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doi:10.2204/iodp.proc.329.103.2011

Operations

Papeete port call

IODP Expedition 329 began with the first line ashore on Papeete, Tahiti (French Polynesia), at 0734 h on 7 October 2010. The first Tahiti port call for the R/V JOIDES Resolution included refueling after the long journey from Victoria, British Columbia (Canada). After refueling, the ship was secured by tugboats and moved to the EPI North Pier, across from the town center, on 8 October. United States Implementing Organization staff, the expedition Co-Chiefs, and some members of the Scientific Party boarded the ship on 9 October to start setting up third-party instrumentation in the ship’s laboratories in preparation for the expedition. The rest of the Science Party moved onboard on 10 October. Port call lasted 5.1 days.

All times in this section are given in local ship time unless otherwise noted. For most of the expedition, local time was Universal Time Coordinated – 10 h.

Transit to Site U1365

The JOIDES Resolution departed Papeete for the 982 nmi journey to Site U1365 in the morning of 12 October 2010. The vessel sailed at full speed, averaging 11.5 kt, and arrived at Site U1365 at 0030 h on 16 October. The position reference was a combination of GPS signals. Although an acoustic beacon was deployed, it was not used for positioning at this site because of an electronic malfunction in the dynamic positioning system. The positioning beacon was deployed at 0805 h on 17 October and recovered at 2044 h on 21 October.

Site U1365

Five holes were cored at Site U1365. The first four holes were cored with the advanced piston coring (APC) system. The fifth and final hole was drilled with a 9⅞ inch rotary core bit. Downhole logging was originally scheduled for this site but was canceled when the target depth of the hole was reduced because of the low penetration rates with the rotary core barrel (RCB) bit. As a proxy for microbial contamination, perfluorocarbon tracer (PFT) was continuously injected into the drilling fluid for all coring of Holes U1365B–U1365E. The advanced piston corer temperature tool (APCT-3) was deployed 8 times on the APC system, and usable data were recovered 7 times. On one of the tool runs, the data were lost while trying to recover it from the tool. For this site, APC system recovery was 95.2% and RCB system recovery was 74.5%. Overall core recovery for this site was 90.8%. A total of 55 cores were recovered after coring 251.1 m. The total length of core recovered was 228.07 m (Table T1).

Hole U1365A

Rig floor operations started at 0030 h on 16 October 2010. The trip to the seafloor was without incident while measuring and drifting the tubulars and assembling the bottom-hole assembly (BHA). The top drive was picked up, the drill string was spaced out, and a washdown hole was drilled to determine depth of basement. The center bit was pulled by wireline, the vessel was offset 20 m west, and the top drive was spaced out to spud Hole U1365A. After making up the first APC core, the core barrel was run to bottom on the wireline and Hole U1365A was spudded at 0530 h on 17 October. Seafloor depth was established with a mudline core at 5706.3 meters below rig floor (mbrf). Nonmagnetic core barrels and the Flexit tool were used for the first four cores and APCT-3 temperature measurements were taken on Cores 329-U1365A-1H, 3H, and 4H. APC coring continued until basement was reached at 75.5 mbsf. A total of 26 cores were taken in Hole U1365A, with a total recovery of 74.06 m (98.1%). All cores after Core 4H were incomplete strokes, and the recovery was slowed by a very thick layer of chert formation from ~42 to 63.5 mbsf. After reaching basement on Core 26H, the bit was tripped back to just above the seafloor, ending Hole U1365A at 0845 h on 19 October.

Hole U1365B

Hole U1365B was offset 20 m north of Hole U1365A and was spudded at 1010 h. The mudline core established seafloor depth at 5705.4 mbrf. APC continued until 42.5 mbsf. Temperature measurements were taken with the APCT-3 on Cores 329-U1365B-3H, 4H, and 5H, although the data on Core 3H was lost trying to download the data from the tool. The center bit was then deployed, and the formation was drilled from 42.5 to 63.5 mbsf. The center bit was pulled and APC continued until basement was reached at 75.6 mbsf. A total of eight cores were taken with a total recovery of 55.79 m (102.2%). All cores after Core 5H were incomplete strokes, and a 21 m section of hole was drilled to avoid coring a very thick layer of chert formation from ~42 to 63.5 mbsf. The drill string was tripped to just above the mudline, clearing the seafloor at 0640 h on 20 October and ending Hole U1365B.

Hole U1365C

After offsetting the vessel 20 m north, Hole U1365C was spudded at 0940 h on 20 October and advanced with the APC system to 37.5 mbsf before encountering the first hard chert layer. Temperature measurements were taken with the APCT-3 on Cores 329-U1365C-3H and 4H. The center bit was then dropped and the subsequent drilled interval ended again at 63.5 mbsf after advancing 26 m. The center bit was pulled and the APC system was redeployed and advanced by recovery until basement was encountered at 74.8 mbsf. A total of 8 cores were taken with a total recovery of 39.67 m (81.3%). All cores after Core 4H were incomplete strokes. The drill string was then tripped to just above the mudline, clearing the seafloor at 0435 h on 21 October and ending Hole U1365C.

Hole U1365D

After offsetting the vessel 20 m east, Hole U1365D was spudded at 0540 h on 21 October. The hole was advanced with the APC system for two cores to 19 mbsf, and 18.89 m of sediment was recovered, for an overall recovery of 99.4%. After the second core, the drill string was tripped to surface and the bit cleared the rotary table at 2030 h, ending Hole U1365D.

Hole U1365E

The objective for Hole U1365E was to drill and core through the sediment/basalt interface and ~100 m into the basaltic basement. However, we cored ~50 m of basement with good recovery, did not capture the sediment/basement interface, and ran out of allocated time because of slow coring rates (<1 m/h). After a 20 m offset to the south, Hole U1365E began at 2030 h on 21 October. The BHA was set back, the APC bit was removed, and the rotary core bit and RCB coring system were assembled in preparation for running the new RCB BHA. The BHA was being assembled when a worrisome noise was noticed on the rig floor. Subsequent investigation revealed a failed crown block sheave bearing on the Number 2 sheave. After discussions with onboard staff, Transocean management, Transocean engineering, and the original equipment manufacturer, a decision was reached to restring the blocks to a 10-part configuration, isolating the damaged sheave from the system. Work was completed on the field modification and repair at 0600 h on 23 October. The BHA was then run into the hole, followed by the drill pipe, the top drive was picked, up and the drill string was spaced out to spud Hole U1365E. Water depth was recorded at 5705 mbrf using the offset from the previous hole. The center bit was deployed, and Hole U1365E was spudded at 2210 h on 23 October. At 71 mbsf, the center bit was pulled and the RCB was dropped and coring began. RCB coring continued from 71 to 124.2 mbsf with good recovery. Because of extremely slow penetration rates, after the first core, half-cores were cut and retrieved. A total of 53.2 m was cored and 39.66 m was recovered (74.6% recovery). Contamination testing was done with fluorescent microspheres (as well as PFT) on all cores after the sediment/basement interface core. The drill string was then tripped back to the rig floor and secured for the 494 nmi transit to the next site, ending Hole U1365E and Site U1365 at 2115 h on 27 October.

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