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doi:10.2204/iodp.proc.341.103.2014

Operations

Transit to Site U1417

After a 1038 nmi transit from Victoria, British Columbia (Canada), averaging 10.8 kt, the vessel arrived at Site U1417. The vessel stabilized over the site at 1101 h (UTC – 8 h) on 4 June 2013. The positioning beacon was deployed at 1121 h on 4 June and remained on the seafloor for the duration of the week. The position reference was a combination of GPS signals and a single acoustic beacon.

Site U1417

Site U1417 consists of five holes (Table T1), ranging in depth from 168.0 to 709.5 m drillers depth below seafloor (DSF) (Fig. F9). A total of 198 cores were recorded for the site. The interval cored with the advanced piston corer (APC) system was 836.5 m, with 811.18 m recovered (97%). The interval cored with the extended core barrel (XCB) system was 381.8 m, with 140.77 m recovered (36.9%). The interval cored with the rotary core barrel (RCB) system was 348.7 m, with 146.92 m recovered (42.1%). The overall recovery for Site U1417 was 70.1%. Total time spent on Site U1417 was 18.6 days.

Hole U1417A

Hole U1417A was spudded at 0315 h on 5 June 2013. The seafloor was calculated to be 4198.6 m drillers depth below rig floor (DRF) (4187.7 meters below sea level). Nonmagnetic core barrels and the APC system were used for Cores 341-U1417A-1H through 20H. Temperature measurements were taken with the advanced piston corer temperature tool (APCT-3) on Cores 4H, 10H, and 13H with good results. APC coring with the wireline continued through Core 22H with the half APC coring system using steel core barrels. Partial APC strokes were recorded on Cores 6H, 8H, 18H, 19H, 20H, and 21H. The early incomplete strokes were likely due to an obstruction caused by large lonestones. Hole U1417A was terminated after Core 22H (168.0 m DSF). At the conclusion of coring, the top drive was set back and the drill string was pulled from the hole. The seafloor was cleared at 0935 h on 6 June, ending Hole U1417A. A total of 22 piston cores were taken over a 168.0 m interval, with 167.74 m recovered (99.8%).

Hole U1417B

After clearing the seafloor, the vessel was offset 20 m east of Hole U1417A. Hole U1417B was spudded at 1225 h on 6 June 2013. Initially, orientation was planned, and the FlexIT tool was deployed. High heave conditions and mechanical shearing forced abandonment of core orientation measurements in Hole U1417B. Nonmagnetic core barrels and the APC system were used for Cores 341-U1417B-1H through 20H. Cores 21H through 33H were cored using the half APC coring system. The XCB system was deployed for Cores 34X through 47X. Hole U1417B was terminated after Core 47X (358.8 m DSF). At the conclusion of coring, the top drive was set back and the drill string was pulled from the hole. The seafloor was cleared at 1645 h on 9 June, ending Hole U1417B. A total of 33 piston cores were taken over a 223.4 m interval, with 211.97 m recovered (94.9%). A total of 14 XCB cores were cut over a 135.4 m interval, with 50.99 m recovered (37.7%). Total core recovery for Hole U1417B was 262.96 m for the 358.8 m cored interval (73.3%).

Hole U1417C

After clearing the seafloor, the vessel was offset 20 m south of Hole U1417B. Hole U1417C was spudded at 1950 h on 9 June 2013, and the hole was washed down 1 m DSF. Orientation with the FlexIT tool was performed for Cores 341-U1417C-3H through 20H with satisfactory results. Nonmagnetic core barrels and the APC system were used for Cores 2H through 25H. Cores 26H through 29H were cored using the half APC coring system. Hole U1417C was terminated after Core 29H. The final depth of Hole U1417C was 226.0 m DSF. At the conclusion of coring, the top drive was set back and the drill string was pulled from the hole. The seafloor was cleared at 0725 h on 11 June, ending Hole U1417C. A total of 28 piston cores were taken over a 225.0 m interval, with 216.83 m recovered (96.4%).

Hole U1417D

After clearing the seafloor, the vessel was offset 20 m west of Hole U1417C. Hole U1417D was spudded at 1155 h on 11 June 2013. Nonmagnetic core barrels and the APC system were used for Cores 341-U1417D-1H through 18H. After Core 18H, the half APC coring system was deployed, and APC coring continued through Core 37H. After Core 20H, a 3.8 m interval was drilled. The XCB system was deployed starting with Core 38X. Coring with the XCB system continued through Core 59X, when the XCB cutting shoe returned to the surface without the cutting structure plus another 1 inch of the length of the shoe. Another XCB core barrel was dropped and was also damaged on recovery. The cutting shoe was then changed to a “softer sediment” type shoe, and coring continued. There was continuing evidence of an obstruction remaining in the hole, and after two more cutting shoe failures, coring was terminated after Core 65X at a final depth of 470.3 m DSF. The drill string was then pulled from the hole, and the bit cleared the rotary table at 1430 h on 16 June, ending Hole U1417D. A total of 36 piston cores were taken over a 220.1 m interval, with 214.64 m recovered (97.5%). One drilled interval during the APC section of the hole was 3.8 m long. A total of 28 XCB cores were cut over a 246.4 m interval, with 89.78 m recovered (36.4%). Total core recovery for Hole U1417D was 304.42 m for the 466.5 m cored interval (65.3%).

Hole U1417E

After clearing the seafloor, the vessel was offset 20 m west of Hole U1417D. Hole U1417E was spudded at 0230 h on 17 June 2013, and the hole was drilled down to 264 m DSF. The wash barrel was then pulled, and Cores 341-U1417E-2R through 5R were cut to 302.2 m DSF. The wash barrel was again deployed, and the hole was advanced with a drilled interval to 399.0 m DSF. The wash barrel was pulled, and RCB coring with nonmagnetic RCB core barrels began with Core 7R and continued through Core 39R to a final depth of 709.5 m DSF. In total, 37 rotary cores were taken over a 348.7 m interval, with 146.92 m recovered (42.1%). There were two drilled intervals in Hole U1417E that added up to 360.8 m of advance without recovery.

A total of 195 bbl of high-viscosity mud was used during the drilling/coring process, and at the conclusion of the drilling/coring phase of Hole U1417E, an additional 50 bbl sweep of high-viscosity mud was pumped to condition the hole for logging. After pumping the final sweep, the rotary shifting tool was deployed by wireline and the shifting sleeve inside the mechanical bit release was pulled, releasing the bit at the bottom of Hole U1417E. After releasing the bit, the sleeve was shifted back and the top drive was set back. The drill string was then tripped out of the hole, and the end of pipe was set at 81.4 m DSF for logging.

The triple combo tool string was then rigged up and run into the hole, reaching a total depth of 624.0 m wireline log depth below seafloor (WSF) at 0245 h on 21 June. The hole was then logged up, a short repeat pass was recorded, and the tools were pulled to the surface and rigged down. After rigging down the triple combo tool string, the Versatile Seismic Imager (VSI) tool string was rigged up. During the rig up time, the Protective Species Observation watches began, and it became immediately apparent that a small group of northern fur seals were present within the 940 m diameter exclusion zone for this site. The decision was made to terminate the VSI run for the day, pull back the VSI tool string, rig down, and prepare the Formation MicroScanner (FMS)-sonic tool string for deployment. The FMS-sonic tool string was then rigged up and deployed to 571.5 m WSF. Two full passes were made with the tool string, and it was then pulled to the surface and rigged down. The Magnetic Susceptibility Sonde (MSS) tool string was then rigged up and run; this run was the first deployment of the full MSS tool during the Integrated Ocean Drilling Program (IODP). The maximum depth the MSS tool string reached was 204.0 m WSF because of a constriction in the hole. This shallow part of the hole was then logged with two runs, and the tool string was pulled to the surface and rigged down. The VSI tool string was then rigged up and run into the hole. Protective Species Observation watches began at first light. No protected marine species were observed during this period within the exclusion zone, so the seismic source (a parallel cluster of two 250 inch³ Sercel G. Guns) was ramped up starting 1 h after the watches commenced. Watches continued throughout the VSI run, with the guns fired manually as the tool string was run into the hole. The guns were powered down because of the presence of a whale during the manual firing stage. The whale entered the exclusion zone when the guns were powered down and then exited the exclusion zone. As the whale was observed to exit the zone within a short period of time, the guns were then ramped back up using a soft start procedure. Once the VSI tool string was in the hole, firing control was delivered to the Schlumberger engineer. After attempting to position the tool at the deepest possible depth and then moving it up to shallower stations, only one station was successfully completed at ~211 m WSF, which consisted of two good shots. The tool string was pulled out of the hole to the surface and rigged down. The guns were secured, and the Protective Species Observation watches ceased. All logging equipment was rigged down by 1605 h on 22 June, and the knobbies were removed from the drill string. The drill string was then pulled from the hole.

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