Suspected Drillstring Washout

Good day all,

On two different occassions, different wells as well. I have experienced loss of SPP with corresponding reduction in MWD turbine RPM. 1st experience was gradual loss of 500psi SPP with 12-1/4" motorised RSS and 2nd experience was a sudden loss of 1500psi SPP immediately after connection with 6-1/8" motorised RSS.

Investigated surface equipment- tested each mud pumps against closed standpipe valve - all ok. Confirmed active mud system not aerated, changed suction pit, changed mud pumps and pumps combination, all these still indicated same loss of SPP.

POOH and inspected DP (slip area and tool joints sealing faces) and BHA no visual anomalies detected. Surface tested PBL circulating sub on surface no leaks. Stripped BHA and inspected same in the workshop no anomalies found.

Could you kindly share your experiences of investigating drill string washout and no visual washout seen on drill pipe or BHA. 

The common denominator here was we changed the whole BHA on the aforementioned experiences and everything was normal.

0 Answer(s)

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