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doi:10.2204/iodp.proc.338.107.2014

Operations

Site C0022

Hole C0022A

Operations began with dropping transponders at Site C0022 from 2030 h on 27 December 2012. The transponders were all confirmed on the seabed by 0143 h on 28 December, whereupon dynamic positioning calibration began, finishing at 0530 h. The vessel moved 1.5 nmi upcurrent from the well center, and the crew began making up and running the LWD bottom-hole assembly (BHA) into the hole from 0730 h. The LWD BHA was run to 260 m drilling depth below rig floor (DRF) by 1445 h, when time was taken to test the active heave compensator (AHC). After 30 min in standby mode, the AHC test was suspended because there was a malfunction. The cause of the malfunction could not be found. Running into the hole continued to the seabed, when Hole C0022A was spudded at 1600 h (water depth = 2675.5 meters below sea level [mbsl]) and the next 40.5 mbsf was washed down. From 1730 h, LWD commenced following the same rotation speed increase with depth plan to total depth as for IODP Holes C0018B and C0021A: 15 rotations per minute [rpm] × 0.6–2.5 kNm (40.5–45.5 mbsf), 30 rpm × 0.9–3.4 kNm (45.5–50.5 mbsf), 45 rpm × 0.5–4.7 kNm (50.5–60.5 mbsf), 60 rpm × 0.8–4.4 kNm (60.5–82.5 mbsf), 70 rpm × 1.1–7.9 kNm (82.5–111.5 mbsf), and 80 rpm × 0.9–14.1 kNm (111.5–420.5 mbsf). Kill mud was spotted from 2200 h, and the LWD BHA was pulled out of the hole to 36 mbsf for wait on weather. At 0300 h on 29 December, the LWD BHA was run down to 96 mbsf and then reamed down from 0330 h to 136.0 mbsf. Once back at 136.0 mbsf, drilling ahead with the LWD BHA resumed to total depth (420.5 mbsf), finishing at 1645 h. From 1715 h, the LWD BHA was pulled out of the hole to 2692.6 m DRF (11 m above seabed) while a damaged drill pipe joint was laid down. Pulling out of the hole continued from 1930 h and the BHA reached the surface by 0315 h on 30 December.

Hole C0022B

At 1800 h on 30 December 2012, the vessel moved 10 nmi north of Site C0022 into the low-current area to begin loading bentonite and drilling equipment. From 2130 h, the hydraulic piston coring system (HPCS)/extended shoe coring system (ESCS) BHA was made up and tested. From 0115 h, the BHA was run into the hole and the vessel began drifting toward the well center by 0300 h on 31 December. The HPCS BHA reached 2960 m DRF by 0745 h and stood by for the next 2 h while the core blowout preventer ball valve underwent maintenance. The bit was lowered to 2700 m DRF (2 m above the seabed), the sinker bar was run down at 1130 h in preparation for cutting the first core, and spud-in and shooting took place at 1245 h (seafloor = 2674 mbsl). Washing down to 19.5 mbsf ended at 1500 h, and piston coring resumed at 1600 h. By 0515 h on 1 January 2013, HPCS Core 338-C0022B-8H had been cut at 84.5 mbsf. At that point, coring operations switched from HPCS to the extended punch coring system (EPCS), cutting the first EPCS core (9T) by 0945 h to 89.5 mbsf. At 1730 h, the coring system was changed from EPCS to ESCS, cutting from 99.5 mbsf. ESCS coring continued, pausing at 1315 h on 2 January to drill ahead from 162 to 190.5 mbsf. ESCS coring from 190.5 mbsf resumed at 1715 h. ESCS coring paused again at 0315 h on 3 January, while drilling ahead from 228.5 to 266.5 mbsf (38 m advance) was completed. ESCS Core 338-C0022B-24X was cut from 0900 h, after which coring resumed. Coring in Hole C0022B finished at 0745 h on 5 January with the recovery of Core 41X. Kill mud was spotted, and the ESCS BHA was pulled out of the hole to the surface by 2330 h. As drill pipe was laid down, the transponders were released and recovered on the surface by the watch boat. The vessel began moving to Site C0021 in preparation for coring operations.

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