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doi:10.2204/iodp.proc.338.105.2014

Operations

Hole C0018B

The D/V Chikyu moved to Site C0018 (water depth = 3084.5 m) after completing all operations at Site C0002. Making up and running the LWD bottom-hole assembly (BHA) started at 1400 h on 25 December 2012. The 12¼ inch LWD BHA components were similar to Hole C0012H operations with the exception of the sonicVISON tool, which was not used in Hole C0018B. Function tests on the LWD were conducted at 76, 1060, 2006, and 3100 m drilling depth below rig floor (DRF), respectively, while lowering the LWD BHA. Spud-in of Hole C0018B was confirmed by real-time resistivity data at 0430 h on 26 December. Washing down with a controlled rate of penetration (ROP) at an average of 40 m/h (maximum = 50 m/h) changed to drilling ahead from 40 mbsf at 0600 h. Rotation speed was gradually increased step-wise to total depth (350 mbsf): 15 rpm × 1.8–2.5 kNm (40–45 mbsf), 30 rpm × 0–5.0 kNm (45–50 mbsf), 45 rpm × 0–5.0 kNm (50–67 mbsf), 60 rpm × 0–5.0 kNm (67–242 mbsf), and 80 rpm × 1.6–8.3 kNm (242–350 mbsf). The target depth was reached by 1130 h on 26 December. After spotting kill mud, the LWD BHA was pulled out of the hole to 2813 m DRF (300 m above the seafloor) by 2000 h on 26 December in preparation for operations at Site C0021.

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