JA Daily Science Report for Expedition 312, 17 November 2005


LOCATION: Site 1256


SCIENCE UPDATE: Washing and reaming the tight hole continues. A 25 barrel high viscosity mud sweep was pumped to clean the hole of debris. The pipe was pulled back to 924 mbsf and the wash barrel retrieved, which contained several rounded basalt cobbles and basaltic gravel, sand, and silt. A deplugger was dropped to clear the throat of the bit, a new wash barrel was dropped, and another pill of high viscosity mud was pumped to sweep the hole. Reaming and washing continued from 924 to 944 mbsf but hole conditions did not improve significantly so the wash barrel was recovered and the drill string was tripped back to the rig floor. The used CC-9 RCB bit, top sub, and head sub were laid down and a new 9 7/8 tricone bit was affixed to the drilling BHA. The pipe was then tripped back to the sea floor for reentry in Hole 1256D.