A method for controlling the trajectory of large-offset three-dimensional horizontal wells

Abstract

The present invention discloses a method for controlling the borehole trajectory of a large-offset three-dimensional horizontal well. The method simulates and calculates a series of key parameters, such as target vertical depth, target front distance, and offset distance, and divides the entire three-dimensional horizontal well into seven control sections. The key parameters are simulated and calculated using horizontal well calculation software. During the drilling process, drilling parameters are strengthened, and the stabilization section considers the natural stabilization and increase of well inclination characteristics of the formation. The twisting azimuth section should reasonably select a twisting azimuth method based on the well inclination. The final horizontal section controls the well inclination to 89-91 degrees using a fine-tuning method. The horizontal section inclination rate is between 0.1-0.3 degrees / 10m. When the estimated bottomhole inclination approaches 91 degrees, sliding deflection reduction control is performed to prevent drilling out of the oil layer due to well inclination changes. The method has a smooth borehole trajectory and low actual drilling friction and torque. It can achieve precise three-dimensional trajectory control and target entry, as well as safe and rapid drilling. It has strong adaptability to on-site large-offset three-dimensional horizontal wells and is valuable for promotion.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling engineering, and in particular relates to a method for controlling a wellbore trajectory of a large-offset three-dimensional horizontal well. Background Art

[0002] With the deepening of oil and gas field development, wellsite land acquisition and environmental approval are difficult and construction costs are high in the loess plateau topography. To fully utilize the wellsite, large-offset 3D horizontal well clusters are needed to reduce development costs. As a result, the number of large-offset 3D horizontal wells deployed has increased annually. Large-offset 3D horizontal wells are drilled at a given vertical depth, where the projections of the wellhead and horizontal section are not aligned, resulting in a certain offset. This leads to technical difficulties such as large offsets, high friction and torque during drilling, difficulty in trajectory control, and low drilling efficiency, requiring more sophisticated control technology. Current field construction of large-offset 3D horizontal wells, while based on the theoretical basis of 3D horizontal well profile optimization design methods, lacks a refined and systematic approach to trajectory control during field implementation.

[0003] The present invention starts from the aspects of three-dimensional trajectory design and process control, drill tool assembly, drilling parameters and new tool application. Through a series of technical measures such as optimizing trajectory design, refining process control, optimizing drill tool assembly, strengthening drilling parameters, and matching new tools, a high-quality, fast and accurate three-dimensional horizontal well actual drilling trajectory control method is formed. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling the borehole trajectory of a large-offset three-dimensional horizontal well. By starting from the aspects of trajectory design and process control, drill tool assembly, and drilling parameters, a series of technical measures such as optimizing trajectory design, refining process control, optimizing drill tool assembly, strengthening drilling parameters, and rationalizing the matching of new tools are formed to form a high-quality, fast, accurate, and safe three-dimensional horizontal well actual drilling trajectory control method.

[0005] The technical solution adopted by the present invention is: a method for controlling the wellbore trajectory of a large-offset three-dimensional horizontal well. The specific operating steps are as follows:

[0006] Step 1: Trajectory design: Based on a series of key data such as target vertical depth, target front distance, and offset distance, simulation calculations are performed to divide the entire 3D horizontal well into seven control well sections, forming a seven-section design and control model. The seven control well sections are, from top to bottom, the vertical well section, the inclination section, the inclination stabilization section, the azimuth twist section, the first inclination increase section, the second inclination increase section, and the horizontal section.

[0007] Step 2: Use horizontal well landmark calculation software to simulate and calculate the key parameters L1, K1, K2, and α, and control the slope increase rate of the entire well section to 4.5 degrees to 4.8 degrees / 30 meters. If the effective target front distance cannot meet the slope increase rate requirement, select an azimuth greater than or less than 90 degrees from the target azimuth to correct the deviation and extend the target front distance. Control the well inclination in the twisting section within 30 degrees. If the twisting section fails to complete the twisting, increase the inclination and twist the azimuth in the increasing section to complete it. The remaining azimuth in the increasing section must be less than 15 degrees from the target design azimuth.

[0008] Wherein, L1: length of vertical well section;

[0009] K1: build-up rate of the first increasing slope section;

[0010] K2: build rate of the second increasing slope section;

[0011] α: Correction well deviation, that is, the well deviation controlled by the correction section;

[0012] Step 3: During the drilling process, strengthen the drilling parameters, focusing on high bit weight, high displacement, and high rotation speed to maximize the efficiency of the equipment and power drilling tools; the inclination rate of the inclination section is controlled at 6.5 degrees / 30m; the well inclination of the inclination section is controlled to be 2-3 degrees less than the designed well inclination of the correction section;

[0013] Step 4: Considering the formation's characteristics of stable well inclination, the drill string enters the stable inclination section at a deviation 2-3 degrees less than the stable inclination section, minimizing slippage in this section and ensuring rapid drilling.

[0014] Step 5: The azimuth twisting method should be selected according to the well inclination. When the well inclination is greater than 12 degrees, in order to reduce the difficulty of twisting the azimuth during drilling, the well inclination must be reduced to within 12 degrees before twisting the azimuth. If the well inclination is within 12 degrees, the azimuth twisting can be carried out directly.

[0015] Step 6: During the first inclination increase section, the trajectory control should always ensure that the well inclination is 1 degree ahead of the design value, and 8-10 meters of composite footage should be reserved to prevent insufficient well inclination caused by the tool face not being in place during construction. The "sliding + composite" method should be used for adjustment to ensure a smooth wellbore.

[0016] Step 7: Pre-landing control essentials: After the well inclination reaches 60 degrees, the drill string naturally increases inclination by 0.7-1.0 degrees to reduce sliding footage. When the actual drilling trajectory deviates from the planned trajectory, the remaining well sections need to be redesigned. After the well inclination reaches 75 degrees, a well section with a smaller full-angle change rate is planned to reserve adjustment space to avoid trajectory errors caused by changes in the vertical depth of the target formation. The window entry posture adopts a small well inclination of 88-89 degrees and enters the window in the upper target area to lay the foundation for drilling the horizontal section.

[0017] Step 8: The horizontal section controls the well inclination to 89-91 degrees using fine-tuning. The horizontal section inclination rate is between 0.1-0.3 degrees / 10m. When the estimated bottom hole inclination approaches 91 degrees, sliding inclination reduction control is performed to prevent drilling out of the oil layer due to changes in well inclination.

[0018] The present invention is also characterized in that:

[0019] The drilling method for the vertical well section is composite drilling, with a drilling pressure of 80-140KN and a screw pressure difference of 3.5Mpa; the rotation speed is 90rpm and the displacement is 38-45L / s.

[0020] The drilling method for the deflection building, stabilization, azimuth twisting, first and second deflection increasing sections is sliding + combined drilling, with a weight on bit of 100-150 kN, a screw differential pressure of 2.0-3.0 MPa, a rotational speed of 70 rpm, and a displacement of 42-45 liters / second. The horizontal section is drilled using combined drilling, with a weight on bit of 60-80 kN, a screw differential pressure of 1.5-2.0 MPa, a rotational speed of 60 rpm, and a displacement of 30-34 liters / second.

[0021] The vertical well section, inclination section, inclination stabilization section, azimuth twist section, first inclination increase section, and second inclination increase section use drilling assembly A, while the horizontal section uses drilling assembly B.

[0022] Drilling tool assembly A: φ215.9mm Bit6 blade PDC + φ165mm 1.5-degree single-bend screw + MWD + Φ168mm NDC × 1 pc + Type II hydraulic oscillator + Φ127mm HWDp × 9 pcs + Φ127mm Dp + Φ127mm HWDp × 45 pcs + Φ127mm Dp;

[0023] Drilling tool assembly B: φ215.9mm Bit5 blade PDC + Φ172mm 1.25 degree single-bend screw (+Φ212mm ball support + MWD + Φ168mm NDC × 1 piece + Φ127mm HWDp × 9 pieces + Φ127mm Dp + Φ127mm HWDp × 45 pieces + Φ127mm Dp;

[0024] Step 1: The vertical depth of the target point refers to the vertical distance from the target point to the horizontal plane where the wellhead turntable surface is located, that is, the vertical depth of the target point; the target front distance refers to the distance between the first target point of the horizontal well and the plumb line of the wellhead; the offset distance refers to the vertical distance from the wellhead to the extension line of the horizontal section orientation when the line connecting the wellhead and the first target point is not on the same line as the horizontal section orientation.

[0025] Step 7: The build-up rate for the well section with the smallest full-angle change rate is 2-5 degrees / 30m.

[0026] The beneficial effects of the present invention are as follows: the present invention simulates and calculates key data such as target vertical depth, target front distance, and offset distance, and uses the "seven-segment system" to design the optimal three-dimensional horizontal wellbore profile. In combination with the currently mature drill tool assembly and hydraulic oscillator, the drilling parameters are strengthened and the trajectory process control is refined. The drilled wellbore trajectory is smooth, with low friction and torque, and can achieve precise target entry, safe and rapid drilling, strong field adaptability, and has promotional value. The present invention relates to a real-time drilling trajectory control method for large-offset three-dimensional horizontal wells used in the petroleum industry, and is suitable for the field of trajectory control in the drilling construction of three-dimensional horizontal wells in oil and gas fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a full-well trajectory simulation diagram in a large-offset three-dimensional horizontal wellbore trajectory control method of the present invention;

[0028] Figure 2 This is a schematic diagram of a large-offset three-dimensional horizontal well according to the present invention;

[0029] Figure 3 This is a horizontal projection diagram of the drilling trajectory of Well A1 in an embodiment of the present invention;

[0030] Figure 4 It is a horizontal projection diagram of the drilling trajectory of Well A2 in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] A method for controlling a large-offset three-dimensional horizontal wellbore trajectory of the present invention is specifically implemented according to the following steps:

[0032] Step 1: Trajectory design: Figure 2 As shown in the figure, based on a series of key data such as target vertical depth, target front distance and offset distance, simulation calculation is carried out to divide the entire well section of the 3D horizontal well into seven control well sections (such as Figure 1 As shown in the figure, a seven-section design pattern is formed; the seven control sections are vertical well section, deflection section, stable deflection section, azimuth twist section, first deflection increase section, second deflection increase section and horizontal section from top to bottom;

[0033] Step 2: Use horizontal well landmark calculation software to simulate and calculate the key parameters L1, K1, K2, and α, and control the full-well slope increase rate to 4.5-4.8 degrees / 30 meters. If the effective target front distance cannot meet the slope increase rate requirement, select an azimuth greater than or less than 90 degrees from the target azimuth to correct the deviation and extend the target front distance. Control the wellbore inclination within 30 degrees during the twisting section. If the twisting section fails to complete the twisting, complete it by increasing the inclination and twisting the azimuth in the increasing section. The remaining azimuth in the increasing section must be less than 15 degrees from the target design azimuth.

[0034] Wherein, L1: length of vertical well section;

[0035] K1: build-up rate of the first increasing slope section;

[0036] K2: build rate of the second increasing slope section;

[0037] α: Correction well deviation, that is, the well deviation controlled by the correction section;

[0038] Step 3: During the drilling process, strengthen the drilling parameters, focusing on high bit pressure, high displacement, and high rotation speed to maximize the efficiency of the equipment and power drilling tools; control the inclination rate of the inclination section at 6.5 degrees / 30m; and build the inclination to a level 2-3 degrees lower than the correction well deviation;

[0039] Step 4: Considering the formation's characteristics of stable well inclination, the drill string enters the stable inclination section at a deviation 2-3 degrees less than the stable inclination section, minimizing slippage in this section and ensuring rapid drilling.

[0040] Step 5: The azimuth twisting method should be selected according to the well inclination. If the well inclination is greater than 12 degrees, the well inclination must be lowered to within 12 degrees before the azimuth twisting is performed. If the well inclination is less than 12 degrees, the azimuth twisting can be performed directly.

[0041] Step 6: During the first inclination increase section, the trajectory control should always ensure that the well inclination is 1 degree ahead of the design value. 8-10 meters of composite footage should be reserved to prevent insufficient well inclination caused by the tool face not being in place during construction. A "sliding + composite" method should be used for adjustment to ensure a smooth wellbore.

[0042] Step 7: Pre-landing control essentials: After the well inclination reaches 60 degrees, the drill string naturally increases inclination by 0.7-1.0 degrees to reduce sliding footage. When the actual drilling trajectory deviates from the planned trajectory, the remaining well sections need to be redesigned. After the well inclination reaches 75 degrees, a well section with a smaller full-angle change rate is planned to reserve adjustment space to avoid trajectory errors caused by changes in the vertical depth of the target formation. The window entry posture adopts a small well inclination of 88-89 degrees and enters the window in the upper target area to lay the foundation for drilling the horizontal section.

[0043] Step 8: The horizontal section controls the well inclination to 89-91 degrees using fine-tuning. The horizontal section inclination rate is between 0.1-0.3 degrees / 10m. When the estimated bottom hole inclination approaches 91 degrees, sliding inclination reduction control is performed to prevent drilling out of the oil layer due to changes in well inclination.

[0044] The drilling method for the vertical well section is composite drilling, with a drilling pressure of 80-140KN and a screw pressure difference of 3.5Mpa; the rotation speed is 90rpm and the displacement is 38-45L / s.

[0045] The drilling mode of the inclination section, inclination stabilization section, azimuth twisting section, first inclination increase section and second inclination increase section is sliding + compound, the bit pressure is 100-150KN, the screw pressure difference is 2.0-3.0Mpa; the rotation speed is 70rpm, and the displacement is 42-45L / s.

[0046] The horizontal section drilling method is compound drilling, the bit pressure is 60-80KN, the screw pressure difference is 1.5-2.0Mpa; the rotation speed is 60rpm, and the displacement is 30-34L / s.

[0047] The vertical well section, inclination section, inclination stabilization section, azimuth twist section, first inclination increase section, and second inclination increase section use drilling assembly A, while the horizontal section uses drilling assembly B.

[0048] Drilling tool assembly A: φ215.9mm Bit6 blade PDC + φ165mm 1.5-degree single-bend screw + MWD + Φ168mm NDC × 1 pc + Type II hydraulic oscillator + Φ127mm HWDp × 9 pcs + Φ127mm Dp + Φ127mm HWDp × 45 pcs + Φ127mm Dp;

[0049] Drilling tool assembly B: φ215.9mm Bit5 blade PDC + Φ172mm 1.25 degree single-bend screw (+Φ212mm ball support + MWD + Φ168mm NDC × 1 piece + Φ127mm HWDp × 9 pieces + Φ127mm Dp + Φ127mm HWDp × 45 pieces + Φ127mm Dp;

[0050] Wherein, Bit stands for drill bit, MWD stands for measurement while drilling, NDC stands for non-magnetic drill collar, HWDp stands for heavy-weight drill pipe, and Dp stands for drill pipe.

[0051] Step 1: Target vertical depth: The vertical distance from the target to the horizontal plane where the wellhead turntable is located, that is, the target vertical depth; Target front distance refers to the distance between the first target point of the horizontal well and the plumb line of the wellhead; Offset distance: The vertical force from the wellhead to the horizontal section azimuth line is called the offset distance when the line connecting the wellhead and the first target point is not on the same line as the horizontal section azimuth.

[0052] Step 7: The build-up rate for the well section with the smallest full-angle change rate is 2-5 degrees / 30m.

[0053] To clearly compare the differences between trajectory control methods under different designs, we simulated the trajectory design and budget control methods for four wells. Using the same wellhead coordinates and vertical depth, we applied trajectory control methods at different target front distances and offsets. The following well examples used the same geographic information, with basic data shown in Table 1.

[0054] Table 1 Basic data table

[0055]

[0056]

[0057] 1. The offset distance is the same, but the target front distance is different;

[0058] Implementation well example 1

[0059] Table 2 A1 well trajectory node control data

[0060]

[0061] Implementation well example 2

[0062] Table 3 A2 well trajectory node control data

[0063]

[0064]

[0065] Based on the design data of Wells A1 and A2, the track design is optimized and the data of each node is finely controlled, as shown in Table 4 below.

[0066] Table 4 Trajectory control data of wells A1 and A2

[0067]

[0068] Analysis results, such as Figure 3 、 4 As shown:

[0069] 1. With the same offset distance, the target front distance in Well A2 was shortened by 152 meters. This reduction in target front distance reduced the entire controlled well section. Therefore, a correction azimuth of approximately 283.45 was selected, creating a negative correction displacement trend. This ensured that the full-angle change rates of K1 and K2 remained within a reasonable range in the later stages, as described in Steps 2 and 8 of the present invention.

[0070] 2. The node data show that with the reduction of the target front distance of Well A2 and the small difference in the twisting azimuth section, the twisting azimuth construction cannot be completed in the twisting azimuth section. In this case, the twisting azimuth construction is completed by increasing the well inclination in the increasing inclination section.

[0071] 3. The difference between the two wellbore trajectories can be clearly seen through the horizontal projection diagram. The optimized trajectory can ensure rapid increase in inclination in the key well section in the later stage and reduce sliding.

[0072] 4. At the end of the first inclination increase section, the two trajectories are designed to reach a well inclination of about 75 degrees. The second inclination increase section is planned to be a slight increase, and the composite inclination rate is basically 0.7-1.0 degrees, which is conducive to rapid drilling. This is referred to in step 7 of the present invention.

[0073] Table 5 B1 well trajectory node control data

[0074]

[0075] Implementation well example 4

[0076] Table 6 B2 well trajectory node control data

[0077]

[0078] Based on the design data of wells B1 and B2, the trajectory design is optimized and the data of each node is finely controlled, as shown in Table 4 below;

[0079] Table 7 Trajectory control data of wells B1 and B2

[0080]

[0081]

[0082] analyze:

[0083] 1. While the distance to the target is the same, the offset distance of Well B2 increases by 100 meters, making construction more difficult and requiring a larger well inclination to correct the deviation. After optimizing the design, the initial well inclination is controlled at 12-13 degrees for correction. Although a larger well inclination angle will correct the deviation faster, it will make it difficult to twist the azimuth. Selecting a reasonable angle can reduce the difficulty of twisting the azimuth and avoid large well inclinations that cause inefficient construction. This approach embodies step 5 of the present invention.

[0084] 2. The node data show that the target front distance is sufficient and the offset distance is increased. Therefore, the correction direction needs to be selected at 264 degrees, which is closer to the vertical angle of the target direction, to carry out the correction construction. The offset distance can be increased as much as possible within the limited well section.

[0085] 3. Node data indicates that the offset of Well B2 is too large. Azimuth twisting cannot be fully completed in the azimuth twisting section alone. This requires increasing the inclination and azimuth in the inclination-increasing section. This section is designed with a full-angle variation rate of 4.2 degrees / 30 meters, which easily enables increased inclination and azimuth twisting. This control strategy embodies Step 2 of the present invention.

[0086] 4. The horizontal projection shows the difference between the two well trajectories. The upper well section with large offset requires more work and is more difficult to construct.

[0087] 5. At the end of the first inclination increase section, the well inclination of the two trajectories is designed to reach about 75 degrees. The second inclination increase section is planned to be slightly increased, with a composite inclination rate of 0.7-1.0 degrees, which is conducive to rapid drilling. This is referred to as step 7 of the present invention.

Claims

1. A method for controlling the trajectory of a large-offset three-dimensional horizontal well, characterized in that: The specific steps are as follows: Step 1: Trajectory design: Based on a series of key data such as target vertical depth, target front distance, and offset distance, simulation calculations are performed to divide the entire 3D horizontal well into seven control well sections, forming a seven-segment design model. The seven control well sections are, from top to bottom, the vertical well section, the inclination building section, the inclination stabilization section, the azimuth twist section, the first inclination increase section, the second inclination increase section, and the horizontal section. Step 2: Use horizontal well landmark calculation software to simulate and calculate the key parameters L1, K1, K2, and α, and control the full-well slope increase rate to 4.5-4.8 degrees / 30m. If the effective target front distance cannot meet the slope increase rate requirement, select an azimuth greater than or less than 90 degrees from the target azimuth to correct the deviation and extend the target front distance. Control the wellbore inclination within 30 degrees during the twisting section. If the twisting section is not completed, complete it by increasing the inclination and twisting the azimuth in the first inclination increase section. The remaining azimuth in the first inclination increase section must be less than 15 degrees from the target design azimuth. Wherein, L1: length of vertical well section; K1: build-up rate of the first increasing slope section; K2: build rate of the second increasing slope section; α: Correction well deviation, that is, the well deviation controlled by the correction section; Step 3: During the drilling process, strengthen the drilling parameters and control the inclination rate of the inclination section at 6.5 degrees / 30m; build the inclination to 2-3 degrees less than the correction well inclination; Step 4: Considering the formation's characteristics of stable well inclination, the drill string enters the stable inclination section at a deviation 2-3 degrees less than the stable inclination section. This section reduces slippage and allows for faster drilling. Step 5: The azimuth twisting method should be selected according to the well inclination. If the well inclination is greater than 12 degrees, the well inclination must be lowered to within 12 degrees before the azimuth twisting is performed. If the well inclination is less than 12 degrees, the azimuth twisting can be performed directly. Step 6: During the first inclination increase section, the trajectory control should always ensure that the well inclination is 1 degree ahead of the design value. 8-10 meters of composite footage should be reserved to prevent insufficient well inclination caused by the tool face not being in place during construction. The "sliding + composite" method should be used for adjustment to ensure a smooth wellbore. Step 7: Control tips before landing: After the well inclination reaches 60 degrees, the drill tool's natural inclination rate is 0.7-1.0 degrees to reduce sliding footage. When the actual drilling trajectory deviates from the design, the remaining well sections need to be redesigned for drilling. After the well inclination reaches 75 degrees, a well section with a smaller full-angle change rate is planned to reserve an adjustment space to avoid trajectory passivity caused by changes in the vertical depth of the target layer. The window entry posture adopts a small well inclination of 88-89 degrees and enters the window in the upper target area. Step 8: The horizontal section controls the well inclination to 89-91 degrees using fine-tuning. The horizontal section inclination rate is between 0.1-0.3 degrees / 10m. When the estimated bottom hole inclination approaches 91 degrees, sliding inclination reduction control is performed to prevent drilling out of the oil layer due to changes in well inclination.

2. A method for controlling the trajectory of a large-offset three-dimensional horizontal well according to claim 1, characterized in that: The vertical well section is drilled using a composite drilling method with a drilling pressure of 80-140 KN and a screw pressure difference of 3.5 MPa; a rotation speed of 90 rpm and a displacement of 38-45 liters / second.

3. The method for controlling the trajectory of a large-offset three-dimensional horizontal well according to claim 1, wherein: The drilling mode of the deflection section, deflection stabilization section, azimuth twisting section, first deflection increasing section and second deflection increasing section is sliding + compound, the bit pressure is 100-150 KN, the screw pressure difference is 2.0-3.0 MPa; the rotation speed is 70 rpm, and the displacement is 42-45 liters / second.

4. The method for controlling the trajectory of a large-offset three-dimensional horizontal well according to claim 1, wherein: The horizontal section drilling method is compound drilling, with a bit pressure of 60-80 KN, a screw pressure difference of 1.5-2.0 MPa, a rotation speed of 60 rpm, and a displacement of 30-34 liters / second.

5. The method for controlling the trajectory of a large-offset three-dimensional horizontal well according to claim 1, wherein: The vertical well section, the inclination section, the inclination stabilization section, the azimuth twist section, the first inclination increase section, and the second inclination increase section use drilling tool assembly A, and the horizontal section uses drilling tool assembly B; Drilling tool assembly A: φ215.9mm Bit6 blade PDC + φ165mm 1.5-degree single-bend screw + MWD + Φ168mm NDC × 1 pc + Type II hydraulic oscillator + Φ127mm HWDp × 9 pcs + Φ127mm Dp + Φ127mm HWDp × 45 pcs + Φ127mm Dp; Drilling tool assembly B: φ215.9mm Bit5 blade PDC + Φ172mm 1.25 degree single-bend screw + Φ212mm ball support + MWD + Φ168mm NDC×1 piece + Φ127mm HWDp×9 pieces + Φ127mm Dp + Φ127mm HWDp×45 pieces + Φ127mm Dp.

6. The method for controlling the trajectory of a large-offset three-dimensional horizontal well according to claim 1, wherein: The target vertical depth in step 1 represents the vertical distance from the target to the horizontal plane where the wellhead turntable surface is located; the target front distance refers to the distance between the first target point in the horizontal well and the plumb line of the wellhead; the offset distance refers to the vertical distance from the wellhead to the extension line of the horizontal section azimuth when the line connecting the wellhead and the first target point is not aligned with the horizontal section azimuth.

7. The method for controlling the trajectory of a large-offset three-dimensional horizontal well according to claim 1, wherein: The inclination rate of the well section with the smaller full-angle change rate described in step 7 is 2-5 degrees / 30m.

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