A high-precision horizontal well cluster drilling method and related horizontal well cluster

Abstract

This invention discloses a method for high-precision horizontal well cluster drilling and related horizontal well clusters. The method includes: determining the deployment scheme of the horizontal well cluster in the target oil and gas-bearing formation; selecting corresponding positions to deploy data horizontal wells outside the horizontal direction of the deployed horizontal well cluster; the trajectory of the data horizontal well's horizontal section is parallel or nearly parallel to the trajectory of the horizontal well sections of each horizontal well in the horizontal well cluster; drilling the data horizontal wells according to the deployed data horizontal wells; and sequentially drilling each horizontal well in the horizontal well cluster according to the drilled data horizontal wells. This invention, by increasing the drilling operation of deployed data horizontal wells, ensures that the drilling operation of the first horizontal well in the horizontal well cluster can obtain a wellbore trajectory that meets the accuracy requirements, avoiding the risk of deviation of the overall trajectory of the horizontal well cluster, and helping to improve the safe and efficient development benefits of oil and gas resources.

Description

Technical Field

[0001] This invention relates to the field of technology, and in particular to a method for high-precision horizontal well cluster drilling and related horizontal well clusters. Background Technology

[0002] A horizontal well cluster is a group of horizontal wells with small spacing and near parallelity drilled within a limited formation area, used to develop unconventional oil and gas resources, such as medium- and low-maturity source rock oil and gas resources and oil and gas resources that cannot flow under conventional conditions.

[0003] Horizontal well clusters can include several types, such as process horizontal wells, production horizontal wells, and auxiliary horizontal wells. Typically, the distance between the horizontal well sections of adjacent horizontal wells in a horizontal well cluster is less than 50 meters, or even only a few meters. This requires that the horizontal sections of each well in the cluster be approximately parallel, with small tolerances for trajectory position (generally <±1m, or even lower). The depth of the horizontal well cluster also makes its construction more difficult.

[0004] To ensure the quality of the wellbore trajectory in a horizontal well cluster, magnetic ranging technology is needed to measure the relative position between the well being drilled and the existing horizontal well sections. This guides directional drilling operations and controls the wellbore trajectory. Therefore, the drilling of the first horizontal well in a horizontal well cluster is extremely critical, as its trajectory serves as a reference for the trajectories of subsequent wells in the cluster. The quality of its wellbore trajectory determines the spatial position of the entire horizontal well cluster. If the trajectory error of the first horizontal well is significant, it will affect the drilling quality of the entire horizontal well cluster, and may even lead to wells on the periphery of the cluster deviating from the target formation, posing risks to the efficient development and even safe operation of oil and gas resources. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a method and apparatus for high-precision horizontal well cluster drilling that overcomes or at least partially solves the above problems.

[0006] In a first aspect, embodiments of the present invention provide a method for high-precision horizontal well cluster drilling, comprising:

[0007] Determine the deployment plan for horizontal well clusters in the target oil and gas-bearing formation;

[0008] Outside the horizontal direction of the deployed horizontal well cluster, data horizontal wells are deployed at corresponding locations; the trajectory of the horizontal well segments of the data horizontal wells is parallel or nearly parallel to the trajectory of the horizontal well segments of each horizontal well in the horizontal well cluster.

[0009] The drilling of the data horizontal well is completed according to the deployed data horizontal well;

[0010] Based on the data obtained from the drilling of the horizontal wells, the drilling of each horizontal well in the horizontal well cluster is completed sequentially.

[0011] Select the corresponding location to deploy data horizontal wells, specifically including:

[0012] Determine the horizontal distance between the horizontal section of the data horizontal well and the space where the horizontal well cluster is located, and determine the vertical depth of the horizontal section of the data horizontal well;

[0013] Based on the horizontal distance and the depth, the location of the horizontal section of the data horizontal well in the target oil and gas-bearing formation is determined.

[0014] In one embodiment, the horizontal distance L between the horizontal section of the data horizontal well and the space where the horizontal well cluster is located is less than or equal to the maximum detection distance of the magnetic ranging system.

[0015] In one embodiment, determining the vertical depth of the horizontal section of the data horizontal well includes:

[0016] If the target oil and gas-bearing formation contains a marker formation, then the horizontal well section of the data horizontal well will be deployed near the depth of the marker formation;

[0017] If the target oil and gas formation does not contain a marker formation, the horizontal well section of the data horizontal well will be deployed near the top depth, bottom depth, or middle depth of the target oil and gas formation.

[0018] In one embodiment, deploying the horizontal well section of the data horizontal well at the top depth, bottom depth, or intermediate depth of the target oil and gas formation includes:

[0019] If the depth difference between the top and bottom of the target formation is less than the preset thickness threshold m, the horizontal well section of the data horizontal well is deployed at the middle depth M of the target oil and gas formation; otherwise, the horizontal well section of the data horizontal well is deployed near the top depth or near the bottom depth. The m is determined according to the maximum detection range diameter of the logging-while-drilling instrument.

[0020] In one embodiment, the method for high-precision horizontal well cluster drilling further includes:

[0021] The length of the deployed data horizontal well is less than or approximately equal to the length of the horizontal wells in the horizontal well cluster.

[0022] In one embodiment, drilling the data horizontal well based on the deployed data horizontal well includes:

[0023] Drill the straight or inclined pilot hole of the horizontal well to penetrate the target oil and gas formation and complete the drilling to help identify the top depth, bottom depth and thickness of the target oil and gas formation;

[0024] The wellbore trajectory of the vertical section of the horizontal well is measured using a drilling directional measurement instrument, which guides the wellbore trajectory to drill along the designed path. The well inclination measurement error of the drilling directional measurement instrument is less than 0.1°, and the azimuth measurement error is less than 1°.

[0025] The directional and horizontal sections of the data-supported horizontal wells were explored using a drilling-while-drilling directional measurement instrument and a drilling-while-drilling geological steering instrument.

[0026] After the horizontal well is completed, the wellbore trajectory data and geological steering data are re-measured to determine whether the wellbore trajectory is in the predetermined position of the target oil and gas formation.

[0027] After the data horizontal well is completed, the horizontal section of the data horizontal well shall be completed using open hole completion method, screen pipe completion method or non-magnetic casing completion method.

[0028] In one embodiment, based on the data from the completed horizontal wells, the drilling of each horizontal well in the horizontal well cluster is completed sequentially, including:

[0029] Based on the data from the completed drilling of the horizontal well, the drilling of the first horizontal well in the aforementioned horizontal well cluster was completed.

[0030] Using the wellbore trajectory of the first horizontal well in the horizontal well cluster as a reference horizontal well, a horizontal well magnetic ranging system is used to guide the drilling of other horizontal wells in the horizontal well cluster.

[0031] In one embodiment, based on the data from the completed drilling of the horizontal well, drilling the first horizontal well in the horizontal well cluster is performed, including:

[0032] The horizontal well in the horizontal well cluster whose horizontal section is closest to the data horizontal well is designated as the first horizontal well.

[0033] The wellbore trajectory is measured using a drilling directional measurement instrument to guide the vertical section of the first horizontal well to drill along the designed trajectory;

[0034] The wellbore trajectory was measured using a drilling-while-drilling directional measurement instrument, and drilling was assisted by a horizontal well magnetic ranging system to drill the directional section and horizontal section of the first horizontal well.

[0035] In one embodiment, a drilling directional measurement instrument is used to measure the wellbore trajectory, and a horizontal well magnetic ranging system is used to assist drilling to explore the directional section or horizontal section of the first horizontal well, including:

[0036] Based on the actual wellbore trajectory of the horizontal section of the horizontal well, adjust the spatial design positional relationship between its different positions and the designed trajectory of the horizontal section of the first horizontal well.

[0037] The spatial relationship between the first horizontal well section measured in real time by the horizontal well magnetic ranging system and the actual wellbore trajectory of the data horizontal well section is compared and adjusted with the design spatial position of the first horizontal well section at different positions of the data horizontal well section. This guides the drilling operation of the first horizontal well section, ensuring that the actual wellbore trajectory of the first horizontal well is within the designed position of the target oil and gas formation, until the drilling operation of the first horizontal well section is completed.

[0038] In one embodiment, the method further includes:

[0039] Using the wellbore trajectory of the first horizontal well as a reference horizontal well, during the process of sequentially guiding the drilling of other horizontal wells in the horizontal well cluster, if there is a large well spacing between the horizontal well to be drilled and the first horizontal well, or if there is a situation where a well has already been drilled between the two, then from all the drilled horizontal wells in the horizontal well cluster other than the first horizontal well, select the horizontal well closest to the horizontal well to be drilled as the reference well for the horizontal well to be drilled, and complete the drilling of the horizontal well to be drilled.

[0040] Secondly, embodiments of the present invention provide a horizontal well cluster, which is obtained by drilling a high-precision horizontal well cluster as described above.

[0041] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0042] This invention, by adding data-driven horizontal well drilling operations, avoids the need for drilling separate vertical or directional data wells while accurately obtaining target oil and gas formation data. Simultaneously, it serves as a reference well for magnetic ranging drilling technology, ensuring that the drilling operation of the first horizontal well in a horizontal well cluster achieves a wellbore trajectory that meets accuracy requirements. This avoids the risk of the entire horizontal well cluster deviating from its trajectory, overcoming the problem in existing technologies where the first horizontal reference well in a horizontal well cluster cannot accurately and smoothly drill into the target oil and gas formation when magnetic ranging drilling guidance technology is not available. Furthermore, depending on the actual situation, the data-driven horizontal well that has completed drilling guidance operations can also be used as an auxiliary horizontal well or even a process horizontal well in subsequent oil and gas production operations, contributing to improved safety and efficiency in oil and gas resource development.

[0043] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a flowchart of a high-precision horizontal well cluster drilling method according to an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the structure of each section of the horizontal well in an embodiment of the present invention;

[0048] Figure 3 This is a flowchart of the drilling of a horizontal well in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the horizontal well magnetic ranging system in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the horizontal well cluster deployment in an embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram showing the distribution of different types of horizontal wells in a well cluster according to an embodiment of the present invention;

[0052] Figure 7 This is a schematic diagram showing the location of the horizontal section of the data horizontal well in an embodiment of the present invention;

[0053] Figure 8 This is a schematic diagram showing the location of the horizontal section of the data horizontal well in the vertical formation in an embodiment of the present invention;

[0054] Figure 9 This is a schematic diagram of the drilling of a pilot well in an embodiment of the present invention;

[0055] Figure 10 This is a schematic diagram illustrating the changes in the horizontal wellbore trajectory in an embodiment of the present invention;

[0056] Figure 11 This is a schematic diagram illustrating the spatial relationship between the data horizontal well and the first horizontal well in the horizontal well cluster in an embodiment of the present invention. Detailed Implementation

[0057] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0058] A horizontal well cluster is a group of horizontal wells with closely spaced, nearly parallel horizontal sections drilled within a limited formation area. It is used to develop unconventional oil and gas resources, such as low-maturity source rock oil and gas resources and oil and gas resources that cannot flow under conventional conditions. Typically, the horizontal well sections between adjacent wells in a horizontal well cluster are less than 50 meters apart, or even only a few meters. This requires that the horizontal sections of each well within the cluster be nearly parallel, with a small tolerance for trajectory position (generally <±1m, or even lower).

[0059] The inventors of this invention discovered that, to ensure the quality of the wellbore trajectory in the horizontal sections of a horizontal well cluster, it is necessary to use magnetic ranging technology to measure the relative position between the well being drilled and the already drilled horizontal sections, thereby guiding directional drilling operations and controlling the wellbore trajectory. At this point, the drilling of the first horizontal well in the cluster (which can also serve as a reference well for other wells in the cluster) is extremely crucial, as its wellbore trajectory determines the spatial position of the entire horizontal well cluster. However, when drilling the first horizontal reference well in a horizontal well cluster, since there are no existing wells nearby, magnetic ranging technology cannot be used, and only existing conventional directional drilling technology can be employed. Conventional directional drilling trajectory measurement tools have significant elliptic errors, which, combined with variations in the target formation space, can easily lead to large spatial variations in the trajectory of the horizontal reference well. During subsequent well drilling, using this reference well as a reference may cause significant changes in the overall trajectory of the well cluster, and may even result in wells at the edges or top / bottom of the horizontal well cluster deviating from the target formation, posing risks to the efficient development and even safe operation of oil and gas resources.

[0060] Based on this, embodiments of the present invention provide a method for high-precision horizontal well cluster drilling, referring to... Figure 1 Shown, including:

[0061] S11. Determine the deployment plan for horizontal well clusters in the target oil and gas-bearing formation;

[0062] S12. On the outer side of the horizontal well cluster in the space, select a corresponding position to deploy a data horizontal well; wherein the trajectory of the horizontal well section of the data horizontal well is parallel or nearly parallel to the trajectory of the horizontal well section of each horizontal well in the horizontal well cluster.

[0063] S13. Complete the drilling of the data horizontal wells according to the deployed data horizontal wells;

[0064] S14. Based on the data from the completed drilling of the horizontal wells, drill each horizontal well in the horizontal well cluster in sequence.

[0065] In one embodiment, in step S11 above, the horizontal well cluster is deployed as a whole in the target oil and gas-bearing formation, including a certain number of process horizontal wells, production horizontal wells, and auxiliary horizontal wells.

[0066] The target oil and gas-bearing formation has a certain thickness of top tight layer and bottom tight layer, which can isolate the oil and gas in the target formation to prevent migration and leakage during development.

[0067] Each horizontal well consists of a vertical section, a directional section, and a horizontal section. Within a specific target formation, the horizontal sections of each well are approximately parallel to each other, have approximately the same length, and are spaced relatively close together.

[0068] Technological horizontal wells refer to special technological wells implemented to achieve unconventional oil and gas development, including fracturing stimulation, electric heating, high-temperature fluid heating, electromagnetic radiation heating, and media combustion heating;

[0069] Production wells are wells that harvest fluids containing oil and gas mixtures from formations. Each group of horizontal well clusters must have at least one production horizontal well, but the total number of these wells is far less than the number of process horizontal wells described above.

[0070] Auxiliary horizontal wells refer to horizontal wells drilled to ensure the normal construction, production, and management of horizontal well clusters, such as measuring wells used to measure reservoir production parameters and observation wells used to observe reservoir production dynamics.

[0071] In horizontal well clusters, the spacing between adjacent horizontal well sections is relatively small, generally within 50m, usually less than 20m, or even less than 5m.

[0072] Furthermore, the horizontal well sections of the process horizontal wells are usually distributed in different planes, and each plane has a portion of the horizontal wellbore trajectory; the plane is a horizontal plane or a near-horizontal plane, and in some special cases, it may also have a certain inclination angle parallel to the target oil and gas formation.

[0073] Furthermore, production wells and auxiliary horizontal wells may be located in the same plane as process horizontal wells, or they may not be located in the same plane as the process wells.

[0074] Furthermore, the number of layers in the process horizontal well network is determined by the petroleum geology or oil and gas reservoir engineering scheme, ranging from 3 to 8 layers, usually between 3 or 4 layers.

[0075] In one embodiment, in step S12 above, the horizontal distance L between the horizontal section of the data horizontal well and the space where the horizontal well cluster is located is less than or equal to the maximum detection distance of the magnetic ranging system. For example, if the maximum detection distance of the magnetic ranging system is 10 meters, then an additional data horizontal well can be deployed within a 10-meter range on the side of the horizontal well cluster in the horizontal direction, for example, within a range of 4 to 6 meters, which can be adjusted appropriately as needed.

[0076] In one embodiment, determining the vertical depth of the horizontal section of the data horizontal well in step S12 above can be achieved in the following manner:

[0077] If the target oil and gas formation contains a marker formation, the horizontal section of the data horizontal well will be deployed near the depth of the marker formation.

[0078] If the target oil and gas formation does not contain a marker formation, the horizontal well section of the data horizontal well will be deployed near the top depth, bottom depth, or middle depth of the target oil and gas formation.

[0079] The horizontal well section of the data horizontal well is deployed in the target oil and gas formation. If there is a small layer or segment of special lithological characteristics in the target formation, namely the marker layer, the marker layer can be identified by drilling cuttings, geological logging, and geological logging while drilling. If the marker layer exists, the horizontal well section of the data horizontal well is deployed near the depth of the marker layer.

[0080] The horizontal well section of the data horizontal well is placed in the marker layer because the marker layer is easy to identify, making it easier to locate the horizontal well section of the data horizontal well during drilling and ensuring the accuracy of the drilling trajectory.

[0081] If there is no marker layer in the target oil and gas formation, the data horizontal well section can be deployed at an intermediate depth, or at a depth near the top or bottom of the target formation.

[0082] When the depth difference between the top and bottom of the target oil and gas formation is less than the thickness threshold m, the horizontal well section of the data well can be deployed at the middle depth of the target oil and gas formation. Otherwise, the horizontal well section of the data well can be deployed at a depth that is closer to the top or bottom.

[0083] The above m value is determined based on the maximum detection range diameter of the drilling geological logging instrument.

[0084] The reason for deploying the horizontal section of the data horizontal well at a depth slightly above or below the top of the target oil and gas formation when the depth difference between the top and bottom is greater than the value m is to facilitate precise positioning using logging-while-drilling (LWD) instruments during drilling, thus ensuring the accuracy of the drilling trajectory. If the depth difference between the top and bottom of the target oil and gas formation is less than the value m, deploying the horizontal section of the data horizontal well at a depth in the middle of the target oil and gas formation better ensures that the horizontal section of the data horizontal well is located within the target oil and gas formation during drilling, and its position is more easily determined by LWD measurements.

[0085] Similar to the horizontal wells in a horizontal well cluster, data horizontal wells also include vertical, directional, and horizontal sections. The horizontal sections of data horizontal wells are approximately parallel to the horizontal sections of the horizontal well cluster, and their lengths can be approximately the same or shorter than the horizontal sections of the cluster. Preferably, the difference between the two does not exceed 200 meters.

[0086] Reference Figure 2 As shown, each horizontal well in the horizontal well cluster, or data horizontal well, can be configured according to... Figure 2 As shown, each section includes a vertical section 21, a directional section 22, and a horizontal section 23. The starting point of the directional section is the build-up point KOP, and the starting point of the horizontal section is point A, with the ending point being point B.

[0087] In one embodiment, in S13 above, reference is made to Figure 3 As shown, the drilling of the data horizontal well can be completed by following these steps:

[0088] S31. Drill the straight or inclined pilot hole of the horizontal well described in the data, and complete the drilling after drilling through the target oil and gas formation to help identify the top depth, bottom depth and thickness of the target oil and gas formation.

[0089] Regardless of whether it is a straight or inclined pilot hole, cement must be injected to fill the pilot hole after it is completed. Core drilling can be carried out during pilot hole drilling to help obtain the rock mechanics of the drilled formation or the oil and gas content and physical properties of the target reservoir.

[0090] S32. Use a drilling directional measurement instrument to measure the wellbore trajectory of the vertical section of the horizontal well in the data, and guide the wellbore trajectory to drill along the designed track. The well inclination measurement error of the drilling directional measurement instrument is less than 0.1°, and the azimuth measurement error is less than 1°.

[0091] S33. Use drilling directional measurement instruments and drilling geological steering instruments to assist in drilling data exploration of the directional and horizontal well sections of horizontal wells;

[0092] For horizontal wells, geological steering instruments such as logging-while-drilling instruments and near-bit geological steering instruments are added to the directional section or the later part of the directional section and the horizontal section to assist drilling operations.

[0093] S34. After the horizontal well is completed, re-measure the wellbore trajectory data and geological steering data to determine whether the wellbore trajectory is in the predetermined position of the target oil and gas formation.

[0094] During the re-measurement, based on the wellbore trajectory data and geological steering data of the horizontal well section in the data, the drilling situation of the actual drilling trajectory of the horizontal well section in the target oil and gas formation is analyzed. It is analyzed whether the trajectory is still within the target oil and gas formation, whether the trajectory can still meet the drilling requirements of the horizontal well cluster to develop the target oil and gas formation after the change of the trajectory relative to the design trajectory, and whether it can ensure that the spatial position relationship with the horizontal well section trajectory of the first horizontal well in the horizontal well cluster is still within the magnetic ranging drilling guidance range, etc.

[0095] S35. After the data horizontal well is completed, the horizontal section of the data horizontal well shall be completed using the open hole completion method, the screen pipe completion method, or the non-magnetic casing completion method.

[0096] During horizontal well drilling operations, core drilling can be performed to help obtain rock mechanics parameters of the encountered formation or oil and gas content and physical properties of the target reservoir.

[0097] In one embodiment, in step S13 above, based on the data from the completed drilling of the horizontal wells, the drilling of each horizontal well in the horizontal well cluster is completed sequentially. This can be implemented in the following manner:

[0098] 1) Based on the data from the completed drilling of the horizontal wells, complete the drilling of the first horizontal well in the horizontal well cluster;

[0099] 2) The wellbore trajectory of the first horizontal well in the horizontal well cluster will be used as a reference horizontal well, and the drilling of other horizontal wells in the horizontal well cluster will be guided by a horizontal well magnetic ranging system.

[0100] In step 1) above, the drilling of the first horizontal well in the horizontal well cluster is completed based on the completed data. This can be achieved through the following steps:

[0101] The horizontal well in the horizontal well cluster whose horizontal section is closest to the data horizontal well is designated as the first horizontal well.

[0102] The wellbore trajectory is measured using a drilling directional measurement instrument to guide the vertical section of the first horizontal well to drill along the designed trajectory.

[0103] The wellbore trajectory is measured using a drilling-while-drilling directional measurement instrument, and drilling is assisted by a horizontal well magnetic ranging system to drill the directional section (or at least the latter half of the directional section) and the horizontal section of the first horizontal well.

[0104] Specifically, the drilling process of the horizontal section of the first horizontal well mentioned above is as follows:

[0105] The horizontal well in a horizontal well cluster whose horizontal section is closest to the data horizontal well is designated as the first horizontal well in the horizontal well cluster.

[0106] Based on the actual wellbore trajectory of the horizontal section of the horizontal well, adjust the spatial design positional relationship between its different positions and the designed trajectory of the horizontal section of the first horizontal well.

[0107] The spatial relationship between the first horizontal well section measured in real time by the horizontal well magnetic ranging system and the actual wellbore trajectory of the data horizontal well section is compared and adjusted with the designed spatial position relationship between different positions of the data horizontal well section and the first horizontal well section. This guides the drilling operation of the first horizontal well section, ensuring that the actual wellbore trajectory of the first horizontal well is within the target oil and gas formation, until the drilling operation of the first horizontal well section is completed.

[0108] In this embodiment of the invention, reference is made to Figure 4 As shown, the horizontal well magnetic ranging system includes, for example, a dynamic magnetic field generator 51, an environmental magnetic field acquisition instrument 52, a magnetic field signal transmission system 53, a surface signal processor 54, and a magnetic ranging guidance software system 55. The magnetic field generator 51 is installed in the drill string of the first horizontal well 4 in the horizontal well cluster, specifically behind the drill bit 56, and can generate a dynamically changing magnetic field. The environmental magnetic field acquisition instrument 52 is located in the data horizontal well 3. The magnetic field signal transmission system 53 connects to the environmental magnetic field acquisition instrument 52 and transmits the acquired magnetic field information to the surface signal processor 54. The surface signal processor 54 converts the magnetic signal into a digital signal and transmits it to the magnetic ranging guidance software system 55, analyzing and determining the spatial positional relationship between the dynamic magnetic field generator and the environmental magnetic field acquisition instrument, including distance and azimuth, and determining the spatial positional relationship between the drill bit in the first horizontal well 4 and the data horizontal well 3 in the horizontal well cluster based on this spatial relationship.

[0109] Of course, the horizontal well magnetic ranging system is not limited to the combination of the above-mentioned magnetic testing equipment, and the embodiments of the present invention do not limit this.

[0110] In this embodiment of the invention, the first horizontal well can be used as a reference well, and a horizontal well magnetic ranging system can be used to guide the drilling of other horizontal wells in the horizontal well cluster.

[0111] Specifically, when drilling other horizontal wells, the spatial positional relationship between the dynamic magnetic field generator and the environmental magnetic field acquisition instrument is measured in real time to determine the spatial position of the drill bit of the horizontal section of the horizontal well being drilled in the horizontal well cluster and the horizontal section of the reference well. Based on the difference between the actual spatial positional relationship and the design, the directional drilling direction is adjusted in reverse to ensure that the actual wellbore trajectory of other horizontal wells in the horizontal well cluster is within the design error range.

[0112] Other horizontal wells in a drilling horizontal well cluster can be referenced wells, which can be the first horizontal well in the cluster or one of the other completed horizontal wells in a subsequent drilling cluster.

[0113] Furthermore, when using the wellbore trajectory of the first horizontal well as a reference horizontal well to guide the drilling of other horizontal wells in the horizontal well cluster, if there is a large well spacing between the horizontal well to be drilled and the first horizontal well, or if there is a situation where a well has already been drilled between them, then from all the drilled horizontal wells in the horizontal well cluster other than the first horizontal well, select the horizontal well closest to the horizontal well to be drilled as the reference well for the horizontal well to be drilled, and complete the drilling of the horizontal well to be drilled.

[0114] The above method can be repeated until all horizontal wells in the horizontal well cluster have been drilled.

[0115] Furthermore, the horizontal well sections of the horizontal wells selected as reference wells for drilling horizontal wells are completed using open-hole completion, screen completion, or non-magnetic casing completion methods.

[0116] The high-precision horizontal well cluster drilling method provided in this invention deploys a data horizontal well outside the space where the horizontal well cluster is located, and uses the data horizontal well as a reference well in the horizontal well cluster. The horizontal wells in the cluster are then drilled sequentially. This avoids the problem in existing technologies where the first horizontal reference well in a horizontal well cluster cannot be drilled relatively accurately and smoothly in the target oil and gas formation when magnetic ranging drilling guidance technology cannot be used. By using the data horizontal well as a reference well for the horizontal well cluster, the first horizontal well in the cluster (which may serve as a reference well for subsequent horizontal wells) can be drilled relatively accurately in the target oil and gas formation, avoiding the risk of the entire horizontal well cluster deviating from its trajectory and improving the safe and efficient development benefits of oil and gas resources.

[0117] The following specific embodiment will be used for illustration:

[0118] The specific steps of this embodiment are as follows:

[0119] Step 1: Determine the deployment of the horizontal well cluster system.

[0120] like Figure 5The diagram shows a horizontal well cluster, where 1 represents the encountered formation and 11 represents the target oil and gas-bearing formation. The target oil and gas-bearing formation 11 has a certain thickness of top tight layer 111 and bottom tight layer 112, which can isolate the oil and gas in the target formation to prevent migration and leakage during development. Numerous horizontal wells 2 are deployed within 11. The horizontal well section 23 of each well is located within a specific target formation 11 underground. The relative positions of the horizontal well sections 23 of adjacent wells are approximately parallel, and they have approximately the same length.

[0121] like Figure 6 As shown, the horizontal well cluster system 1 includes a certain number of process horizontal wells 231, production horizontal wells 232, and auxiliary horizontal wells 233 (distinguished by circular, triangular, and square graphics, respectively). The distance d between the horizontal well segments 23 of adjacent horizontal wells 2 in the horizontal well cluster 1 is less than 50 meters, usually less than 20 meters, and even less than 5 meters.

[0122] Horizontal wells with advanced technology (231) refer to specialized wells implemented for unconventional oil and gas development, including fracturing, electric heating, high-temperature fluid heating, electromagnetic radiation heating, and media combustion heating. For example... Figure 6 As shown, the horizontal well sections of process horizontal wells 321 are typically distributed within different planar layers. Each planar layer contains a portion of the horizontal wellbore trajectory. The planar surface is horizontal or nearly horizontal. In some special cases, it may also be parallel to the strike of the formation with a certain inclination angle. The number of layers in the process horizontal well network is determined by the petroleum geology or oil and gas reservoir engineering scheme, ranging from 3 to 8 layers, usually between 3 or 4 layers.

[0123] Production wells 232 are wells that recover oil and gas mixtures from formations. Each horizontal well cluster must contain at least one production horizontal well, but the total number of production horizontal wells is far less than the number of process horizontal wells mentioned above. Auxiliary horizontal wells 233 are horizontal wells drilled to ensure the normal well construction, production, and management of the horizontal well cluster, such as measurement wells to measure reservoir production parameters and observation wells to observe the production dynamics of the target oil and gas formation. Figure 3 As shown, production wells and auxiliary horizontal wells may be located in the same plane as the process horizontal wells, or they may not be located in the same plane as the process wells.

[0124] Step 2: Deploy an additional data horizontal well within a 10m radius to the side of the horizontal well cluster.

[0125] To improve drilling accuracy in the horizontal sections of a horizontal well cluster, a data horizontal well can be deployed outside the volume formed by the horizontal section. Drilling this data horizontal well allows for monitoring of formation changes, which in turn enables dynamic adjustment of the wellbore trajectory of the first horizontal well in the cluster. For example... Figure 7 As shown, in Figure 7In this design, to distinguish between data horizontal wells and horizontal wells within a horizontal well cluster, data horizontal wells are represented by triangles, while horizontal wells within a horizontal well cluster are represented by circles. Data horizontal wells 3 can be selectively deployed on the sides A and B within the volume formed by the horizontal well section 23 of the horizontal well cluster. The wellbore trajectory of the data horizontal wells also includes... Figure 2 The diagram shows vertical well section 21, directional well section 22, and horizontal well section 23. The horizontal well sections in the data are approximately parallel to the horizontal well sections of the horizontal well cluster, and their deployment lengths are approximately the same. They can also be shorter than the horizontal sections of the horizontal well cluster, but to ensure the guiding effect on the first horizontal well in the cluster, the difference q should not exceed 200 meters.

[0126] The distance L between the horizontal section of a horizontal well and the horizontal section of a horizontal well cluster is usually less than 10 meters, generally in the range of 4 to 6 meters, and can be adjusted appropriately as needed. Figure 8 As shown. In Figure 8 Similarly, to distinguish between data horizontal wells and horizontal wells in a horizontal well cluster, data horizontal wells are represented by triangles, while horizontal wells in a horizontal well cluster are represented by circles.

[0127] From a vertical formation perspective, the data well horizontal section 31 is deployed within the target oil and gas formation 11. If a specific layer or segment of formation with unique lithological characteristics exists within the target formation 11, it can be identified through drilling cuttings, geological logging, and geological logging while drilling. In other words, if a marker layer exists, the data well horizontal section 31 is deployed near the depth of that marker layer. If no marker layer exists in the target oil and gas formation 11, the data well horizontal section 31 can be deployed at an intermediate depth, or at a depth near the top (T) or bottom (B) of the target formation. When the depth difference between the top and bottom of the target formation is less than m, the data well horizontal section is preferentially deployed at the intermediate depth (M) of the target oil and gas formation; otherwise, it is preferentially deployed at a depth near the top (T) or bottom (B). The value of m is determined based on the maximum detection range diameter of the geological logging while drilling instrument.

[0128] The spatial distance and positional relationship between the deployed data horizontal wells and the horizontal well sections of the horizontal well cluster are relatively certain in the design. The positional relationship between the two can be determined by using the directional drilling wellbore trajectory calculation method.

[0129] Step 3: Drilling data for horizontal wells.

[0130] The data horizontal well 3 can achieve three functions: First, it can accurately obtain target oil and gas formation data, such as top and bottom depths, formation strike, and oil and gas content, providing reference data for subsequent drilling operations of the horizontal well cluster. Second, under conventional directional drilling conditions, the wellbore trajectory has a large elliptic error, which cannot meet the high-precision wellbore trajectory requirements of the horizontal well cluster. The advance drilling of the data horizontal well can serve as a reference well for magnetic ranging drilling technology, ensuring that the drilling operation of the first horizontal well in the horizontal well cluster can obtain a wellbore trajectory that meets the accuracy requirements. Third, the data horizontal well can also be used as an auxiliary horizontal well or even a process horizontal well in subsequent oil and gas production operations, depending on the actual situation.

[0131] To ensure accurate acquisition of target oil and gas formation data, during the drilling of data horizontal well 3, such as Figure 9 As shown, a straight pilot hole 241 or an inclined pilot hole 242 can be drilled first, penetrating the target oil and gas formation before completion. This assists geological engineers in identifying the top and bottom plate depths and thicknesses of the target oil and gas formation 11, guiding the drilling and steering operations of the subsequent directional well section 22 and horizontal well section 23 of data well 3. After the pilot hole is completed, it needs to be cemented. Core drilling can be performed during pilot hole drilling to help obtain the rock mechanics of the encountered formation or the oil and gas content and physical properties of the target reservoir.

[0132] In the vertical section 21 of the data horizontal well 3, a high-precision measurement-while-drilling (MWD) instrument is used to measure the wellbore trajectory, guiding the wellbore along the designed path. The MWD instrument's deviation measurement error is less than 0.1°, and its azimuth measurement error is less than 1°, reducing the elliptic error of the data horizontal well trajectory. In the directional section 23, or at least the latter part of the directional section 23 and the horizontal section 23, drilling operations are assisted by drilling geological steering instruments, such as logging-while-drilling instruments and near-bit geological steering instruments. With the assistance of the drilling geological steering instruments, the drilling direction can be adjusted based on the identification results of the encountered formation lithology, ensuring that the horizontal section of the data horizontal well 3 is within the target oil and gas formation. If the drilling operation unexpectedly deviates from the target oil and gas formation, the drilling direction of the data horizontal well should be adjusted promptly. After the data horizontal well 3 is completed, the wellbore trajectory data and geological steering data need to be re-measured to determine whether the wellbore trajectory is at the predetermined position of the target oil and gas formation. After the horizontal well is completed, the horizontal section should be completed using open-hole completion, screen completion, or non-magnetic casing completion methods to avoid the magnetic shielding effect of subsequent magnetic ranging drilling operations.

[0133] Step 4: Complete the drilling of the first horizontal well in the aforementioned horizontal well cluster.

[0134] The first horizontal well in a horizontal well cluster should be the well closest to the horizontal well 3 in the data section. In special cases, a closer well can be selected if the magnetic ranging requirements are met.

[0135] like Figure 10 As shown, generally speaking, during the drilling of data-supported horizontal wells, since nearby wells have not yet been drilled (i.e., there are no reference wells), the wellbore trajectory of the horizontal section is not as smooth and straight as the designed trajectory due to the instability, heterogeneity, and even the influence of the directional engineer's level of orientation of the target oil and gas formation. The actual drilling process involves significant curvature and variation, resulting in a large difference between the actual trajectory and the designed trajectory. If data-supported horizontal wells are not drilled, directly drilling the first horizontal well in a horizontal well cluster will also result in a large variation in the wellbore trajectory due to the lack of nearby reference wells, failing to meet the wellbore trajectory quality requirements of the horizontal well cluster. By deploying data-supported horizontal wells, the drilling process of the first horizontal well in the horizontal well cluster can refer to the wellbore trajectory control of nearby data-supported horizontal wells and the changes in the target oil and gas formation, allowing for smoother wellbore trajectory control and ensuring that it meets the high-precision horizontal well section trajectory control requirements of the horizontal well cluster.

[0136] exist Figure 10 In order to distinguish between data horizontal wells and horizontal wells in a horizontal well cluster, data horizontal wells are represented by triangles, while horizontal wells in a horizontal well cluster are represented by circles.

[0137] During the drilling of the first horizontal well in a horizontal well cluster, the following technical measures need to be adopted, such as... Figure 4 As shown, in the first horizontal well 4 of the horizontal well cluster, the vertical section 21 uses a high-precision measurement-while-drilling (MWD) instrument to measure the wellbore trajectory and guide the wellbore trajectory along the designed path. The inclination measurement error of the high-precision MWD instrument is less than 0.1°, and the azimuth measurement error is less than 1°, thus reducing the elliptic error of the horizontal wellbore trajectory data. A horizontal well magnetic ranging system is added to the directional section 22, or at least the latter part of the directional section 22, and the horizontal well section 23 to assist drilling.

[0138] The specific process of horizontal well magnetic ranging system-assisted drilling is as follows: The first step is to analyze the drilling encounters of the actual drilling trajectory of the horizontal section 23 of horizontal well 3 in the target oil and gas formation based on the re-measurement data of the wellbore trajectory and geological steering data. This includes determining whether the trajectory is still within the target oil and gas formation, whether the trajectory, after changing relative to the designed trajectory, still meets the drilling requirements for developing the target oil and gas formation in the horizontal well cluster, and whether it ensures that the spatial relationship with the trajectory of the first horizontal well 4 in the horizontal well cluster remains within the magnetic ranging drilling guidance range. Figure 11As shown, in one hypothetical scenario, the spatial distance between the designed trajectory of the data horizontal well and the designed trajectory of the first horizontal well in the horizontal well cluster is determined by d1, d2, ..., dn. After the data horizontal well is actually drilled, the spatial distance becomes d1', d2', ..., dn'. During the drilling of the first horizontal well in the horizontal well cluster, the trajectory should be controlled according to the changing spatial distance group. The second step is to adjust the spatial design position relationship between the different positions of the horizontal section 23 of the data horizontal well 3 and the horizontal section 23 of the first horizontal well 4 in the horizontal well cluster, based on the actual wellbore trajectory of the horizontal section 23. The third step utilizes the horizontal well magnetic ranging system to measure in real time the spatial relationship between the horizontal well section 23 of the first horizontal well 4 in the horizontal well cluster and the wellbore trajectory of the horizontal well section 23 of the data horizontal well 3. By comparing and adjusting the different positions of the wellbore trajectory of the horizontal well section 23 of the data horizontal well 3 with the designed spatial position relationship of the horizontal well section 23 of the first horizontal well 4 in the horizontal well cluster, the drilling operation of the horizontal well section 23 of the first horizontal well 4 in the horizontal well cluster is guided, so that its wellbore trajectory is in the target oil and gas formation, until the drilling operation of the horizontal well section 23 of the first horizontal well 4 in the horizontal well cluster is completed.

[0139] Step 5: Complete the drilling of the horizontal well cluster.

[0140] After the first horizontal well (4) in the horizontal well cluster is drilled, it has relatively high trajectory control accuracy because it was completed with reference to the data from horizontal well (3). Therefore, it can serve as a reference well for subsequent horizontal well drilling in the cluster, allowing for the sequential completion of drilling in the cluster. Specifically, this involves using the wellbore trajectory of the first horizontal well (4) as a reference well, and employing a horizontal well magnetic ranging system to guide the drilling of other horizontal wells in the cluster. During drilling, similarly, in the vertical well section, a high-precision measurement-while-drilling (MWD) instrument is used to measure the wellbore trajectory, guiding the wellbore trajectory along the designed path. The high-precision MWD inclination measurement error is less than 0.1°, and the azimuth measurement error is less than 1°, reducing the elliptic error of the data-based horizontal well trajectory. In the directional drilling section, or at least the latter part of the directional drilling section and the horizontal well section, a horizontal well magnetic ranging system is added to assist drilling.

[0141] Furthermore, when drilling other horizontal wells within a horizontal well cluster, if the first horizontal well in the cluster has a large spacing between wells or other drilled wells exist between them, making it impossible to use a horizontal well magnetic ranging system to assist drilling, a reference well can be selected from among the other completed horizontal wells in the cluster. The specific distance is determined based on the distance between the horizontal well to be drilled and the horizontal well sections of other completed horizontal wells in the cluster, with priority given to selecting the closest completed horizontal wells as reference wells. The horizontal well section selected as the reference well for the horizontal well to be drilled is then completed using open-hole completion, screen completion, or non-magnetic casing completion methods.

[0142] Through the above process, horizontal wells that are closer to the well to be drilled can be selected from the completed horizontal wells in the horizontal well cluster as reference wells to complete the drilling of the well to be drilled, until all horizontal wells in the horizontal well cluster have completed drilling operations, thus achieving high-precision horizontal well cluster drilling operations.

[0143] This invention also provides a horizontal well cluster, which is obtained by drilling a high-precision horizontal well cluster according to the aforementioned embodiments.

[0144] This invention, by adding data-deploying horizontal well drilling operations, avoids the need for separate data well drilling while accurately obtaining target oil and gas formation data. Simultaneously, it serves as a reference well for magnetic ranging drilling technology, ensuring that the drilling operation of the first horizontal well in a horizontal well cluster achieves a wellbore trajectory that meets accuracy requirements, thus avoiding the risk of overall trajectory deviation in the horizontal well cluster. Furthermore, depending on the actual situation, the data-deploying horizontal wells that have completed drilling guidance operations can be used as auxiliary horizontal wells or even process horizontal wells in subsequent oil and gas production operations, contributing to improved safety and efficiency in the development of oil and gas resources.

[0145] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for high-precision horizontal well cluster drilling, characterized in that, include: Determine the deployment plan for horizontal well clusters in the target oil and gas-bearing formation; Outside the horizontal direction of the deployed horizontal well cluster, data horizontal wells are deployed at corresponding locations; the trajectory of the horizontal well segments of the data horizontal wells is parallel or nearly parallel to the trajectory of the horizontal well segments of each horizontal well in the horizontal well cluster. The drilling of the data horizontal well is completed according to the deployed data horizontal well; Based on the data obtained from the drilling of the horizontal wells, the drilling of each horizontal well in the horizontal well cluster is completed in sequence. The drilling of each horizontal well in the horizontal well cluster is completed sequentially based on the data obtained from the drilling of the horizontal wells, including: Based on the data from the completed drilling, the first horizontal well in the horizontal well cluster was drilled. The wellbore trajectory of the first horizontal well in the horizontal well cluster is used as a reference horizontal well, and a horizontal well magnetic ranging system is used to guide the drilling of other horizontal wells in the horizontal well cluster. The process of drilling the first horizontal well in a horizontal well cluster, based on the data obtained from the drilling, includes: The horizontal well in the horizontal well cluster whose horizontal section is closest to the data horizontal well is designated as the first horizontal well. The wellbore trajectory is measured using a drilling directional measurement instrument to guide the vertical section of the first horizontal well to drill along the designed trajectory; The wellbore trajectory was measured using a drilling-while-drilling directional measurement instrument, and drilling was assisted by a horizontal well magnetic ranging system to drill the directional section and horizontal section of the first horizontal well. The method of using a drilling-while-drilling directional measurement instrument to measure the wellbore trajectory and using a horizontal well magnetic ranging system to assist drilling, to drill the directional section or horizontal section of the first horizontal well, includes: Based on the actual wellbore trajectory of the horizontal section of the horizontal well, adjust the spatial design positional relationship between its different positions and the designed trajectory of the horizontal section of the first horizontal well. The spatial relationship between the first horizontal well section measured in real time by the horizontal well magnetic ranging system and the actual wellbore trajectory of the data horizontal well section is compared and adjusted with the design spatial position of the first horizontal well section at different positions of the data horizontal well section. This guides the drilling operation of the first horizontal well section, ensuring that the actual wellbore trajectory of the first horizontal well is within the designed position of the target oil and gas-bearing formation, until the drilling operation of the first horizontal well section is completed.

2. The method as described in claim 1, characterized in that, Select the corresponding location to deploy data horizontal wells, specifically including: Determine the horizontal distance between the horizontal section of the data horizontal well and the space where the horizontal well cluster is located, and determine the vertical depth of the horizontal section of the data horizontal well; Based on the horizontal distance and the depth, the location of the horizontal section of the data horizontal well in the target oil and gas-bearing formation is determined.

3. The method as described in claim 2, characterized in that, The horizontal distance L between the horizontal section of the data horizontal well and the space where the horizontal well cluster is located is less than or equal to the maximum detection distance of the magnetic ranging system.

4. The method as described in claim 2, characterized in that, Determining the vertical depth of the horizontal section of the data horizontal well includes: If the target oil and gas-bearing formation contains a marker formation, then the horizontal well section of the data horizontal well will be deployed near the depth of the marker formation; If the target oil and gas formation does not contain a marker formation, the horizontal well section of the data horizontal well will be deployed near the top depth, bottom depth, or middle depth of the target oil and gas formation.

5. The method as described in claim 4, characterized in that, Deploying the horizontal well section of the data horizontal well at the top, bottom, or intermediate depth of the target oil and gas-bearing formation includes: If the depth difference between the top and bottom of the target formation is less than the preset thickness threshold m, the horizontal well section of the data horizontal well is deployed at the middle depth M of the target oil and gas-bearing formation; otherwise, the horizontal well section of the data horizontal well is deployed near the top depth or near the bottom depth. The m is determined according to the maximum detection range diameter of the logging-while-drilling instrument.

6. The method as described in claim 2, characterized in that, Also includes: The length of the deployed data horizontal well is less than or approximately equal to the length of the horizontal wells in the horizontal well cluster.

7. The method as described in claim 1, characterized in that, Drilling of the data horizontal well according to the deployed data horizontal well includes: Drill the straight or inclined pilot hole of the horizontal well described in the data, and complete the drilling after penetrating the target oil and gas formation, in order to help identify the top depth, bottom depth and thickness of the target oil and gas formation; The wellbore trajectory of the vertical section of the horizontal well is measured using a drilling directional measurement instrument, which guides the wellbore trajectory to drill along the designed path. The well inclination measurement error of the drilling directional measurement instrument is less than 0.1°, and the azimuth measurement error is less than 1°. The directional and horizontal sections of the data-supported horizontal wells were explored using a drilling-while-drilling directional measurement instrument and a drilling-while-drilling geological steering instrument. After the horizontal well is completed, the wellbore trajectory data and geological steering data are re-measured to determine whether the wellbore trajectory is in the predetermined position of the target oil and gas-bearing formation. After the data horizontal well is completed, the horizontal section of the data horizontal well shall be completed using open hole completion method, screen pipe completion method or non-magnetic casing completion method.

8. The method as described in claim 1, characterized in that, The method further includes: Using the wellbore trajectory of the first horizontal well as a reference horizontal well, during the process of sequentially guiding the drilling of other horizontal wells in the horizontal well cluster, if there is a large well spacing between the horizontal well to be drilled and the first horizontal well, or if there is a situation where a well has already been drilled between the two, then from all the drilled horizontal wells in the horizontal well cluster other than the first horizontal well, select the horizontal well closest to the horizontal well to be drilled as the reference well for the horizontal well to be drilled, and complete the drilling of the horizontal well to be drilled.

9. A horizontal well cluster, characterized in that, The horizontal well cluster is obtained by drilling a high-precision horizontal well cluster as described in any one of claims 1-8.

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