Development analysis of horizontal directional drilling technology

Large horizontal directional drilling rig is an ideal equipment for laying super large underground pipelines such as oil, natural gas, water supply and drainage, electric power, coal water slurry, etc. it is an trenchless equipment for energy conservation, environmental protection and construction.

Most foreign products have automatic drill pipe automatic access device, fast anchoring and positioning device, anti electric shock alarm and other automatic and protection systems. Although domestic horizontal directional drilling rigs started late, due to the promotion of a large number of construction projects, the development speed is extremely fast. The national conditions of our country are different from those of foreign countries, resulting in the gap between the use demand and current situation of drilling rigs and the state-owned ones, mainly in the following aspects.

1. Different chassis structure types

China has a vast territory and diverse geological conditions. Large tonnage drilling rigs are mainly operated in the field. Due to the limitations of the construction site, domestic drilling rigs often use self-propelled crawler chassis, which has low requirements for roads and has the advantages of strong passing capacity.

Foreign drilling rigs benefit from good supporting conditions of basic equipment. The chassis is mainly a trailer chassis. Under the condition of convenient transportation, it has the advantages of convenient and fast transfer.

2. The structure of drill frame is different

Because the crawler chassis is adopted, the engine is generally arranged on the side of the width of the whole machine, which limits the width direction of the drill frame. Although the rear engine arrangement can be used to increase the width of the drill frame, the rear engine arrangement often leads to the disadvantage of small walking approach angle or departure angle. In order to overcome the shortcomings of crawler chassis, the drilling frame body also needs to adopt measures such as rocker arm structure and drilling frame sliding to adjust the angle of construction personnel and soil.

3. Power head with force increasing structure

The drilling rig with force increasing function can ensure smooth construction and reduce construction risks when the drag back resistance is large. It caters to the idea of "spending small money to do big things" of domestic users.

4. Vise

A reliable clamping mechanism is the basis for the construction of directional drilling rigs. The horizontal directional drilling technology comes from oil drilling. However, due to the great difference between the construction conditions of horizontal directional drilling rigs and oil drilling, the torque of horizontal directional drilling rigs is large, and it is very easy to have problems such as rod removal and slipping of drill pipes.

At present, large-scale drilling rigs generally use three cylinder clamping vise, which can reduce the clamping stress of drill pipe and improve the shackle torque by increasing the wrapping angle and contact area of drill pipe.

In addition, in long-distance construction, it is generally necessary to run the casing. In order to adapt to the casing construction method, the vise of the drilling rig is mostly designed into a full floating type.

5. Move

The power of large drilling rigs is large, and the domestic and foreign drilling rigs use dual engines as the power source. The overall cost of dual engine configuration is slightly lower. When guiding operation or small power output, one engine can be used to work, saving energy and reducing construction costs. More importantly, construction can still be carried out even if one engine fails.

6. Hydraulic system

In trenchless construction, there are generally three stages: pilot hole, back reaming hole and back dragging pipe. In these three stages, the requirements of rotating torque and pushing force on the power output of the engine are different: in the construction stage of guide hole, the torque and pushing force are small, and the output power is small; In the construction stage of back reaming, the power demand of rotation is large, and the power demand of push-pull is small; In the stage of pipeline pullback, the power output demand of push-pull is large.

According to the construction needs, the rotating system generally adopts the energy-saving closed hydraulic system, so as to achieve the goal of energy saving. Therefore, in large drilling rigs, the rotating system generally adopts the closed system. At the same time, in order to improve the efficiency of the hydraulic system, pumps, motors and so on use high-efficiency plunger motors as energy conversion and execution components.

7. Gas system

With the progress of modern electronic technology, PLC controller has been widely promoted and applied because of its reliable performance, stable quality and strong logic intelligence.

8. Ergonomics research and Yi

The construction of large-scale drilling rigs usually involves large-diameter and long-distance engineering construction. The construction period is often long, and the working environment needs to be operated to improve the operation of operators.

9. High cost performance of configured parts

Not only users in China, but also users all over the world attach great importance to the cost performance of products. On the basis of meeting the product performance, reliability and good maintenance performance, value engineering analysis method is carried out for drilling rigs to remove the redundant functions of products and reduce the manufacturing cost of equipment.