Precautions for construction of water well drilling tools1. The construction principle of Water Well Drilling Tools: Drilling pilot holes is to use directional drilling equipment to start directional drilling at the entrance. During the drilling process, the drilling is extended according to the design trajectory through monitoring means. And drill the surface from the other end to complete the pilot hole construction. When the pipeline to be installed is large and the reaming and dragging operations cannot be completed at the same time, the 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. Pull back and reaming can generally be used. Pipeline pullback means that the directional drilling machine connects the pipe with the drill pipe through the pullback head, reamer bit and transfer case at the exit, and uses the drilling equipment to rotate and pull back at the same time. Drilling, reaming and dragging processes are performed continuously. There should be no long non-work pauses in between.2. Directional drilling technology is an advanced technology developed from the field of oil drilling. It adopts technical means such as rock drilling and directional drilling rig measurement and control. The laying construction technology of public pipelines such as water supply, gas, natural gas, sewage, telecommunication cables, etc., without trenching on the surface and with minimal damage to the stratum structure. Directional drilling rigs are used in a wide range of applications. They can use bottom hole motors or rigid drill rods to drive the drill bit to rotate and drill holes, and can also be used for hard rock or pebble layer construction.3. Precautions: First, according to the geological conditions of the crossing, select the appropriate drill bit and guide plate or downhole mud motor, and start the mud pump at the entry point for drilling. The drilling rig is driven to rotate to cut the stratum and move forward continuously. After each drilling, the position should be measured, and the drilling direction of the drill bit should be adjusted in time to ensure that the completed drilling guide curve meets the design requirements. Repeat until the hole is drilled. The problem that the position deviation of the drill bit affects the working efficiency of the machine can be avoided. Generally, when using a small drilling machine, when the diameter is greater than 200mm, pre-expanding is required. When using a drilling machine, when the diameter of the product pipe is greater than 350mm, pre-expanding is required. The scope and quantity of pre-reaming depends on the type of drilling rig and geological conditions. Using this method to carry out horizontal directional drilling not only reduces the resistance, but also protects the anti-corrosion layer of the pipeline. The construction cost is saved and the working efficiency of Reaming Bit is improved.