Daily Report for IODP Expedition 311, October 8, 2005
LOCATION: Site U1327 (CAS-01B)
SCIENCE UPDATE: After completing pressure coring operations in Hole U1327D, we switched over to the wireline logging program. Adverse ship heave conditions delayed the start of the downhole logging program until just after midnight. The first tool deployed was the standard triple-combo, which was able to reach a depth of 295.4 mbsf and the hole was logged without incident until near the top of the log run. The combination of a ship heave event (+3.0 m) and the oversized borehole apparently caught and tore off the density tool caliper arm. The damaged triple-combo tool string was returned to the ship without further incident. The VSP logging program in Hole U1327D began at 07:20 hr in the morning with the pre-shooting, one-hour marine mammal observation period. After this period we started to ramp up the firing pressure for the GI gun. At 10:00 hr the VSP tool (WST) had reached TD at 276.4 mbsf and the VSP program began. We moved in 5 m increments up the hole and had completed sixteen positions at about 11:00 hr. Around 136 mbsf the WST was unable to clamp although the caliper log from the triple-combo run showed that the hole should have been suitable for clamping. It was decided to pull the WST back to the ship for inspection. Unfortunately the tool became stuck at the drill bit and we were unable to pull it back into the drill pipe. Two attempts to clamp the logging wireline were unsuccessful; however, the tool was finally worked back into the drill pipe and pulled to the surface by 23:00 hr. Because of the critical nature of the downhole acoustic log data to achieve the goals of the expedition, it was decided to drill a dedicated wireline logging hole and to acquire additional PCS, HRC, and FPC pressure cores from several critical intervals not successfully cored in the two previous holes at this site.