Priority:
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Primary:
- Chikyu Expedition 314 (LWD)
- Chikyu Expedition 315 (Megasplay Riser Pilot)
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Position:
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33°14.30′N, 136°42.65′E
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Water depth (m):
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2178
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Target drilling depth (mbsf):
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1000 m
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Approved maximum penetration (mbsf):
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1250; approved by CDEX and TAMU safety panels based on EPSP Jan 2007 recommendation
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Survey coverage:
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CDEX 2006 3-D MCS; extensive survey data outlined in Proposal 603A-Full2 (www.iodp.org/nantroseize-downloads):
- Track map (Fig. AF23)
- 3-D Inline 2675 (Figs. AF27, AF28)
- 3-D Crossline 5475 (Fig. AF29)
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Objective
(see text for full details):
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Sample forearc basin sediments and deformed prism
Preparatory site for 3.5 km deep Stage 2 riser site (Stage 2 will characterize megasplay fault zone system by intersecting it at intermediate depth of 3.5 km)
Integration with proposed Sites NT2-01A and NT3-01 is essential
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Drilling, coring, and downhole measurement program:
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Chikyu Expedition 314 (LWD):
- Pilot hole using MWD
- Hole A - MWD/LWD to 1000 m
Chikyu Expedition 315 (Megasplay Riser Pilot): Hole B:
- Jet-in test
- APC/XCB coring and downhole measurements (temperature, core orientation)
Hole C:
- Install reentry cone and 20 inch casing
- Drill without coring to depth of Hole B
- RCB core to TD
- Wireline logging (DSI, VSP)
- Deploy reentry cone and 13-3/8 inch casing if required to achieve TD
- Wireline logging only as contingency in case Chikyu Expedition 314 LWD is not successful
Hole D:
- Initiate riser drill hole
- Install 36 inch conductor casing
- Drill 26 inch hole to 700 mbsf
- Install and cement 20 inch casing
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Anticipated lithology:
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0–210 mbsf: slope sediments
210–800 mbsf: accretionary prism (deformed, compacted turbidites)
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