Drilling Operation Technology

① Proper casing shall be put into the hole to avoid hole collapse.

② When the drilling tool is lowered into the hole, first use low-pressure slow rotation to sweep the hole to the bottom. When the resistance of the drill bit in the hole is small, it can be turned into normal drilling. If the resistance in the hole is large, it cannot be forced to open the high speed.

③ During normal drilling, the drilling parameters shall not be changed arbitrarily, and the drilling tools shall not be lifted to prevent the core from being blocked.

④ When the core is found to be blocked, the drilling tool can be lifted appropriately. If the treatment is ineffective, the drilling tool should be lifted immediately.

⑤ If the formation is loose, the particle size of sand and gravel is very small, and it is difficult to coring, the pump volume should be reduced.

⑥ If the drilling speed of sand and gravel suddenly accelerates, it may be to drill into the sand layer or the gravel layer with small particle size. It is not necessary to change the drilling parameters, but the pump volume should be reduced as much as possible.

⑦ In order to ensure that the core is drilled into thin sand and mud layers, it is best to drill more than 10 cm into the pebble layer after drilling. If the sand layer is thick, when one round of drilling cannot be penetrated, the pump should be stopped at the end of the round to dry drilling for more than 10 cm and then lift the drill to prevent the core from falling off.

⑧ Carefully operate during drilling, and often observe whether the water supply system is unblocked and whether the water pump operates normally. When there is no slurry return in the hole, slurry breaking shall be prevented. In case of sudden increase in pump pressure, immediately lift the drill for inspection to prevent burning.

⑨ When drilling and sampling in important hole sections, the drill rod should be slowly lifted and screwed down to prevent the core from falling off. When withdrawing the core, the drill bit should be removed and then the core should be gently poured out.