of correcting the overlying stratum reference surface based on the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface and the correction coefficient to obtain the paleotectonic relative height data includes:

[0087] The relative height data of the ancient structure is obtained according to the following formula:

[0088] y(i)=[H max -h(i)]×G;

[0089] Where y(i) is the relative height data of the paleotectonic structure, h(i) represents the second thickness value of the i-th well, and H max Let G be the maximum thickness value and G be the correction coefficient. In this step, using the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface determined in step 204, and the correction coefficient, the overlying stratum reference surface is corrected. This allows the determination of the first thickness value of each well in the preset area, which is the paleotectonic relative height data of the preset area. Based on the difference between the maximum thickness value and the second thickness values ​​of multiple wells, the first thickness values ​​of multiple wells are corrected. The corrected first thickness values ​​of the multiple wells are the paleotectonic relative height data of the overlying stratum reference surface. The difference between the maximum thickness value and the second thickness value of each well is: using the maximum thickness value of the preset area to correct the first thickness value of each well in the preset area, thereby simulating the paleotectonic relative height data corresponding to each well. The paleotectonic relative height data of multiple wells in the preset area constitute the paleotectonic relative height data of the preset area.

[0090] Figure 3This is a flowchart illustrating a method for determining standard lithology within a preset region, as described in this embodiment. This method utilizes standard lithology within the preset region to correct paleotectonic relative data. Specifically, obtaining the standard lithology within the preset region includes the following steps:

[0091] Step 301: Calculate the fineness ratio of multiple wells in the preset area. The fineness ratio is the ratio of the sum of the thicknesses of mudstone and siltstone in the overlying strata to the first thickness value. That is, the ratio of the total thickness of the overlying strata during the fine-grained depositional period to the total thickness of the overlying strata. Further, the fineness ratio represents the ratio of the fine-grained rock above the target stratum in the preset area to the first thickness value. Figure 7 As shown, the fine-grained ratio is the ratio of k to m in the figure. A larger fine-grained ratio indicates a greater fine-grained thickness and a lower paleogeographic depth; conversely, a smaller fine-grained ratio indicates a smaller fine-grained thickness and a higher paleogeographic depth. By using the ratio of the total thickness of the overlying strata during the fine-grained depositional period to the total thickness of the overlying strata, paleotectonic maps can be corrected, thereby obtaining relative paleogeographic data.

[0092] Step 302: Determine the benchmark well based on the arithmetic mean of the fine-grained ratios of multiple wells. Different wells have different fine-grained ratios. The fine-grained ratio characterizes the ratio of the sum of the thicknesses of mudstone and siltstone in a well to a first thickness value. The well corresponding to the arithmetic mean of the fine-grained ratios of multiple wells is selected as the benchmark well. For example, if there are 5 wells in a preset area (e.g., well A, well B, well C, well D, and well E), with corresponding fine-grained ratios of 0.5, 0.6, 0.7, 0.8, and 0.9 respectively, then the arithmetic mean of the fine-grained ratios of the multiple wells in this area is 0.7. The well corresponding to this value is well C, and well C is selected as the benchmark well for this preset area. The ratio of the sum of the thicknesses of mudstone and siltstone in the overlying strata of the benchmark well (well C) to the first thickness value is 7:10, that is, the thickness of mudstone and siltstone in the overlying strata of the benchmark well accounts for 7 / 10 of the first thickness value. In this step, when the well corresponding to the arithmetic mean of the fine-grained ratios of multiple wells does not exist in the preset area, the well in the preset area whose fine-grained ratio is closest to the arithmetic mean is selected as the benchmark well. For example, if there are 5 wells in the preset area (e.g., well A, well B, well C, well D, and well E), with corresponding fine-grained ratios of 0.3, 0.4, 0.6, 0.7, and 0.8 respectively, then the arithmetic mean of the fine-grained ratios of the multiple wells in this area is 0.56. Since there are no wells in the preset area with a fine-grained ratio of 0.56, and well C's fine-grained ratio is closest to the arithmetic mean, well C is selected as the benchmark well for this preset area. In this step, a virtual well can also be set based on the arithmetic mean of the fine-grained ratios of multiple wells in the preset area, and this virtual well can be directly used as the benchmark well, with the fine-grained ratio of the virtual well serving as the standard lithology for the preset area.

[0093] Step 303: The fine-grained ratio of the reference well is used as the standard lithology of the preset area. The fine-grained ratio of the reference well can reflect the standard lithology of the preset area, that is, the lithology distribution of the preset area.

[0094] In some embodiments of this specification, correcting the paleotectonic relative height data based on the standard lithology within the preset area to obtain paleogeographic relative height data includes: determining the paleogeographic relative height data according to the following formula: X(i)=y(i)×{1-(j(i)-j p )};where X(i) represents the relative height data of the paleogeography, y(i) represents the relative height data of the paleotectonic structure, j(i) represents the fineness ratio of multiple wells, j p The fineness ratio of the reference well P.

[0095] j p The following formula is used to obtain: j p =k p / m p , where k p This represents the sum of the thicknesses of mudstone and siltstone in the overlying strata of the reference well; m p The first thickness value of the reference well is represented by j(i). j(i) is obtained according to the following formula: j(i) = k(i) / m(i). Where k(i) represents the sum of the thicknesses of mudstone and siltstone in the overlying strata of the i-th well; m(i) represents the first thickness value of the i-th well. In this step, based on the difference between the fineness ratio of each well in the preset area and the fineness ratio of the reference well, the paleotectonic relative height data obtained above is further corrected to obtain the paleogeographic relative height data. For example, the fineness ratio j of the reference well P in the preset area is determined. p Given a reference well with a fineness ratio of 0.5, the fineness ratios of the four wells in the preset area (excluding the reference well) are 0.4, 0.45, 0.7, and 0.6, respectively. Therefore, the paleogeographic relative height data for these four wells can be determined as 1.1y(i), 1.2y(i), 0.8y(i), and 0.9y(i). This is used to determine the paleogeographic relative height data for the preset area. In other embodiments of this specification, any number of other wells can be set in the preset area, and the paleotectonic relative height data of these wells can be corrected according to the method described in this step to obtain the paleogeographic relative height data for the preset area.

[0096] like Figure 4 The above is a flowchart illustrating a method for determining paleomorphological slope maps according to an embodiment of this paper. Specifically, it includes the following steps:

[0097] Step 401: Determine the paleomorphic depth data based on the difference between the paleomorphic relative height data and the maximum thickness value. In this step, the paleomorphic depth data can be determined using the following formula:

[0098] f(i)=X(i)-H max Where f(i) represents paleogeographic depth data; X(i) represents paleogeographic relative height data; and H... max This represents the maximum thickness between the overlying strata reference level and the underlying strata reference level. In this step, the maximum thickness value H is... max Using the maximum thickness value as the basis, the relative height data of ancient landforms is converted into the depth data of ancient landforms at the location with an elevation of 0.

[0099] For example, three wells, A, B, and C, are set in a predetermined area. After the aforementioned processing steps, the relative paleomorphological heights of these three wells are obtained as 308 meters, 312 meters, and 306 meters, respectively. The maximum thickness of the predetermined area is also determined to be 320 meters. Using the maximum thickness of the predetermined area as a zero plane, the relative paleomorphological heights of the three wells in the predetermined area can be determined as -12 meters, -8 meters, and -14 meters, respectively. Thus, the relative paleomorphological heights of the predetermined area can be converted into paleomorphological depth data. In some embodiments of this specification, any number of wells can be set in the predetermined area, and the paleomorphological depth data corresponding to any number of wells can be determined based on the maximum thickness of the predetermined area. This application does not limit the number of relative paleomorphological heights and paleomorphological depths of the predetermined area.

[0100] In some other embodiments of this specification, paleogeographic depth data can be plotted on a map to form a paleogeographic depth schematic diagram (e.g., Figure 8 As shown in the image, this is a contour map. In a contour map, the denser the contour lines, the steeper the actual slope of the terrain; the sparser the contour lines, the gentler the actual slope. When the contour lines are closed, the elevation is lower on the outside and higher on the inside, indicating convex terrain such as peaks, mountains, or hilltops; when the contour lines are higher on the outside and lower on the inside, it indicates concave terrain such as basins or depressions.

[0101] Step 402: Convert the paleogeographic depth data into paleogeographic slope data. This step performs mathematical processing on the paleogeographic depth data to convert it into slope data. Slope is the ratio of the vertical height to the horizontal width of a slope. In some embodiments of the specification, methods such as percentage method, degree method, mil method, and fraction method can be used to convert the depth data into slope data.

[0102] Specifically, the Earth is considered an ellipsoid, and paleogeographic slope data for a predefined area is calculated by measuring the angle between the topographic surface and a reference datum surface. The slope of a surface unit is the angle between the tangent plane passing through a point on the surface and the horizontal plane; slope describes the degree of inclination of the surface at that point. Specifically, the slope is calculated from a paleogeographic depth map. At least a portion of the paleogeographic depth map is taken as the study area, which is then gridded, with multiple units set within the area, dividing the study area into multiple minimum units. For each minimum unit, it is used as the central unit, and the maximum rate of change of the values ​​of this central unit and its eight adjacent units in both the horizontal and vertical directions is calculated. Figure 9 The diagram illustrates the relationship between the central cell and its adjacent cells. E represents the smallest cell whose slope is being calculated, and A, B, C, D, F, G, H, and I represent adjacent cells surrounding E. In some embodiments of this specification, the slope can be calculated based on the central cell and its eight adjacent cells, and the slope in eight directions of the central grid can be solved. The average of the slopes in the eight directions is then taken as the slope of the central cell. This application does not limit the method for determining the slope of the central cell.

[0103] In some embodiments of this specification, the horizontal and vertical increments are determined based on the three-dimensional coordinates of the central element and its eight adjacent elements. The maximum rate of change of elevation as the distance between the central element E and the other eight adjacent elements is taken as the steepest slope of the central element.

[0104] In some embodiments of this specification, the slope is determined by the rate / increment of change of the central element in the horizontal and vertical directions. The slope is calculated using the following formula:

[0105] in, This represents the rate of change / increment of the central unit in the horizontal direction. This represents the rate of change / increment of the central unit in the vertical direction.

[0106] Furthermore, the rate of change / increment of the central unit in the horizontal direction is calculated using the following formula:

[0107] In this formula, E represents the smallest unit for calculating the slope, and A, B, C, D, F, G, H, and I represent the three-dimensional coordinates of adjacent units surrounding E. The horizontal unit size is the unit length of the unit. For example, if a plane is considered to have a 3×3 km neighborhood around the central unit whose slope is to be calculated, then the unit size of the central unit and its eight adjacent units is 1 km. The order of the three-dimensional coordinates of adjacent units within the same parenthesis is not specified in this formula.

[0108] The rate of change / increment of unit E in the vertical direction is calculated using the following formula:

[0109] Where E represents the smallest unit for calculating the slope, and A, B, C, D, F, G, H, and I represent the three-dimensional coordinates of adjacent units surrounding E. The unit size in the horizontal direction is the unit length of the unit. The order of the three-dimensional coordinates of adjacent units within the same set of parentheses is not specified in this formula.

[0110] When the slope angle is 45°, the elevation increment equals the horizontal increment. When the slope angle approaches a right angle, the percentage of elevation increment begins to approach infinity.

[0111] Step 403: Determine the ancient landform slope map based on the ancient landform slope data.

[0112] By plotting the paleogeographic slope data of the preset area obtained in step 402 onto a plan view, a paleogeographic slope map can be determined. The lines in the slope map have a natural distribution and can reflect the rate of slope change, such as... Figure 10 The diagram shown illustrates the slope of an ancient landform as described in this embodiment. The magnitude and steepness of the surface slope can be observed from the diagram.

[0113] like Figure 5 The diagram shown is a structural schematic of a paleogeographic slope calculation device based on lithology, as described in this embodiment. The basic structure of the paleogeographic slope calculation device is illustrated in this diagram. The functional units and modules can be implemented using software, or using general-purpose chips or specific chips. The device specifically includes:

[0114] The first determining unit 501 is used to determine the overlying stratum reference surface and the underlying stratum reference surface of the target stratum in the preset area.

[0115] The first acquisition unit 502 is used to correct the overlying stratum reference surface based on the maximum thickness values ​​of the overlying stratum reference surface and the underlying stratum reference surface, and obtain the paleotectonic relative height data of the overlying stratum reference surface.

[0116] The second acquisition unit 503 is used to correct the paleotectonic relative height data according to the standard lithology within the preset area, so as to obtain the paleotectonic relative height data.

[0117] The third acquisition unit 504 is used to correct the paleotectonic relative height data according to the standard lithology within the preset area, so as to obtain the paleogeographic relative height data.

[0118] The second determining unit 505 is used to determine the ancient landform slope map based on the ancient landform relative height data.

[0119] As one embodiment of this article, reference may also be made to, for example, Figure 6 The diagram shows a specific structure of a paleogeographic slope calculation device based on lithology in this embodiment. The first acquisition unit 502 further includes: acquiring the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface, and correcting the overlying stratum reference surface according to the maximum thickness value.

[0120] As an embodiment of this document, the first acquisition unit 502 further includes:

[0121] The thickness value first calculation module 5021 is used to calculate the distance between the target layer and the overlying stratum reference surface of each well in the preset area, as well as the distance between the target layer and the underlying stratum reference surface of each well.

[0122] The second thickness calculation module 5022 is used to calculate the thickness values ​​of multiple wells between the overlying stratum reference surface and the underlying stratum reference surface.

[0123] The maximum thickness value screening module 5023 is used to screen out the maximum thickness value from the thickness values ​​of multiple wells between the overlying formation reference surface and the underlying formation reference surface.

[0124] The overlying stratum reference plane correction module 5024 is used to correct the overlying stratum reference plane based on the selected maximum thickness value.

[0125] The second acquisition unit 503 is also used to select a reference well from a plurality of wells in a preset area.

[0126] As an embodiment of this document, the second acquisition unit 503 further includes:

[0127] The fineness ratio calculation module 5031 is used to calculate the fineness ratio of all wells in a preset area;

[0128] The benchmark well determination module 5032 is used to select a benchmark well based on the fineness ratio of all wells in a preset area.

[0129] The third acquisition unit 504 is further configured to correct the relative height data of paleotectonic structures. As one embodiment of this document, the third acquisition unit 504 further includes:

[0130] The paleotectonic relative height data correction module 5041 is used to correct paleotectonic relative height data based on the standard lithology within a preset area.

[0131] The second determining unit 505 is further configured to determine ancient landform depth data based on the ancient landform relative height data, and convert the ancient landform depth data into ancient landform slope data.

[0132] As one embodiment of this document, the second determining unit 505 further includes:

[0133] The depth data determination module 5051 is used to determine the depth data of ancient landforms based on the relative height data of ancient landforms.

[0134] The slope data determination module 5052 is used to determine the ancient landform slope data based on the ancient landform depth data.

[0135] Using the embodiments described in this paper, the overlying strata reference surface is corrected to obtain more accurate paleogeographic depth data, making the topographic features of paleogeography more prominent, the paleogeographic reconstruction effect better, and easier to identify. Furthermore, the paleogeographic depth data is converted into slope data to establish a high-precision paleogeographic slope map, providing an analytical basis for karst paleogeographic prediction and sedimentary pattern analysis, and meeting the needs of oil and gas exploration.

[0136] like Figure 11 As shown in this embodiment, a computer device 1102 may include one or more processors 1104, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 1102 may also include any memory 1106 for storing information of any kind, such as code, settings, data, etc. Without limitation, for example, the memory 1106 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Further, any memory can provide volatile or non-volatile retention of information. Further, any memory may represent a fixed or removable component of the computer device 1102. In one case, when the processor 1104 executes associated instructions stored in any memory or combination of memories, the computer device 1102 can perform any operation of the associated instructions. The computer device 1102 also includes one or more drive mechanisms 1108 for interacting with any memory, such as hard disk drive mechanisms, optical disk drive mechanisms, etc.

[0137] Computer device 1102 may also include an input / output module 1110 (I / O) for receiving various inputs (via input device 1112) and providing various outputs (via output device 1114). A specific output mechanism may include a presentation device 1116 and an associated graphical user interface (GUI) 1118. In other embodiments, the input / output module 1110 (I / O), input device 1112, and output device 1114 may be omitted, and the device may function solely as a computer device within a network. Computer device 1102 may also include one or more network interfaces 1120 for exchanging data with other devices via one or more communication links 1122. One or more communication buses 1124 couple the components described above together.

[0138] Communication link 1122 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 1122 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0139] Corresponding to Figures 1 to 4 In addition to the method shown, this embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above method.

[0140] This embodiment also provides a computer-readable instruction, wherein when a processor executes the instruction, the program therein causes the processor to perform the following: Figures 1 to 4 The method shown.

[0141] It should be understood that in the various embodiments of this document, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0142] It should also be understood that, in the embodiments herein, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0143] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this document.

[0144] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0145] In the embodiments provided herein, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0146] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described herein, depending on actual needs.

[0147] Furthermore, the functional units in the various embodiments of this document can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0148] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this paper, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this paper. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0149] This document uses specific embodiments to illustrate the principles and implementation methods of this document. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this document. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this document. Therefore, the content of this specification should not be construed as a limitation of this document.

Claims

1. A paleogeographic slope calculation method based on lithology, characterized in that, The method includes: Determine the overlying and underlying stratigraphic reference levels of the target strata in the preset area; Based on the maximum thickness between the overlying strata reference surface and the underlying strata reference surface, the overlying strata reference surface is corrected to obtain paleotectonic relative height data; Based on the standard lithology within the preset area, the relative height data of the paleotectonic structures are corrected to obtain the relative height data of the paleogeography. The paleomorphic depth data is determined based on the difference between the paleomorphic relative height data and the maximum thickness value. Based on the paleogeographic depth data, a paleogeographic depth diagram is determined, and at least a portion of the paleogeographic depth diagram is identified as the study area. The study area is gridded to determine multiple minimum units; For each of the minimum units, the minimum unit is determined as the central unit. Based on the central unit and the eight units adjacent to the central unit, the slope of the central unit in eight directions is determined, and the average value of the slopes in the eight directions is determined as the slope of the central unit, so as to obtain the paleomorphological slope data of the preset area. Based on the paleomorphological slope data, a paleomorphological slope map was determined.

2. The paleogeographic slope calculation method based on lithology according to claim 1, characterized in that, The process of determining the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface includes: Based on the overlying stratum reference surface and the underlying stratum reference surface, calculate the first thickness value and the second thickness value of multiple wells in the preset area. The first thickness value is the distance between the target layer of each well and the overlying stratum reference surface, and the second thickness value is the distance between the target layer of each well and the underlying stratum reference surface. Based on the first and second thickness values ​​of the plurality of wells, the thickness values ​​of the plurality of wells between the overlying formation reference surface and the underlying formation reference surface are calculated; The maximum thickness value is selected from the thickness values ​​of the multiple wells between the overlying formation reference surface and the underlying formation reference surface; The maximum thickness value selected is taken as the maximum thickness value between the overlying stratum reference surface and the underlying stratum reference surface.

3. The paleogeographic slope calculation method based on lithology according to claim 2, characterized in that, The process of correcting the overlying strata reference surface based on the maximum thickness between the overlying strata reference surface and the underlying strata reference surface to obtain the paleotectonic relative height data further includes: Based on the maximum thickness value and correction coefficient between the overlying strata reference surface and the underlying strata reference surface, the overlying strata reference surface of the multiple wells is corrected to obtain the paleotectonic relative height data; The correction coefficient is calculated using the first and second thickness values ​​of multiple wells in the preset region.

4. The paleogeographic slope calculation method based on lithology according to claim 3, characterized in that, Based on the maximum thickness between the overlying strata reference surface and the underlying strata reference surface and the correction coefficient, the overlying strata reference surface is corrected to obtain the paleotectonic relative height data, including: The relative height data of the ancient structure is obtained according to the following formula: y(i)= [H max -h(i) ]×G; Where y(i) is the relative height data of the paleotectonic structure, h(i) represents the second thickness value of the i-th well, and H max G is the maximum thickness value, and G is the correction coefficient.

5. The paleogeographic slope calculation method based on lithology according to claim 4, characterized in that, The process of determining the standard lithology within the preset area includes: Calculate the fineness ratio of multiple wells in a preset area, where the fineness ratio is the ratio of the sum of the thicknesses of mudstone and siltstone in the overlying strata to the first thickness value; The benchmark well is determined based on the arithmetic mean of the fineness ratios of multiple wells; The fineness ratio of the benchmark well is used as the standard lithology for the preset area.

6. The paleogeographic slope calculation method based on lithology according to claim 5, characterized in that, Based on the standard lithology within the preset area, the paleotectonic relative height data is corrected to obtain paleogeographic relative height data, including: The relative height data of ancient landforms are determined according to the following formula: X(i)=y(i)× 1-(j(i)- )}; where X(i) represents the relative height data of the paleogeography, y(i) represents the relative height data of the paleotectonic structure, and j(i) represents the fineness ratio of multiple wells, The fineness ratio of the benchmark well P.

7. A paleogeographic slope calculation device based on lithology, characterized in that, The device includes: The first determining unit is used to determine the overlying stratum reference surface and the underlying stratum reference surface of the target layer in the preset area. The first acquisition unit is used to correct the overlying stratum reference surface based on the maximum thickness values ​​of the overlying stratum reference surface and the underlying stratum reference surface, and obtain the paleotectonic relative height data of the overlying stratum reference surface. The second acquisition unit is used to correct the paleotectonic relative height data according to the standard lithology within the preset area, and obtain the paleogeographic relative height data. The third acquisition unit is used to correct the paleotectonic relative height data according to the standard lithology within the preset area, and obtain the paleogeographic relative height data. The second determining unit is used to determine the ancient landform depth data based on the difference between the ancient landform relative height data and the maximum thickness value; Based on the paleogeographic depth data, a paleogeographic depth diagram is determined, and at least a portion of the paleogeographic depth diagram is identified as the study area. The study area is gridded to determine multiple minimum units; For each of the minimum units, the minimum unit is determined as the central unit. Based on the central unit and the eight units adjacent to the central unit, the slope of the central unit in eight directions is determined, and the average value of the slopes in the eight directions is determined as the slope of the central unit, so as to obtain the paleomorphological slope data of the preset area. Based on the paleomorphological slope data, a paleomorphological slope map was determined.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method of any one of claims 1-6.

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