A large platform horizontal well design method based on a three-dimensional geological model
By optimizing the well location and trajectory design of multiple horizontal wells using a three-dimensional geological model, the problem of inaccurate reservoir and structural prediction in existing technologies has been solved, and three-dimensional visualization and efficient drilling of horizontal well design have been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2022-02-07
- Publication Date
- 2026-06-26
AI Technical Summary
Existing horizontal well geological design methods are inaccurate in reservoir and structural prediction, especially in multi-well profile design, where it is difficult to accurately calculate inter-well offsets and consider reservoir changes, which increases the design difficulty.
A design method based on three-dimensional geological models is adopted. By establishing structural models, lithofacies models and attribute models, and combining well logging data, the well location coordinates and trajectory design of multiple horizontal wells are optimized to achieve three-dimensional visualization of well locations and accurate reflection of reservoir changes.
It improves the accuracy of well location design and reservoir prediction, reduces the risk of encountering non-reservoir areas, and increases the drilling rate and work efficiency of horizontal wells.
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Figure CN116595700B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of oilfield technology, and in particular to a design method for large-platform horizontal wells based on a three-dimensional geological model. Background Technology
[0002] Horizontal wells, as a current method for effective oil development, have been widely promoted and applied in tight oil development both domestically and internationally. In order to save costs and reduce surface investment, factory-style operations have begun to be used on a large scale during oilfield development. Multiple wells are drilled on a single platform, which can reduce the relocation cost of a single well, share mud pits, and circulate drilling fluids, thereby reducing the risk of drilling into non-reservoir areas.
[0003] Horizontal well geological design currently employs methods such as well-connected profile design, well group design, and 3D geological modeling. Designing trajectories within a multi-well-connected profile is simple and suitable for designing a single horizontal well, but its accuracy is poor due to two main problems: First, the reference well is not near the horizontal well or its extension, requiring elevation offsets of adjacent wells to be moved to that location, but the amount of offset lacks a basis. Second, simply moving wells not on the design trajectory to the horizontal well or its extension location does not consider reservoir variations, especially when there are multiple wells laterally and significant reservoir variations, increasing design difficulty and failing to reflect these variations in the design profile. Well group design allows for multi-well analysis, calculating reservoir thickness using virtual wells at the design trajectory location; however, this simple interpolation method suffers from the same problems, such as inaccurate reservoir and structural predictions. Summary of the Invention
[0004] This application provides a design method for large-platform horizontal wells based on a three-dimensional geological model to solve the problems of inaccurate reservoir and structural prediction in existing well group design methods.
[0005] The technical solution adopted in this application is as follows:
[0006] This invention discloses a design method for large-platform horizontal wells based on a three-dimensional geological model, comprising:
[0007] A construction model is established, wherein the construction model is established by using well point layered data as constraints;
[0008] A lithofacies model is established based on first obtaining the sandstone connectivity results from multiple wells, determining whether the sandstone layers in the sandstone connectivity results are connected, and then establishing the lithofacies model with the connectivity results as constraints.
[0009] An attribute model is established, which is constrained by the lithofacies model. A clay content model, a porosity model, a gamma model, and an interpretation conclusion model are established by the difference of well logging data.
[0010] The well location coordinates of multiple horizontal wells are determined. These coordinates are generated based on the measured wellhead coordinates, using the target distance, the horizontal well spacing, and the horizontal section length.
[0011] Establish a design profile, select the coordinates of one well from the coordinates of the multiple horizontal wells, establish a vertical profile through the well in a two-dimensional window, add the coordinates of nearby adjacent horizontal wells to the vertical profile, design the structure of adjacent horizontal wells according to the well point layering data, and select the preset model corresponding to the structure of adjacent horizontal wells as the design profile. The preset model is a clay content model or an interpretation conclusion model.
[0012] The first well trajectory design involves selecting a stable oil and gas reservoir segment based on the attribute model, establishing a horizontal well trajectory, and adjusting the target point to the optimal position, where the optimal position is the target point located within the oil and gas reservoir range.
[0013] The design of multiple well trajectories on a large platform involves repeatedly establishing and updating the attribute model, repeatedly establishing the design profile, repeating the trajectory design of the first well, and designing other wells on the large platform excluding the first well based on the trajectory of the first well.
[0014] In one feasible embodiment, the well point stratification data includes:
[0015] Layered data of formations encountered in completed directional wells, horizontal wells, or currently being drilled horizontal wells.
[0016] In one feasible embodiment, the well logging data includes:
[0017] Sediment quality (SH), natural gamma (GR), porosity (POR), and interpretation of the data.
[0018] In one feasible embodiment, determining whether sandstone layers are connected, and establishing constraints based on the connectivity results, includes:
[0019] Determine whether the sand layers of sandstone are connected;
[0020] If the sand layers of sandstone are connected, then constraints are established based on the connectivity results;
[0021] If the sandstone layers are disconnected, adjust them to be connected, and establish constraints based on the connection results.
[0022] Furthermore, the profile is a clay content model or an interpretative conclusion model.
[0023] Furthermore, the reservoir-stable oil and gas segment refers to a segment where the thickness of a single oil layer is greater than 4m, the oil layer thickness is at its maximum, and the oil layers are interconnected between multiple wells; or a segment where the thickness of a single layer is between 2 and 4m, and the oil layers are interconnected.
[0024] Furthermore, the target point is located within the oil layer. In lithologic and tight oil reservoirs, the target point is located within 1 / 3 to 2 / 3 of the oil layer thickness from the top, in a position with low natural gamma, high porosity, and continuous oil layer. In bottom-water reservoirs, the target point of horizontal wells is located within 1 / 4 to 1 / 3 of the oil layer thickness from the top, and in a continuous section of the oil layer.
[0025] The beneficial effects of adopting the technical solution of this application are as follows:
[0026] This invention provides a large-platform horizontal well deployment method based on three-dimensional geological modeling. It accurately calculates well elevation offsets within the three-dimensional model and optimizes horizontal well trajectories in three-dimensional space, achieving three-dimensional visualization of horizontal well design. Simultaneously, it considers lithological and physical property variations, designing coordinates and trajectories for multiple wells on a single platform. When deploying the first well on the platform, optimal well location can be selected. When designing multiple wells, the drilling conditions of adjacent wells are referenced, providing a more comprehensive basis for new well trajectory design. This effectively solves the challenges of rapid reservoir changes, well location selection, and visualized horizontal well trajectory design in shale oil horizontal wells. Attached Figure Description
[0027] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a flowchart of the technology of the present invention;
[0029] Figure 2a This is a hand-drawn plan view of a horizontal well platform in this invention;
[0030] Figure 2b It is a construction model, in which X312-1 is the projection well of well X312 onto horizontal well #1, located at the position where the extension line of design well H1-1 is perpendicularly projected onto the reference well;
[0031] Figure 3 This is a schematic diagram of the horizontal well location design for the large platform of this invention. The platform-based well network is the basic well network design, which includes six basic elements: 1—wellhead coordinates, 2—reference well, 3—horizontal well, 4—target distance, 5—well spacing, and 6—horizontal section length. During implementation, the horizontal section length, the number of horizontal wells, and the well spacing can be adjusted according to the oil layer distribution characteristics. When the horizontal section length is greater than 1000m, the target distance is greater than 250m.
[0032] Figure 4 This is a well location distribution diagram for single-layer and multi-layer development of the large platform of this invention;
[0033] Figure 5This is a schematic diagram of the reference well elevation offset in this invention. When A# is projected to position A#-1, it is assumed that the reservoir change is not significant, the structure changes by h, the actual structure is h higher than the formation, and the overall elevation of the well decreases by h, so that the elevation of the standard layer is consistent;
[0034] Figure 6 This is a schematic diagram of the trajectory design of the H1-1 horizontal well in the reservoir profile in this invention;
[0035] Figure 7 This is a schematic diagram of the natural gamma attribute profile of the H1-1 horizontal well in this invention;
[0036] Figure 8 This is a cross-sectional view of the horizontal well trajectory design of horizontal well H1-2 added to adjacent horizontal well H1-1 in this invention. Detailed Implementation
[0037] The embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following examples do not represent all embodiments consistent with this application.
[0038] It should be noted that geological steering of horizontal wells requires the use of various technical methods, including geological stratigraphic profiling, 3D seismic profiling, and azimuth gamma-ray profiling. To meet the requirements of geological steering, a 3D geological model needs to be established. Based on the difference in elevation between the structural model at the design coordinate points and the reference well, the offset is calculated and elevation correction is performed. The geological model and seismic model are compared to improve the accuracy of inter-well structural and reservoir prediction. After adjusting the stratification of a single well based on actual drilling conditions, or after adding a new stratification, the structural and reservoir models are adjusted to quickly update the model and guide the design of the next well. The details are as follows:
[0039] See Figures 1 to 8 .
[0040] A construction model is established, wherein the construction model is established by using well point layered data as constraints;
[0041] A lithofacies model is established. The lithofacies model is established based on the comparison of sandstone connectivity results from multiple wells to determine whether the sandstone layers are connected. The model is established based on the connectivity results as constraints.
[0042] An attribute model is established, which is constrained by the lithofacies model. A clay content model, a porosity model, a gamma model, and an interpretation conclusion model are established by the difference of well logging data.
[0043] The well location coordinates of multiple horizontal wells are determined. These coordinates are generated based on the measured wellhead coordinates, using the target distance, the horizontal well spacing, and the horizontal section length.
[0044] Establish a design profile diagram, select the coordinates of one well from the coordinates of the multiple horizontal wells, and establish a vertical profile through the well in a two-dimensional window. The profile is displayed as a clay content model or an interpretation conclusion model. Use the clay content model or interpretation conclusion model displayed in the profile as the profile diagram.
[0045] The first well trajectory design involves selecting a stable oil and gas reservoir segment based on the attribute model, establishing a horizontal well trajectory, and adjusting the target point to the optimal position, where the optimal position is the target point located within the oil and gas reservoir range.
[0046] The design of multiple well trajectories on a large platform involves repeatedly establishing and updating the attribute model, repeatedly establishing the design profile, repeating the trajectory design of the first well, and designing other wells on the large platform excluding the first well based on the trajectory of the first well.
[0047] This application provides a design method for large-platform horizontal wells based on a three-dimensional geological model, including:
[0048] S100: Establish a construction model, which is established by using well point layered data as constraints.
[0049] Using the standard layer structure as a trend surface constraint, the structure of this layer and other adjacent layers are established, and the structure models of each layer are established. Under the same structure surface constraint, the structures derived from the differences between the layers remain parallel as a whole.
[0050] The well point stratification data includes: stratification data of formations encountered by completed directional wells, horizontal wells, or horizontal wells currently being drilled.
[0051] In step S100, a construction model is established by using well point layering data and hand-drawn standard layers to construct trend surface constraints.
[0052] Furthermore, by utilizing the well point stratification data in the work area for the strata encountered by completed directional wells, horizontal wells, or horizontal wells under drilling, a standard layer is selected and a structural map is generated by interpolating the well point elevation. The structure is then manually modified to conform to geological understanding.
[0053] Step 100 uses the standard layer structure as a trend surface to constrain the structure of this layer and other adjacent layers, and establishes the structure model of each layer. Under the same structure surface constraint, the structures derived from the differences between layers remain parallel as a whole.
[0054] S200: Establish a lithofacies model. The lithofacies model is established based on the results of multi-well comparison of sandstone connectivity, determining whether the sand layers in the sandstone connectivity results are connected, and then using the connectivity results as constraints.
[0055] The process of determining whether sandstone layers are connected and establishing constraints based on the connection results includes: determining whether sandstone layers are connected; if sandstone layers are connected, establishing constraints based on the connection results; if sandstone layers are disconnected, adjusting to be connected and establishing constraints based on the connection results.
[0056] In step 200, the connectivity of sand layers under structural constraints is calculated. A multi-well interconnected profile is established for the horizontal well deployment area. Based on the reservoir analysis, interconnected sand layers can be set as connected or disconnected in the middle. The sandstone connectivity results from the multi-well comparison are used as model constraints, and well logging is used to interpret the sandstone and mudstone to establish a lithofacies model.
[0057] S300: Establish an attribute model, which is constrained by the lithofacies model. The model includes a clay content model, a porosity model, a gamma model, and an interpretation conclusion model, all established using well logging data differences.
[0058] The well logging data includes: sediment mass (SH), natural gamma ray (GR), porosity (POR), and interpretation conclusions.
[0059] In step S300, the lithofacies model is used as a constraint, and the well logging data SH (shale content), GR (natural gamma), POR, and interpretation conclusion difference are used to calculate and establish the shale content model, natural gamma model, porosity model, and interpretation conclusion model.
[0060] S400: Determine the well location coordinates of multiple horizontal wells. The well location coordinates of the multiple horizontal wells are generated based on the measured wellhead coordinates, using the target distance, horizontal well distance, and horizontal section length.
[0061] Specifically, based on the measured wellhead coordinates, the target distance required for the drilling project, and the well network parameters such as horizontal well spacing and horizontal section length, the coordinates of multiple horizontal wells are generated.
[0062] S500: Establish a design profile, select the coordinates of one well from the coordinates of the multiple horizontal wells, establish a vertical profile through the well in a two-dimensional window, add the coordinates of nearby adjacent horizontal wells to the vertical profile, design the structure of adjacent horizontal wells according to the well point layering data, and select the preset model corresponding to the structure of adjacent horizontal wells as the design profile. The preset model is a clay content model or an interpretation conclusion model.
[0063] In this process, the coordinates of one well from the coordinates of the multiple horizontal wells are selected, a well profile is created in a two-dimensional window, and nearby wells are added to the profile. The elevation difference of the adjacent wells is calculated based on the well point layering data and the structural model. The structural offset is automatically corrected based on the elevation difference, and a model is selected as the design profile.
[0064] The profile is a clay content model or an explanatory conclusion model.
[0065] The designed horizontal well trajectory is projected onto a 3D model. Based on the comparison of the natural gamma ray model, mud content model, and interpretation conclusion model for each well, the well with the longest sandstone encounter and the most stable structure is selected as the first horizontal well to be implemented.
[0066] Select the coordinates of a horizontal well in the designed well network, and create a vertical profile of the well. The profile will be displayed as either a clay content model or an interpretation model. If there is no actual drilled reference well at the profile point, adjacent wells need to be projected onto the extended line of the profile.
[0067] Nearby wells are added to the profile, and the elevation difference is calculated based on the stratified data and model construction. The elevation is then shifted based on the difference to adjust the stratified data points to the structural level.
[0068] S600: First well trajectory design. The well trajectory design is based on the attribute model, selecting oil and gas intervals with low clay content and stable reservoirs, establishing a horizontal well trajectory, and adjusting the target point structure to the optimal position, where the optimal position is that the target point is located within the oil and gas layer.
[0069] The term "stable oil and gas reservoir" refers to a reservoir segment with a single oil layer thickness greater than 4m, the maximum oil layer thickness, and interconnected oil layers between multiple wells; or a reservoir segment with a single layer thickness between 2-4m and interconnected oil layers.
[0070] The target point is located within the oil layer. In lithologic and tight oil reservoirs, the target point is located within 1 / 3 to 2 / 3 of the oil layer thickness from the top, in a position with low natural gamma, high porosity, and continuous oil layer. In bottom-water reservoirs, the target point of horizontal wells is located within 1 / 4 to 1 / 3 of the oil layer thickness from the top, and in a continuous section of the oil layer.
[0071] Establish a horizontal well trajectory and adjust the target structure to the optimal position. The horizontal well target should be located within the oil-bearing reservoir. In lithologic and tight reservoirs, the target should be located within 1 / 3 to 2 / 3 of the oil-bearing layer thickness from the top, in areas with low natural gamma ray, high porosity, and continuous oil layer. In bottom-water reservoirs, the horizontal well target should be located within 1 / 4 to 1 / 3 of the oil-bearing layer thickness from the top, and within a continuous oil-bearing section.
[0072] The designed horizontal well trajectory is projected onto the 3D model, and the well profile is translated back and forth to check reservoir properties such as mud content. The trajectory is designed at the location where the oil layer is most stable.
[0073] After the trajectory design of multiple horizontal wells on the large platform was completed, the well with the longest sandstone encounter and the most stable structure was selected as the first horizontal well to be implemented, based on the comparison of the natural gamma model, mud content model and interpretation conclusion model of each well.
[0074] S700: Large platform multi-well trajectory design, select the neighboring wells that have been completed, repeatedly build the attribute model and update the model, repeatedly build the design profile, project the adjacent horizontal wells that have been completed onto the design profile, repeat the trajectory design of the first well, and design the other wells on the large platform except for the first well based on the trajectory of the first well.
[0075] Specifically, the attribute model is repeatedly established and updated, the design profile is repeatedly established, the adjacent horizontal wells that have been drilled are projected into the design profile, the trajectory design of the first well is repeated, and the location of the most stable oil layer is analyzed based on the logging interpretation conclusions of the adjacent horizontal wells that have been drilled and the experience of adjustment while drilling, and the optimal trajectory is designed based on the structural offset.
[0076] This invention provides a large-platform horizontal well deployment method based on three-dimensional geological modeling. It accurately calculates well elevation offsets within the three-dimensional model and optimizes horizontal well trajectories in three-dimensional space, achieving three-dimensional visualization of horizontal well design. Simultaneously, it considers lithological and physical property variations, designing coordinates and trajectories for multiple wells on a single platform. When deploying the first well on the platform, optimal well location can be selected. When designing multiple wells, the drilling conditions of adjacent wells are referenced, providing a more comprehensive basis for new well trajectory design. This effectively solves the challenges of rapid reservoir changes, well location selection, and visualized horizontal well trajectory design in shale oil horizontal wells.
[0077] Example 1:
[0078] To effectively address the challenges of large-scale horizontal well deployment on a platform, and the design of horizontal well trajectories using 3D visualization on a large platform, a multidisciplinary well deployment method integrating seismic, logging, and geological data has been developed. This method, based on a 3D geological model, includes the following steps:
[0079] 1) By collecting and organizing the coordinates of completed wells, logging data, and stratification data in the deployment area, structural contour surfaces are established using the well point stratification data. Contour lines are manually adjusted to eliminate anomalies and ensure the structural surfaces conform to geological understanding (e.g., Figure 2a Using standard layers, trend surfaces are constructed to constrain multiple adjacent layers, and construction models for each layer are established. Figure 2b During the depositional process in a stable basin, the thickness of the strata does not vary much in the plane. Constrained by the same structural plane, the structures derived from the differences between the layers remain generally parallel.
[0080] 2) Establish a lithofacies model, establish sand body interconnections within the formation, manually modify the interconnection scheme, especially adjusting the correspondence of sand bodies around the horizontal well deployment area, and identify interconnected sand layers based on reservoir analysis to predict oil layer connectivity. The H1-1 well is predicted to have good sand layer connectivity. Sandstone connectivity analysis is used as the basic constraint, and a corresponding three-dimensional attribute model is established using logging data SH (shale content), GR (natural gamma), and POR (porosity).
[0081] 3) Based on the measured wellhead coordinates, the target distance and well network parameters required for the drilling project (horizontal well spacing, horizontal section length), generate the coordinates of multiple horizontal wells. Figure 3 The horizontal well spacing is 100m-600m, and the horizontal section length is 300m-3000m. The target layer combination relationship of the upper and lower layers is determined according to the vertical oil layer combination relationship, forming a three-dimensional well network. The well spacing for single-layer development is d, the plane well spacing for double-layer development is 2d, and the actual well spacing for triple-layer development is 3d. The well spacing within the same layer is expanded by three-dimensional well layout.
[0082] 4) Project the designed horizontal well trajectory into the three-dimensional model. Based on the comparison of the natural gamma model, mud content model, and interpretation conclusion model of each well, select the well with the longest sandstone encounter and the most stable structure as the first horizontal well to be implemented.
[0083] 5) Select the first horizontal well in the designed well network (e.g., well H1-1), and after creating a vertical well profile, select the reservoir profile. Figure 6 Alternatively, interpret the conclusion model. Since there are no actual drilled reference wells at the profile points, adjacent wells need to be projected onto the extended profile line. Add nearby wells to the profile in a 2D window, calculate the elevation difference based on the stratification data and model construction, and perform elevation offset based on the difference to adjust the stratification data points to the structural plane. Adjust the elevation offset amount according to the structural plane. Figure 6 For example, when A# moves to position A#-1, the stratum 1 of the structural surface needs to descend by h.
[0084] 6) Select relatively stable oil layers, place target points on the profile map, and adjust the target point guides to reasonable positions. Stable layers refer to sections with a single oil layer thickness greater than 4m and interconnected between multiple wells; or sections with a single layer thickness between 2-4m and interconnected oil layers. Establish horizontal well trajectories in the reservoir profile, adjust the target point structure to the optimal position, and ensure the horizontal well target points are within the oil layer area. In lithologic and tight reservoirs, the target points should be located within 1 / 3-2 / 3 of the distance from the top of the oil layer, in areas with low natural gamma, high porosity, and continuous oil layer. In bottom-water reservoirs, the horizontal well target points should be within 1 / 4-1 / 3 of the distance from the top of the oil layer, and in continuous oil layer sections.
[0085] 7) When designing other wells, refer to the data of the first completed well and update the model. When designing a single well, refer to the structural trend of the first well, select the design parallel to the trajectory of the first well, avoid the poor location encountered in the first drilling, and retain a longer oil layer section.
[0086] This invention provides a design method for large-platform horizontal wells based on a three-dimensional geological model, offering a three-dimensional visualization approach for the design of large-platform horizontal well combinations and horizontal well trajectory optimization. It describes the spatial distribution characteristics of multiple parameters in the reservoir, including natural gamma ray, clay content, sand layers, and well logging interpretation, in three-dimensional space. Utilizing actual drilling data from adjacent wells on the large platform to guide horizontal well design can effectively improve the horizontal well drilling success rate.
[0087] Example 2:
[0088] The Hua H40 platform is a large horizontal well platform located in the Chang 7 shale oil development area of a basin oilfield. It has 20 horizontal wells deployed on the platform, with deployment layers Chang 72, Chang 71 and Chang 63. The mudstone interval between the three layers is 10-20m. The well spacing on the plane is mainly 400m, and the average horizontal section length is 2000m. It is the largest horizontal well platform in Asia.
[0089] The northern 3km of the Hua H40 platform lacks horizontal well control. The two nearest east-west control wells in the northern part of the platform are 3.5km apart, while the southern reference well is 4km away, indicating low well control. During the horizontal well design process, the reference wells below the well site were used as a benchmark. Taking into account seismic tectonic trends, a top surface structural map was drawn, and a three-dimensional geological model was established. During horizontal well construction, drilling began with well H40-1 in the north and progressed eastward. In the south, well 40-4 was the first well drilled, and drilling continued eastward. After each well was completed, the previous well was used as a reference for the design of the next horizontal well. Finally, wells were added on both sides, bringing the total number of wells on the platform to 20. By continuously referencing the actual drilling results of the previous wells for the design of the next well, the understanding of the formation structure and reservoirs was continuously deepened, resulting in a high overall horizontal well encounter rate, averaging 84.4%. The platform controls geological reserves of 7.2 million tons.
[0090] The horizontal well placement method described above is currently being widely adopted in a certain shale oilfield, effectively improving the oil reservoir encounter rate and increasing work efficiency. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.
[0091] Scope of application:
[0092] The design of large-platform horizontal wells is suitable for geological design of low-permeability, tight oil, and shale oil production blocks. The horizontal well trajectory method is currently being promoted on a large scale in a certain oilfield shale oil area, which can effectively improve the oil layer drilling rate and improve work efficiency.
[0093] Similar parts between the embodiments provided in this application can be referred to mutually. The specific implementation methods provided above are only a few examples under the overall concept of this application and do not constitute a limitation on the scope of protection of this application. For those skilled in the art, any other implementation methods extended from the solution of this application without creative effort shall fall within the scope of protection of this application.
Claims
1. A design method for large-platform horizontal wells based on a three-dimensional geological model, characterized in that, include: A construction model is established, wherein the construction model is established by using well point layered data as constraints; A lithofacies model is established based on first obtaining the sandstone connectivity results from multiple wells, determining whether the sandstone layers in the sandstone connectivity results are connected, and then establishing the lithofacies model with the connectivity results as constraints. An attribute model is established, which is constrained by the lithofacies model. A clay content model, a porosity model, a gamma model, and an interpretation conclusion model are established by the difference of well logging data. The well location coordinates of multiple horizontal wells are determined. These coordinates are generated based on the measured wellhead coordinates, using the target distance, the horizontal well spacing, and the horizontal section length. Establish a design profile, select the coordinates of one well from the coordinates of the multiple horizontal wells, establish a vertical profile through the well in a two-dimensional window, add the coordinates of nearby adjacent horizontal wells to the vertical profile, design the structure of adjacent horizontal wells according to the well point layering data, and select the preset model corresponding to the structure of adjacent horizontal wells as the design profile. The preset model is a clay content model or an interpretation conclusion model. The first well trajectory design involves selecting a stable oil and gas reservoir segment based on the attribute model, establishing a horizontal well trajectory, and adjusting the target point to the optimal position, where the optimal position is the target point located within the oil and gas reservoir range. The design of multiple well trajectories on a large platform involves repeatedly establishing and updating the attribute model, repeatedly establishing the design profile, repeating the trajectory design of the first well, and designing other wells on the large platform excluding the first well based on the trajectory of the first well.
2. The design method for large-platform horizontal wells based on a three-dimensional geological model according to claim 1, characterized in that, The well point stratification data includes: Layered data of formations encountered in completed directional wells, horizontal wells, or currently being drilled horizontal wells.
3. The design method for large-platform horizontal wells based on a three-dimensional geological model according to claim 1, characterized in that, The well logging data includes: Sediment quality (SH), natural gamma (GR), porosity (POR), and interpretation of the data.
4. The method for designing large-platform horizontal wells based on a three-dimensional geological model according to claim 1, characterized in that, To determine whether sandstone layers are connected, constraints are established based on the connectivity results, including: Determine whether the sand layers of sandstone are connected; If the sand layers of sandstone are connected, then constraints are established based on the connectivity results; If the sandstone layers are disconnected, adjust them to be connected, and establish constraints based on the connection results.
5. The design method for large-platform horizontal wells based on a three-dimensional geological model according to claim 1, characterized in that, The profile is a clay content model or an explanatory conclusion model.
6. The method for designing large-platform horizontal wells based on a three-dimensional geological model according to claim 1, characterized in that, The term "stable oil and gas reservoir" refers to a reservoir segment with a single oil layer thickness greater than 4m, the maximum oil layer thickness, and interconnected oil layers between multiple wells; or a reservoir segment with a single layer thickness between 2-4m and interconnected oil layers.
7. The design method for large-platform horizontal wells based on a three-dimensional geological model according to claim 1, characterized in that, The optimal location refers to the target point being located within the oil and gas reservoir. For lithologic and tight oil reservoirs, the target point is located within 1 / 3 to 2 / 3 of the oil layer thickness from the top of the oil layer, with low natural gamma, high porosity, and continuous oil layer. In bottom-water reservoirs, the target point of a horizontal well is located within 1 / 4 to 1 / 3 of the oil layer thickness from the top of the oil layer, and the oil layer is continuous.