Site NNB-03A
Priority: 2
Position: 45°19.6'N; 44°37.9'W
Water Depth: 4553 m
Sediment Thickness: 1240 m, from stacking and wide-angle velocity models
Target Drilling Depth: 1340 mbsf
Approved Maximum Penetration: 1600 mbsf; drill without coring to 500 mbsf
Seismic Coverage: Ewing 00-07 line 2 MCS; SP 28731 (CMP 230858) (see Figs. F3, F5, F8)
Operational Program: The drilling/logging plan consists of a twocasing string strategy with a 103/4-in casing liner as contingency to ensure we can obtain deep sediments and basement. We will drill 20-in casing in to ~80 mbsf and then 16-in casing to ~475 mbsf. RCB coring will extend from 500 mbsf down to, and into, basement. Logging will consist of the two standard logging strings and a checkshot with the WST. After the primary deep objectives have been achieved, if time permits, we will core the upper ~500 m of section in order to obtain a complete sedimentary record at this site. See "Alternate Sites: Proposed Site NNB-03A" section and Table T2.
Logging and Downhole: Three logging runs (1) triple combo tool string, (2) FMS-sonic tool string, and (3) checkshot with WST. Core orientation and temperature tools if alternate plan for shallow coring occurs.
Nature of Rock Anticipated: From top to base: clays, silty clays, and claystones (equivalent to Blake Ridge formation); siliceous and/or cherty claystones (equivalent to Bermuda Rise formation); multicolored claystones (equivalent to Hatteras formation).