A method for determining the trajectory of a multi-zone dense section horizontal well

Abstract

The present application belongs to the technical field of oil and gas reservoir exploration and development, and particularly relates to a method for determining the trajectory of a multi-oil-layer dense section horizontal well. After determining the landing point, build-up point and wellhead position of the horizontal well, a first geological target point is determined at a position with a set first geological target point front distance from the build-up point. The first geological target point is located on the bottom surface of the oil layer. A plurality of geological target points are then set, with the distance between two adjacent geological target points being a set multiple of the limit drainage radius. The two adjacent geological target points are located on the bottom surface of the oil layer and the top surface of the oil layer, respectively. Based on the build-up point, landing point, each geological target point and termination point, the trajectory of the horizontal well is determined. The present application takes into account the influence of reservoir properties on the drainage radius of the horizontal well, sets the distance between two adjacent geological target points as a set multiple of the limit drainage radius, and designs repeated crossing of multiple layers, thereby fully improving the drilling degree of the oil layer, increasing the contact area with the oil layer, and improving the degree of reservoir reserve production controlled by the horizontal well.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas reservoir exploration and development technology, specifically relating to a method for determining the trajectory of horizontal wells in densely packed sections with multiple oil layers. Background Technology

[0002] Currently, there are four common types of horizontal wells: 1) Horizontal wells travel within a single layer; 2) Horizontal wells descend from the top of an upper layer and traverse multiple layers; 3) Horizontal wells traverse multiple oil layers in a plane or longitudinal direction; 4) Stepped horizontal wells can ascend and descend on the vertical profile and traverse oil layers of different depths, or traverse oil layers in different directions within the same horizontal plane.

[0003] For example, Chinese invention patent application CN105093308A discloses a well trajectory design method and system. Specifically, it discloses the synthesis of a first synthetic seismic record based on the actual well logging curves of the reservoir, obtaining a well logging curve after fluid replacement based on the changes in reservoir characteristic parameters caused by fluid replacement, synthesizing a second synthetic seismic record based on the well logging curve after fluid replacement, obtaining the relationship between the seismic response characteristics of the reservoir and the changes in reservoir characteristic parameters based on the changes in the characteristics of the first and second synthetic seismic records, performing seismic comparison and tracking based on the actual seismic profile and the relationship between the seismic response characteristics and the changes in reservoir characteristic parameters, determining the vertical and horizontal distribution of oil and gas in the reservoir, and designing the well trajectory based on the vertical and horizontal distribution of oil and gas in the reservoir. For example, Chinese invention patent application CN112983275A discloses a method for controlling the geological steering trajectory of a horizontal section in a shale gas horizontal well with continuous undulations. This method involves setting marker points at the undulation changes at the top and bottom interfaces of the target layer, forming an optimal trajectory control path by combining the entry and exit points, and using corresponding formulas to obtain the well inclination angle required to reach the entry point and the well inclination angle required to reach the next point in each segment. This achieves geological steering trajectory control of the horizontal section of a continuous undulation reservoir. This invention specifically addresses the setting of marker points at undulation changes in continuous undulation reservoirs. For example, Chinese invention patent application CN112523744A discloses a method for well location design and real-time tracking guidance of horizontal wells in thin, poorly shaped formations. This method addresses the problem that existing methods for horizontal well deployment and guidance only address seismic and geological aspects and lack effective workflows. The specific steps include: S1, horizontal well deployment method: including optimal deployment; sand body characterization; simulation analysis; S2, horizontal well guidance method: including three stages: e (determining marker layers), f (determining the entry point), and g (horizontal section control), with different workflows defined; the horizontal section control includes three methods: three-dimensional model control, seismic reservoir prediction, and integrated control. Through comprehensive analysis of multiple methods, the horizontal well deployment and guidance process is streamlined and node-based, forming a complete horizontal well deployment and guidance method. This invention is specifically designed for thin, poorly shaped formations. For example, Chinese invention patent application CN109899054A discloses a method for determining drilling trajectory and a V-shaped well. The method for determining drilling trajectory includes: conducting a detailed reservoir geology study on the target reservoir to obtain the geological parameters of the target reservoir; determining the drilling trajectory based on the geological parameters, wherein the position of the entry point of the drilling trajectory is higher than the position of the exit point of the drilling trajectory, both the entry point and the exit point are located at the top of the target layer of the target reservoir, and at least two points of the drilling trajectory are located at the bottom of the target layer of the target reservoir.For example, application publication number CN102392601A discloses a method for determining the wellbore trajectory of a multi-target horizontal well. First, a reservoir planar structural map or contour map is drawn based on seismic data, geological logging data, and geophysical logging data to determine the distribution of reservoir sand bodies. Then, the displacement in front of the target is determined in combination with the wellbore size and drilling rig capacity. The wellhead coordinates, target coordinates, and target vertical depth are determined in combination with the field exploration results. The wellbore trajectory from the wellhead to the first target point is determined: the curvature of the horizontal section of the wellbore is determined based on the parameters of the first target point and the coordinates, vertical depth, and directional drilling capability of each control target point. The inclination angle of each control target point is determined, thereby determining the wellbore trajectory of the horizontal section. This invention is applicable to thin reservoirs with strong heterogeneity.

[0004] The above Chinese invention patent applications are only intended to ensure that the designed well trajectory can encounter oil and gas layers. However, they can only guarantee that the designed well will encounter oil layers but not that the well will produce high oil. This leads to the problem of low reserve utilization rate in the oil layer where the designed well trajectory is located. Summary of the Invention

[0005] The purpose of this invention is to provide a method for determining the trajectory of horizontal wells in densely packed multi-oil-layer sections, in order to solve the problem that existing methods for determining well trajectories result in low reserve utilization rates in the oil-bearing layers where the horizontal wells are located.

[0006] To address the aforementioned technical problems, this invention provides a method for determining the trajectory of a horizontal well in a densely packed section with multiple oil layers, comprising the following steps:

[0007] 1) Obtain reservoir profiles of the horizontal well trajectory region to be determined, based on the design well trajectory.

[0008] 2) Determine the landing point, build-up point, and wellhead location of the horizontal well on the reservoir profile map of the designed well trajectory; determine the ultimate drainage radius of the reservoir geology based on the empirical formula for the ultimate drainage radius of low-permeability oilfields;

[0009] 3) Determine the first geological target of the horizontal well at the position where the distance from the build-up point of the horizontal well is set to the target distance of the first geological target, and the first geological target is located on the bottom surface of the oil layer; set up multiple geological targets of the horizontal wells between the first geological target and the termination point of the horizontal well, and set the distance between the geological targets of each horizontal well to be a set multiple of the limit oil drainage radius, and set up the geological targets of two adjacent horizontal wells on the bottom surface and the top surface of the oil layer, respectively.

[0010] 4) Determine the trajectory of the horizontal well based on the build-up point, landing point, various geological target points, and termination point.

[0011] The beneficial effects are as follows: The method of this invention, by determining the first geological target point of the horizontal well at the bottom of the oil layer, ensures that the well trajectory of the horizontal well encounters multiple oil layers from the landing point to the first geological target point. Furthermore, by setting the geological target points of two adjacent horizontal wells at the bottom and top of the oil layer respectively, the well trajectory of the horizontal well also encounters multiple oil layers at adjacent geological target points. In other words, the method of determining the geological target point of the horizontal well in this invention aims to encounter multiple oil layers and drill through a group of layers multiple times, improving the control of the oil layer by a single well, thereby increasing the utilization of oil reserves, resulting in high production capacity and significantly saving drilling costs. Moreover, the horizontal well of this invention fully considers the influence of reservoir properties on the drainage radius, setting the distance between the geological target points of two adjacent horizontal wells as a predetermined multiple of the limit drainage radius, and designing repeated traversal of multiple layers to fully improve the degree of oil layer encounter, increase the contact area with the oil layer, and improve the utilization of reserves controlled by the horizontal well.

[0012] Furthermore, in step 3), when determining each geological target point, the inclination rate between two adjacent geological target points is calculated to ensure that each determined geological target point satisfies the condition that the inclination rate between two adjacent geological target points does not exceed the set inclination rate value.

[0013] Furthermore, in step 3), when determining the first geological target point, the inclination rate from the inclination point to the landing point and the inclination rate from the landing point to the first geological target point are calculated to ensure that the determined position of the first geological target point satisfies that the inclination rate from the landing point to the first geological target point does not exceed the set inclination rate value.

[0014] The build-up rate is a quantitative indicator that measures the build-up capability of a directional drilling tool. Numerically, it is equal to the curvature of the wellbore drilled using the tool, or the rate of change of wellbore inclination without altering the wellbore azimuth. The method of this invention, when determining various geological target points in a horizontal well, further calculates the build-up rate between two geological target points, as well as the build-up rate between the landing point and the first geological target point, ensuring that each determined geological target point meets the build-up rate requirements.

[0015] Furthermore, in step 3), if the inclination rate from the landing point to the first geological target exceeds the set inclination rate value, the inclination angle from the landing point to the first geological target is reduced by increasing the inclination angle from the landing point to the landing point, so that the inclination rate from the landing point to the first geological target does not exceed the set inclination rate value.

[0016] Further, in step 3), if the inclination rate between two adjacent geological target points exceeds the set inclination rate value, the bottom surface of the oil layer is redefined so that the distance between the bottom surface and the top surface of the oil layer is less than the distance between the bottom surfaces of the oil layer originally determined, or the set multiple is increased so that the inclination rate between two adjacent geological target points does not exceed the set inclination rate value.

[0017] The method of this invention, when determining the first geological target point, calculates the build-up rate from the landing point to the first geological target point. If the build-up rate does not meet the requirements, the location of the first geological target point that meets the build-up rate requirement is determined by reducing the build-up angle from the landing point to the first geological target point. When determining other geological targets, the method calculates the build-up rate of two adjacent geological targets. If the build-up rate of two adjacent geological targets does not meet the requirements, the method redetermines the bottom surface of the oil-bearing layer. This redetermines either reduces the distance between the bottom surface and the top surface of the oil-bearing layer or increases it by a predetermined factor, i.e., increases the horizontal spacing between two adjacent geological targets, to determine the location of each geological target point that meets the build-up rate requirement. In other words, when the build-up rate of the build-up section does not meet the requirements, the method of this invention appropriately reduces the true thickness of the designed oil-bearing formation or increases the horizontal target spacing until the build-up rate of the build-up section does not exceed the predetermined build-up rate value.

[0018] Furthermore, in step 3), the formula for calculating the slope is: Where, β ij S is the angle of inclination from position i to position j; ij R is the distance from position i to position j; R is the slope per 30m.

[0019] In the method of the present invention, the inclination rate of two adjacent geological target points is determined by using an inclination rate of 30m as a standard, thereby determining the location of each geological target point that meets the inclination rate requirement.

[0020] Furthermore, the empirical formula for the limiting drainage radius of the low-permeability oilfield is as follows: Where, r 极限 p is the limiting oil drain radius; e Formation pressure; p w ρ is the bottom-hole flowing pressure of the production well; k is the average air permeability; μ is the underground viscosity of crude oil.

[0021] Further, in step 4), the horizontal well trajectory is determined using well trajectory design software.

[0022] The method of the present invention, after determining each geological target point of the horizontal well, uses well trajectory design software to calculate and design the well trajectory of the entire well, and draws a reservoir profile diagram of the designed well trajectory, so as to calculate and design the well trajectory of the entire well through well trajectory design software.

[0023] Furthermore, in step 2), the method for determining the landing point is as follows: at a horizontal distance L from the fault... o The landing point was determined at a horizontal distance L. o The value range is 30-80m.

[0024] Furthermore, in step 2), the method for determining the inclination point is as follows: at a distance L in front of the target at the landing point... so The wellhead location is determined at the specified location, and the startup point is determined at a vertical depth equal to the set startup point depth from the wellhead; where L so The value range is 100-200m.

[0025] The method of the present invention determines the landing point, the start-up point, and the wellhead position of a horizontal well by first determining the landing point position based on the fault position, then determining the wellhead position based on the landing point position, and finally determining the start-up point position directly below the wellhead position. Attached Figure Description

[0026] Figure 1 This is a flowchart of the method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to the present invention;

[0027] Figure 2 This is a schematic diagram of the principle of the method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to the present invention;

[0028] Figure 3 This is a partially enlarged view illustrating the principle of the method for determining the trajectory of a horizontal well in a densely packed multi-oil-layer section according to the present invention.

[0029] Figure 4 This is an example diagram of the method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to the present invention;

[0030] Figure 5 This is a partially enlarged view of an example of the method for determining the trajectory of a horizontal well in a densely packed multi-oil-layer section according to the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] Example of a method for determining the trajectory of horizontal wells in densely packed oil-bearing sections:

[0033] The flowchart of the method for determining the trajectory of a horizontal well in a densely packed multi-oil-layer section in this embodiment is as follows: Figure 1 As shown, the principle is as follows Figure 2 , Figure 3 As shown, this method determines the coordinates and relative positions of the target points S, O, A, B, C, and D, thereby enabling multiple upward or downward penetrations of the same oil layer, improving the single well's control over the oil layer's reserves, and achieving high production from a single well.

[0034] The principle of the multi-oil-layer dense section horizontal well trajectory determination method of the present invention is as follows: from the wellhead to target point A, it is equivalent to a deviated well passing downward through a group of oil layers; from target point A to target point B, it is equivalent to a deviated well passing upward through the same group; from target point B to target point C, it is equivalent to a deviated well passing downward through the same group of oil layers; and from target point C to target point D, it is equivalent to a deviated well passing upward through the same group. That is, multiple downward and upward passes through the same group of oil layers are equivalent to multiple wells only having footage in the oil-layer section, thereby reducing the footage above the oil layer to the surface. The oil well productivity is equivalent to one vertical well for each group of oil layers passed through, and the productivity of 4 targets for this well is equivalent to the productivity of 4 vertical wells.

[0035] The method for determining the trajectory of horizontal wells in densely packed multi-oil-layer sections in this embodiment, for oil and gas well design, adopts the following steps:

[0036] The trajectory of the target well must be designed to be parallel to the current minimum principal stress of the structural level, or at a 45-degree angle to the current minimum principal stress of the structural level, avoiding a 90-degree angle. This will maximize the conductivity of the fracturing fractures and improve the oil production capacity of a single well.

[0037] 1) On the reservoir profile map of the designed well trajectory, first determine the O target (i.e., the landing point of the horizontal well). The method for determining the O target is the horizontal distance L from the fault. o Horizontal distance L o The distance from the fault is generally 30-80m; in this example, it is 82m, with a vertical depth of h. o The target well trajectory O requires drilling to reach a depth of 2967.6m at the top of the oil layer.

[0038] 2) On the reservoir profile map following the designed well trajectory, determine the position of the wellhead on the profile based on the target O determined in step 1), with the distance L in front of the target. so Target distance L so The horizontal distance from the wellhead to the start-up point S is generally 100-200m; in this example, it is taken as 143.2m. The position of the wellhead on the profile is determined, with a vertical depth of h. s The designed well trajectory has a vertical depth of 2600m for the wellhead.

[0039] 3) On the reservoir profile map along the designed well trajectory, based on the positions of the O-target and the build-up point S determined in steps 1) and 2), calculate the build-up rate from the build-up point S to the O-target: Ensure that the inclination rate of each 30m inclination section does not exceed ±5°, and is generally controlled within ±4°;

[0040] The slope rate calculation formula is used in this embodiment:

[0041] Where β ij S is the angle of inclination from point i to point j, in degrees. ij The distance from point i to point j is in meters.

[0042] 4) Determine the horizontal target spacing, which is based on the empirical formula for the limiting drainage radius of low-permeability oilfields:

[0043]

[0044] In this embodiment, the target spacing is determined to be twice the r-limited oil drain radius, i.e., the target spacing is 200m.

[0045] r 极限 p is the limiting oil drain radius, in meters. e The formation pressure is 49.0 MPa in this embodiment; p w The bottom-hole flowing pressure of the production well is 39.0 MPa in this embodiment; k is the average air permeability, which is 2.3 mD in this embodiment; μ is the underground viscosity of crude oil, which is 0.348 mPa·s in this embodiment.

[0046] 5) Determine the locations of geological target points A, B, C, and D.

[0047] In this embodiment, the location of geological target points A, B, C, and D is determined as an example. Specifically, target A (i.e., the first geological target point) is designed to be located at the bottom of a group of oil layers encountered during drilling, target B is designed to be located at the top of the same group of oil layers encountered during drilling, target C is located at the bottom of the same group of oil layers encountered during drilling, target D is designed to be located at the top of the same group of oil layers encountered during drilling, and so on for subsequent points.

[0048] When determining each geological target point, it is essential to ensure that the build-up rate between any two adjacent targets does not exceed a predetermined build-up rate value, and that the build-up rate from the landing point to the first geological target point does not exceed a predetermined build-up rate value. Therefore, when determining each geological target point, the build-up rate R per 30m is calculated to ensure that each geological target point meets the requirements. The formulas for calculating the build-up rate of geological targets A, B, C, and D are as follows:

[0049]

[0050] L ij The horizontal target spacing from target point i to target point j is 200m in this embodiment; h is the designed true thickness of the oil-bearing formation, which is 26.5m in this embodiment; α is the formation dip angle, which is 23° in this embodiment; i and j refer to target points A, B, C, and D, respectively. The build-up rate is a quantitative indicator measuring the build-up capability of a directional drilling tool. Numerically, it is equal to the curvature of the wellbore drilled using the directional drilling tool, or equal to the rate of change of wellbore inclination without changing the wellbore azimuth angle. When determining the geological target points of a horizontal well, the build-up rate between two geological target points and the build-up rate between the landing point and the first geological target point are also calculated to ensure that each determined geological target point meets the build-up rate requirements.

[0051] 5.1) Determine the inclination rate from target O to target A:

[0052]

[0053] Since the calculated build-up rate from target O to target A is already greater than the set build-up rate value in this embodiment (the result is not within ±4°), the build-up rate from point S to target O is increased to reduce the build-up rate from target O to target A. Based on this process, the build-up rate from target O to target A is re-estimated:

[0054]

[0055] Recalculate the inclination rate from inclination point S to target O:

[0056]

[0057] To ensure that the inclination rate of each 30m incline section does not exceed ±4°, the horizontal distance of target A from point S is determined to be 300m, and the vertical depth is 3084m.

[0058] 5.2) Determine the inclination rate from target A to target B:

[0059] Ensure that the inclination rate of each 30m inclination section does not exceed ±4°, and determine that the horizontal distance from the B target coordinate to the S point is 500m and the vertical depth is 3156m.

[0060] 5.3) Determine the inclination rate from target B to target C:

[0061] Ensure that the inclination rate of each 30m inclination section does not exceed ±4°, and determine that the horizontal distance from the C target coordinate to the S point is 700m and the vertical depth is 3284m.

[0062] 5.4) Determine the inclination rate from target C to target D:

[0063] Ensure that the inclination rate of each 30m incline section does not exceed ±4°, and determine that the horizontal distance from the D target coordinate to the S point is 900m and the vertical depth is 3353m.

[0064] If the calculated build-up rate of each 30m section exceeds ±4° (i.e. the result is not within -4° to 4°), then the true thickness h of the designed oil-bearing formation can be appropriately reduced, or the horizontal target spacing can be increased, until the build-up rate of each 30m section does not exceed ±4°.

[0065] 6) The determined build-up locations, including point S, target O, target A, target B, target C, and target D, are used to calculate and design the entire well trajectory using well trajectory design software. This involves applying the well trajectory design software to calculate and design the entire well trajectory and drawing a reservoir profile diagram based on the designed well trajectory, as shown below. Figure 4 , Figure 5 As shown.

[0066] The results of the well trajectory design software are shown in the following tables, where Table 1 contains the corresponding data of the well trajectory design table, Table 2 contains the trajectory parameters, and Table 3 contains the data of each point of the trajectory:

[0067] Table 1 Trajectory Design Table

[0068]

[0069] Table 2 Trajectory Parameters

[0070]

[0071]

[0072] Table 3 Data for each point on the trajectory

[0073]

[0074] This embodiment's method, by determining the first geological target point of the horizontal well at the bottom of the oil layer, ensures that the well trajectory from the landing point to the first geological target point encounters multiple oil layers. Furthermore, by setting the geological target points of two adjacent horizontal wells at the bottom and top of the oil layer respectively, the well trajectory at two adjacent geological target points also encounters multiple oil layers. In short, this embodiment's method for determining the geological target point of a horizontal well aims to encounter multiple oil layers and drill through a group of layers multiple times, improving the control of the oil layer by a single well, thereby increasing the utilization of oil reserves, resulting in high production capacity and significant savings in drilling costs. Moreover, this embodiment fully considers the influence of reservoir properties on the drainage radius, setting the distance between the geological target points of two adjacent horizontal wells as a predetermined multiple of the limit drainage radius, and designing repeated traversal of multiple layers to fully improve the degree of oil layer encounter, increase the contact area with the oil layer, and enhance the utilization of reserves controlled by the horizontal well.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A method for determining the trajectory of a horizontal well in a densely packed section with multiple oil layers, characterized in that, Includes the following steps: 1) Obtain reservoir profiles of the horizontal well trajectory region to be determined, based on the design well trajectory. 2) On the reservoir profile map of the designed well trajectory, first at a horizontal distance from the fault... Determine the landing point of the horizontal well; then, at a distance of [missing information] from the target at the landing point. The location of the wellhead was determined, among which The value range is 100-200m; then, the drilling point is determined at a vertical depth of the set drilling point from the wellhead; the limit drainage radius of the reservoir is determined according to the empirical formula of the limit drainage radius of low-permeability oilfields. 3) Determine the first geological target of the horizontal well at a position where the distance from the build-up point of the horizontal well is set to the target distance of the first geological target, and the first geological target is located on the bottom surface of the oil layer; set up multiple geological targets of the horizontal wells between the first geological target and the termination point of the horizontal well, and the horizontal distance between the geological targets of each horizontal well is the limit drainage radius of a set multiple. The geological targets of any two adjacent horizontal wells are located on the bottom surface and the top surface of the oil layer, respectively, and each geological target satisfies the condition that the build-up rate between two adjacent geological targets does not exceed the set build-up rate value, and the build-up rate from the landing point to the first geological target does not exceed the set build-up rate value; 4) Determine the trajectory of the horizontal well based on the build-up point, landing point, various geological target points, and termination point.

2. The method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to claim 1, characterized in that, In step 3), when determining the first geological target point, the inclination rate from the inclination point to the landing point is also calculated to ensure that the inclination rate from the inclination point to the landing point does not exceed the set inclination rate value.

3. The method for determining the trajectory of a horizontal well in a densely packed section with multiple oil layers according to claim 2, characterized in that, The set slope ratio is 4º / 30m.

4. The method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to any one of claims 1-3, characterized in that, In step 3), if the inclination rate from the landing point to the first geological target exceeds the set inclination rate value, the inclination angle from the landing point to the landing point is increased and the inclination angle from the landing point to the first geological target is decreased so that the inclination rate from the landing point to the first geological target does not exceed the set inclination rate value.

5. The method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to any one of claims 1-3, characterized in that, In step 3), if the build-up rate between two adjacent geological target points exceeds the set build-up rate value, the bottom surface of the oil layer is redefined so that the distance between the bottom surface and the top surface of the oil layer is less than the distance between the bottom surfaces of the oil layer originally determined, or the set multiple is increased so that the build-up rate between two adjacent geological target points does not exceed the set build-up rate value.

6. The method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to any one of claims 1-3, characterized in that, In step 3), the formula for calculating the slope is: ,in, Create a slant angle from position i to position j; R is the distance from position i to position j; R is the slope per 30m.

7. The method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to claim 1, characterized in that, The empirical formula for the limiting drainage radius of low-permeability oilfields is: ,in, This is the limit of the oil drain radius; Formation pressure; For the bottom flow pressure of the production well; denoted as average air permeability; μ represents the underground viscosity of crude oil.

8. The method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to claim 1, characterized in that, In step 4), the horizontal well trajectory is determined using well trajectory design software.

9. The method for determining the trajectory of a horizontal well in a densely packed section of multiple oil layers according to claim 1, characterized in that, The set slope ratio is 5º / 30m.

10. The method for determining the trajectory of a horizontal well in a densely packed multi-oil-layer section according to claim 1, characterized in that, The set multiplier is 2.

Images