IODP

doi:10.2204/iodp.sp.315.2007

Site summaries (continued)

Proposed Site NT2-03B
Priority:
Primary:
Chikyu Expedition 314 (LWD)
Chikyu Expedition 315 (Megasplay Riser Pilot)
Position:
33°14.30′N, 136°42.65′E
Water depth (m):
2178
Target drilling depth (mbsf):
1000 m
Approved maximum penetration (mbsf):
1250; approved by CDEX and TAMU safety panels based on EPSP Jan 2007 recommendation
Survey coverage:
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)
Objective
(see text for full details):
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
Drilling, coring, and downhole measurement program:
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:
• Deploy reentry cone and 20 inch casing in case TD is not reached in pilot and LWD holes
• Drill without coring to depth of Hole B
• 13-3/8 inch casing if required
• RCB core to TD
• Wireline logging (triple combo, FMS-Sonic) 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
Anticipated lithology:
0–210 mbsf: slope sediments
210–800 mbsf: accretionary prism (deformed, compacted turbidites)