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2006 October 30
Weekly Topics from Chikyu #10 -Shimokita Shakedown Cruise- Back to list
Furious sea: A developed low pressure passed on October 7-8 brought very stormy weather.
Week #10 [10/8-10/14]
Dr. Kan Aoike, CDEX staff scientist reports:

The Chikyu experienced the most severe condition since her birth from last weekend to earlier this week with the riser pipe being connected to the seabed. A large low pressure developed to the same scale of a typhoon hits the off Shimokita area, bringing strong winds exceeding 30 m/s and high waves up to 7 m. Even the Chikyu being a huge ship, where nobody perceives usually rolling and pitching, labored in so much that not a few people felt seasick. Finally the Emergency Disconnect Sequence (EDS) of BOP was executed on October 7. The heaving exceeded 10 m. Several damages on the LMRP of the BOP were found by observation with a ROV (Remotely Operated Vehicle). Inspections of damages were carried out immediately after pulling up above the Moon Pool, and it was deemed that the operation plan should be changed and equivalent to the problems.

In the laboratory, we were dealing mainly with cuttings samples delivered last week. These cuttings samples were recovered from the riser drilling hole (C90001D) from October 5 to 6. Cuttings are retrieved from the circulating drilling mud and the formation depth from where the cuttings are originated can be estimated based on the flow rate of the drilling mud. Therefore, we can roughly estimate the lithology of the formation from the cuttings samples even without cores. In case that coring is conducted in intervals, cuttings that are only direct materials from subseafloor formations will play an important scientific role. Against this background, we were conducting methodological investigations on cuttings sample processing and analyses with connection to interstitial gas, bulk sediment chemistry, mineralogy, and moisture and density.

Week #11 [10/15-10/21] (To be Released)arrow

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