Operations at Site 1197 (proposed Site CS-08A) began when a beacon was dropped on site coordinates at 0711 hr on 6 February 2001. The corrected precision depth recorder indicated a water depth of 352.3 m.
After the drill string was deployed to 342 m, operations were put on standby to wait on weather. The maximum heave was exceeding 3 m, which was outside the limits permitted in operations in such shallow water. After 3.25 hr, the heave had dropped to 1.7 m. Hole 1197A was spudded with the advanced hydraulic piston corer (APC) at 1230 hr on 6 February (Table T2 in the "Leg 194 Summary" chapter; Tables T1, T2). The water depth estimated from the recovery of the first core was 348.3 m. Piston coring advanced to 54.6 mbsf, where a hardground was contacted. The average recovery for this interval was 101.6%. Because of the expected shallow interval, the piston cores were not oriented. Coring continued with the extended core barrel (XCB) to 203.8 m, where operations were terminated because of very low recovery. The XCB cored 149.2 m and recovered only 0.71 m (0.48% average recovery). Eleven of the 16 XCB cores had zero recovery. After the bit was recovered, the bit seal, lockable float valve, and bit were inspected to see if there was some mechanical reason for the poor performance. No mechanical reason could be found, and it was decided to end operations at Site 1197 and consider a return at a later time.
Starting at 1100 hr, the vessel remained in standby mode and on location to wait for the third helicopter arrival from Mackay, Australia, during Leg 194. The aircraft landed on the vessel at 1158 hr, took on 300 L of fuel, dropped off miscellaneous goods, and departed with Marine Specialist Shannon Center at 1227 hr. After the helicopter's departure, the beacon was recovered and the vessel proceeded to Site 1198 at 1345 hr on 7 February.
After completion of Site 1198 and a return to Site 1196, Site 1197 was revisited to drill the deep hole to basement in anticipation of better recovery through the critical interval below 60 mbsf. Thoughts were raised that perhaps the polycrystalline diamond compact (PDC) drill bit used with the XCB system, with its small-surface cutting wings, was crushing the friable formation and that the rotary core barrel (RCB) bit might in fact be a little easier on the weakly cemented reefal debris formation.
The second operation at Site 1197 began at 1700 hr on 13 February. Hole 1197B was spudded with the RCB, drilled to 50 mbsf with a center bit in place, and cored to 175.0 mbsf, where erratic torque was experienced after attempting a connection (this depth corresponded to a major unconformity at the bottom of the elusive Megasequence C). To maintain the integrity of the hole, a wiper trip was made up to 67 mbsf. Rotary coring then advanced from 175.0 to 348.0 mbsf. No hole problems were encountered, but a second wiper trip was made to 162.9 mbsf as a preventive measure. Coring was resumed and deepened the hole to 444.3 mbsf (Core 194-1197B-41R), where it was suspended for one hour to repair abrasion damage to the outer wrapping of the active heave compensator electrical and hydraulic umbilical. Coring once again was initiated and deepened the hole to 569.4 mbsf, where a third wiper trip was made to 345.8 mbsf. The driller experienced tight hole conditions in the interval from 451.5 to 422.6 mbsf on the way up the hole. RCB coring was resumed and finally penetrated basement with Core 194-1197B-65R. The final depth of 674.9 mbsf was 25 m below the 650.0 mbsf limit imposed by the Pollution Prevention and Safety Panel. Approval was given by Ocean Drilling Program (ODP)/Texas A&M University headquarters to exceed this depth.
The interval from 54.6 to 203.8 mbsf, which had an average recovery of 0.48% with the XCB in Hole 1197A, had 2.40 m recovery (1.56%) in Hole 1197B. The average recovery for the entire hole was 213.64 m (34.2%).
On 15 February, a planned rendezvous with the Wyllaway from Mackay took place. The vessel brought two bit releases, epoxy, video tapes, Schlumberger parts, and fresh produce and returned the stretcher used to evacuate Brooke Olson earlier in the leg. The vessel also returned operations engineer Leon Holloway to shore. Virtually at the last minute, Transocean Sedco Forex employee David Pence required evacuation for medical reasons. The vessel was alongside at 0700 hr and away by 0740 hr.
The hole was flushed and displaced with sepiolite mud, and the bit was released at the bottom of the hole in preparation for the logging program. As the bit was pulled up to the logging depth of 81.6 mbsf, several places in the hole required overpull to pass tight spots. In addition, the wind and sea conditions worsened by the time the logging equipment was being rigged up. The tool could not be advanced past the end of the open pipe. The tool suite was recovered and the logging equipment was partially rigged down. The pipe was repositioned with the end at 65.6 mbsf, and the tool was redeployed but only advanced to 81.6 mbsf, where the tool contacted an obstruction. When the tool was recovered, the compensating section of the digital dual induction tool was missing, presumably because the bit release top connector at the end of the pipe descended on the tool and severed this section. Logging was cancelled after attempts to clear the blockage with the drill string were unsuccessful. The drill string was recovered, both beacons were retrieved by 2335 hr on 17 February, and the vessel was slowly offset to Site 1199 (proposed Site CS-16A) using the dynamic positioning system.