Transit to Site 1130

The 45-nmi transit to Site 1130 required 4.5 hr at an average speed of 10.0 kt. A beacon was launched at 2207 hr on 11 November, followed by a second beacon, initiating Site 1130.

Hole 1130A

The ship was stabilized on position and an APC BHA was run to 476 mbrf, based on the readings from the precision depth recorder (PDR). The first two attempts to spud the hole resulted in no recovery, indicating that the PDR depth was inaccurate. The PDR computer was reinitialized and the bit was positioned at 497 mbrf, closer to the estimated water depth in the leg prospectus. Hole 1130A was spudded at 0200 hr on 11 November, and Core 1H recovered 8.48 m, indicating a water depth of 486.7 mbsl. APC coring advanced to 170.0 mbsf, ceasing when 90 kips could not dislodge Core 18H, which required drilling over the core barrel to release it. The nonmagnetic shoe, flapper, and liner seal sub were deployed on Cores 3H, 5H, 7H, and 9H. The bottom portion of Core 3H was lost when the single, nonmagnetic flapper core catcher failed. Cores 3H–18H were oriented and Adara tool heat-flow measurements were taken on Cores 4H and 8H. The DVTP temperature probe was deployed after Core 12H at 113.0 mbsf.

Coring resumed with the XCB from 170.0 to 380.5 mbsf. The last six cores (Cores 36X–41X) had 3.4% recovery in interbedded cherts and chalks. Two soft-formation XCB shoes were destroyed when chert beveled out the throat of each shoe. As a safety precaution before penetrating Sequence 7 sandstones, operations were slowed (after Core 33X) to allow hydrocarbon gas monitoring to be completed before proceeding with each succeeding core. Only background levels of gas were detected. The pipe became stuck at 378 mbsf after Core 41X; however, it was pulled free with 70 kips overpull. Hole 1130A was terminated because of poor recovery in the sandstones with the XCB system. The hole was filled with mud, and the drill string was recovered, clearing the seafloor at 1815 hr on 13 November.

Hole 1130B

The ship was moved 20 m west and Hole 1130B was spudded at 1915 hr on 13 November. The bit was positioned at 494 mbrf, and Core 1H recovered 3.93 m, indicating a water depth of 488.1 mbsl. APC coring advanced to 156.0 mbsf. Cores 3H–17H were oriented and an Adara tool heat-flow measurement was taken on Core 6H. The nonmagnetic core barrel assembly was deployed on Cores 3H, 5H, 7H, 9H, 11H, and 13H. Core 3H was lost when it slipped past the single nonmagnetic flapper catcher; thus, a steel 10-finger core catcher was added to the nonmagnetic core barrel assembly thereafter. XCB coring was advanced to the depth objective of 310.4 mbsf with 101.2% recovery in chalk. After plugging the hole with mud, the drill string was recovered, clearing the rig floor at 1530 hr on 14 November.

Hole 1130C

The ship was moved 20 m north and Hole 1130C was spudded with the RCB at 1830 hr on 14 November. The interval from 0 to 299.2 mbsf was drilled, followed by a one-stand wiper trip to 331 mbsf to condition the hole. Coring resumed with the RCB from 299.2 to 395.2 mbsf. The rotary stalled while cutting Core 9R; however, the pipe was worked free in 15 min with 50 kips overpull. Rotation and circulation were regained, and a mud sweep was circulated. Core 10R was cut from 385.6 to 395.2 mbsf, after which the pipe became stuck again in presumably friable and variably indurated sandstones. The pipe could not be freed, so the bit was released with the MBR. The pipe was worked free after 2.5 hr, and circulation and rotation were reestablished. However, coring operations were terminated because hole conditions were too unstable to continue under shallow-water operational guidelines. The end of pipe was pulled to 106 mbsf in preparation for logging. Logging tools were run in the following order: (1) triple combo (368.5 mbsf, 26.7 m off bottom, to the mudline) in two runs because of failure of the wireline heave compensator on the first run; (2) FMS/Sonic (368.9–90.5 mbsf) in two runs; and (3) well seismic tool (WST; 363.5 mbsf to the end of the pipe) with eight stations ~30 m apart. After conclusion of logging operations, the hole was plugged with mud, the rig secured for transit, and the vessel departed for Site 1131 at 0845 hr on November 16.

To 182 Summary of Engineering and Drilling Operations for Site 1131

To 182 Table of Contents