IODP NanTroSEIZE Stage 1:
Expedition 315: NanTroSEIZE "Megasplay Riser Pilot"
Weekly Report #3
Date 07/Dec/2007
Restarted RCB coring in Hole C0001H on 30 Nov. After taking two cores (25R and 26R), stopped coring at 456.2 mbsf due to bad hole condition. Pull-out-of-hole the RCB assembly, and started make-up of 10-5/8" drilling assembly. ROV retrieving required another wait on weather for sea current. Retrieved ROV and started run-in-hole on 1 Dec. Run-in-hole 10-5/8" drilling assembly and re-entered the Hole C0001H. Washed and reamed down to 458.3 mbsf, then drilled down to 600 mbsf for two days. Pulling-out-of-hole drilling assembly in the morning of 4 Dec, moved 6 miles upstream of the current and started run-in-hole of RCB assembly. Ship on location in the evening, re-entered the Hole C0001H and continued run-in-hole to 275 mbsf. Having high weight on bit,
washed and reamed from 268 to 345 mbsf.
Despite of repeated washing and reaming, borehole condition of the Hole C0001H did not improved. Abandoned the hole and pulled-out-of-hole the coring assembly to the seafloor. Moved 60 meastward and spud a new hole (Hole C0001I) at 1550hr, 5 Dec. Jetted in down to 70 mbsf, then drilled down to 433 mbsf with RCB assembly with center bit. Continued drilling from 433 mbsf with RCB assembly with center bit at the Hole C0001I. Having several times small stuck (high torque), repeated washing and reaming down to 522 mbsf. While reaming 433 to 467 mbsf, had pipe stuck at 467 mbsf, which required 700 kN for freeing pipe.After escaping from this zone, we gave up further drilling and coring, and started pull-out-of-hole in the morning of 7 Dec.
Drilled and cored 10.6 m in Hole C0001H. Total 2 cores were taken and routinely described, measured and sampled by Science Party. Routine measurements (see Lab Activity below) have completed for all cores including Hole C0001B cores taken in the Exp 314.
Bio- and paleomagnetic stratigraphies are providing good inter-hole correlation between C0001E and F. Also, core–log integration is successfully ongoing with corrected P-wave velocity and electric resistivity data obtained by discrete sample measurements.
Personal sampling from the working halves were proceeded in parallel with routine measurements . MSCL-W NGR, XRD, UV-Vis were fixed, and these postponed analyses have also been completed. Other routine measurement subjects are listed below.
Whole-round (WR) sampling for interstitial water at Core Cutting Area
CT-scan
WR sampling for microbiology
MSCL and thermal conductivity for WR core (no thermal conductivity for RCB cores)
WR sampling for other purposes (geotechnical, structural)
Visual description
Image scanning
Colorimetry
Magnetic property
Moisture and density
Shear strength (Vane shear / penetrometer)
Microfossil age determination (nanno, foraminifer)
Sampling for element analyses (total / inorganic C, N, S)
P-wave velocity and electric conductivity for discrete cubes
In addition to the above-listed routine measurements,element analyses (C, N, S), inorganic carbon analysis, cation analyses for interstitial water were carried out.
