A method for obtaining vertical depth and true thickness of horizontal wells based on well logging data

Abstract

The present invention relates to a method for obtaining the vertical depth and true thickness of a horizontal well formation based on logging data, namely, using the logging data of the original well to obtain the spatial parameters of the wellbore trajectory; selecting a marker layer and obtaining the original vertical depth of the marker layer; dividing the well sections into downcutting, upcutting, and along-bedding drilling sections according to the characteristics of the horizontal well trajectory in the formation; selecting the along-bedding well section and calculating the apparent formation dip angle ⍺; performing well section curve splicing; adding the apparent formation dip angle ⍺ value to the well inclination curve, using the added well inclination data to recalculate the well trajectory spatial parameters of the spliced curve, and obtaining the vertical depth of the marker layer after the well inclination is added; restoring the marker layer, and automatically obtaining the final required formation vertical depth and true thickness based on a computer. This technical solution uses the existing logging data of the horizontal well to perform accurate vertical depth correction, and can provide a reliable path for obtaining more reference data for shale gas production projects under the condition of a limited number of exploration wells.

Description

Technical Field

[0001] The present invention belongs to the technical field of unconventional shale oil and gas resource evaluation, and particularly relates to a method for obtaining the vertical depth and true thickness of a horizontal well formation based on well logging data. Background Art

[0002] Shale gas refers to unconventional natural gas found in reservoir rock systems dominated by organic-rich shales. It is a continuously generated biochemical gas, thermogenic gas, or a mixture of the two. It can exist in a free state in natural cracks and pores, in an adsorbed state on the surface of kerogen and clay particles, and a very small amount is stored in a dissolved state in kerogen and asphaltene. The proportion of free gas is generally between 20% and 85%.

[0003] In the early stages of shale gas development, exploratory wells are drilled on-site to determine the presence of reservoirs within the field, delineate reservoir boundaries, conduct industrial evaluations, and obtain the geological data necessary for oil and gas development. However, exploratory wells are not economically viable in the later stages of shale gas development, so the number of exploratory wells is limited. With the accelerated development of shale gas demonstration areas, the geological data obtained from these limited exploratory wells is no longer sufficient to meet the needs of shale gas development projects. Specifically, there is currently no mature technology for vertical depth correction of long, complex horizontal wells in shale gas reservoirs to obtain vertical depth, true thickness, and corresponding logging data. Instead, reservoir evaluation in horizontal wells is often performed using the vertical depth and true thickness of surrounding evaluation wells. Consequently, the limited geological data obtained from these exploratory wells is inaccurate, further resulting in poor well control in the early stages of evaluation wells. This hinders accurate reservoir evaluation and target layer selection, thus hindering the smooth progress of shale gas development projects. Summary of the Invention

[0004] In response to the shortcomings of the above-mentioned existing technologies, the present invention proposes a method for obtaining the vertical depth and true thickness of horizontal well formations based on logging data. The logging data of the long complex horizontal wells in the upper and lower branches of the existing shale gas development platform in the shale gas extraction project are used to perform correct vertical depth correction, and the vertical depth, true thickness and corresponding original logging and processed interpretation data of each small layer of the shale gas reservoir are obtained, so as to finely depict the vertical and horizontal distribution changes of the shale gas reservoir and gradually realize the continuous expansion from the core area to the expansion area and the peripheral area.

[0005] The present invention is specifically achieved through the following technical solutions:

[0006] A method for obtaining the vertical depth and true thickness of a horizontal well formation based on well logging data comprises the following steps:

[0007] S1, taking an existing horizontal well as an original well, and calculating and recording the wellbore trajectory spatial parameters based on the logging data of the original well;

[0008] S2, select a marker layer near the target point of the original well and obtain the original vertical depth of the marker layer in the well trajectory spatial parameters;

[0009] S3: Comprehensively analyze the logging data of the original well and the trajectory of the original well in the formation according to the logging curve. Based on the target layer, the original well is divided into down-cut, up-cut and along-layer drilling sections;

[0010] S4, selecting a well section in the bedding area near the target point, and calculating the apparent formation dip angle ⍺ of the well section in the bedding area based on the wellbore trajectory spatial parameters;

[0011] S5, performing well section curve splicing for the up-dip well and down-dip well of the original well respectively;

[0012] S6, based on the well section curve splicing result, the apparent formation dip angle ⍺ value is added to the well deviation curve to obtain additional well deviation data, and the vertical depth correction calculation is performed on the spliced logging curve using the additional well deviation data to obtain the corrected vertical depth of the marker layer;

[0013] S7, keep the vertical depth of the target point in the additional well inclination unchanged, restore the corrected vertical depth of the marker layer to the original vertical depth of the marker layer, and automatically obtain the final required formation vertical depth and true thickness based on the computer.

[0014] Furthermore, in step 2, the marker layer is selected from the comprehensive well logging, cuttings elements, and gamma spectrum logging chart indexed by the vertical depth calculated based on the original well inclination and azimuth, and the apparent horizontal displacement.

[0015] Furthermore, the logging data include conventional logging data, gamma while drilling, azimuthal gamma imaging, gamma spectrum and rock cutting elements.

[0016] Furthermore, in step S3, during the drilling section division process, the method of combining logging curves with azimuthal gamma imaging and the method of combining logging curves with cuttings element logging are used to jointly participate in the determination of the downcutting section, upcutting section and bedding section.

[0017] Furthermore, in step S4, the apparent formation dip angle ⍺ is calculated based on the vertical depth and apparent horizontal displacement corresponding to the selected bedding well section in the wellbore trajectory spatial parameters, and the calculation formula is:

[0018]

[0019] Where H is the vertical depth and L is the apparent horizontal displacement.

[0020] Furthermore, the well section curve splicing includes the following steps:

[0021] S51, analyzing the correspondence between the logging data of the original well from the target entry point to the target exit point and the logging curves of the evaluation well or adjacent evaluation wells on the same platform, and selecting and moving the curve segments corresponding to the wellbore trajectory down-cutting well section in the formation from the logging curves of the original well one by one;

[0022] S52, all selected curve segments are sequentially connected end to end to obtain a well logging splicing curve segment; during this period, if the corresponding stratum is cut downward, the splicing is directly performed; if the corresponding stratum is cut upward, the splicing is performed in a mirror symmetrical manner relative to the tail splicing point of the upper curve segment.

[0023] Furthermore, in step 6, the additional range of the formation dip angle ⍺ in the well deviation curve is from the inclination point to the tail of the well logging splicing curve segment.

[0024] Furthermore, in step 6, the apparent formation dip angle ⍺ value is added to the spliced well inclination curve data, that is, the well inclination data of the updip formation is subtracted from the apparent formation dip angle ⍺ value, and the well inclination data of the downdip formation is added to the apparent formation dip angle ⍺ value; the addition formula is: DEVˊ=DEV±⍺.

[0025] The beneficial effects brought by the present invention are:

[0026] 1) This technical solution combines the existing horizontal well logging data to obtain the corrected vertical depth of the marker layer, and obtains more accurate formation vertical depth and true thickness data. Under the condition of a limited number of exploration wells, it provides a reliable path for obtaining more reference data for shale gas extraction projects, and is simple to operate. Parameter calculations can be easily completed based on the existing logging data system platform inside the computer. Compared with the reference data used in the implementation of shale gas extraction projects in the existing technology, the parameters obtained by this technical solution are more accurate, laying a good foundation for the implementation of shale gas extraction projects, and providing a favorable basis for the detailed characterization of the vertical and horizontal directions of the reservoir. Based on this, this technical solution can be applied to shale gas horizontal well staged fracturing schemes, accurate vertical determination of the optimal target position of regional horizontal wells, statistics on box drilling rates, and well site deployment adjustments in the research area. Illustrations

[0027] Figure 1 Schematic diagram of shale gas horizontal well formation rotation to horizontal plane;

[0028] Figure 2 This is an example diagram of marker layer selection and vertical depth calculation based on the original well inclination azimuth;

[0029] Figure 3 This is a discriminant diagram of the shale gas horizontal well's movement in the formation;

[0030] Figure 4This is the model diagram for calculating the apparent formation dip;

[0031] Figure 5 Selection diagram of stitching curve segments for vertical depth correction in up-dip formations of shale gas horizontal wells;

[0032] Figure 6 A selection diagram of spliced curve segments for vertical depth correction in down-dip formations of horizontal shale gas wells;

[0033] Figure 7 This is a schematic diagram of the formation dip added to the spliced well inclination curve;

[0034] Figure 8 This is a schematic diagram of vertical depth correction using the added well deviation data;

[0035] Figure 9 Schematic diagram for flag layer recovery;

[0036] Figure 10 This is a schematic diagram comparing a horizontal well before and after correction. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings. It should be understood that the embodiments described are only some, not all, of the present invention. The components of the present invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

[0038] Therefore, the following detailed description of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0039] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the structure and working principle of the present invention are further explained below in conjunction with the accompanying drawings and specific implementation methods, but the scope of protection of the present invention is not limited to this.

[0040] Example 1

[0041] This embodiment discloses a method for obtaining the vertical depth and true thickness of a horizontal well formation based on well logging data. As a basic implementation scheme of the present invention, the method includes the following steps:

[0042] S1: Take the existing horizontal well as the original well and calculate and record the wellbore trajectory spatial parameters based on the logging data of the original well. The calculation results of the horizontal wellbore trajectory spatial parameters are shown in the following table (this table does not list all parameter items):

[0043]

[0044] S2, select a marker layer near the target point of the original well, and obtain the original vertical depth of the marker layer in the wellbore trajectory spatial parameters as the basis for subsequent depth recovery. The wellbore trajectory spatial parameter table can record the spatial parameters of all well sections. The spatial parameters of these well sections can also include the original vertical depth of the marker layer. If there is no original vertical depth of the marker layer, it can also be calculated based on the existing relevant parameters. It should be noted that: a marker layer refers to a layer or a group of rock layers with obvious characteristics that can be used as stratigraphic comparison markers. The marker layer should have obvious fossil and lithological characteristics, stable stratigraphic position, wide distribution range, and easy identification. Therefore, the selected marker layer is easy to identify, has obvious characteristics, stable lateral distribution, and is near the horizontal target point.

[0045] S3, such as Figure 3 As shown in the figure, the original well's logging data is integrated, and the original well trajectory's trajectory in the formation is analyzed based on the logging curves. Based on the target layer, the original well is divided into drilling sections based on downcutting, upcutting, and along-bedding. The drilling sections are divided into downcutting, upcutting, and along-bedding sections. The target layer is the rock formation from the target entry point to the target exit point.

[0046] S4, select a bedding well section near the target point, and calculate the apparent formation dip angle ⍺ value of the bedding well section based on the wellbore trajectory spatial parameters. Specifically, a well section that is bedding and has a large length should be selected to calculate the apparent formation dip angle ⍺ value to maximize the accuracy of the calculation results.

[0047] S5, performing well section curve splicing for the up-dip well and the down-dip well of the original well respectively.

[0048] S6: Based on the well section curve splicing results, the apparent formation dip angle ⍺ value is added to the well deviation curve to obtain additional well deviation data. The vertical depth correction calculation of the spliced logging curve is performed using the additional well deviation data to obtain the corrected vertical depth of the marker layer.

[0049] S7, such as Figure 9 As shown in the figure, the vertical depth of the target point in the additional well inclination is kept unchanged, the corrected vertical depth of the marker layer is restored to the original vertical depth of the marker layer, and the final required formation vertical depth and true thickness are automatically obtained based on the computer. With the generation of formation vertical depth and true thickness, the original data and result data of the transmission and logging can be easily obtained.

[0050] This technical solution combines the existing horizontal well logging data to obtain the corrected vertical depth of the marker layer, and obtains more accurate formation vertical depth and true thickness data. Under the condition of a limited number of exploration wells, it provides a reliable path for obtaining more reference data for shale gas extraction projects, and is simple to operate. Parameter calculations can be easily completed based on the existing logging data system platform inside the computer. Compared with the reference data used in the implementation of shale gas extraction projects in the existing technology, the parameters obtained by this technical solution are more accurate, laying a good foundation for the implementation of shale gas extraction projects, and providing a favorable basis for the detailed characterization of the vertical and horizontal directions of the reservoir. Based on this, this technical solution can be applied to shale gas horizontal well staged fracturing schemes, accurate vertical determination of the optimal target position of regional horizontal wells, statistics on box drilling rates, and well site deployment adjustments in the research area. Further, from the attached Figure 10 It can be seen that the complex horizontal well logging correction curve completed according to the above scheme is highly consistent with the adjacent shale gas evaluation vertical well (reference) in terms of reservoir curve characteristics, vertical depth and true thickness, and has good consistency, achieving the expected goals and making up for the shortcomings of low well control and small data in the evaluation well. It is worthy of promotion and use in complex horizontal well data evaluation.

[0051] Example 2

[0052] This embodiment discloses a method for obtaining the vertical depth and true thickness of a horizontal well formation based on well logging data, which, as a preferred embodiment of the present invention, includes the following steps:

[0053] S1, taking an existing horizontal well as an original well, and calculating and recording the wellbore trajectory spatial parameters based on the logging data of the original well, wherein the logging data includes logging data and while-drilling gamma, azimuthal gamma imaging, gamma spectrum and cuttings elements.

[0054] S2, select the marker layer from the vertical depth calculated based on the original well inclination and apparent horizontal displacement, the integrated logging and cuttings elements, and the gamma spectrum logging chart, and obtain the original vertical depth of the marker layer in the wellbore trajectory spatial parameters as the basis for subsequent depth recovery, such as Figure 2 As shown in the figure, the original vertical depth of the marker layer is recorded as 2889.924m. The wellbore trajectory spatial parameter table can record the spatial parameters of all well sections. The spatial parameters of these well sections can also include the original vertical depth of the marker layer. If the original vertical depth of the marker layer is not available, it can be calculated based on the existing relevant parameters.

[0055] S3, integrate the logging data of the original well, analyze the penetration of the original well trajectory in the formation according to the logging curve, and divide the drilling section of the original well into down-cutting, up-cutting and along-layer penetration based on the target layer, such as Figure 3 The target layer is the rock layer from the target entry point to the target exit point.

[0056] S4, select a bedding well section near the target point, and calculate the apparent formation dip angle ⍺ value of the bedding well section based on the wellbore trajectory spatial parameters. Specifically, a well section that is bedding and has a large length should be selected to calculate the apparent formation dip angle ⍺ value to maximize the accuracy of the calculation results.

[0057] S5, performing well section curve splicing for the up-dip well and the down-dip well of the original well respectively.

[0058] S6: Based on the well section curve splicing results, the apparent formation dip angle ⍺ value is added to the well deviation curve to obtain additional well deviation data. The vertical depth correction calculation of the spliced logging curve is performed using the additional well deviation data to obtain the corrected vertical depth of the marker layer.

[0059] S7, such as Figure 9 As shown in the figure, the vertical depth of the target point in the additional well inclination is kept unchanged, the corrected vertical depth of the marker layer is restored to the original vertical depth of the marker layer, and the final required formation vertical depth and true thickness are automatically obtained based on the computer. With the generation of formation vertical depth and true thickness, the original data and result data of the transmission and logging can be easily obtained.

[0060] Example 3

[0061] This embodiment discloses a method for obtaining the vertical depth and true thickness of a horizontal well formation based on well logging data, which, as a preferred embodiment of the present invention, includes the following steps:

[0062] S1, taking an existing horizontal well as an original well, and calculating and recording the wellbore trajectory spatial parameters based on the logging data of the original well, wherein the logging data includes logging data and while-drilling gamma, azimuthal gamma imaging, gamma spectrum and cuttings elements.

[0063] S2, select the marker layer from the vertical depth calculated based on the original well inclination and apparent horizontal displacement, the integrated logging and cuttings elements, and the gamma spectrum logging chart, and obtain the original vertical depth of the marker layer in the wellbore trajectory spatial parameters as the basis for subsequent depth recovery, such as Figure 2 As shown in the figure, the original vertical depth of the marker layer is recorded as 2889.924m. The wellbore trajectory spatial parameter table can record the spatial parameters of all well sections. The spatial parameters of these well sections can also include the original vertical depth of the marker layer. If the original vertical depth of the marker layer is not available, it can be calculated based on the existing relevant parameters.

[0064] In step S3, the original well's logging data is integrated, and the trajectory of the original well trajectory in the formation is analyzed based on the logging curves. Based on the target layer, the original well is divided into drilling sections according to the incision, upcut, and along-bedding patterns. The drilling sections are divided into downcut sections, upcut sections, and along-bedding sections. Furthermore, during the drilling section division process, the downcut sections, upcut sections, and along-bedding sections are determined using both the logging curve combined with azimuthal gamma imaging and the logging curve combined with rock cuttings logging. In other words, this technical solution uses these two methods to mutually align to ensure the reliability of the division of each drilling section. Specifically, either of the two aforementioned methods is used to perform a preliminary division of the original well trajectory according to the upcut, downcut, and along-bedding patterns, and then the other method is used to further increase the accuracy of the preliminary division results. This ensures not only the accuracy of the apparent formation dip angle ⍺ value calculated based on the selected along-bedding section in step S4, but also the reliability of the well section curve splicing result in step S5.

[0065] S4. The key to obtaining the apparent formation dip is to find the well section with the same layer near the target point. Therefore, a well section with the same layer near the target point is selected, and the apparent formation dip ⍺ value of the well section with the same layer is calculated based on the wellbore trajectory spatial parameters. The calculation formula is:

[0066]

[0067] Where H is the vertical depth and L is the apparent horizontal displacement. Figure 4 As shown, the apparent formation dip angle ⍺=7.18286° can be calculated.

[0068] S5, performing well section curve splicing for the up-dip well and the down-dip well of the original well respectively.

[0069] S6: Based on the well section curve splicing results, the apparent formation dip angle ⍺ value is added to the well deviation curve to obtain additional well deviation data. The vertical depth correction calculation of the spliced logging curve is performed using the additional well deviation data to obtain the corrected vertical depth of the marker layer.

[0070] S7, such as Figure 9 As shown in the figure, the vertical depth of the target point in the additional well inclination is kept unchanged, the corrected vertical depth of the marker layer is restored to the original vertical depth of the marker layer, and the final required formation vertical depth and true thickness are automatically obtained based on the computer. With the generation of formation vertical depth and true thickness, the original data and result data of the transmission and logging can be easily obtained.

[0071] Example 4

[0072] This embodiment discloses a method for obtaining the vertical depth and true thickness of a horizontal well formation based on well logging data. As a preferred embodiment of the present invention, in step S5 of Examples 1, 2, or 3, for well segment curve splicing, the following steps are specifically performed: analyzing the correspondence between the well logging data from the entry point to the exit point of the original well and the well logging curves of the same platform evaluation well or adjacent evaluation wells, and selecting and moving the curve segments corresponding to the well segments where the well trajectory cuts down in the formation along the centerline of the well logging curve of the original well. Furthermore, all selected curve segments are sequentially connected end to end (i.e., well segment curve splicing) to obtain well logging spliced curve segments. In principle, when selecting curve segments, curve segments with repeated formations (i.e., cutting up formations) should be avoided to ensure that, during splicing, the starting point of each curve segment is the end point of the upper curve segment, and the formation cuts down, with the end point of the last curve segment being the end point of the lowest formation.

[0073] In actual shale gas production projects, horizontal wells crossing the target layer are divided into up-dip wells and down-dip wells. Both up-dip wells and down-dip wells contain several up-cut well sections, down-cut well sections and bedding well sections, so curve splicing is also divided into two cases, such as Figure 5 and Figure 6 As shown in the figure, in the process of splicing the well curves, the depth of the top of the next curve is moved to the depth of the bottom of the upper curve based on the selected bottom depth of the upper curve for splicing. In the curve segments involved in splicing, if the corresponding formation is cut down, the splicing is directly implemented. If the corresponding formation is cut up, it is necessary to perform a mirror symmetrical flip relative to the tail splicing of the upper curve segment to ensure that the formation of the next segment is cut from top to bottom from the splicing point to the end of this segment, that is, the terminal point of the lower logging curve is the lowest point of the formation and has the largest oblique depth. In this way, segment-by-segment splicing is implemented.

[0074] Example 5

[0075] This embodiment discloses a method for obtaining the vertical depth and true thickness of a horizontal well formation based on well logging data. As a preferred embodiment of the present invention, based on step 6 of Example 4, the apparent formation dip angle ⍺ value is added to the well inclination data corresponding to the well inclination curve after splicing, that is, the well inclination data of the formation updip is subtracted from the apparent formation dip angle ⍺ value, and the well inclination data of the formation downdip is added to the apparent formation dip angle ⍺ value, such as Figure 1 As shown, it is equivalent to rotating the stratum by an apparent stratum dip angle ⍺ to the horizontal plane; the additional formula is: DEVˊ=DEV±⍺. The purpose of this technical solution is to rotate the up- and down-dipping strata by an apparent stratum dip angle value to rotate the stratum to a horizontal state, such as Figure 7 As shown in Figure 2, both the updip and downdip formation inclination data can be directly obtained from the original well logging data. Furthermore, the additional range of the formation dip angle ⍺ in the inclination curve is from the inclination point to the end of the well logging splicing curve segment.

Claims

1. A method for obtaining vertical depth and true thickness of a horizontal well formation based on well logging data, characterized in that: The following steps are involved: S1, taking an existing horizontal well as an original well, and calculating and recording the wellbore trajectory spatial parameters based on the logging data of the original well; S2, select a marker layer near the target point of the original well and obtain the original vertical depth of the marker layer in the well trajectory spatial parameters; S3: Comprehensively analyze the logging data of the original well and the trajectory of the original well in the formation according to the logging curve. Based on the target layer, the original well is divided into down-cut, up-cut and along-layer drilling sections; S4, selecting a well section in the bedding area near the target point, and calculating the apparent formation dip angle ⍺ of the well section in the bedding area based on the wellbore trajectory spatial parameters; S5, performing well section curve splicing on the up-dip well and the down-dip well of the original well, specifically comprising the following steps: S51, analyzing the correspondence between the logging data of the original well from the target entry point to the target exit point and the logging curves of the evaluation well or adjacent evaluation wells on the same platform, and selecting and moving the curve segments corresponding to the wellbore trajectory down-cutting well section in the formation from the logging curves of the original well one by one; S52, all selected curve segments are sequentially connected end to end to obtain a well logging splicing curve segment; during this process, if the corresponding stratum is cut downward, the splicing is directly performed; if the corresponding stratum is cut upward, the splicing is performed in a mirror symmetric manner relative to the tail splicing point of the upper curve segment; S6. Based on the well curve splicing results, the apparent formation dip angle ⍺ value is added to the spliced well inclination curve data to obtain additional well inclination data. The spliced well logging curve is then vertically corrected using the additional well inclination data to obtain the corrected vertical depth of the marker layer. That is, the apparent formation dip angle ⍺ value is subtracted from the well inclination data for updip formations, and the apparent formation dip angle ⍺ value is added to the well inclination data for downdip formations. The additional formula is: DEVˊ=DEV±⍺. The additional range of the apparent formation dip angle ⍺ in the well inclination curve is from the build-up point to the end of the well logging splicing curve segment. S7, keep the vertical depth of the target point in the additional well inclination unchanged, restore the corrected vertical depth of the marker layer to the original vertical depth of the marker layer, and automatically obtain the final required formation vertical depth and true thickness based on the computer.

2. The method for obtaining vertical depth and true thickness of a horizontal well formation based on well logging data according to claim 1, characterized in that: In step 2, a marker layer is selected from the comprehensive well logging chart indexed by vertical depth calculated from the original well inclination and apparent horizontal displacement, as well as cuttings elements and gamma spectrum logging chart.

3. The method for obtaining vertical depth and true thickness of a horizontal well formation based on well logging data according to claim 1, characterized in that: The logging data include logging data and while-drilling gamma, azimuthal gamma imaging, gamma spectrum and rock cutting elements.

4. The method for obtaining vertical depth and true thickness of a horizontal well formation based on well logging data according to claim 1, characterized in that: In step S3, during the drilling section division process, the method of combining logging curves with azimuthal gamma imaging and the method of combining logging curves with cuttings element logging are used to jointly participate in the determination of the downcutting section, upcutting section and bedding section.

5. The method for obtaining vertical depth and true thickness of a horizontal well formation based on well logging data according to claim 1, characterized in that: In step S4, the apparent formation dip angle ⍺ is calculated based on the vertical depth and apparent horizontal displacement corresponding to the selected bedding well section in the wellbore trajectory spatial parameters. The calculation formula is: Where H is the vertical depth and L is the apparent horizontal displacement.

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