Construction Principle and Precautions of Horizontal Directional Drilling Rig

1. Construction principle of horizontal directional drilling rig: Drilling the pilot hole is to use directional drilling equipment to start directional drilling at the entrance, and during the drilling process, the drilling hole is extended according to the design trajectory through monitoring and control means. And drill the surface from the other end to complete the construction of the pilot hole. If the pipeline to be installed by the designated drilling rig for reaming is too large to complete the reaming and dragging operations at the same time, reaming shall be carried out step by step, and the diameter of each reaming shall be determined according to the equipment capacity, formation conditions and site conditions. Generally, pull-back reaming can be used. Pipeline pullback means that the directional drilling rig connects the pipeline to the drill pipe through the pullback head, the reamer bit and the transfer case at the exit, and uses the drilling equipment to rotate while pulling back, and at the same time, the flushing fluid is sent to the expansion pipe through the drill pipe. Hole drill bit, the reaming and pull-back process is carried out continuously. There must be no long non-job pauses in the middle.

2. Directional drilling rig technology is an advanced technology developed from the field of oil drilling. It utilizes technical means such as rock drilling and directional drilling rig measurement and control, without digging grooves on the ground surface and with minimal damage to the stratum structure, to control such as water supply, gas, Construction technology for laying public pipelines such as natural gas, sewage, and telecommunication cables. The directional drilling rig has a wide range of applications. It can use the motor at the bottom of the hole or the rigid drill rod to drive the drill bit to rotate and drill into the hole. It can also be used in hard rock or pebble layers.

3. Precautions: Firstly, according to the geological conditions of the crossing, select the appropriate drill bit and guide plate or underground mud motor, and start the mud pump to drill at the entry point. During directional drilling construction, the drill bit is driven by the thrust of the drill The drilling rig is driven to rotate and cut the formation, and keeps moving forward. After each drilling, the position must be measured, so as to adjust the drilling direction of the drill bit in time, and ensure that the completed drilling guide curve meets the design requirements. Repeat this operation until the drilling is completed. The problem of affecting the working efficiency of the machine due to the position deviation of the drill bit can be avoided. In general, when using a small drilling rig, when the diameter is greater than 200mm, pre-expanding is required. When using a drilling rig, when the diameter of the product pipeline is greater than 350mm, pre-expanding is required. The scope and number of pre-expanding, It depends on the drilling rig model and geological conditions. In this way, the use of horizontal directional drilling not only reduces the resistance, but also protects the anti-corrosion layer of the pipeline. The cost of construction is saved, and the working efficiency of the machine is improved.