Shipboard scientists examined the drill cuttings (rocks) that remained in the drill pipe through a loupe. Sanny Saito (JAMSTEC), Harold Tobin (Univ. of Wisconsin) and Kylara Martin (Univ. of Texas) (Left to right) >>Expedition 314 Photo Gallery

IODP NanTroSEIZE Stage 1:
Expedition 314: NanTroSEIZE LWD Transect
Weekly Report #5
Date 26/Oct/2007

The week has been mixture of the happiness at the beginning after seeing great data from the C0002A and smooth drilling up to the 500 meters below seafloor (mbsf) at the C0003A, and kind of shock for disconnection of LWD assembly at the C0003A and recovering days.

Drilling assembly deployment for Site C0003 was done while drifting downstream at 2 knots for 12 nm from 14:00 on 19 October. On the way, an Azimuth Thruster blower motor was replaced and arrived at the site at 10:45, beacons were calibrated, the bit was positioned above the seafloor and then a first check-shot for seismic data acquisition was performed. Hole C0003A was spudded at 12:45 and jetted in 50 m. Rotary drilling began at 13:30 and drilled to more than 500 mbsf without much difficulty. At about 530 mbsf, sticky hole conditions came on relatively suddenly and drilling went to with excessive torque and rising pump pressure. The bit became stuck, and rotation was not possible though circulation continued. While trying to turn and move the pipe to free it, the lower part of drill pipe and LWD tools became disconnected at 14:15 on 21 October. Continued to attempting to recover the remaining string and LWD tools by overshot and fishing assembly many times, but it did not go successfully at this moment.

During the recovery operation, scientists processed and interpreted the LWD data taken from Site C0002A continuously. Report drafts for the Site C0001 are under the final review by co-chief Scientists and editor-in-chief. The scientific party reviewed and discussed the results at a first site summary meeting on October 24. A second, final meeting will be held on 27 October to finalize the site reports.