CN102003140B - A horizontal directional drilling pipeline crossing reverse circulation drilling method and special drill bit - Google Patents

Abstract

The invention provides a traversing reverse circulating drilling method of a horizontal directional drilling pipeline and a special drilling bit, which are suitable for laying oil-gas pipelines and municipal pipelines. The drilling method comprises the following steps of: mounting a gravel pump at the outer end of a drilling machine or a pit, wherein hollow cavities are formed in the drilling bit and the drilling stem in use; arranging a slag suction port communicated with a borehole circular space on a reaming drilling bit; sleeving a roller cone seat with a roller cone outside the body of the reaming drilling bit, wherein the position of the roller cone corresponds to that of the slag suction port; arranging a plug for blockage at one end of the reaming drilling bit; and circularly flowing slurry according to a flowing direction from a slurry pond to the borehole circular space, the reaming drilling bit, the drilling stem, the gravel pump and the slurry pond during drilling so as to reach the aim of deslagging. The method and the drilling bit of the invention can be adopted to effectively remove drilling slag and gravel in the horizontal borehole and solve various problems in the traversing construction of the large-diameter horizontal directional drilling pipeline.

Description

A horizontal directional drilling pipeline crossing reverse circulation drilling method and special drill bit

Technical field

The invention relates to a horizontal directional drilling pipeline crossing reverse circulation drilling method and a special drill bit. The horizontal directional drilling pipeline crossing reverse circulation drilling method is particularly suitable for laying oil and gas or municipal pipelines and belongs to the field of non-excavation engineering.

Background technique

At present, in the construction of pipelines laid by horizontal directional drilling, the length and diameter of construction pipelines are getting larger and larger. As the length of the pipeline and the diameter of the borehole increase, the cuttings generated during the reaming process also doubles, and the particle size of the cuttings generated during the drilling of the rock formation is larger, so it is more difficult to remove the slag when drilling into the rock formation . Especially for large-diameter, long-distance crossing projects like the Second West-East Gas Pipeline, how to effectively remove the drilling slag in the borehole is a very difficult problem. A key reason is that the flow rate of mud in the annular space of the borehole is very low, which cannot meet the minimum critical flow rate requirement for effective slag discharge.

In addition, the construction equipment required for large-scale horizontal directional drilling crossing projects is also particularly large, and the torque of the drilling rig often reaches more than 100,000 Nm, which puts forward high requirements for the design and manufacture of drilling rigs and tools for horizontal directional drilling. The following technical and economic problems exist in the existing horizontal directional drilling process:

1) The problem of sand carrying under the condition of extra large wellbore, ultra-low flow rate and high cuttings concentration. It is difficult to remove the mud and sand in the borehole, especially the larger particles of drilling slag or pebbles.

2) Slurry channeling in the formation. During the drilling process, the mud needs to have a certain pressure to ensure the effective discharge of cuttings. However, the strata traversed by horizontal directional drilling are generally shallow strata with a depth of 15-25m. Under the action of pressure, the mud can easily penetrate the loose topsoil Or leak to the surface through formation fissures.

3) Multiple hole washing operations are required, which consume a large amount of mud materials; for example, a 950-meter directional drilling river crossing project on the Second West-East Gas Pipeline consumes more than 5,000 tons of bentonite.

4) There are many construction procedures, and many times of hole washing are required, and the construction period is long.

5) The engineering risk is high, because it is difficult to remove the muck in the hole, and it is easy to cause the failure of the pipeline to drag back.

6) Due to the large amount of sediment in the hole and the large content of sand in the mud, it is easy to cause serious wear of the drilling tool, excessive reaming torque, and engineering accidents such as drill sticking and drilling tool breakage.

7) Due to the above-mentioned many adverse effects, the engineering cost is relatively high.

Contents of the invention

In order to overcome the above-mentioned problems in the prior art, the present invention provides a horizontal directional drilling pipe crossing reverse circulation drilling method and a special drill bit. The process is based on the traditional drilling mud positive circulation, by changing the drilling mud The circulation direction makes it just opposite to the circulation direction of the mud in the prior art. The circulation speed of the mud carrying the drilling slag is greatly improved, and the drilling slag and gravel in the horizontal drilling can be effectively removed. By adopting the technological method and the drill bit of the present invention, many problems that currently plague the crossing construction of large-diameter horizontal directional drilling pipelines can be easily solved.

The technical solution adopted by the present invention to solve the technical problem is: a horizontal directional drilling pipe crossing reverse circulation drilling method, the drill pipe of the drilling rig enters the annular space of the drilling hole through the pit, and the other end of the annular space of the drilling hole is the unearthed The drill pipe is connected to the reaming bit through the drill pipe joint. Both the inside of the drill pipe and the reaming bit are hollow cavities. , the slag suction port and the drilling annular space together form a mud channel, and the gravel pump is placed at the outer end of the drilling rig or the excavation pit; when the gravel pump is placed at the outer end of the drilling rig, the pit is used as a mud pool, and the gravel pump is The drill pipe is connected with the hollow reaming drill bit, and the end of the reaming drill bit close to the excavation pit is sealed with a plug; The rod is connected with the hollow reaming bit, and the end of the reaming bit close to the pit is blocked with a plug, and the mud is drilled according to the mud pool → drilling annular space → reaming bit → drill pipe → gravel pump → The flow direction of the mud pool circulates the flow.

And in the present invention, the mud discharged during drilling can be deposited and reused.

The present invention also provides a special drill bit capable of realizing the horizontal directional drilling pipeline crossing reverse circulation drilling process. The inside of the drill body of the drill bit is a hollow cavity, and the cone seat on which the cone is installed is sleeved on the drill body. The middle part of the drill bit body is provided with a slag suction port, the position of the slag suction port corresponds to the cone, and one end of the drill bit body is provided with a plug for sealing.

It can be seen from the above technical scheme that the present invention uses the positive circulation mode of the mud in the existing reaming process, that is, in the reaming process, the circulation path of the mud is: mud pool→mud pump→drill pipe→reaming drill bit→drilling ring Shaped space → mud pool, change to reverse circulation direction flow, that is: mud pool → drilling annular space → reaming drill bit → drill pipe → gravel pump → mud pool. By changing the installation position of the gravel pump and using a hollow drill bit with a slag suction port, the invention can not only realize the reverse circulation reaming drilling from the side of the drilling rig, but also realize the reverse circulation reaming drilling from the side of the pipeline entering the soil It can double the effective construction length of the reverse circulation reaming process.

The present invention has the following outstanding advantages:

1. The reverse circulation drilling mud has a relatively high upward flow velocity (up to 2-4m/s) in the center channel of the drill pipe, which will greatly improve the drilling efficiency, and will greatly reduce power consumption and reduce The consumption of rock-breaking tools greatly shortens the construction period and greatly reduces the construction cost.

2. It can efficiently and completely remove every drilling slag in the whole drilling without leaving any dead ends. Therefore, the diameter expansion coefficient of drilling can be effectively reduced, thereby reducing the number of reaming stages and hole washing times.

3. The reciprocating mud pump used in the positive circulation slag removal system has very strict requirements on the sand content in the mud. Even if the mud purification device is used, it is not easy to treat the used mud up to the standard, while the reverse circulation slag removal system uses sand The stone pump has almost no requirements on the sand content in the mud, and the mud that carries the drilling slag back out of the hole can be reused only after a little precipitation.

4. Can greatly reduce the amount of mud used. The use of reverse circulation technology can greatly reduce the amount of mud used, thereby greatly reducing construction costs and reducing the pollution of mud to the environment.

5. It can greatly reduce the requirements for the equipment configuration of the pumping station. The use of reverse circulation technology can reduce the specifications of the configured reciprocating mud pumps and reduce the requirements for mud treatment equipment, thus greatly reducing equipment configuration costs and equipment entry and exit costs, saving mud treatment costs, and avoiding failure due to untimely mud treatment. Forced to stop work etc.

6. It can greatly improve the safety of pipeline dragging back. The reverse circulation slag removal system can efficiently and completely remove every slag in the entire drilling without leaving any dead angle, so the safety of the pipe drawing operation can be greatly improved.

7. During the horizontal directional drilling reverse circulation drilling construction, there will be no problems of mud leakage and ground slurry leakage. The mud in the annulus flows almost by gravity and has no pressure, so it generally does not seep through the loose topsoil to the surface.

Description of drawings

Fig. 1 is a schematic diagram of hole reaming using the reverse circulation drilling process when the gravel pump is placed on the outer end of the drilling rig in Example 1.

Fig. 2 is a schematic diagram of hole reaming by reverse circulation drilling process when the gravel pump in embodiment 2 is placed at the outer end of the excavation pit.

Figure 3 is a schematic diagram of the structure of the drill used in Example 1.

FIG. 4 is a schematic diagram of the structure of the drill used in Example 2.

In the figure 1. Gravel pump; 2. Drilling rig; 3. Drill pipe; 4. Burying pit; 5. River course; 6. Centralizer; 7. Reaming bit; 10. Protective spokes; 11. Cone cone; 12. Cone seat; 13. Slag suction port; 14. Drill bit cone; 15. Plug; 16. Pencil cone; 17. Drill pipe joint.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in Figure 1 and Figure 2, the horizontal directional drilling pipeline crossing reverse circulation drilling method provided by the present invention is based on the traditional drilling mud circulation, by changing the supporting equipment and adopting a new structure of the drill bit, the mud in the drilling process is realized according to Mud pool→drilling annular space→reaming drill bit→drill pipe→sand pump→mud pool flows in a circular flow direction. In this process, the drill pipe 3 of the drilling rig 2 enters the drilling annular space 9 through the entry pit 4, and the drilling The other end of the hole annular space 9 is an excavation pit 8, the drill pipe 3 of the drilling rig 2 is provided with a centralizer 6, the drill pipe 3 is connected with the reaming bit 7 through the drill pipe joint, and the inside of the drill pipe and the reaming bit are both Hollow cavity, the reaming bit 7 is provided with a slag suction port 13 communicating with the drilling annular space 9, the two cavities, the slag suction port 13 and the drilling annular space 9 jointly form a mud channel, and the gravel pump 1 Be placed on the outer end of drilling machine 2 or excavation pit 8. In the embodiment 1 shown in Fig. 1, the gravel pump 1 is placed on the outer end of the drilling rig 2, and the pit 4 is used as a mud pool, the gravel pump 1 communicates with the hollow drill pipe 3, and the drill pipe 3 is placed close to the excavation pit 8 When drilling, the gravel pump 1 continuously extracts the mud filled in the annular space 9 of the borehole through the slag suction port 13 at the drill pipe 3 and the reaming bit 7, and the reaming bit 7 The cut drilling slag is entrained by the suspension of the mud, and as the extracted mud enters the cavity of the drill bit through the slag suction port 13, it is carried to the surface through the drill pipe 3 and the gravel pump 1, thereby realizing slag discharge, the arrow in Figure 1 Indicates the flow direction of the mud. After testing, the upward return flow velocity of the mud in the drill pipe is as high as 2-4m/s. As the mud at the bottom of the hole is continuously pumped out, the mud in the mud pool enters the annular space of the drill hole by gravity 9 pairs The mud in the circulation system is replenished; the pumped mud can be reused after purification treatment (such as sedimentation) to remove drilling slag. In the embodiment 2 shown in Fig. 2, the gravel pump 1 is placed on the outer end of the excavation pit 8, and the excavation pit 8 is used as a mud pool, the gravel pump 1 communicates with the hollow drill pipe 3, and the drill pipe 3 is placed close to the centralizer One end of 6 is blocked with a plug 14. Under the suction of the gravel pump 1 during drilling, the mud flows from the annular space 9 of the borehole through the slag suction port 13 at the reaming drill bit and the hollow passage inside the drill pipe 3. The arrows in Figure 2 indicate the flow direction of the mud, and the drilling slag cut by the reaming bit 7 directly falls into or is sucked into the cavity of the drill pipe with the mud, and is carried to the surface with the circulating mud , so as to achieve the purpose of reverse circulation slagging. The horizontal directional drilling pipeline crossing reverse circulation drilling process provided by the present invention is particularly suitable for non-excavation projects, as shown in Fig. 1 and Fig. 2 , the crossing project at the bottom of the river channel 5.

The inside of the drill body of the drill bit used in the present invention is a hollow cavity, and the middle section of the drill body is provided with a slag suction port 13, and the diameter of the drill body at the 13 place of the slag suction port is greater than the diameter of the rest of the drill body to form a larger The cavity is used for slag suction, and the cone base 12 with the cone 11 installed is set outside the drill body. The back of the cone base 12 is provided with a drill cone 14. During drilling, the drill rod drives the drill body to rotate and drives the cone 11 to operate. Rotational movement, the position of the cone 11 corresponds to the slag suction port 13, the front of the drill body is provided with a pen-shaped cone 16, and the pen-shaped cone 16 is provided with a protective spoke 10, and one end of the drill body is provided with a plug for plugging. Plug 15, the plug 15 of the drill used in embodiment 1 is positioned at the outside of the drill cone 14 (as shown in Figure 3), and the plug 15 of the drill used in embodiment 2 is positioned at the outside of the pen-shaped cone 15 (as shown in Figure 4 Show). The reaming bit communicates with the drill pipe through the drill pipe joint. The hollow cavity in the drill pipe and the hollow cavity in the reaming bit communicate with the annular space of the drilling hole through the slag suction port. The two cavities, the slag suction port and the drill hole The annular space together forms a mud channel to meet the requirement that the mud can circulate in the direction of mud pool→drilling annular space→reaming bit→drill pipe→sand pump→mud pool during drilling.

Claims (7)

1. A horizontal directional drilling pipe crossing reverse circulation drilling method is characterized in that: the drilling rod of the drilling rig enters the drilling annular space through the entry pit, the other end of the drilling annular space is the excavation pit, and the drilling rod passes through the drilling rod The joint is connected with the reaming bit, and both the inside of the drill pipe and the reaming bit are hollow cavities. The annular space together forms a mud channel. The gravel pump is placed at the outer end of the drilling rig or the excavation pit; The drill bit is connected, and the end of the reaming drill bit close to the excavation pit is blocked with a plug; when the gravel pump is placed at the outer end of the excavation pit, the excavation pit is used as a mud pool, and the gravel pump passes through the drill pipe and the hollow reaming bit Connected, and the end of the reaming bit near the pit is blocked with a plug; during drilling, the mud is circulated according to the flow direction of the mud pool → drilling annular space → reaming bit → drill pipe → gravel pump → mud pool flow. 2. The horizontal directional drilling pipeline crossing reverse circulation drilling method according to claim 1, characterized in that the mud discharged during drilling is repeatedly used after removing drilling slag. 3. The horizontal directional drilling pipeline crossing reverse circulation drilling method according to claim 1, characterized in that: the drill pipe of the drilling rig is provided with a centralizer. 4. A reaming drill bit used for the horizontal directional drilling pipeline crossing reverse circulation drilling method according to claim 1, comprising at least a drill bit body, characterized in that: the inside of the drill bit body is a hollow cavity, and the cone cone is installed. The wheel seat is set on the drill body, the middle part of the drill body is provided with a slag suction port, the position of the slag suction port corresponds to the cone, and one end of the drill body is provided with a plug for sealing. 5. The drill bit according to claim 4, characterized in that: the diameter of the drill bit body at the slag suction port is larger than the diameter of the rest of the drill bit body. 6. The drill bit according to claim 4, characterized in that: the back of the cone seat is provided with a drill bit cone. 7. The drill bit according to claim 4, characterized in that: the front part of the drill body is provided with a pen-shaped cone, and protective spokes are provided outside the cone.

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