Failure Analysis

If the PDM has some anomalies during the course of use, the trouble can be basically shot by checking the problems against the following table. If you meet any problems not covered in the following table, you may contact our technical service department to deal with your problems.

PDM failure analysis and troubleshooting table

Anomalies	Possible Cause	Diagnosis and troubleshooting methods
The riser pressure gauge index suddenly elevated	Motor drag	Lift the drill 0.5-1m away from the bottom of the well; if the circulating pressure is correct, slowly increase the bit weight.
The riser pressure gauge index suddenly elevated	The drive shaft of the motor is stuck	Lift the drill 0.5-1m away from the bottom of the well; if the circulating pressure is too high, pull out the drill for checking and change the drill.
Standpipe pressure gauge index increased, but not with the drilling depth increases growth of normal pressure drop	Ice drill’s melting water eyes or the drill’s internal water eye was blocked	Lift the drill off the bottom of the well; if the circulating pressure is still higher than the normal value, change the cyclic flow or move the drill up and down; if it not effective, pull out the drill for check and change the drilling bit.
	Drill bit wear	Continue drilling if there is not any footage, pull out the drill for check and replace the drill bit.
	Stratigraphic changes	Lift the drill off the bottom of the well; if the circulating pressure is normal, continue drilling.
The pressure gauges index decreased slowly	Drill pipe damage	Lift the drill off the bottom of the well; if the circulating pressure is lower than the normal value, pull out the drill for check.
The pressure gauges index decreased slowly	Change of circulating pressure loss	Check whether the drilling fluid flow is changed
No footage	Stratigraphic changes	Appropriately change the flow and bit weight within the allowable range
	The bypass valve is in the “open position”	Lift the drill off the bottom of the well; if the circulating pressure is lower than the normal value, start and stop the mud pump respectively twice. If it is not effective, pull out the drill to check the bypass valve.
	Motor drag	Lift the drill 0.5-1m away from the bottom of the well; if the circulating pressure is correct, slowly increase the bit weight
	Cardan shaft damage	It is accompanied by pressure fluctuations and if the PDM is lifted, the pressure fluctuation range will be reduced; pull out the drill for check and replace the drill.
	Drill bit wear	If the circulating pressure is normal, pull out the drill for check and replace the drill bit.