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OPERATIONS (continued)

Site 1219
Transit to Site 1219 (PAT-17C)

The 398-nmi voyage to proposed Site PAT-17C was accomplished in 36.0 hr at an average speed of 11.1 kt. After the vessel slowed to 5 kt at 0100 hr on 23 November, a short 3.5-kHz survey was made from east to west across the site. Upon conclusion of the 1-hr survey, the vessel came about and returned to site as the thrusters were lowered and the DPS was activated. The GPS receiver interface to the DPS was employed to situate the vessel over the coordinates of the new location by 0200 hr. A beacon was deployed at 0300 hr. The corrected PDR depth was 5084.4 mbrf.

Hole 1219A

After the drill string was deployed to a depth of 5071 mbrf, the driller further lowered the bit until the heave compensator appeared to activate, suggesting contact with a firm seafloor. The contact was at a bit depth of ~5075 mbrf. Hole 1219A was then spudded with the APC at 1200 hr, on 23 November, with the bit at 5071.0 mbrf. The seafloor depth indicated by the recovery of the initial core was 5074.5 mbrf. This depth was 9.9 m deeper than the PDR depth.

Hole 1219A was deepened to 224.5 mbsf with the APC before the XCB was deployed to accomplish the deeper objectives of the hole. Orientation began with Core 3H. All 24 piston cores were fully stroked events, but six core barrels (Cores 18H and Cores 20H through 24H) could not be pulled free of the sediment even with 80,000 pounds of overpull. The core barrels had to be drilled over to release them from the sediment. The active heave compensator (AHC) was engaged during drill-over operations for the majority of these cores. The average recovery in the APC section was 103.7% (Table T1).

XCB coring (Cores 25X through 27X) deepened the hole from 244.5 to 250.8 mbsf. A small sample of basalt was obtained in the last core confirming basement contact. XCB coring advanced 26.3 m and recovered 7.67 m (29.2%). The total recovery of Hole 1219B was 240.41 m representing 95.9% of the cored interval (Table T1).

Downhole Logging, Hole 1219A

To prepare the hole for logging, the drill string was pulled to 80.5 mbsf and then lowered back to 250.8 mbsf. The hole was then displaced with 100 bbl of 8.9-lb/gal sepiolite mud and the bit was placed at the logging depth of 83.3 mbsf. Logging then began at 1530 hr on 25 November.

The triple combo configuration with the MGT was deployed first. Two passes were made with the triple combo tool in Schlumberger mode followed by two passes in Lamont mode for MGT data acquisition. The triple combo configuration was followed by two passes of the FMS-Sonic toolstring. In all, six passes were made with no bridges encountered and the bottom of the hole was reached on all passes. Logging operations were completed by 1200 hr on 26 November.

Hole 1219B

After logging operations were completed, the bit was pulled free of the seafloor at 1230 hr on 26 November and the vessel was offset 20 m north of Hole 1219A. Hole 1219B was spudded with the APC at 1330 hr on 26 November. In order to obtain a good stratigraphic overlap with results from the first hole, Hole 1219B was drilled to 21 mbsf before piston coring was initiated. The plan for this hole was to deepen it with APC/XCB coring to ~240 mbsf. This depth objective was thwarted when the core barrel containing Core 16H could not be retrieved with the wireline. The piston core was fully-stroked and was pulled free of the sediment with a moderate amount of overpull (60 klb). However, the core barrel jammed in the BHA and could not be recovered in a routine manner. The Kinley Cutter was used to sever the wireline, after which the drill string and BHA, with the core barrel and Tensor tool, were recovered.

In light of the operational difficulties in Hole 1219B and the successes of both Hole 1219A and Site 1218, the shipboard party made a collective decision to abandon Site 1219 earlier than planned. This decision was made in order to target additional and more complete programs at forthcoming sites having lower and middle Eocene objectives. The vessel departed for the next site (PAT-9D) at 0445 hr on 27 November.

Sixteen piston cores were recovered at Hole 1219B with orientation starting on Core 1H. Heat flow measurements were obtained at 49.5 mbsf (Core 4H), 78.0 mbsf (Core 7H), and 116.0 mbsf (Core 11H). The average recovery in the Hole 1219B cores was 101.1% (Table T1).

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