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doi:10.2204/iodp.proc.342.103.2014

Operations

All times shown are local ship time (Universal Time Coordinated – 3 h).

Hole U1402A summary

• Latitude: 39°13.518′N
• Longitude: 72°16.5488′W
• Water depth (m): 638.6
• Date started: 1542 h, 6 June 2012
• Date finished: 0110 h, 8 June 2012
• Time on hole (days): 1.4
• Seafloor depth below rig floor (m drilling depth below rig floor [DRF]): 650.5
• Seafloor depth estimation method: previous drilling at Site 1073
• Rig floor to sea level (m): 11.4
• Penetration depth below seafloor (m drilling depth below seafloor [DSF]): 96.4
• Cored interval (m): none
• Drilled interval (m): 96.4
• Drilling system: 11 inch APC/extended core barrel (XCB) bit with 126.58 m BHA
• Objective: wash down to ~100 mbsf and begin engineering test of MDHDS and temperature-dual-pressure probe (T2P) tools. Spot core per instructions.
• Result: initial trip and the in-pipe test of the electronic RS (ERS; “RS” is an oil-field designation for a particular geometry of fishing tool), MDHDS, and T2P tool was aborted when the tool prematurely released at 250 m DRF. After trying to reattach the ERS and trying to fish the assembly, the drill string was tripped to the surface and the test equipment was rigged down and tested. The second test was partially successful and required another trip out of the hole.

Hole U1402B summary

• Latitude: 39°13.518′N
• Longitude: 72°16.535′W
• Water depth (m): 639.1
• Date started: 0110 h, 8 June 2012
• Date finished: 1330 h, 8 June 2012
• Time on hole (days): 0.5
• Seafloor depth below rig floor (m DRF): 650.5
• Seafloor depth estimated method: APC-calculated depth
• Rig floor to sea level (m): 11.4
• Penetration depth below sea floor (m DSF): 15
• Cored interval (m): 15
• Recovered length (m): 15.05
• Recovery (%): 100
• Drilled interval (m): none
• Drilling system: 11 inch APC/XCB bit with 126.58 m BHA
• Objective: core until time expires at Site U1402.
• Result: recovered Cores 342-U1402B-1H through 2H.

Description

After a 582 nmi transit from Bermuda to Site U1402 averaging 10.1 kt, the vessel arrived at the first expedition location to perform engineering qualification tests on the MDHDS. The vessel was at Site U1402 at 1542 h on 6 June 2012.

The BHA was picked up and drifted, and the drill pipe was lowered to 608 m DRF and circulated out to remove any debris. The MDHDS with the temperature-dual-pressure probe (T2P) was made up for deployment using the developmental ERS on Schlumberger wireline. After running the tools through the blocks, a surface test was performed to check all components prior to deployment. A communication problem with the tool was fixed, and the Schlumberger wireline was run into the drill pipe to ~250 m DRF. At that point, the ERS released prematurely, allowing the MDHDS and T2P to fall 400 m to the landing seat in the BHA. An attempt was made to reattach the ERS to the MDHDS, without success, and the Schlumberger wireline was pulled from the drill pipe. An MDHDS mechanical latch assembly with sinker bars was assembled and deployed on the coring line in an attempt to fish the MDHDS tool, without success. Upon retrieval of the coring line, the sinker bars were observed to have parted from the retrieval sub overshot, leaving a configuration that was impossible to fish. The decision was made to pull the drill string out of the hole to retrieve the test equipment inside the BHA.

At 0800 h, the M/V North Star arrived on location and was secured to the port side of the R/V JOIDES Resolution within reach of the number 3 crane. Three pallets of provisions and a pallet of severing explosives were unloaded from the North Star, which was released and cleared of the JOIDES Resolution at 0828 h.

After tripping out of the hole, the test equipment was removed from the BHA and inspected for damage. The drill string was again deployed, and Hole U1402A was spudded at 1405 h on 7 June, with the seafloor recorded at 650 m DRF. Hole U1402A was washed down to 96.4 m DSF (746.4 m DRF), and the MDHDS, T2P, and ERS were assembled and deployed for a second test. Both temperature and pressure signals were successfully transmitted to the rig floor for ~30 min and recorded. When circulation was reestablished to test the effects of circulation on formation pore pressure, telemetry was lost. It was found that the tool could not be withdrawn using the wireline system. The ERS was released, the Schlumberger wireline was pulled from the hole, the top drive was set back, and the drill string was tripped from the hole. The bit cleared the rotary table at 0110 h on 8 June, ending Hole U1402A. It was found that the tether within the MDHDS had worked between the tool and the inside of the BHA aperture, jamming the tool in place and preventing recovery. This concluded the MDHDS sea trial.

When the MDHDS tests were concluded, several hours remained until a helicopter would arrive to exchange departing engineers with arriving science support technicians. The science party requested that a few cores be obtained from Site U1402 to test lab equipment and provide experience for the science staff. The vessel was offset 20 m east, the drill string was deployed a third time, and Hole U1402B was spudded at 0625 h on 8 June. Two cores were taken from 0–15 m DSF, with 100% recovery (Table T1). Core 342-U1402B-1H was a 7 m long mudline core, and Core 2H was an 8 m long partial stroke core that suffered significant core liner damage. The coring system had to be disassembled to remove the core and liner and was reassembled.

While working on retrieving the second core, a scheduled helicopter arrived on deck at 0932 h with four United States Implementing Organization (USIO) staff. The helicopter refueled, took on five MDHDS scientists/engineers and luggage, and departed the JOIDES Resolution at 1020 h. The rig floor was secured at 1330 h on 8 June, ending Hole U1402B, and the vessel was under way at full speed to Site U1403.

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