Directional drilling crossing construction process for inclined shaft

Abstract

The invention relates to an inclined shaft directional drilling crossing construction technology, and belongs to the technical field of horizontal directional drilling construction. The method specifically comprises the steps of construction preparation before drilling; the directional drilling machine conducts guide hole drilling along the designed traverse drilling track curve, and drilling fluid mixed by water and sodium dodecyl benzene sulfonate is pumped in in the drilling process; after the guide hole drilling procedure is completed, the hole reaming procedure and the hole cleaning procedure are alternately constructed, and drilling fluid formed by mixing water and sodium dodecyl benzene sulfonate is pumped in the hole reaming and hole cleaning procedures; and pipeline section connection pipe installation is conducted according to a hole track formed by the designed penetrating drilling track curve. The method aims at solving the two construction problems of inclined shaft directional drilling crossing construction precision and bentonite slurry treatment, achieving the purposes of precisely controlling unearthed point deviation and not needing to transfer and treat slurry, greatly improving the construction efficiency and reducing the construction cost.

Description

Technical Field

[0001] This invention relates to a directional drilling construction process for inclined wells, belonging to the field of horizontal directional drilling construction technology. Background Technology

[0002] Common drilling methods in the drilling industry include reverse drilling and directional drilling. Reverse drilling involves drilling the drill bit backwards from the wellhead. It begins with drilling a small-diameter borehole at the wellhead, then uses drilling rigs and drill bits to drill backwards into the target formation, followed by logging and borehole wall preparation. Directional drilling, on the other hand, involves drilling the drill bit into a specific underground location. directional drilling uses exploration techniques and tools to control the drill bit at a specific direction and angle, ensuring precise penetration into the target formation. Enlargement in directional drilling is a technique that uses rotating and advancing the drill bit to complete trenchless underground engineering projects. Directional drilling reaming is primarily used in construction engineering, bridges and tunnels, underground pipelines, and geological exploration.

[0003] In the prior art, Chinese invention patent application number 202311308168.4 discloses a secondary well construction method based on reverse drilling technology. This method involves using a directional drilling rig to drill a directional drill bit. After completing the directional borehole construction, the directional drill rod and rig are withdrawn, the deviation of the directional borehole is measured, and a reverse drilling rig is installed. A small reverse drill rod and a reaming bit are connected, and the reaming bit is drilled along the directional borehole to perform secondary reaming, forming a pilot hole. Next, the reaming bit is replaced with a small reverse drill bit, and the small reverse drill rod is withdrawn, driving the small reverse drill bit to excavate along the pilot hole direction to form a pilot well. The small reverse drill rod and drill bit are removed, and a large reverse drill rod is lowered into the pilot well from top to bottom along the vertical / inclined well design direction. The large reverse drill bit is horizontally connected, and the reverse drilling rig drives the drill bit to excavate the well along the pilot well direction. The second enlargement technique, which involves drilling a pilot well using the first reverse drilling rig, effectively eliminates the impact of directional borehole deviation on well completion.

[0004] Because inclined shaft crossings only have a build-up section, the large deviation at the soil exit point during the single-stage directional drilling process makes subsequent hole repair difficult, resulting in an unadjustable deviation in the overall pipeline. This increases the difficulty of connecting to the main pipeline, extends construction time, and raises construction costs. For large-angle inclined shaft horizontal directional drilling crossings, boron-based bentonite mud is used as the drilling fluid throughout the entire process of guidance, hole enlargement, and hole cleaning. During construction, each single inclined shaft directional drilling crossing project requires the excavation of at least one mud storage pit and one mud diversion pit, increasing the work area. The bentonite mud required for inclined shaft directional drilling crossings contains chemical agents such as caustic soda, lye, polyaluminum chloride, and polyacrylamide. Under the influence of scouring and gravity, it is highly susceptible to leakage and seepage into the surrounding soil layers, causing a certain impact on the ecological environment. The mud transportation during construction and the disposal of waste mud after construction also require considerable time and cost. Summary of the Invention

[0005] This invention provides a high-precision bentonite-free directional drilling construction process suitable for large-angle inclined shaft crossings. Its purpose is to solve two major construction problems: the accuracy of inclined shaft directional drilling and the treatment of bentonite mud. It achieves precise control of the soil exit point deviation and eliminates the need for mud transportation and treatment, thereby significantly improving construction efficiency and reducing construction costs.

[0006] To achieve the above objectives, the present invention provides a deviated well directional drilling construction process, specifically including:

[0007] S1, Construction preparation before drilling;

[0008] S2, the directional drilling rig drills the pilot hole along the designed borehole trajectory curve, and pumps in a drilling fluid mixed with water and sodium dodecylbenzene sulfonate during the drilling process;

[0009] S3, after the pilot hole drilling process is completed, the hole enlargement and hole cleaning processes are carried out alternately. During the hole enlargement and hole cleaning processes, a drilling fluid mixed with water and sodium dodecylbenzene sulfonate is pumped in.

[0010] S4, install and connect pipe sections according to the hole trajectory formed by the design through the borehole trajectory curve.

[0011] Furthermore, the pre-drilling construction preparation includes surveying and setting out, site layout, drilling platform fabrication, and drilling rig installation and commissioning.

[0012] Furthermore, the surveying and setting out specifically involves first establishing a horizontal control network and an elevation control network, and then using surveying instruments to conduct surveying and setting out based on the route plan, cross-section diagram, control stakes, crossing stakes, and leveling stakes.

[0013] Furthermore, the surveying and setting out includes re-measuring the crossing length based on the crossing stakes, control stakes, and leveling stakes; setting out the drilling rig axis based on the control stakes and crossing stakes; setting up additional stakes on the crossing axis; setting out the boundary lines of the pipeline construction work zone and the drilling rig construction work zone according to the site layout plan; after the construction site is leveled, the positions of the exit point and the entry point should be measured and determined, with the allowable deviation of the elevation of the exit point and the entry point being within ±50mm, and the allowable deviation of the planar position of the exit point and the entry point being within ±50mm.

[0014] Furthermore, the site layout specifically includes setting up a topsoil storage area, a native soil storage area, a drainage ditch, a control room, a power supply area, a drill rod placement area, a drilling rig placement area, and an accessory and drill bit placement area within the site area. A rectangular working pit with the same design angle as the crossing needs to be excavated at the top of the site slope. The directional drilling rig and the center line of the working pit are on the same straight line. Then, according to the terrain and the designed entry angle, the drilling rig is installed and debugged to ensure that the center line of the drill rod is concentric with the axis of the inclined shaft crossing and to ensure the entry angle. An operating pit needs to be excavated at the exit point, and the exit end of the directional drilling crossing is located in the operating pit.

[0015] Furthermore, the drilling platform is specifically constructed by filling and compacting soil to create a drilling rig positioning platform that conforms to the drilling angle. The drilling positioning platform is trapezoidal in shape, and the top of the drilling rig positioning platform adopts a sloping design with a slope angle not exceeding 5°.

[0016] Furthermore, the directional drilling rig drills the guide hole along the designed cross-hole trajectory curve. Specifically, before drilling begins, geological data is carefully analyzed to determine the directional control scheme. The directional control equipment uses a gyroscope guidance system. Based on the soil entry angle of the directional drilling rig's crossing section, the directional drilling line adopts a curved shape, running from the soil entry point along the curve to the soil exit point. During drilling, the directional drilling rig collects directional control data at least once for each drill rod drilled, and adjusts the deviation between the actual guide hole curve and the designed cross-hole curve in a timely manner based on the collected directional control data. The deviation should not exceed 1%, and the lateral deviation of the guide hole exit point should be within ±3m, the allowable elevation deviation should be between -2m and +1m, and the longitudinal deviation should be between -3m and +9m.

[0017] Furthermore, the hole enlargement and hole cleaning process is carried out in a graded, multiple-stage enlargement manner, with hole cleaning performed after each stage of enlargement.

[0018] Furthermore, the first stage of hole reaming uses a rotary hole reamer, while the remaining stages of hole reaming all use barrel-type hole reamers for hole washing.

[0019] Furthermore, the weight ratio of water to sodium dodecylbenzenesulfonate in the drilling fluid is 3000:1.

[0020] Furthermore, the sectioned installation of the pipeline according to the borehole trajectory formed by the design through the borehole trajectory curve specifically involves welding adjacent steel pipes end to end and then using hoisting equipment to lift the sections of pipe along the guide hole.

[0021] This invention discloses a directional drilling construction process for inclined wells. Its advantages are as follows: compared to existing technologies, by utilizing a gyroscope guidance system, the directional drilling rig collects directional control data at least once for each drill rod drilled, and corrects deviations in real time during the process. This improves the accuracy of the soil exit point of the inclined well guide hole, ensuring successful construction of the guide hole in one go and saving construction time. Furthermore, during drilling, reaming, and cleaning, a drilling fluid mixture of water and sodium dodecylbenzene sulfonate is pumped in to replace bentonite mud, eliminating the need for mud transport, sand removal, and post-treatment processes. This saves costs while eliminating environmental risks and significantly reducing project costs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of the directional drilling construction process for inclined shafts in Embodiment 1 of the present invention;

[0024] Figure 2 This is a schematic diagram of the drilling process in Embodiment 1 of the present invention;

[0025] Figure 3 This is a schematic diagram of the first steel pipe being lowered in Embodiment 1 of the present invention;

[0026] Figure 4 This is a schematic diagram showing the completed installation of pipe sections in Embodiment 1 of the present invention;

[0027] Figure 5 This is a schematic diagram of the site layout in Embodiment 1 of the present invention;

[0028] Figure 6 This is a schematic diagram of the welding of adjacent steel pipe groups in Embodiment 1 of the present invention.

[0029] The diagram shows: 1. Directional drilling rig; 2. Drilling rig positioning platform; 3. Designed drilling trajectory; 4. Ground surface; 5. First steel pipe; 6. Pipe laying machine; 7. Crane. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] To further understand the invention, the technical solution will be further described below in conjunction with specific embodiments.

[0032] Example 1: As Figures 1-6 As shown, this embodiment provides a directional drilling construction process for inclined shafts. Taking the construction of an inclined shaft and pipeline installation project as an example, the inclination angle of this inclined shaft is within 30°, specifically including:

[0033] S1, Pre-drilling construction preparation; the pre-drilling construction preparation includes surveying and setting out, site layout, drilling platform fabrication, and drilling rig installation and commissioning.

[0034] The surveying and setting out process includes re-measurement by surveyors after stake assignment, verification of ground elevation at entry and exit points, and verification of design handover reference points and leveling points. A horizontal control network and an elevation control network are established, and surveying and setting out are conducted based on the route plan, cross-section diagrams, control stakes, crossing stakes, and leveling stakes.

[0035] The main contents of the measurement include length re-measurement, placement of additional stakes along the axis, establishment of work zone boundary lines, protection of crossing stakes, and detection of underground obstacles. Specifically, the crossing length is re-measured based on the crossing stakes, control stakes, and leveling stakes to ensure it conforms to the length given in the design drawings. If not, timely coordination is carried out. The drilling rig axis is laid out based on the control stakes and crossing stakes, and additional stakes are set on the crossing axis, with 3 to 5 additional stakes set on one side of the directional drilling rig 1. The drilling rig axis serves as the drilling rig positioning baseline, and the crossing axis represents the designed crossing borehole trajectory curve to be drilled by the drilling rig. The boundary lines of the pipeline construction work zone and the drilling rig construction work zone are laid out based on the site layout plan. The crossing control stakes and leveling stakes are protected. After the construction site is leveled, the locations of the exit and entry points should be measured and determined. The accuracy of these measurements should comply with the relevant provisions of the design documents and the "Engineering Surveying Standard" GB50026-2020. The allowable deviation of the elevation of the exit and entry points is within ±50mm, and the allowable deviation of the planar position of the exit and entry points is also within ±50mm. At the same time, the calibration locations for the wired control direction should be measured according to the control direction requirements of the guide hole, and relevant measurement records should be kept.

[0036] The site layout is as follows: Figure 5 The construction site area is divided into topsoil storage area, original soil storage area, drainage ditch, control room, power supply area, drill rod storage area, drilling rig storage area, and accessory and drill bit storage area. The specific placement locations can be adjusted according to the actual site conditions. A rectangular working pit with the same design angle as the crossing needs to be excavated at the top of the slope. The directional drilling rig 1 and the center line of the working pit are on the same straight line. Then, according to the terrain and the designed entry angle, the directional drilling rig 1 is installed and debugged to ensure that the center line of the drill rod is concentric with the axis of the inclined shaft crossing and to ensure the entry angle. An operating pit needs to be excavated at the soil exit point, and the soil exit end of the directional drilling crossing is located in the operating pit.

[0037] The drilling platform is constructed by backfilling and compacting soil on the ground surface 4 to create a platform that conforms to the drilling angle. The platform is trapezoidal in shape, with a base area of ​​5m × 10m and a top area of ​​3m × 7m. The slope angle is similar to the drilling angle, and the top of the platform is designed with a slope angle not exceeding 5°. The drilling platform is covered with waterproof tarpaulin.

[0038] The drilling rig installation and commissioning process involves first installing a detector inside the anti-magnetic drill rod before the equipment arrives on site, and then using an excavator to measure the directional control parameters. This is done by taking at least 10 measurements along the centerline on both sides of the entry and exit points and averaging them to determine the initial directional control parameters. Then, the detector is removed, and the directional control parameters are measured using only the detector. The average value is then compared with the previous average. If the difference is small, the average value can be used to obtain the actual directional control parameters; if the difference is large, the measurements must be repeated. After obtaining the optimal directional control parameters through actual measurement, the original records are made.

[0039] Debug and test the drilling fluid mixing system, check if it is working properly, and inspect all connecting pipelines for drilling fluid leaks. Identify and resolve any problems. The drilling fluid is a mixture of water and sodium dodecylbenzenesulfonate at a weight ratio of 3000:1. Check and test the mud pump to ensure it is working properly and that the mud pump pressure gauge is functioning correctly. Check that all connecting pipelines and joints of the directional drilling rig 1 are securely connected.

[0040] S2, the directional drilling rig 1 drills the pilot hole along the designed traversal borehole trajectory 3 curve. During the drilling process, a drilling fluid mixed with water and sodium dodecylbenzene sulfonate is pumped in. Specifically, in this embodiment, the lithology of the traversed strata by the directional drilling rig 1 is mainly loess. According to the entry angle of the directional drilling rig 1 through the traversed section, the track shape of the pilot hole of the directional drilling rig 1 adopts an approximately straight line, which can be understood as a curve. From the entry point to the exit point along an approximately straight line, or in other words, from the entry point to the exit point along the trajectory line. Drilling was carried out using milled tooth roller cone drill bits, 1.5° skew section, non-magnetic drill collars, and drill rods. To prevent deviation between the pilot hole and the designed crossing curve during drilling, geological data was carefully analyzed before drilling began to determine the directional control scheme. The directional control equipment adopted a gyroscope guidance system, and directional control data was collected at least once after each drill rod was drilled. Based on the collected directional control data, the deviation between the actual pilot hole curve and the designed crossing curve was adjusted in a timely manner. The deviation should not exceed 1%, and the lateral deviation of the pilot hole exit point should be within ±3m, the allowable elevation deviation should be between -2m and +1m, and the longitudinal deviation should be between -3m and +9m. During drilling, the drilling fluid discharge rate was controlled at 0.4m³ / min. 3 / min or less.

[0041] S3. After the pilot hole drilling is completed, the reaming and cleaning processes are carried out. During the reaming and cleaning processes, a drilling fluid mixture of water and sodium dodecylbenzene sulfonate is pumped in. Specifically, after the pilot hole is completed, a short-circuit slurry is used to pull back and flush the hole once, while the control line is extracted. The reaming is carried out in stages and multiple times. In this embodiment, it is divided into five stages of reaming: the first stage, the second stage, the third stage, the fourth stage, and the fifth stage. The first stage of reaming uses a flying rotary reamer in reverse to reduce the risk of stuck pipe. The remaining stages all use barrel reamers. The reaming levels use the following diameters: 700mm, 1000mm, 1300mm, 1600mm, and 1800mm. If the formation conditions and auxiliary equipment allow, the number of reaming stages can be reduced. After each stage of reaming is completed, the hole is cleaned. After the hole is cleaned, reaming continues until the diameter of the reamed hole meets the construction requirements. The purpose of reaming is to facilitate the smooth pullback of the pipeline; therefore, the reaming diameter needs to be determined according to the specifications of the pipeline under construction. In this embodiment, the diameter after reaming reaches 1.5 times the diameter of the main pipeline. A barrel-type reamer is used in the hole cleaning process. This mixed drilling fluid replaces bentonite mud in the drilling and reaming processes of the directional drilling rig 1, and is pumped into the drilling rig and drill rod system by the mud pump. During the drilling and reaming process, it is sprayed into the underground borehole through the drill bit and reamer orifice, cooling and lubricating the drilling tools and scouring the formation. In the hole cleaning process, after the mixed drilling fluid is mixed with silty clay, loess, etc. in the formation, it is squeezed by the rotation of the barrel-type reamer, which also helps to solidify the wall. This solves the problems of the environmental unfriendliness and high subsequent treatment costs of boronite mud.

[0042] S4, based on the borehole trajectory formed by the borehole trajectory curve 3, the pipeline is installed in sections. Specifically, adjacent steel pipes are welded together end to end, and then the sections are hoisted down along the guide hole using hoisting equipment. For example... Figure 6 As shown, a conical end cap is welded to the front end of the first steel pipe 5, and lifting lugs are welded to both ends of the conical end cap. U-shaped rings are used to connect the lifting lugs to the wire rope. Two pipe-laying machines 6 are each connected to a wire rope to control the speed and position of the pipe's descent. Before sliding the pipe, shackles, wire ropes, and other components are first connected to the front end of the first steel pipe 5. The pipe-laying machine 6 and crane 7 are used to send the first steel pipe 5 into the inclined shaft opening. Then, the pipe-laying machine 6, crane 7, and excavator work together to allow the steel pipe to slowly descend under its own weight. Simultaneously, the two pipe-laying machines 6 pull the wire rope connected to the steel pipe as an auxiliary to prevent slippage. When the end of the first steel pipe 5 protrudes 1.5–2.0 m to facilitate pipe alignment, the descent of the pipe is stopped, and the pipe-laying machine 6 is used to hold and fix the steel pipe. The next steel pipe is then lifted using the pipe-laying machine 6 and aligned using an external alignment tool. The first steel pipe 5 and the next steel pipe are then welded together outside the inclined shaft opening. After the pipeline is connected and passes inspection and corrosion prevention, the pipeline is slowly moved downwards to the predetermined position with the cooperation of the pipe-laying machine 6 and the crane 7 until the pipeline reaches the exit point and the entry point.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for directional drilling and construction of inclined shafts, characterized in that, S1, Construction preparation before drilling; S2, the directional drilling rig drills the pilot hole along the designed borehole trajectory curve, and pumps in a drilling fluid mixed with water and sodium dodecylbenzene sulfonate during the drilling process; S3, after the pilot hole drilling process is completed, the hole enlargement and hole cleaning processes are carried out alternately. During the hole enlargement and hole cleaning processes, a drilling fluid mixed with water and sodium dodecylbenzene sulfonate is pumped in. S4, install and connect pipe sections according to the hole trajectory formed by the design through the borehole trajectory curve.

2. The inclined shaft directional drilling construction technology according to claim 1, characterized in that, Preparatory work before drilling includes surveying and setting out, site layout, drilling platform fabrication, and drilling rig installation and commissioning.

3. The inclined shaft directional drilling construction technology according to claim 2, characterized in that, The surveying and setting out process involves first establishing a horizontal control network and an elevation control network, and then using surveying instruments to conduct surveying and setting out based on the route plan, cross-section diagram, control stakes, crossing stakes, and leveling stakes.

4. The inclined shaft directional drilling construction technology according to claim 3, characterized in that, The surveying and setting out process includes: re-measuring the crossing length based on the crossing stakes, control stakes, and leveling stakes; setting out the drilling rig axis based on the control stakes and crossing stakes; setting up additional stakes on the crossing axis; setting out the boundary lines of the pipeline construction work zone and the drilling rig construction work zone based on the site layout plan; after the construction site is leveled, the locations of the exit and entry points of the crossing should be measured and determined. The allowable deviation of the elevation of the exit and entry points is within ±50mm, and the allowable deviation of the horizontal position of the exit and entry points is within ±50mm.

5. The inclined shaft directional drilling construction technology according to claim 2, characterized in that, The site layout specifically includes a topsoil storage area, a native soil storage area, a drainage ditch, a control room, a power supply area, a drill rod storage area, a drilling rig storage area, and an accessory and drill bit storage area. A rectangular working pit with the same design angle as the crossing needs to be excavated at the top of the site slope. The directional drilling rig and the center line of the working pit are on the same straight line. Then, according to the terrain and the designed entry angle, the drilling rig is installed and debugged to ensure that the center line of the drill rod is concentric with the axis of the inclined shaft crossing and to ensure the entry angle. An operating pit needs to be excavated at the exit point, and the exit end of the directional drilling crossing is located in the operating pit.

6. The inclined shaft directional drilling construction technology according to claim 2, characterized in that, The drilling platform is specifically constructed by backfilling and compacting soil to create a drilling rig positioning platform that conforms to the drilling angle. The drilling positioning platform is trapezoidal in shape, and the top of the drilling rig positioning platform adopts a sloping design with a slope angle not exceeding 5°.

7. The inclined shaft directional drilling construction technology according to claim 1, characterized in that, The directional drilling rig drills the pilot hole along the designed cross-hole trajectory curve. Specifically, before drilling begins, geological data is carefully analyzed to determine the directional control scheme. The directional control equipment uses a gyroscope guidance system. Based on the entry angle of the directional drilling rig through the soil section, the directional drilling line adopts a curved shape, running from the entry point to the exit point along the curve. During drilling, the directional drilling rig collects directional control data at least once for each drill rod drilled, and adjusts the actual curve of the pilot hole in a timely manner based on the collected directional control data. The deviation between the actual curve and the designed cross-hole curve should not exceed 1%, and the lateral deviation of the exit point of the pilot hole should be within ±3m, the allowable elevation deviation should be between -2m and +1m, and the longitudinal deviation should be between -3m and +9m.

8. The inclined shaft directional drilling construction technology according to claim 1, characterized in that, The hole enlargement and cleaning process is carried out in stages and multiple times, with hole cleaning performed after each stage of enlargement.

9. The directional drilling construction process for inclined shafts according to claim 1, characterized in that, The weight ratio of water to sodium dodecylbenzenesulfonate in the drilling fluid is 3000:

1.

10. The directional drilling construction process for inclined shafts according to claim 1, characterized in that, Based on the borehole trajectory formed by the design through the borehole trajectory curve, the pipeline is installed in sections. Specifically, adjacent steel pipes are welded together end to end, and then the sections are hoisted down along the guide hole using hoisting equipment.

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