Logging Operations in Hole 1081A
In preparation for logging, an aluminum go-devil was dropped to ensure the opening of the lockable float valve. After the hole was flushed with a high-viscosity mud, the drill string was pulled back to 403.7 mbsf, where the top drive was set back. The drill bit was then placed at the logging depth of 101.2 mbsf. Hole 1081A was logged with a full suite of sensors to continuously characterize the sedimentary changes as a proxy for the paleoclimatic record and to provide data for core-log integration. For each run, the pipe was set at 101 mbsf and pulled back to 71 mbsf during logging. The wireline logging heave compensator was started when the logging tools reached the mudline. Logging operations began at 0200 hr on 9 September. The first log was conducted with the seismic-stratigraphic suite (25.8 m long). This suite was made up of the NGT, LSS, DITE-SFR, and TLT sondes. This tool string was deployed in the pipe at 0245 hr and logged the hole up from 450.5 mbsf. The tool was recovered at 0550 hr. The second log was with the lithoporosity suite (19.5 m long) and included the hostile-environment gamma spectrometry (HNGS), accelerator porosity (APS), lithodensity (LDS), and TLT sondes. The tool was deployed at 0655 hr and logged the hole from 450.5 to 71 mbsf. The third log was made with the Formation MicroScanner (FMS) suite (12.10 m long) and included the NGT, general purpose inclinometer (GPIT), and FMS sondes. This tool logged the hole from 450.5 mbsf. The tool was recovered at 1425 hr. The fourth and last log was with the magnetic susceptibility suite (11.8 m long) and included the NGT, magnetic susceptibility (SUMT), and the nuclear resonance magnetometer (NRMT) sondes. The tool was deployed in the pipe at 1455 hr and logged the hole from 450.5 to 71 mbsf. It was retrieved at 1740 hr. The logging equipment was rigged down by 1830 hr on 9 September. The hole was filled with heavy mud. The drill string was then pulled out of the hole, with the bit clearing the seafloor at 2115 hr on 11 September, ending operations at Hole 1081A.
The vessel was offset 30 m to the south, and Hole 1081B was spudded with the APC at 2220 hr on 11 September. The seafloor depth was established at 804.5 mbrf by DPM. APC coring advanced without incident to refusal at 187.6 mbsf with 104.4% recovery. Cores were oriented starting with 4H. The bit cleared the seafloor at 0925 hr on 12 September, thereby ending operations at Hole 1081B.
The vessel was offset 30 m to the south, and Hole 1081C was spudded with the APC at 0955 hr. The seafloor depth was established at 805.2 mbrf by DPM. APC coring advanced routinely to refusal at 155.2 mbsf. The recovery was 103.7%. Cores were oriented starting with 1081C-3H. The bit cleared the seafloor at 1815 hr, thereby ending operations at Site 1081.
To 175 Operations Site 1082
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