Quantitative recovery method, device, medium and equipment for original sedimentary thickness distribution of strata in low exploration degree area

Abstract

This invention relates to a method, apparatus, medium, and equipment for quantitatively restoring the original sedimentary thickness distribution of strata in low-exploration areas. The method includes: statistically analyzing the lithological types and single-layer thicknesses of different lithologies within a target layer in a single well; statistically analyzing the top and bottom interface depths of the target layer in a single well; determining the parameters of each lithology in the target layer in a single well; calculating the average thickness of each overlying strata unit in the target layer; compiling simulation wells for different lithological types and single-layer thicknesses; calculating the thickness of each overlying strata unit in the simulation wells; calculating the current thickness of intermediate-depth and single-layer lithologies; calculating the compaction rate corresponding to each single-layer lithology; calculating its original sedimentary thickness; calculating the original sedimentary thickness of the target layer in a single well; calculating the intermediate-depth and current thickness of the target layer; establishing an identification database for restoring the original sedimentary thickness of the target layer in a single well; and inputting the current thickness distribution and intermediate-depth distribution of the target layer into the original sedimentary thickness restoration function to restore the spatial distribution of the original sedimentary thickness of the target layer.

Description

Technical Field

[0001] This invention relates to a method, apparatus, medium, and equipment for quantitatively restoring the original sedimentary thickness distribution in low-exploration areas, belonging to the field of oil and gas exploration technology. Background Technology

[0002] The original sedimentary thickness refers to the initial thickness of a stratigraphic unit immediately after deposition, before it has undergone burial and compaction. The distribution of the original sedimentary thickness is a key parameter for paleogeomorphological reconstruction, which is an important aspect of the study of the paleosource system, sedimentary facies distribution and evolution, and source-sink system of sedimentary basins.

[0003] In high-exploration areas with high well density, the original sedimentary thickness distribution of formations is reconstructed using inter-well interpolation based on the calculated original sedimentary thickness of individual wells. Reconstructing the original sedimentary thickness of individual wells involves decompaction correction of the current formation thickness, i.e., calculating the compaction loss thickness of the original formation during burial and compaction, and then calculating the original formation thickness of the individual well using the current formation thickness and the compaction loss thickness. Currently, this is mainly achieved using drilling and logging data. By establishing a porosity-depth function and based on the principle of constant skeleton volume, decompaction correction is performed to reconstruct the original sedimentary thickness of individual wells. This method is primarily implemented using BasicMod 1D software. Based on parameters such as the stratification and corresponding geological age of the individual well, the lithology and percentage content of the target layer, the lithology and percentage content of overlying strata units, the initial porosity, compaction coefficient, density of different lithologies, and geothermal gradient, a porosity-depth function relationship is selected to conduct numerical simulations of the burial history of individual wells and reconstruct the original sedimentary thickness of the target layer.

[0004] During the compaction process of sedimentary strata, the compaction rate is controlled by various factors such as lithology, burial depth, and single-layer thickness. The compaction rate is the ratio of the thickness lost during compaction to the original stratum thickness; the thickness lost during compaction is the difference between the original sedimentary thickness and the remaining stratum thickness after compaction. With increasing burial depth, the compaction rate of the same lithology gradually increases. At the same burial depth, the compaction rates of different lithologies differ significantly; for example, coal has a higher compaction rate than mudstone, mudstone has a higher compaction rate than sandstone, and sandstone has a higher compaction rate than carbonate rocks. For the same lithology at the same burial depth, the greater the single-layer thickness, the lower the compaction rate. However, existing methods for restoring the original formation thickness in a single well treat the target layer as a whole, only considering the percentage content of different lithologies within the target layer, without comprehensively considering the differences in lithology, burial depth, and single-layer thickness within the target layer. Even if the percentage content of each lithology within the target layer is the same, the recovered compaction loss thickness and compaction rate will have significant differences due to the differences in the depth of different lithologies and the differences in single-layer thickness within the target layer, resulting in inaccurate calculation of the original sedimentary thickness.

[0005] In low-exploration areas, drilling locations are sparse, and available drilling data is limited. The original sedimentary thickness calculated using a single well cannot accurately reconstruct the distribution of the original sedimentary thickness using the inter-well difference method. Currently, there is no effective method for reconstructing the distribution of the original sedimentary thickness in low-exploration, sparsely networked well areas. Therefore, it is urgent to improve the accuracy of single-well calculations of the original sedimentary thickness and to develop a quantitative method for reconstructing the distribution of the original sedimentary thickness in areas with low exploration levels and low drilling density. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method, apparatus, medium, and equipment for quantitatively restoring the original sedimentary thickness distribution of strata in areas with low exploration levels. This method is based on single-well logging data, and calculates the compaction rate layer by layer, lithology, and thickness in detail to achieve high-precision restoration of the original sedimentary thickness of the target layer in a single well. By establishing a regional original sedimentary thickness restoration function, the original sedimentary thickness of strata in the entire area can be quantitatively restored using seismic data.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A quantitative method for reconstructing the original sedimentary thickness distribution in low-exploration areas includes: Step 1: Statistically analyze the lithological types and single-layer thicknesses of different lithologies within the target layer of all single wells in the study area, and obtain the distribution range of single-layer thicknesses of different lithologies in the target layer of each single well; Step 2: Statistically determine the top and bottom interface depths of the target layer in all single wells in the study area, and use the minimum top depth M and the maximum bottom depth N as the depth distribution range for constructing the compaction rate-depth function of the target layer; Step 3: Determine the initial porosity, density, compaction coefficient, and geothermal gradient of each lithology in the target layer of a single well in the study area; Step 4: Statistically analyze the thickness and lithological percentage of each stratigraphic unit overlying the target layer in the study area, and calculate the average thickness and average lithological percentage of each stratigraphic unit overlying the target layer. Step 5: Based on the lithology types and single-layer thicknesses of different lithologies identified in Step 1, simulated wells are compiled within the depth distribution range of the target layer compaction rate-depth function determined in Step 2. Step 6: Unify the thickness of the overlying strata in the simulated well to M as determined in Step 2. Calculate the thickness of the overlying strata units in the simulated well based on the average thickness of the overlying strata units in Step 4, the initial porosity, density, compaction coefficient, and geothermal gradient of the study area in Step 3. Step 7: Calculate the top depth D of the single-layer lithology within the target layer of each well in the study area. 顶 Bottom depth D 底 Calculate the depth D 中 And the current thickness S of single-layer lithology 现 ; Step 8: Based on the lithology of the target layer and the thickness of the single layer in the study area, and the medium-deep D calculated in Step 7... 中 Substitute the values ​​into the corresponding layer compaction rate-depth function to calculate the compaction rate corresponding to a single layer of lithology; Step 9: Calculate the original sedimentary thickness by using the current thickness of each lithological layer and the compaction rate corresponding to the lithological layer calculated in Step 8. Step 10: Using the formula, sum the original sedimentary thicknesses of each lithology layer in the target layer of a single well to obtain the original sedimentary thickness S of the target layer in a single well. 目原 ; Step 11: Based on single-well logging data, statistically analyze the top depth D of the target layer in all single wells in the study area. 目顶 and bottom depth D 目底 Calculate and statistically analyze the mid-depth D of the target layer. 目中 Calculate and statistically analyze the current thickness S of the target layer. 目现 ; Step 12: Calculate the mid-depth D of the target layer obtained in Step 11. 目中 And the current thickness S 目现 Using the original sedimentary thickness of the target layer in a single well calculated in step 9 as the dependent variable, an identification database for restoring the original sedimentary thickness of the target layer in a single well is established; using the current thickness S of the single well as the independent variable... 目现 and the target layer deep D 目中 As the independent variable, the original sedimentary thickness S of the target layer in a single well in step 10 目原 Construct the original deposition thickness recovery function with the variable as the dependent variable; Step 13: In the Petrel software, input the current thickness distribution and intermediate-depth distribution of the target layer into the original sedimentary thickness recovery function of Step 12 for processing and calculation, so as to recover the original spatial distribution of the sedimentary thickness of the target layer in the study area.

[0008] The quantitative restoration method for the original sedimentary thickness distribution of strata in low-exploration areas, preferably, involves fitting the compaction rate-depth function corresponding to lithology a and single-layer thickness S1 meters, and further adopts the following process in step 6: Procedure 1: The top depth of the first set of strata in the target layer is M, the bottom depth is M+S, and the calculated intermediate depth is M+0.5S; Procedure 2: Use BasicMod 1D software to conduct numerical simulation of the burial history of a single well to reconstruct the original sedimentary thickness S of the first set of strata. 原1 Calculate the compaction rate T1, which corresponds to a depth of M+0.5S; Process 3: Repeat processes 1 and 2 until the nth formation, the top depth is M + (n-1) × S, the bottom depth is M + n × S, the middle depth is M + (n + 0.5) × S, and the bottom interface of the nth layer is (M + n × S) ≥ N, where N is the maximum depth of the bottom interface of the target layer of all single wells in the statistical study area in step 2. Step 4: Fit the compaction rate and depth function corresponding to lithology a and single layer thickness S1 meters using the obtained compaction rate and corresponding depth; Step 5: Repeat steps 1, 2 and 3 to obtain the compaction rate-depth function corresponding to lithology a and single layer thickness S2 meters; Process 6: Repeat processes 1, 2 and 3 to fit the compaction rate-depth function corresponding to other lithologies and different single-layer thicknesses.

[0009] The quantitative reconstruction method for the original sedimentary thickness distribution of strata in low-exploration areas, preferably, in process 1, uses the following formula to calculate the intermediate depth D. 中 That is, M+0.5S: D 中 =(D 顶 +D 底 ) / 2; In process 2, the compaction rate T1 is calculated using the following formula: T=(S 原 -S 现 ) / S 原 ; In the formula, D 中 D represents the middle depth of a single-layer lithology. 顶 D represents the depth of the top surface of a single-layer lithology. 底 The depth of the bottom surface of a single-layer lithology; T is the compaction rate; S 原 The original sedimentary thickness of a single lithological layer; S 现 The current thickness of a single-layer lithology.

[0010] The quantitative reconstruction method for the original sedimentary thickness distribution of strata in low-exploration areas, preferably, in step 7, involves determining the current thickness S of a single lithological layer. 现 The calculation formula is as follows: S 现 =D 底 -D 顶 ; In the formula, S 现 The current thickness of a single-layer lithology; D 顶 D represents the depth of the top surface of a single lithological layer within the target layer. 底 The depth of the bottom surface of a single lithological layer within the target layer.

[0011] The quantitative recovery method for the distribution of original sedimentary thickness in low-exploration areas, preferably, involves, in step 10, using the following formula to sum the original sedimentary thickness S of each lithology layer in the target layer of a single well. 目原 : (S) 目原 = 原i ); In the formula, S目原 S represents the original deposition thickness of the target layer; 原i denoted as , where is the original sedimentary thickness of the i-th single-layer lithology within the target layer; and is the number of single-layer lithology layers within the target layer.

[0012] The quantitative restoration method for the original sedimentary thickness distribution of strata in low-exploration areas, preferably, involves, in step 11, calculating and statistically analyzing the mid-depth D of the target layer using the following formula. 目中 ; D 目中 =(D 目顶 +D 目底 ) / 2; Calculate and statistically analyze the current thickness S of the target layer using the formula. 目现 : S 目现 =D 目底 -D 目顶 ; In the formula, D 目中 D represents the depth at the midpoint of the target layer. 目顶 D is the depth of the top surface of the target layer. 目底 S represents the depth of the bottom surface of the target layer. 目现 D represents the current thickness of the target layer. 目顶 D is the depth of the top surface of the target layer. 目底 The depth of the bottom surface of the target layer.

[0013] The quantitative reconstruction method for the original sedimentary thickness distribution of strata in low-exploration areas, preferably, includes the following specific steps in step 13: In Petrel software, using 3D seismic data, the time-domain seismic reflection interfaces of the target layer's top and bottom are interpreted. The depth distribution of these interfaces is obtained through time-depth transformation, using formula D. 目中 =(D 目顶 +D 目底 The depth distribution of the target layer in the study area is calculated using the formula S / 2. Simultaneously, the depth distribution of the top and bottom interfaces of the target layer is used to calculate the depth distribution of the target layer. 目现 =D 目底 -D 目顶 The current thickness distribution of the target layer in the study area is calculated. In the Petrel software, the current thickness distribution and the intermediate-depth distribution of the target layer are substituted into the original sedimentary thickness recovery function for processing and calculation, so that the original spatial distribution of the sedimentary thickness of the target layer in the study area can be recovered.

[0014] A second aspect of the present invention provides a quantitative reconstruction device for the original sedimentary thickness distribution in low-exploration areas, comprising: The first processing unit is used to statistically analyze the lithological types and single-layer thicknesses of different lithologies within the target layers of all single wells in the study area, and to obtain the distribution range of single-layer thicknesses of different lithologies in the target layers of single wells. The second processing unit is used to statistically analyze the top and bottom interface depths of the target layer in all single wells in the study area, and uses the minimum top depth M and the maximum bottom depth N as the depth distribution range for constructing the compaction rate-depth function of the target layer. The third processing unit is used to determine the initial porosity, density, compaction coefficient, and geothermal gradient of each lithology in the target layer of a single well in the study area. The fourth processing unit is used to statistically analyze the thickness and lithological percentage of each stratigraphic unit overlying the target layer in a single well in the study area, and to calculate the average thickness and average lithological percentage of each stratigraphic unit overlying the target layer. The fifth processing unit is used to compile simulated wells based on the lithology types and single-layer thicknesses of different lithologies statistically determined by the first processing unit, within the depth distribution range of the target layer compaction rate-depth function determined by the second processing unit. The sixth processing unit is used to unify the thickness of the overlying strata in the simulated well to M as determined in the second processing unit. Based on the average thickness of the overlying strata units in the target layer in the fourth processing unit, as well as the initial porosity, density, compaction coefficient and geothermal gradient of the study area in the third processing unit, the thickness of the overlying strata units in the target layer of the simulated well is calculated. The seventh processing unit is used to statistically analyze the top depth D of the single-layer lithology within the target layer of each well in the study area. 顶 Bottom depth D 底 Calculate the depth D 中 And the current thickness S of single-layer lithology 现 ; The eighth processing unit is used to calculate the medium-deep D based on the lithology within the target layer and the thickness of the single layer in the study area, using the data obtained from the seventh processing unit. 中 Substitute the values ​​into the corresponding layer compaction rate-depth function to calculate the compaction rate corresponding to a single layer of lithology; The ninth processing unit is used to calculate the compaction rate of each lithological layer using the current thickness of each lithological layer and the eighth processing unit, and to calculate its original sedimentary thickness. The tenth processing unit is used to sum the original sedimentary thickness S of the target layer in a single well by using a formula to obtain the original sedimentary thickness S of the target layer in a single well. 目原 ; The eleventh processing unit is used to statistically analyze the top depth D of the target layer in all single wells in the study area based on single-well logging data. 目顶 and bottom depth D 目底 Calculate and statistically analyze the mid-depth D of the target layer. 目中 Calculate and statistically analyze the current thickness S of the target layer. 目现 ; The twelfth processing unit is used to process the mid-depth D of the target layer of a single well obtained from the statistical analysis of the eleventh processing unit. 目中 And the current thickness S 目现Using the original sedimentary thickness of the target layer in a single well calculated in the ninth processing unit as the independent variable, an identification database for restoring the original sedimentary thickness of the target layer in a single well is established; using the current thickness S of the single well as the independent variable... 目现 and the target layer deep D 目中 As the independent variable, the original sedimentary thickness S of the target layer in a single well in the tenth treatment unit. 目原 Construct the original deposition thickness recovery function with the variable as the dependent variable; The thirteenth processing unit is used in the Petrel software to input the current thickness distribution and intermediate-depth distribution of the target layer into the original sedimentary thickness recovery function of the twelfth processing unit for processing calculation, so as to recover the original spatial distribution of the sedimentary thickness of the target layer in the study area.

[0015] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the quantitative recovery method for the distribution of the original sedimentary thickness of strata in low-exploration areas as described in any one of the preceding claims.

[0016] A fourth aspect of the present invention 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 steps of the quantitative recovery method for the distribution of the original sedimentary thickness of strata in low-exploration areas as described in any one of the above-mentioned methods.

[0017] The present invention has the following advantages due to the adoption of the above technical solutions: 1. Existing methods for restoring the original formation thickness of a single well treat the target layer as a whole, considering only the percentage content of different lithologies within the target layer. In contrast, this invention comprehensively considers the lithology within the target layer of a single well, the thickness of the single-layer lithology, and the burial depth of the single-layer lithology, achieving accurate restoration of the original sedimentary thickness of the target layer with the same percentage lithology content but different lithological depths and single-layer thicknesses.

[0018] 2. Addressing the challenge that accurate reconstruction of the original sedimentary thickness of strata calculated from single wells in low-exploration areas with few wells cannot be achieved using inter-well interpolation, this invention establishes a functional relationship between the original sedimentary thickness and the current thickness and intermediate depth of the target layer. By integrating 3D seismic data to obtain the current thickness and intermediate depth distribution of the target layer across the entire area, and then inputting this data into the reconstruction function, quantitative reconstruction of the original sedimentary thickness of the target layer in low-exploration areas with few wells can be achieved. This method does not rely on high-density drilling networks, significantly reducing dependence on drilling data and providing reliable technical support for paleogeographic reconstruction, sedimentary facies research, and oil and gas exploration target evaluation in low-exploration basins.

[0019] 3. Existing methods require the establishment of an accurate porosity-depth function and the recovery of the original sedimentary thickness by peeling back layer by layer based on the principle of constant skeleton volume; while the present invention calculates the compaction rate layer by layer, by lithology and by thickness in detail, so as to achieve high-precision recovery of the original sedimentary thickness of the target layer in a single well.

[0020] 4. Existing methods rely on high-density well networks and use interpolation to recover the original sedimentary thickness of a region, which results in large errors when used in areas with few wells and low exploration levels. In contrast, this invention establishes a regional original sedimentary thickness recovery function and uses seismic data to quantitatively recover the original sedimentary thickness of the entire region.

[0021] 5. Existing methods require high-precision drilling and logging data to establish accurate porosity-depth functions for different lithologies, and require layer-by-layer stripping based on different lithological strata, resulting in a large workload. While the initial construction of the compaction rate-depth function in this invention involves a large workload, it can be applied in batches later, resulting in high efficiency. Existing methods use interpolation to recover regional original sedimentary thickness, and the accuracy is controlled by well network density; however, this invention achieves higher reliability by constructing functions and combining them with 3D seismic data. Attached Figure Description

[0022] Figure 1 A flowchart of a method for quantitatively restoring the original sedimentary thickness distribution of strata in low-exploration areas, as provided in an embodiment of the present invention; Figures 2a-2c These are statistical histograms of single-layer thickness for different rock types provided in this embodiment of the invention, wherein... Figure 2a Sandstone, Figure 2b Silty sandstone, Figure 2c It is mudstone; Figure 3 This is a burial history diagram of a simulated well with a single-layer thickness of 100m mudstone provided in this embodiment of the present invention; Figure 4 This is a graph showing the compaction rate-depth function of a simulated well with a single-layer mudstone thickness of 100m provided in this embodiment of the invention. Figure 5 This is a scatter plot of the original depositional thickness recovered from a single well and the original depositional thickness recovered by the fitting function, provided in this embodiment of the invention. Figure 6 This is a map showing the original sedimentary thickness of a large area of ​​the restored study area provided in this embodiment of the invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," "third," "fourth," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0025] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0026] Existing techniques for restoring the original sedimentary thickness of a single-well target layer involve: In high-exploration areas, using drilling and logging data, establishing a porosity-depth function, and restoring the original sedimentary thickness of the formation layer by layer by stripping back and compaction correction based on the principle of constant skeleton volume. For restoring the original sedimentary thickness of a regional target layer, in high-exploration areas with high well density, the distribution of the original sedimentary thickness of the formation is restored using inter-well interpolation based on the calculated original sedimentary thickness of the single well. However, single-well restoration is highly dependent on well data, requiring the establishment of accurate porosity-depth functions for different lithologies based on high-precision drilling and logging data from multiple wells in the region. In low-exploration areas, accurate thickness distribution cannot be restored, and the stripping method itself is a "single-point" technique; restoration of the entire area distribution relies on interpolation using a high-density well network. In low-exploration, sparsely drilled areas, available drilling data is limited, making it impossible to accurately restore the distribution of the original sedimentary thickness of the formation using inter-well interpolation.

[0027] Based on the above-mentioned technical problems, the present invention provides a quantitative method for restoring the original sedimentary thickness distribution of strata in low-exploration areas. This method improves the calculation accuracy of the original sedimentary thickness of the target layer in a single well and solves the problem that the original sedimentary thickness distribution of strata cannot be accurately restored by inter-well interpolation in low-exploration areas with few wells.

[0028] Example 1 This embodiment provides a quantitative method for restoring the original sedimentary thickness distribution of strata in low-exploration areas. Its purpose is to improve the calculation accuracy of the original sedimentary thickness of the target layer in a single well, and to solve the problem that the original sedimentary thickness distribution of strata cannot be accurately restored by inter-well interpolation in low-exploration areas with few wells, so as to guide exploration and development.

[0029] like Figure 1 As shown, the method of the present invention includes the following steps: Step 1: Statistically analyze the lithology within the target layer of all single wells in the study area and the thickness of single layers with different lithologies to obtain the distribution range of single layer thickness with different lithologies in the target layer.

[0030] Step 2: Statistically determine the top and bottom interface depths (positive values) of all single wells in the study area, and use the minimum top depth M and the maximum bottom depth N as the depth distribution range for constructing the compaction rate-depth function of the target layer.

[0031] The depth range of the top and bottom surfaces of the Sanya Formation in all single wells in the study area was statistically analyzed. The minimum top surface depth of 1500m and the maximum bottom surface depth of 4700m were selected as the depth range of the function. The depth range of the Sanya Formation in the study area is between 1500m and 4700m.

[0032] Step 3: Determine the initial porosity, density, compaction coefficient, and geothermal gradient of each lithology in the target layer (as shown in Table 1 below).

[0033] Table 1. Geothermal gradient in the study area and original porosity, compaction coefficient, and density parameters of different lithologies in the target layer.

[0034] Step 4: Statistically analyze the thickness and lithological percentage of each stratigraphic unit overlying the target layer in the study area, and calculate the average thickness and average lithological percentage of each stratigraphic unit overlying the target layer (as shown in Table 2 below).

[0035] Table 2. Statistical table of lithological percentages of the overlying strata of each single well in the study area.

[0036] Note: n, number of single wells in the study area; k, number of overlying stratigraphic units.

[0037] Step 5: Based on the different lithologies and single-layer thicknesses of different lithologies as statistically analyzed in Step 1, simulated wells are compiled within the depth distribution range of the target layer compaction rate-depth function determined in Step 2.

[0038] Step 6: Unify the overlying formation thickness of the simulated well to M meters as determined in Step 2. Calculate the overlying formation unit thickness of the target layer in the simulated well based on the average thickness of each overlying formation unit in Step 4 (as shown in Table 3 below).

[0039] Fitting the compaction rate-depth function corresponding to lithology a and single-layer thickness S1 meters, the following process is further adopted in step 6: Process (1): The top depth of the first set of strata in the target layer is M meters, the bottom depth is M+S meters, and the middle depth is M+0.5S meters using formula (1). The percentage content of lithology a is 100%, and the percentage content of other lithologies is 0%.

[0040] Procedure (2): Use BasicMod 1D software to conduct numerical simulation of the burial history of a single well and reconstruct the original sedimentary thickness S of the first set of strata. 原1 The compaction rate T1 is calculated using formula (2), and the compaction rate corresponds to a depth of M+0.5S meters. Process (3): Repeat process (1) and process (2) until the nth stratum, the top depth is M + (n-1) × S meters, the bottom depth is M + n × S meters, the middle depth is M + (n + 0.5) × S meters (Table 3), the bottom interface of the nth layer is (M + n × S) ≥ N meters, where N is the maximum depth of the bottom interface of the target layer of all single wells in the statistical study area in step 2.

[0041] Process (4): Fit the compaction rate and depth function corresponding to lithology a and single layer thickness S1 meters by the obtained compaction rate and the corresponding depth (Table 4).

[0042] Process (5): Repeat processes (1), (2) and (3) to obtain the compaction rate-depth function corresponding to lithology a and single layer thickness S2 meters.

[0043] Process (6): Repeat processes (1), (2) and (3) to fit the compaction rate-depth function corresponding to other lithologies and different single-layer thicknesses (as shown in Table 4 below).

[0044] D 中 =(D 顶 +D 底 ) / 2 formula (1) In the formula, D 中 : Depth in the middle of a single lithological layer, positive value, m; D 顶 : Depth of the top surface of a single lithological layer, positive value, m; D 底 : Depth of the bottom surface of a single-layer lithology, positive value, m.

[0045] T=(S 原 -S 现 ) / S 原 Formula (2) In the formula, T: compaction ratio, positive value, dimensionless; S 原 : Thickness of the original sedimentary layer of lithology, in meters; S 现 : Current thickness of a single lithological layer, in meters.

[0046] Table 3. Statistical table of fitted compaction rate-depth simulation well data for different lithologies and single-layer thicknesses.

[0047] Note: k, number of overlying stratigraphic units; D k , the thickness of the kth overlying stratum, m; n, the bottommost stratum of the target layer, the bottom interface of the nth layer (M+n×S)≥N meters; S, the current thickness of each stratum of the target layer, m; x, y, z, the percentage content of each lithology in the target layer.

[0048] Table 4 Compaction rate-depth function for different lithologies and single-layer thicknesses

[0049] Note: N, the maximum depth of the bottom interface of the target layer in all single wells in the statistical study area in step 2, m, positive value; M, the minimum depth of the top interface of the target layer in all single wells in the statistical study area in step 2, m, positive value.

[0050] Step 7: Calculate the top depth D of the single-layer lithology within the target layer for each well. 顶 Bottom depth D 底 Using formula D 中 =(D 顶 +D 底 ) / 2 Calculation of depth D 中 Using formula S 现 =D 底 -D 顶 Calculate the current thickness S of a single lithological layer 现 (Table 5).

[0051] S 现 : Current thickness of single-layer lithology, m; D 顶 : Depth of the top surface of a single lithological layer within the target layer, positive value, m; D 底 : Depth of the bottom surface of a single lithological layer within the target layer, positive value, m.

[0052] Table 5. Statistical table of the depth, intermediate depth, and thickness of the top and bottom interfaces of single-layer lithology within the target layer of a single well.

[0053] Note: n, number of single wells in the study area; k, number of single-layer lithologies within the target layer of all single wells in the study area.

[0054] Step 8: Based on the lithology within the target layer of a single well and the thickness of the single-layer lithology, the intermediate-depth D is calculated through the top and bottom interfaces of the single-layer lithology. 中 Substitute the values ​​into the corresponding compaction rate-depth function to calculate the compaction rate corresponding to a single layer of lithology.

[0055] For lithology a, with a thickness between 0 and S meters, the compaction rate of a single layer of lithology a with a thickness of S meters is calculated using the compaction rate-depth function (Table 6); for lithology b, with a thickness between 2S and 3S meters, the compaction rate of a single layer of lithology b with a thickness of 3S meters is calculated using the compaction rate-depth function.

[0056] Table 6. Statistical table of compaction rate of single-layer lithology (a) with a thickness of S meters within the target layer of a single well.

[0057] Note: n, number of single wells in the study area; k, number of single-layer lithologies a within the target layer of a single well in the study area.

[0058] Step 9: Using the current thickness and corresponding compaction rate of each single-layer lithology, apply the formula (S) 原 =S 现 The original deposition thickness is calculated using the formula / (1-T). Where S 原 : Thickness of the original sedimentary layer of lithology, in meters; S 现 : Current thickness of single-layer lithology, m; T: Compaction rate, positive value, dimensionless.

[0059] Step 10: Using the formula (S) 目原 = 原i The original sedimentary thickness S of the target layer in a single well is obtained by summing the original sedimentary thicknesses of each individual lithology layer in the single well. 目原 (Table 7). Where S 目原 : Original depositional thickness of the target layer, m; S 原i : The original sedimentary thickness of the i-th single-layer lithology within the target layer, in meters; n: The number of single-layer lithology within the target layer.

[0060] Table 7. Statistical Table of Original Stratigraphic Thickness within the Target Layer of a Single Well

[0061] Note: n, number of single wells in the study area; k, number of target formations in a single well.

[0062] Step 11: Based on single-well logging data, statistically analyze the top depth D of the target layer in all single wells in the study area. 目顶 and bottom depth D 目底 Using formula (D) 目中 =(D 目顶 +D 目底 ) / 2) Calculate and statistically analyze the mid-depth D of the target layer. 目中 Using the formula (S) 目现 =D 目底 -D 目顶 ) Calculate and statistically analyze the current thickness S of the target layer. 目现 .

[0063] In the formula, D 目中 : Depth at the midpoint of the target layer, positive value, m; D 目顶 : Depth of the top surface of the target layer, positive value, m; D 目底 : Depth of the bottom surface of the target layer, positive value, m.

[0064] In the formula, S 目现 : Current thickness of the target layer, in meters; D 目顶 : Depth of the top surface of the target layer, positive value, m; D 目底 : Depth of the bottom surface of the target layer, positive value, m.

[0065] Table 8 Database for Identifying Original, Intermediate, and Current Thickness of Target Layers in Single Wells

[0066] Note: n, number of single wells in the study area.

[0067] Step 12: Calculate the mid-depth D of the target layer obtained in Step 11. 目中 And the current thickness S 目现 Using the original sedimentary thickness of the target layer in a single well calculated in step 9 as the dependent variable, an identification database for restoring the original sedimentary thickness of the target layer in a single well is established; using the current thickness S of the single well as the independent variable... 目现 and the target layer deep D 目中 As the independent variable, the original sedimentary thickness S of the target layer in a single well in step 10 目原 Using as the dependent variable, construct the original deposition thickness recovery function.

[0068] Step 13: In the Petrel software, input the current thickness distribution and intermediate-depth distribution of the target layer into the original sedimentary thickness recovery function for processing and calculation, so as to recover the original spatial distribution of the sedimentary thickness of the target layer in the study area.

[0069] In Petrel software, using 3D seismic data, the time-domain seismic reflection interfaces of the target layer's top and bottom are interpreted (a mature technology in this field). The depth distribution of the target layer's top and bottom interfaces is obtained through time-depth transformation, using the formula (D... 目中 =(D 目顶 +D 目底 ) / 2) The depth distribution of the target layer in the study area is calculated; at the same time, using the depth distribution of the top and bottom interfaces of the target layer, the formula (S) is used. 目现 =D 目底 -D 目顶 The current thickness distribution of the target layer in the study area was calculated. In the Petrel software, the current thickness distribution and intermediate-depth distribution of the target layer were input into the original sedimentary thickness recovery function for processing and calculation, so that the original spatial distribution of the sedimentary thickness of the target layer in the study area could be recovered.

[0070] The technical solution of the present invention will be described in detail below with reference to specific examples.

[0071] Taking the decompaction correction and restoration of the original sedimentary stratum thickness of the Sanya Formation in a certain area of ​​an oilfield as an example, the specific implementation scheme of this invention is illustrated, which includes the following steps: Step 1: Statistically analyze the lithological types within the target formation of all single wells in the study area, namely sandstone, siltstone, and mudstone. Based on the different lithologies, statistically analyze the thickness of individual layers of different lithologies within the target formation of all single wells in the study area, and summarize the distribution range of individual layer thicknesses for different lithologies in all single wells in the study area. The single-layer lithology thickness of the Sanya Formation in the study area is relatively large, with sandstone single-layer thickness ranging from 0 to 70 m, siltstone single-layer thickness ranging from 0 to 70 m, and mudstone single-layer thickness ranging from 0 to 130 m (e.g., ...). Figures 2a to 2c (As shown).

[0072] Step 2: Statistically analyze the depth range of the top and bottom surfaces of the Sanya Formation in all single wells in the study area, and select the minimum top surface depth of 1500m and the maximum bottom surface depth of 4700m as the depth range of the function. The depth range of the Sanya Formation in the study area is between 1500m and 4700m.

[0073] Step 3: Determine the initial porosity, density, compaction coefficient, and geothermal gradient of each lithology in the target layer of the study area (Table 1, Table 2).

[0074] Table 1. Statistical table of compaction-corrected lithology and corresponding lithology data for single wells in the study area.

[0075] Table 2. Statistical table of compaction-corrected geothermal gradient of single wells in the study area.

[0076] Step 4: The overlying stratigraphic units of the Sanya Formation in the study area, from top to bottom, are the Ledong Formation, Yinggehai Formation, Huangliu Formation and Meishan Formation. The thickness and lithological percentage of each overlying stratigraphic unit of the Sanya Formation in each well in the study area are statistically analyzed, and the average thickness and average lithological percentage of each overlying stratigraphic unit are calculated (Table 3).

[0077] Table 3. Statistical table of lithological percentages of the overlying strata of each single well in the study area.

[0078] Note: n, number of single wells in the study area.

[0079] Step 5: Based on the lithology types and single-layer lithology thicknesses of different lithologies statistically obtained in Step 1, simulated wells are prepared within the depth distribution range (1500-4700m) of the target layer compaction rate-depth function determined in Step 2.

[0080] Step 6: Unify the thickness of the overlying formation in the simulated well to 1500m as determined in Step 2. Calculate the thickness of the overlying formation units in the simulated well based on the average thickness of the overlying formation units in Step 4 (Table 4).

[0081] Fitting the compaction rate-depth function for a single layer of mudstone with a thickness of 100m: Procedure (1): The top depth of the first set of strata in the target layer is 1500m, and the bottom depth is 1600m. Use formula (D) 中 =(D 顶 +D 底 (2) The depth is 1550m, the mudstone content is 100%, and the siltstone and sandstone content is 0%.

[0082] Procedure (2): Use BasicMod 1D software to conduct numerical simulation of the burial history of a single well and reconstruct the original sedimentary thickness S of the first set of strata. 原1 Using the formula (T=(S) 原 -S 现 ) / S 原 Calculate the compaction rate T1, which corresponds to a depth of 1550m.

[0083] Process (3): Repeat steps 1 and 2 until the last stratum, the 32nd stratum, with a top depth of 4600m, a bottom depth of 4700m, and a middle depth of 4650m (e.g. Figure 3 (as shown in Table 4).

[0084] Table 4. Statistical table of fitted compaction rate-depth simulation well data for different lithologies and single-layer thicknesses.

[0085] Process (4): Fit the compaction rate-depth function y=-1 for a single layer of mudstone with a thickness of 100m using the obtained compaction rate and the corresponding depth. -8 ×x 2 +0.0001×x+0.281 (e.g.) Figure 4 (As shown).

[0086] Process (5): Repeat steps 1, 2 and 3 to obtain mudstone with single layer thicknesses of 10m, 20m, 30m... and the corresponding compaction rate-depth function (Table 5). Process (6): Repeat steps 1, 2 and 3 to fit the compaction rate-depth function corresponding to other lithologies and different single-layer thicknesses (Table 5).

[0087] Table 5 Fitting functions for different lithologies and single-layer thicknesses of the Sanya Formation in the study area.

[0088] Step 7: Calculate the top depth D of the single-layer lithology within the target layer for each well. 顶 Bottom depth D 底 Using the formula (T=(S) 原 -S 现 ) / S 原 ) Calculate the depth D 中 Using the formula (S) 现 =D 底 -D 顶 ) Calculate the current thickness S of a single lithological layer 现 For example, the depth and present thickness of single-layer lithological bodies in the Sanya Formation of well BD19 in the study area were calculated and statistically analyzed (Table 6).

[0089] Table 6. Statistical table of medium-deep and present thickness of single-layer lithologic bodies in well BD19 in the study area.

[0090] Step 8: Based on the lithology within the target layer of a single well and the thickness of the single-layer lithology, the intermediate-depth D is calculated through the top and bottom interfaces of the single-layer lithology. 中 Substituting the values ​​into the corresponding compaction rate-depth function, the compaction rate corresponding to a single lithology is calculated. For example, when calculating the compaction rate of the 10-20m thick mudstone of the Sanya Formation in well BD19 in the study area, the compaction rate-depth function y=-1 for the 20m thick mudstone is used. -8 ×x 2 +0.0001×x+0.3017 (Table 7).

[0091] Table 7 Calculated compaction rates of mudstone and 10-20m thick mudstone in the Sanya Formation of Well BD19 in the study area.

[0092] Step 9: Using the current thickness and corresponding compaction rate of each single-layer lithology, apply the formula (S) 原 =S 现 The original deposition thickness is calculated using (1-T).

[0093] Step 10: Using the formula (S) 目原 = 原i The original sedimentary thickness S of the target layer in a single well is obtained by summing the original sedimentary thicknesses of each individual lithology layer in the single well. 目原 For example, the original sedimentary thickness of the Sanya Formation in well BD19 is calculated (Table 8).

[0094] Table 8. Depositional thickness of the original strata of the Sanya Formation in well BD19 in the study area.

[0095] Step 11: Based on single-well logging data, statistically analyze the top depth D of the target layer in all single wells in the study area. 目顶and bottom depth D 目底 Using formula (D) 目中 =(D 目顶 +D 目底 ) / 2) Calculate and statistically analyze the mid-depth D of the target layer. 目中 Using the formula (S) 目现 =D 目底 -D 目顶 ) Calculate and statistically analyze the current thickness S of the target layer. 目现 (Table 9).

[0096] Table 9. Geological-Geophysical Identification Database for Original Sedimentary Thickness Reconstruction

[0097] Step 12: Calculate the mid-depth D of the target layer obtained in Step 11. 目中 And the current thickness S 目现 Using the original sedimentary thickness of the target layer in a single well calculated in step 9 as the dependent variable, an identification database for restoring the original sedimentary thickness of the target layer in a single well is established (Table 9). The current thickness S of the single well is used as the independent variable. 目现 and the target layer deep D 目中 The original sedimentary thickness S of the target layer in a single well is the independent variable. 目原 As the dependent variable, the original deposition thickness recovery function formula 8 is constructed, R. 2 The value is 0.938, indicating a good function fit (e.g., Figure 5 (As shown).

[0098] S 原 =S×(1.243+0.0002325×D 中 ) (Formula 8) S 原 Original sedimentary thickness, m; S: Current thickness, m; D: 中 : Depth in the middle of the stratum, m.

[0099] In Petrel software, using 3D seismic data, the seismic reflection interfaces at the top and bottom of the target layer in the time domain are interpreted (a mature technology in this field), using the time-depth conversion formula: D 深 =0.1339×(D 时 -D 海 ) 1.285 +0.765×D 海 D 深 : Depth domain target interface, positive value, m; D 时 : Time domain target interface, positive value, ms; D 海 : Time domain seabed interface, positive value, ms.

[0100] The depth distribution map of the top and bottom interfaces of the target layer is obtained by time-depth transformation, and the formula (D) is used. 目中 =(D 目顶 +D 目底 ) / 2) Calculate the depth distribution map of the target layer in the study area; simultaneously, using the depth distribution maps of the top and bottom interfaces of the target layer, use the formula (S 目现 =D 目底 -D 目顶 The current thickness distribution map of the target layer in the study area was calculated. In Petrel software, the current thickness distribution and intermediate-depth distribution of the target layer were input into the original sedimentary thickness recovery function for processing and calculation, thus reconstructing the original spatial distribution of the target layer's original sedimentary thickness in the study area (e.g., ...). Figure 6 (As shown).

[0101] A second aspect of the present invention provides a quantitative reconstruction device for the original sedimentary thickness distribution in low-exploration areas, comprising: The first processing unit is used to statistically analyze the lithological types and single-layer thicknesses of different lithologies within the target layers of all single wells in the study area, and to obtain the distribution range of single-layer thicknesses of different lithologies in the target layers of single wells. The second processing unit is used to statistically analyze the top and bottom interface depths of the target layer in all single wells in the study area, and uses the minimum top depth M and the maximum bottom depth N as the depth distribution range for constructing the compaction rate-depth function of the target layer. The third processing unit is used to determine the initial porosity, density, compaction coefficient, and geothermal gradient of each lithology in the target layer of a single well in the study area. The fourth processing unit is used to statistically analyze the thickness and lithological percentage of each stratigraphic unit overlying the target layer in a single well in the study area, and to calculate the average thickness and average lithological percentage of each stratigraphic unit overlying the target layer. The fifth processing unit is used to compile simulated wells based on the lithology types and single-layer thicknesses of different lithologies statistically determined by the first processing unit, within the depth distribution range of the target layer compaction rate-depth function determined by the second processing unit. The sixth processing unit is used to unify the thickness of the overlying strata in the simulated well to M as determined in the second processing unit. Based on the average thickness of the overlying strata units in the target layer in the fourth processing unit, as well as the initial porosity, density, compaction coefficient and geothermal gradient of the study area in the third processing unit, the thickness of the overlying strata units in the target layer of the simulated well is calculated. The seventh processing unit is used to statistically analyze the top depth D of the single-layer lithology within the target layer of each well in the study area. 顶 Bottom depth D 底 Calculate the depth D 中 And the current thickness S of single-layer lithology 现 ; The eighth processing unit is used to calculate the medium-deep D based on the lithology within the target layer and the thickness of the single layer in the study area, using the data obtained from the seventh processing unit. 中 Substitute the values ​​into the corresponding layer compaction rate-depth function to calculate the compaction rate corresponding to a single layer of lithology; The ninth processing unit is used to calculate the compaction rate of each lithological layer using the current thickness of each lithological layer and the eighth processing unit, and to calculate its original sedimentary thickness. The tenth processing unit is used to sum the original sedimentary thickness S of the target layer in a single well by using a formula to obtain the original sedimentary thickness S of the target layer in a single well. 目原 ; The eleventh processing unit is used to statistically analyze the top depth D of the target layer in all single wells in the study area based on single-well logging data. 目顶 and bottom depth D 目底 Calculate and statistically analyze the mid-depth D of the target layer. 目中 Calculate and statistically analyze the current thickness S of the target layer. 目现 ; The twelfth processing unit is used to process the mid-depth D of the target layer of a single well obtained from the statistical analysis of the eleventh processing unit. 目中 And the current thickness S 目现 Using the original sedimentary thickness of the target layer in a single well calculated in the ninth processing unit as the independent variable, an identification database for restoring the original sedimentary thickness of the target layer in a single well is established; using the current thickness S of the single well as the independent variable... 目现 and the target layer deep D 目中 As the independent variable, the original sedimentary thickness S of the target layer in a single well in the tenth treatment unit. 目原 Construct the original deposition thickness recovery function with the variable as the dependent variable; The thirteenth processing unit is used in the Petrel software to input the current thickness distribution and intermediate-depth distribution of the target layer into the original sedimentary thickness recovery function of the twelfth processing unit for processing calculation, so as to recover the original spatial distribution of the sedimentary thickness of the target layer in the study area.

[0102] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the quantitative recovery method for the distribution of the original sedimentary thickness of strata in low-exploration areas as described in any one of the preceding claims.

[0103] A fourth aspect of the present invention 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 steps of the quantitative recovery method for the distribution of the original sedimentary thickness of strata in low-exploration areas as described in any one of the above-mentioned methods.

[0104] This invention is described based on flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to specific embodiments. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the flowcharts and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0105] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0106] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for quantitatively reconstructing the original sedimentary thickness distribution in low-exploration areas, characterized in that, include: Step 1: Statistically analyze the lithological types and single-layer thicknesses of different lithologies within the target layer of all single wells in the study area, and obtain the distribution range of single-layer thicknesses of different lithologies in the target layer of each single well; Step 2: Statistically determine the top and bottom interface depths of the target layer in all single wells in the study area, and use the minimum top depth M and the maximum bottom depth N as the depth distribution range for constructing the compaction rate-depth function of the target layer; Step 3: Determine the initial porosity, density, compaction coefficient, and geothermal gradient of each lithology in the target layer of a single well in the study area; Step 4: Statistically analyze the thickness and lithological percentage of each stratigraphic unit overlying the target layer in the study area, and calculate the average thickness and average lithological percentage of each stratigraphic unit overlying the target layer. Step 5: Based on the lithology types and single-layer thicknesses of different lithologies identified in Step 1, simulated wells are compiled within the depth distribution range of the target layer compaction rate-depth function determined in Step 2. Step 6: Unify the thickness of the overlying strata in the simulated well to M as determined in Step 2. Calculate the thickness of the overlying strata units in the simulated well based on the average thickness of the overlying strata units in Step 4, the initial porosity, density, compaction coefficient, and geothermal gradient of the study area in Step 3. Step 7: Calculate the top depth D of the single-layer lithology within the target layer of each well in the study area. 顶 Bottom depth D 底 Calculate the depth D 中 And the current thickness S of single-layer lithology 现 ; Step 8: Based on the lithology of the target layer and the thickness of the single layer in the study area, and the medium-deep D calculated in Step 7... 中 Substitute the values ​​into the corresponding layer compaction rate-depth function to calculate the compaction rate corresponding to a single layer of lithology; Step 9: Calculate the original sedimentary thickness by using the current thickness of each lithological layer and the compaction rate corresponding to the lithological layer calculated in Step 8. Step 10: Using the formula, sum the original sedimentary thicknesses of each lithology layer in the target layer of a single well to obtain the original sedimentary thickness S of the target layer in a single well. 目原 ; Step 11: Based on single-well logging data, statistically analyze the top depth D of the target layer in all single wells in the study area. 目顶 and bottom depth D 目底 Calculate and statistically analyze the mid-depth D of the target layer. 目中 Calculate and statistically analyze the current thickness S of the target layer. 目现 ; Step 12: Calculate the mid-depth D of the target layer obtained in Step 11. 目中 And the current thickness S 目现 Using the original sedimentary thickness of the target layer in a single well calculated in step 9 as the dependent variable, an identification database for restoring the original sedimentary thickness of the target layer in a single well is established; using the current thickness S of the single well as the independent variable... 目现 and the target layer deep D 目中 As the independent variable, the original sedimentary thickness S of the target layer in a single well in step 10 目原 Construct the original deposition thickness recovery function with the variable as the dependent variable; Step 13: In the Petrel software, input the current thickness distribution and intermediate-depth distribution of the target layer into the original sedimentary thickness recovery function of Step 12 for processing and calculation, so as to recover the original spatial distribution of the sedimentary thickness of the target layer in the study area.

2. The method for quantitatively reconstructing the original sedimentary thickness distribution in low-exploration areas according to claim 1, characterized in that, Fitting the compaction rate-depth function corresponding to lithology a and single-layer thickness S1 meters, the following process is further adopted in step 6: Procedure 1: The top depth of the first set of strata in the target layer is M, the bottom depth is M+S, and the calculated intermediate depth is M+0.5S; Procedure 2: Use BasicMod 1D software to conduct numerical simulation of the burial history of a single well to reconstruct the original sedimentary thickness S of the first set of strata. 原1 Calculate the compaction rate T1, which corresponds to a depth of M+0.5S; Process 3: Repeat processes 1 and 2 until the nth formation, the top depth is M + (n-1) × S, the bottom depth is M + n × S, the middle depth is M + (n + 0.5) × S, and the bottom interface of the nth layer is (M + n × S) ≥ N, where N is the maximum depth of the bottom interface of the target layer of all single wells in the statistical study area in step 2. Step 4: Fit the compaction rate and depth function corresponding to lithology a and single layer thickness S1 meters using the obtained compaction rate and corresponding depth; Step 5: Repeat steps 1, 2 and 3 to obtain the compaction rate-depth function corresponding to lithology a and single layer thickness S2 meters; Process 6: Repeat processes 1, 2 and 3 to fit the compaction rate-depth function corresponding to other lithologies and different single-layer thicknesses.

3. The method for quantitatively reconstructing the original sedimentary thickness distribution in low-exploration areas according to claim 2, characterized in that, In process 1, the following formula is used to calculate the mid-depth D. 中 That is, M+0.5S: D 中 =(D 顶 +D 底 ) / 2; In process 2, the compaction rate T1 is calculated using the following formula: T=(S 原 -S 现 ) / S 原 ; In the formula, D 中 D represents the middle depth of a single-layer lithology. 顶 D represents the depth of the top surface of a single-layer lithology. 底 The depth of the bottom surface of a single-layer lithology; T is the compaction rate; S 原 The original sedimentary thickness of a single lithological layer; S 现 The current thickness of a single-layer lithology.

4. The method for quantitatively reconstructing the original sedimentary thickness distribution in low-exploration areas according to claim 2, characterized in that, In step 7, the current thickness S of the single-layer lithology 现 The calculation formula is as follows: S 现 =D 底 -D 顶 ; In the formula, S 现 The current thickness of a single-layer lithology; D 顶 D represents the depth of the top surface of a single lithological layer within the target layer. 底 The depth of the bottom surface of a single lithological layer within the target layer.

5. The method for quantitatively reconstructing the original sedimentary thickness distribution in low-exploration areas according to claim 1, characterized in that, In step 10, the original sedimentary thickness S of the target layer in a single well is obtained by summing the original sedimentary thicknesses of each individual lithology layer in the single well using the following formula. 目原 : （S 目原 = 原i ）； In the formula, S 目原 S represents the original deposition thickness of the target layer; 原i denoted as , where is the original sedimentary thickness of the i-th single-layer lithology within the target layer; and is the number of single-layer lithology layers within the target layer.

6. The method for quantitatively reconstructing the original sedimentary thickness distribution in low-exploration areas according to claim 1, characterized in that, In step 11, the mid-depth D of the target layer is calculated and statistically analyzed using the following formula. 目中 ; D 目中 =(D 目顶 +D 目底 ) / 2; Calculate and statistically analyze the current thickness S of the target layer using the formula. 目现 : S 目现 =D 目底 -D 目顶 ; In the formula, D 目中 D represents the depth at the midpoint of the target layer. 目顶 D is the depth of the top surface of the target layer. 目底 S represents the depth of the bottom surface of the target layer. 目现 D represents the current thickness of the target layer. 目顶 D is the depth of the top surface of the target layer. 目底 The depth of the bottom surface of the target layer.

7. The method for quantitatively reconstructing the original sedimentary thickness distribution in low-exploration areas according to claim 1, characterized in that, Step 13 includes the following specific steps: In Petrel software, using 3D seismic data, the time-domain seismic reflection interfaces of the target layer's top and bottom are interpreted. The depth distribution of these interfaces is obtained through time-depth transformation, using formula D. 目中 =(D 目顶 +D 目底 The depth distribution of the target layer in the study area is calculated using the formula S / 2. Simultaneously, the depth distribution of the top and bottom interfaces of the target layer is used to calculate the depth distribution of the target layer. 目现 =D 目底 -D 目顶 The current thickness distribution of the target layer in the study area was calculated; In the Petrel software, the current thickness distribution and intermediate-depth distribution of the target layer are input into the original sedimentary thickness recovery function for processing and calculation, so that the original spatial distribution of the sedimentary thickness of the target layer in the study area can be recovered.

8. A quantitative reconstruction device for the original sedimentary thickness distribution in low-exploration areas, characterized in that, include: The first processing unit is used to statistically analyze the lithological types and single-layer thicknesses of different lithologies within the target layers of all single wells in the study area, and to obtain the distribution range of single-layer thicknesses of different lithologies in the target layers of single wells. The second processing unit is used to statistically analyze the top and bottom interface depths of the target layer in all single wells in the study area, and uses the minimum top depth M and the maximum bottom depth N as the depth distribution range for constructing the compaction rate-depth function of the target layer. The third processing unit is used to determine the initial porosity, density, compaction coefficient, and geothermal gradient of each lithology in the target layer of a single well in the study area. The fourth processing unit is used to statistically analyze the thickness and lithological percentage of each stratigraphic unit overlying the target layer in a single well in the study area, and to calculate the average thickness and average lithological percentage of each stratigraphic unit overlying the target layer. The fifth processing unit is used to compile simulated wells based on the lithology types and single-layer thicknesses of different lithologies statistically determined by the first processing unit, within the depth distribution range of the target layer compaction rate-depth function determined by the second processing unit. The sixth processing unit is used to unify the thickness of the overlying strata in the simulated well to M as determined in the second processing unit. Based on the average thickness of the overlying strata units in the target layer in the fourth processing unit, as well as the initial porosity, density, compaction coefficient and geothermal gradient of the study area in the third processing unit, the thickness of the overlying strata units in the target layer of the simulated well is calculated. The seventh processing unit is used to statistically analyze the top depth D of the single-layer lithology within the target layer of each well in the study area. 顶 Bottom depth D 底 Calculate the depth D 中 And the current thickness S of single-layer lithology 现 ; The eighth processing unit is used to calculate the medium-deep D based on the lithology within the target layer and the thickness of the single layer in the study area, using the data obtained from the seventh processing unit. 中 Substitute the values ​​into the corresponding layer compaction rate-depth function to calculate the compaction rate corresponding to a single layer of lithology; The ninth processing unit is used to calculate the compaction rate of each lithological layer using the current thickness of each lithological layer and the eighth processing unit, and to calculate its original sedimentary thickness. The tenth processing unit is used to sum the original sedimentary thickness S of the target layer in a single well by using a formula to obtain the original sedimentary thickness S of the target layer in a single well. 目原 ; The eleventh processing unit is used to statistically analyze the top depth D of the target layer in all single wells in the study area based on single-well logging data. 目顶 and bottom depth D 目底 Calculate and statistically analyze the mid-depth D of the target layer. 目中 Calculate and statistically analyze the current thickness S of the target layer. 目现 ; The twelfth processing unit is used to process the mid-depth D of the target layer of a single well obtained from the statistical analysis of the eleventh processing unit. 目中 And the current thickness S 目现 Using the original sedimentary thickness of the target layer in a single well calculated in the ninth processing unit as the independent variable, an identification database for restoring the original sedimentary thickness of the target layer in a single well is established; using the current thickness S of the single well as the independent variable... 目现 and the target layer deep D 目中 As the independent variable, the original sedimentary thickness S of the target layer in a single well in the tenth treatment unit. 目原 Construct the original deposition thickness recovery function with the variable as the dependent variable; The thirteenth processing unit is used in the Petrel software to input the current thickness distribution and intermediate-depth distribution of the target layer into the original sedimentary thickness recovery function of the twelfth processing unit for processing calculation, so as to recover the original spatial distribution of the sedimentary thickness of the target layer in the study area.

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 steps of the quantitative recovery method for the distribution of the original sedimentary thickness of strata in low-exploration areas as described in any one of claims 1-7.

10. 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 steps of the quantitative recovery method for the distribution of the original sedimentary thickness of strata in low-exploration areas as described in any one of claims 1-7.

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