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doi:10.2204/iodp.proc.307.105.2006

Operations

The rig was secured for transit and the vessel was under way from Site U1316 to Site U1318 on 8 May. After a 7 nmi transit, the vessel came on site and the thrusters were lowered and the vessel was positioned over the site coordinates.

Hole U1318A

A positioning beacon was dropped at 1649 h on 8 May 2005, beginning Hole U1318A. The precision depth recorder provided a seafloor depth of 430.4 meters below rig floor (mbrf). An advanced piston corer (APC)/​extended core barrel (XCB) bottom-hole assembly (BHA) was made up with two stands of collars. Hole U1318A was spudded at 2045 h on 8 May, and a seafloor depth was established at 420.3 mbrf.

Fifteen APC cores advanced to total depth (TD) at 142.2 meters below seafloor (mbsf) (562.5 mbrf; recovery = 90%). Perfluoromethylcyclohexane tracer (PFT) and microsphere tracers were run on all cores, APC temperature measurements were taken at 28.2, 56.7, 85.2, and 113.7 mbsf, and the Tensor orientation tool took measurements from 28.2 to 123.2 mbsf. Overpulls were required on five cores, two of those on the temperature runs. The drill string was pulled clear of the seafloor at 0905 h on 9 May, officially ending operations in Hole U1318A.

Hole U1318B

The drillship was offset 20 m south of Hole U1318A. After the drill string was spaced out, Hole U1318B was spudded at 1010 hr on 9 May 2005, and the seafloor was established at 419.8 mbrf.

Fourteen APC cores advanced to 128.5 mbsf (548.3 mbrf; recovery = 94%). No tracers were run during APC coring, and the Tensor orientation tool took measurements from 24.0 to 128.5 mbsf. Overpulls were required on two cores. The coring assembly was switched to XCB. Cores 15X and 16X had virtually no recovery. The XCB cutting shoe spacer and flow sleeve were reconfigured and recovery increased to 100%. PFT and microsphere tracers began on Core 19X (176.5 mbsf) and ended on Core 26X (235.0 mbsf). Thirteen XCB cores advanced an additional 116.1 m to TD at 244.6 mbsf (644.4 mbrf) at 0630 h on 10 May (recovery = 79%).

Hole U1318B was prepared for logging. A wiper trip was run from bottom up to 60 mbsf and back to bottom. There were no hole problems, and only 1 m of fill was circulated out. The hole was displaced with 102 bbl of sepiolite mud, and the drill pipe was tripped to the logging depth of 70 mbsf.

The Schlumberger wireline logging sheaves were rigged up, and the triple combination (triple combo) tool string was assembled. As the logging string was run in the hole, it took weight at 70 and 96 mbsf. The tools worked their way through the restrictions and were able to get to TD at 244.6 mbsf. From TD the triple combo logged upward to 70 mbsf. The data quality was good, so a second pass was not necessary. The tools were pulled out of the hole and laid out.

The second logging run was with the Formation MicroScanner (FMS)-sonic tool string. The FMS-sonic tool string was assembled and run to bottom with no problems. Two passes were made from 244 to 87 mbsf. The logging string was pulled out of the hole and laid out. The Schlumberger wireline logging sheaves were rigged down, ending the logging operations at 1855 h on 10 May.

The drill pipe was tripped out of the hole and pulled clear of seafloor at 2110 h on 10 May, ending operations in Hole U1318B.

Hole U1318C

The vessel was offset 25 m south of Hole U1318B, and the drill string was spaced out for spudding. Hole U1318C was spudded with the APC at 2245 h on 10 May 2005, and a seafloor depth of 420.9 mbrf was established.

A center bit was dropped and the hole was washed/​drilled down to 70.0 mbsf. The center bit was retrieved with the wireline, and seven APC cores advanced an additional 58.6 m to 125.7 mbsf (546.6 mbrf; recovery = 93%). No PFT or microsphere tracers were run, and the Tensor orientation tool took measurements from 79.5 to 125.7 mbsf. Overpulls were required on two cores, so the coring assembly was switched to XCB. Three XCB cores advanced an additional 28.8 m to TD at 154.5 mbsf (575.4 mbrf). The drill string was pulled clear of the seafloor at 0900 h on 11 May. The positioning beacon was released and recovered on deck at 0920 h, the drill pipe was tripped to surface, and the BHA was racked back. The rig was secured for transit to Site U1317 at 1015 h on 11 May, ending operations at Site U1318 (Table T1).

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