Abnormal phenomenon 1: the value of the pressure gauge rises suddenly.
Possible causes: the motor stalls, or the motor transmission shaft is stuck, and the bit port is blocked.
Judgment and treatment methods:
1) Motor stall: raise the drilling tools by 0.3-0.6m, check the circulating pressure and gradually add WOB. If the value of pressure gauge rises gradually and accordingly, the motor stall can be confirmed.
2) The motor transmission shaft is stuck and the bit port is blocked: lift the bit off the bottom of the well, and if the pressure gauge reading is still very high, we can only lift out the screw drill and check or replace the bit.
Abnormal phenomenon 2: the value of pressure gauge decreases slowly
Possible causes: the change of circulation pressure loss and drill pipe damage
Judgment and treatment method: check the drilling fluid flow rate and slightly lift the screw drill. If the reading of the pressure gauge is still below the circulating pressure, lift out the screw drill and check it.
Abnormal phenomenon 3: no footage
Possible causes: formation change, motor stall, the bypass valve is open, cardan shaft damage, drill damage and bit damage
Judgment and treatment method: properly change the bit pressure and circulation flow (you should note that it must be within the allowable bearing). If the pressure gauge reading is too high, the drilling tool should be lifted off the shaft bottom and the circulation pressure should be checked. Start from small bit pressure and gradually increase bit pressure, if the pressure gauge reading is low, the screw drill should be slightly lifted. If the drilling pump is still invalid after being started and stopped twice, the screw drill should be lifted out of the borehole. The replacement and inspection of the bypass valve is often accompanied by pressure fluctuations, at this time, the screw drill should be slightly lifted. In order to narrow the pressure fluctuation range, you can only take out the drill tool, then check and replace the drill bit.