Method for determining optimal position of wellhead
By obtaining the location of the reservoir sweet spot and calculating the wellhead coordinates, the problem of undetermined wellhead location was solved, the wellbore trajectory was optimized, costs were reduced, and the reservoir contact area was increased, thus achieving optimal wellhead location determination.
Patent Information
- Application Number
- CN202511758592.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-01-16
AI Technical Summary
There is currently no method to determine the optimal wellhead location in the existing technology, which leads to high wellbore trajectory complexity, large platform size, high construction and installation costs in the subsea development mode, and small reservoir contact area, affecting the production layer utilization rate.
By obtaining the location of the reservoir sweet spot, the entry point and bottom of the well in the horizontal reservoir section are determined as the target point. Geodetic coordinates are obtained, azimuth and total angle change rate are calculated, and the X-axis and Y-axis coordinates of the wellhead are determined. Combined with geological structure map and marine seismic data, the wellhead location is optimized.
It enabled the determination of the optimal wellhead location, reduced the complexity of the wellbore trajectory, reduced the platform size, lowered construction and installation costs, and significantly increased the reservoir contact area, thereby improving the production layer utilization rate.
Smart Images
Figure CN121345504A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of marine drilling engineering, and in particular to a method for determining the optimal wellhead location. Background Technology
[0002] Subsea development is a "strategic fulcrum" for deepwater oil and gas development. It reduces wellbore trajectory complexity and platform size by 30%, significantly lowering construction and installation costs. In particular, drilling horizontal wells under subsea development can substantially increase reservoir contact area and improve production formation utilization. Before commencing engineering design, the wellhead location and wellbore trajectory must be known to conduct well site surveys and identify the risks of encountering shallow gas formations and crossing faults. However, current technology lacks a method to determine the optimal wellhead location. Summary of the Invention
[0003] The purpose of this application is to provide a method for determining the optimal location of a wellhead, so as to solve the problem that there is currently no method for determining the optimal location of a wellhead in the prior art.
[0004] This application provides a method for determining the optimal wellhead location, including:
[0005] Find the location of the reservoir dessert;
[0006] Based on the location of the sweet spot, the entry point of the horizontal reservoir section is taken as the first target point, and based on the location of the sweet spot, the bottom of the well in the horizontal reservoir section is taken as the second target point.
[0007] Obtain the geodetic coordinates X and Y of target point one and target point two;
[0008] Obtain the total angle change rate and target distance of the horizontal well;
[0009] The azimuth angle is determined based on the axis differences between target point one and target point two.
[0010] The X-axis coordinate of the horizontal well's build-up end point is determined based on the X-coordinate of target point one, the differences between target point two and target point one along each axis, and the target distance.
[0011] The Y-axis coordinate of the skewing end point is determined based on the Y-coordinate of target point one, the differences between target point two and target point one along each axis, and the target front distance.
[0012] The X-axis coordinate of the horizontal wellhead is determined based on the X-axis coordinate of the directional drilling termination point, the differences between each axis of the directional drilling termination point and target point two, and the total angle variation rate; and
[0013] The Y-axis coordinate of the wellhead of the horizontal well is determined based on the Y-axis coordinate of the end point of the directional drilling, the difference between each axis of the end point of the directional drilling and the target point 2, and the total angle change rate.
[0014] Optionally, the entry point of the horizontal reservoir section is designated as target point one based on the sweet spot location, and the bottom of the horizontal reservoir section is designated as target point two based on the sweet spot location, including:
[0015] Draw geological structure maps;
[0016] Based on the geological structure map, traps that meet the conditions for hydrocarbon generation were identified; and
[0017] The target points one and two are selected from the sweet spots of sandstone reservoirs for horizontal wells.
[0018] Optionally, the geological structure map is drawn by scanning the seabed using a sonic geophysical instrument.
[0019] Optionally, the azimuth angle is determined based on the axis differences between target point one and target point two as follows:
[0020]
[0021] in, Let x1 be the azimuth angle, x2 be the x-coordinate of target point 1, y1 be the ordinate of target point 1, y2 be the ordinate of target point 2, x1-x2 be the difference between the geodetic coordinates of target point 1 and target point 2 on the X-axis, and y1-y2 be the difference between the geodetic coordinates of target point 1 and target point 2 on the Y-axis.
[0022] Optionally, the X-axis coordinate of the skew casting termination point is determined based on the X-coordinate of target point one, the differences between target point two and target point one along each axis, and the target forward distance:
[0023]
[0024] Where x3 is the X-axis coordinate of the end point of the slant buildup, s is the distance in front of the target, x1 is the x-coordinate of target point one, x2 is the x-coordinate of target point two, y1 is the y-coordinate of target point one, and y2 is the y-coordinate of target point two.
[0025] Optionally, the Y-axis coordinate of the skew casting end point is determined based on the Y-coordinate of target point one, the differences between target point two and target point one along each axis, and the target forward distance:
[0026]
[0027] Where y3 is the Y-axis coordinate of the end point of the slant buildup, s is the distance in front of the target, x1 is the x-coordinate of target point one, x2 is the x-coordinate of target point two, y1 is the y-coordinate of target point one, and y2 is the y-coordinate of target point two.
[0028] Optionally, the X-axis coordinate of the wellhead of the horizontal well is determined based on the X-axis coordinate of the directional drilling termination point, the differences between each axis of the directional drilling termination point and the target point two, and the total angle change rate:
[0029]
[0030] Where X4 is the X-axis coordinate of the starting point of the slant, x2 is the x-coordinate of target point two, x3 is the X-axis coordinate of the ending point of the slant, y2 is the y-coordinate of target point two, y3 is the Y-axis coordinate of the ending point of the slant, and DLS is the total angle change rate.
[0031] Optionally, the Y-axis coordinate of the wellhead of the horizontal well is determined based on the Y-axis coordinate of the directional drilling termination point, the differences between each axis of the directional drilling termination point and the target point two, and the total angle change rate:
[0032]
[0033] Where Y4 is the Y-axis coordinate of the starting point of the slant, x2 is the x-coordinate of target point two, x3 is the x-axis coordinate of the ending point of the slant, y2 is the y-coordinate of target point two, y3 is the Y-axis coordinate of the ending point of the slant, and DLS is the total angle change rate.
[0034] Optionally, the location of the reservoir sweet spot is obtained through the interpretation of marine seismic data.
[0035] Optionally, the acquisition of the full angle change rate and target distance of the horizontal well is determined by the field operation capability of the directional tool.
[0036] The beneficial effects of this application are as follows: It obtains the location of the reservoir sweet spot; based on the sweet spot location, it designates the entry point of the horizontal reservoir section as target point one, and based on the sweet spot location, it designates the bottom of the horizontal reservoir section as target point two; it obtains the X and Y geodetic coordinates of target point one and target point two; it obtains the total angular variation rate and target distance of the horizontal well; it determines the azimuth angle based on the differences between the axes of target point one and target point two; and it determines the horizontal well's... The X-axis coordinate of the wellhead is determined by: the Y-axis coordinate of the wellhead at the end of the directional drilling operation; the Y-axis coordinate of the wellhead at the end of the directional drilling operation is determined by: the Y-axis coordinate of target point 1, the differences between target point 2 and target point 1 along each axis, and the distance in front of the target; the X-axis coordinate of the wellhead at the end of the directional drilling operation is determined by: the X-axis coordinate of the wellhead at the end of the directional drilling operation, the differences between target point 2 and target point 2 along each axis, and the rate of change of the total angle; and the Y-axis coordinate of the wellhead at the end of the directional drilling operation is determined by: the X-axis coordinate of the wellhead at the end of the directional drilling operation, the Y ... and the rate of change of the total angle. Thus, the optimal position of the wellhead can be obtained.
[0037] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the following describes the application in detail with reference to the preferred embodiments and accompanying drawings. Attached Figure Description
[0038] Figure 1 This is a flowchart of a method for determining the optimal wellhead location in one embodiment of this application;
[0039] Figure 2 This is a flowchart of a sub-step of step S2 in one embodiment of this application.
[0040] In the attached figures, the following labels are used:
[0041] Steps for determining the optimal location of wellheads S1-S9
[0042] S20-S22 Sub-steps of step S2 Detailed Implementation
[0043] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification.
[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the accompanying drawings and embodiments. To enable those skilled in the art to better understand the solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.
[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.
[0046] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0047] like Figure 1 As shown, this embodiment provides a method for determining the optimal wellhead location, including:
[0048] S1: Obtain the location of the reservoir dessert;
[0049] S2: Based on the sweet spot location, the entry point of the horizontal reservoir section is taken as the first target point, and based on the sweet spot location, the bottom of the well in the horizontal reservoir section is taken as the second target point.
[0050] S3: Obtain the geodetic coordinates X and Y of target point one and target point two;
[0051] S4: Obtain the total angle change rate and target distance of the horizontal well;
[0052] S5: Determine the azimuth angle based on the differences between the axes of target point one and target point two;
[0053] S6: Determine the X-axis coordinate of the horizontal well's build-up end point based on the X-coordinate of target point one, the differences between target point two and target point one across each axis, and the distance in front of the target.
[0054] S7: Determine the Y-axis coordinate of the skewing end point based on the Y-coordinate of target point one, the differences between target point two and target point one on each axis, and the distance in front of the target.
[0055] S8: Determine the X-axis coordinate of the horizontal wellhead based on the X-axis coordinate of the build-up endpoint, the differences between each axis of the build-up endpoint and target point two, and the total angle change rate; and
[0056] S9: Determine the Y-axis coordinate of the wellhead of the horizontal well based on the Y-axis coordinate of the start-up point, the differences in each axis between the start-up point and target point two, and the total angle change rate. The optimal location of the wellhead can be obtained through the above steps. The optimal location of the wellhead includes its X-axis coordinate, Y-axis coordinate, and azimuth angle in the geodetic coordinate system.
[0057] In this embodiment, the optimal wellhead location determination method preferably uses a horizontal wellhead. A horizontal well is a type of well where the wellbore trajectory extends horizontally or nearly horizontally using drilling technology. Compared to traditional vertical wells, its core characteristic is that the wellbore trajectory extends laterally within the reservoir to maximize the contact area with the reservoir and improve the efficiency of oil and gas resource extraction. The reservoir sweet spot refers to the area within an oil and gas reservoir with the best physical properties, the highest oil and gas content, and the highest development benefits; it is a core objective in oil and gas exploration and development.
[0058] Based on the sweet spot location, the entry point of the horizontal reservoir section is designated as target point one; that is, the entry point within the sweet spot of the horizontal reservoir section is selected as target point one. Based on the sweet spot location, the bottom of the well within the horizontal reservoir section is designated as target point two; that is, the bottom of the well within the sweet spot of the horizontal reservoir section is selected as target point two.
[0059] The entry point refers to the critical location where the drill bit accurately reaches the predetermined target layer during the drilling process. Obtaining the geodetic coordinates (X and Y) of target point one and target point two includes obtaining the X and Y coordinates of target point one and target point two respectively. Geodetic coordinates are a coordinate system used to determine the position of points on the Earth's surface. Based on the Earth's ellipsoidal model, it accurately describes the spatial position of any point on the Earth's surface using three parameters: longitude, latitude, and elevation. The commonly used geodetic coordinate system is the CGCS2000 coordinate system.
[0060] The coordinates of the target points (including target point one and target point two) are preferably obtained through a GPS receiver. The hydrocarbon content of the trap is determined by wave impedance inversion analysis, and the sweet spot location is identified, that is, the X-axis values, Y-axis values, and height above sea level of target point one and target point two in the CGCS2000 geodetic coordinate system are determined.
[0061] Target lead distance refers to the vertical or horizontal distance from the starting position of the perforating gun (or completion tool) to the target formation (such as the producing layer, reservoir, or specific geological interface). In horizontal wells, it typically refers to the horizontal distance between the bottom of the perforating gun and the starting point of the horizontal section (or the entry point of the target formation). The target lead distance is generally about 30 meters before the target entry point.
[0062] The difference between axes refers to the difference in coordinates between two points (such as the target point, the start point of drilling, and the end point of drilling) on the X-axis and the difference in coordinates on the Y-axis in a geodetic coordinate system. The azimuth angle usually refers to the angle formed by rotating clockwise from true north to the drilling direction line, expressed in degrees (°).
[0063] The build-up point is a key node in the directional drilling process, marking the transition from the build-up phase (using specific tools or methods to deviate the wellbore trajectory from the vertical direction) to the stabilization phase (maintaining a certain inclination to continue drilling).
[0064] like Figure 2 As shown, optionally, the entry point of the horizontal reservoir section is taken as target point one based on the sweet spot location, and the bottom of the horizontal reservoir section is taken as target point two based on the sweet spot location (i.e., step S2) includes:
[0065] S20: Draw a geological structure map;
[0066] S21: Identify traps that meet the conditions for hydrocarbon generation based on geological structural maps; and
[0067] S22: Select target point one and target point two for horizontal wells from sandstone reservoir sweet spots.
[0068] Geological structural maps are important tools in geology used to illustrate underground rock structures, stratigraphic relationships, and geological structural morphology. They visually present complex geological information through symbols, lines, and colors. Traps are a core concept in petroleum and natural gas geology, referring to locations that prevent the continued migration of oil and gas and allow them to accumulate. They consist of three parts: reservoir, caprock, and obstruction, and are the foundation for oil and gas reservoir formation. By analyzing seismic wave reflection signals, three-dimensional images of underground structures can be drawn, identifying favorable traps such as anticlines and faults.
[0069] Optionally, the geological structure map is drawn by scanning the seabed using an acoustic geophysical instrument. The preferred acoustic geophysical instrument is a sonar.
[0070] Optionally, the azimuth angle can be determined based on the differences between the axes of target point one and target point two as follows:
[0071]
[0072] in, Let x1 be the azimuth angle, x2 be the x-coordinate of target point 1, y1 be the ordinate of target point 1, y2 be the ordinate of target point 2, x1-x2 be the difference between the geodetic coordinates of target point 1 and target point 2 on the x-axis, and y1-y2 be the difference between the geodetic coordinates of target point 1 and target point 2 on the y-axis. The x-coordinate is the coordinate value on the x-axis, and the y-coordinate is the coordinate value on the y-axis.
[0073] Optionally, the X-axis coordinate of the skew casting end point can be determined based on the X-coordinate of target point one, the differences between target point two and target point one along each axis, and the distance in front of the target:
[0074]
[0075] Where x3 is the X-axis coordinate of the end point of the slant buildup, s is the distance in front of the target, x1 is the x-coordinate of target point one, x2 is the x-coordinate of target point two, y1 is the y-coordinate of target point one, and y2 is the y-coordinate of target point two.
[0076] Optionally, the Y-axis coordinate of the skew casting end point is determined based on the Y-coordinate of target point one, the differences between target point two and target point one along each axis, and the distance in front of the target:
[0077]
[0078] Where y3 is the Y-axis coordinate of the end point of the slant buildup, s is the distance in front of the target, x1 is the x-coordinate of target point one, x2 is the x-coordinate of target point two, y1 is the y-coordinate of target point one, and y2 is the y-coordinate of target point two.
[0079] Optionally, the X-axis coordinate of the horizontal wellhead can be determined based on the X-axis coordinate of the build-up endpoint, the differences between the build-up endpoint and target point two along each axis, and the total angle change rate:
[0080]
[0081] Where X4 is the X-axis coordinate of the starting point of the directional drilling, x2 is the x-coordinate of target point two, x3 is the X-axis coordinate of the ending point of the directional drilling, y2 is the y-coordinate of target point two, y3 is the Y-axis coordinate of the ending point of the directional drilling, and DLS is the dogleg severity. The starting point of the directional drilling is the wellhead of the horizontal well. Dogleg Severity (DLS) is a percentage of the total angle variation in the horizontal well's directional drilling section, calculated based on the field operation capabilities of the directional drilling tool. According to this embodiment, the dogleg severity is less than 3.5° / 30m. In this embodiment, the dogleg severity is based on the actual situation during development well implementation in the East China Sea and South China Sea, and is between 1.5° / 30m and 3° / 30m.
[0082] Optionally, the Y-axis coordinate of the horizontal wellhead can be determined based on the Y-axis coordinate of the build-up endpoint, the differences between each axis of the build-up endpoint and target point two, and the total angle change rate:
[0083]
[0084] Where Y4 is the Y-axis coordinate of the starting point of the slant, x2 is the x-coordinate of target point two, x3 is the x-axis coordinate of the ending point of the slant, y2 is the y-coordinate of target point two, y3 is the Y-axis coordinate of the ending point of the slant, and DLS is the total angle change rate.
[0085] Optionally, the location of the reservoir sweet spot can be obtained through the interpretation of marine seismic data. The preferred marine seismic data are seismic wave data and layer velocity data.
[0086] Optionally, the total angle change rate and target distance of the horizontal well are determined by the field operation capability of the directional drilling tool. Considering the construction accuracy of different directional drilling tools, this embodiment refers to the current field use of directional drilling tools in the East China Sea and South China Sea, and the target distance is taken as 1 column, i.e., 30m.
[0087] The above provides a detailed description of the method for determining the optimal wellhead location provided in the embodiments of this application. For those skilled in the art, based on the ideas of the embodiments of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application. All equivalent modifications or changes made in accordance with the spirit and technical concept of this application should still be covered by the claims of this application.
Claims
1. A method for determining an optimal wellhead location, characterized by, The method comprises the following steps: acquiring a reservoir sweet spot position; acquiring a target point one position of a horizontal reservoir section according to the sweet spot position and a target point two position of the horizontal reservoir section according to the sweet spot position; acquiring X and Y coordinates of the target point one and the target point two; acquiring a full angle change rate and a target front distance of the horizontal well; determining an azimuth angle according to an axis difference between the target point one and the target point two; determining an X axis coordinate of a build-up end point of the horizontal well according to an X coordinate of the target point one, the axis difference between the target point two and the target point one and the target front distance; determining a Y axis coordinate of the build-up end point according to a Y coordinate of the target point one, the axis difference between the target point two and the target point one and the target front distance; determining an X axis coordinate of a wellhead of the horizontal well according to the X axis coordinate of the build-up end point, the axis difference between the build-up end point and the target point two and the full angle change rate; and determining a Y axis coordinate of the wellhead of the horizontal well according to the Y axis coordinate of the build-up end point, the axis difference between the build-up end point and the target point two and the full angle change rate. The step of acquiring a target point one position of a horizontal reservoir section according to the sweet spot position and a target point two position of the horizontal reservoir section according to the sweet spot position comprises the following steps:
2. The method of claim 1, wherein, drawing a geological structure map; acquiring a trap meeting an oil and gas generation condition according to the geological structure map; and selecting the target point one and the target point two of the horizontal well from a sandstone reservoir sweet spot. The geological structure map is drawn by scanning a seabed through a sonic wave geophysical detector.
3. The method of claim 2, wherein, The step of determining an azimuth angle according to an axis difference between the target point one and the target point two comprises the following steps:
4. The method of claim 1, wherein, The step of determining an X axis coordinate of a build-up end point of the horizontal well according to an X coordinate of the target point one, the axis difference between the target point two and the target point one and the target front distance comprises the following steps: wherein, is an azimuth angle, the normal vector of the Y axis is (0, 1), x1 is the horizontal coordinate value of the first target point, x2 is the horizontal coordinate value of the second target point, y1 is the vertical coordinate value of the first target point, y2 is the vertical coordinate value of the second target point, x1-x2 is the difference in the X axis of the geodetic coordinates of the first target point and the second target point, and y1-y2 is the difference in the Y axis of the geodetic coordinates of the first target point and the second target point.
5. The method of claim 1, wherein, wherein x3 is the X axis coordinate of the build-up end point, s is the target front distance, x1 is an X coordinate value of the target point one, x2 is an X coordinate value of the target point two, y1 is a Y coordinate value of the target point one and y2 is a Y coordinate value of the target point two. The step of determining a Y axis coordinate of the build-up end point according to a Y coordinate of the target point one, the axis difference between the target point two and the target point one and the target front distance comprises the following steps:
6. The method of claim 1, wherein, wherein y3 is the Y axis coordinate of the build-up end point, s is the target front distance, x1 is an X coordinate value of the target point one, x2 is an X coordinate value of the target point two, y1 is a Y coordinate value of the target point one and y2 is a Y coordinate value of the target point two. The step of determining an X axis coordinate of a wellhead of the horizontal well according to the X axis coordinate of the build-up end point, the axis difference between the build-up end point and the target point two and the full angle change rate comprises the following steps:
7. The method of claim 1, wherein, wherein X4 is an X axis coordinate of a build-up start point, x2 is an X coordinate value of the target point two, x3 is the X axis coordinate of the build-up end point, y2 is a Y coordinate value of the target point two, y3 is the Y axis coordinate of the build-up end point and DLS is the full angle change rate. The step of determining a Y axis coordinate of the wellhead of the horizontal well according to the Y axis coordinate of the build-up end point, the axis difference between the build-up end point and the target point two and the full angle change rate comprises the following steps:
8. The method of claim 1, wherein, wherein Y4 is a Y axis coordinate of the build-up start point, x2 is an X coordinate value of the target point two, x3 is the X axis coordinate of the build-up end point, y2 is a Y coordinate value of the target point two, y3 is the Y axis coordinate of the build-up end point and DLS is the full angle change rate. 9. The method of claim 1, wherein, The obtaining of the reservoir sweet spot position is obtained through marine seismic data interpretation.
10. The method of claim 1, wherein, The obtaining of the full angle change rate and the target front distance of the horizontal well is determined through the field operation capability of the directional tool.