Location: Offshore, Southeast Asia
Job type: Drilling
Fluid type: Mineral oil base, 13.0 ppg
An offshore operator was making an open whole displacement of a water base system to a mineral oil system when sloughing coal and partial loss of returns occurred. Several attempts were made to combat the problem with various types of LC materials. None of these attempts were successful.
A 100bbl sweep of 40ppb FRACSEAL (fine) was pumped around and full circulation was regained. Final displacement was made and drilling resumed. The hole was then swept on a regular basis to control sloughing and any seepage losses. Prior to logging the well, a 50bbl pill of 12ppb FRACSEAL (fine) was left on the bottom.
No losses were incurred while logging. Prior to running casing, a 50bbl sweep of 12ppb FRACSEAL (fine) was pumped around. No losses were encountered while running casing and full returns were maintained during the primary cement job.