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doi:10.2204/iodp.pr.342.2012 OperationsAll times shown in the hole summaries are UTC. Site U1402Hole U1402A summary
Hole U1402B summary
DescriptionAfter a 582 nmi transit from Bermuda to Site U1402 (Site 1073) averaging 10.1 kt, the vessel arrived at the first expedition location to perform engineering qualification tests on the MDHDS. The vessel was on Site U1402 at 1542 h (UTC – 3 h) on 6 June 2012. The BHA was picked up and drifted, and the drill pipe was lowered to 608 mbrf and circulated out to remove any debris. The MDHDS with the T2P tool was made up for deployment using the developmental ERS tool 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 mbrf. 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 tool 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 #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 CSF-A (746.4 m DRF), and the MDHDS and the T2P and ERS tools 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 tool 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 mbsf, with 100% recovery. 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 reassembled. While working on retrieving the second core, a scheduled helicopter arrived on deck at 0932 h with four 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. Site U1403Hole U1403A summary
Hole U1403B summary
DescriptionAfter a 946 nmi transit from Site U1402 at a speed averaging 12.6 kt, the vessel arrived at Site U1403 (proposed Site JA-1A), the first site of the Paleogene Newfoundland sediment drifts project. The local vessel time was advanced one-half hour during the transit, placing the vessel in the timezone for Newfoundland. The original plan for this site called for three holes to a depth of ~250 m DSF, but the science decision was ultimately to complete operations with two holes, Hole U1403A to 253.3 m DSF and Hole U1403B to 265.1 m DSF. The decision was made to log Hole U1403B; however, the logging attempt failed because the tool became stuck and part of it broke off. Attempts to recover the tool also failed resulting in loss of time. Hole U1403A coringThe vessel stabilized over Site U1403 at 1708 h (UTC – 2.5 h) on 11 June 2012. The drill pipe was prepared and run to the seafloor. The PDR-calculated depth for the site was 4957.7 mbsl, and after some consideration, 4952 m DRF was selected as the shoot depth for the first core. Hole U1403A was spudded at 1020 h on 12 June. The mudline core recovered 5.85 m of sediment and seafloor depth was established at 4955.7 m DRF (4944.3 mbsl). However, this water depth was later suspected to be ~4 m too high, based on the seafloor depth for Hole U1403B and correlative features found in Hole U1403B. The APC recovered Cores 342-U1403A-1H through 17H, where a hard layer was encountered at ~148 m DSF. Nonmagnetic core barrels were used for APC coring, and orientation was performed on all APC cores with the FlexIt tool. The XCB was deployed from Core 18X through 29X to a final depth of 253.3 m DSF. The seafloor was cleared at 1240 h on 14 June, ending Hole U1403A. Overall core recovery for Hole U1403A was 231.82 m for the 253.3 m interval cored (91% recovery). Hole U1403B coringThe vessel was offset 20 m east and Hole U1403B was spudded at 1730 h on 14 June. The 3.9 m long mudline core established seafloor depth at 4960.1 m DRF (4948.7 mbsl), which is 4.4 m deeper than recorded in Hole U1403A. This finding, along with other indicators, called into question the accuracy of the mudline core depth calculation in Hole U1403A. Cores 342-U1403B-1H through 16H were recovered using nonmagnetic core barrels, and orientation was performed with the FlexIt tool. The chert layer identified in Hole U1403B was found to be exactly at the depth expected from Hole U1403A data, confirming the initial error in water depth for Hole U1403A. The XCB was deployed for Cores 17X through 18X, until we broke through the chert layers at 150.4 m DSF. The APC coring system was again deployed for Cores 19H through 22H to a depth of 175.9 m DSF. After a partial stroke core with a 2.97 m recovery, the XCB was again deployed for Cores 23X through 32X to a final depth of 265.1 m DSF. Overall, core recovery for Hole U1403B was 229.81 m for the 265.1 m cored interval (87% recovery). At the conclusion of coring at 2200 h on 16 June, the hole was swept clean with 30 bbl of high-viscosity mud and the drill string was pulled from the hole to 78.43 m DSF for logging with the triple combo and FMS-sonic tool strings. At 2215 h, the Schlumberger Engineer began rigging up the logging equipment. The first logging run reached the BHA but was unable to exit the BHA. The tools were returned to surface and examined to determine cause, and after making some corrections to the wireline tools, they were again deployed at 0710 h on 17 June. The tool string was run back to the BHA and again failed to pass through. This time the tools became firmly stuck inside the BHA with ~17 m of the tool string extending out from the bit. After working the tools for several hours with no progress, the Kinley crimp was set on the wireline above the tool to prevent the tool from falling out, and the logging line was severed at 1830 h on 17 June using the Kinley cutter. The wireline was retrieved and spooled back onto the winch drum. The drill string was pulled from the hole with a carefully calculated space out, which should have resulted in the bottom of the Schlumberger tool string being at least 5 m above seafloor when the pipe was set down on the dual elevator stool. At 0630 h on 18 June, with ~117 m of the BHA remaining below the rig floor, the end of the Schlumberger wireline was found. The tool string was freed from the BHA and rigged down on the drill floor. It was discovered that the triple combo tool string had parted at the lower (MC) centralizer. This left ~17 m of tools missing from the bottom of the tool string, including the nuclear sources for the density and porosity tools. When the bit cleared the rig floor, inspection revealed manganese nodules lodged between the roller bit cones, along with other typical seafloor sediments. A close examination of the tool failure supports the speculation that when the BHA cleared the rig floor, the high bottom current that we had been experiencing since first coming onto site had caused the BHA to shift with the current while the logging tool string remained in the hole. At this point all parties involved contacted their respective shore counterparts and informed them of the loss of the nuclear sources. Shipboard personnel outlined the limited actions that could be taken toward identifying the location and condition of the sources. The plan included a seafloor survey using a 100 m × 100 m search grid centered over Hole U1403B. While the drill string was being tripped toward the seafloor, the subsea camera system and vibration isolation transport (VIT) were readied for deployment. A grapple was attached to the underside of the camera frame, which would have been able to grab the “fish” while the winch, in combination with the drill string, was used to lift the tools toward the surface. The VIT frame is designed to not slide over the bit on the end of the drill string. After tripping the drill string to 3499 m DRF, the rig was secured at 1645 h on 18 June. Installation of the VIT system around the drill pipe in the moonpool, which routinely takes 30 min, proved complicated because of the ocean current pushing the pipe all the way to the side of the lower guide horn, which could therefore not be opened. The ship was eventually powered up, and using a combination of drift and powering down current, we were able to centralize the drill pipe in the moonpool, which allowed us to open the doors. After the VIT was deployed to 100 m DRF, the doors were closed and the upper guide horn was replaced. It took almost 2.5 h to accomplish this task. The camera was run to the bottom while the drill string was tripped to bottom. During the entire camera run, the camera was shaking, vibrating, and rotating around the pipe at different depths. At 2145 h, with the bit ~30 m from seafloor, the signal from the subsea camera was lost. The Mesotech sonar, which is also mounted on the VIT frame, failed as well. While pulling the camera to surface, the winch operator noticed that the effort required to pull the camera frame up was much less than normal for the water depth. Our suspicion that the coaxial cable supporting the camera system had failed was confirmed when the camera cable arrived at the rig floor. At that point there was no option other than to pull the drill string from just above the seafloor and to recover the VIT frame with subsea camera and sonar. Preliminary estimates for the time to repair the camera system were 24–48 h. Siem Offshore and IODP personnel determined that another attempt at a survey, if the camera could be repaired, would very likely result in another failure of the VIT subsea camera system. The impact of the ocean currents on the VIT frame resulted in two failures of the camera and sonar during the first deployment and nearly resulted in the loss of the only reentry system that IODP has available to continue the program. Further attempts could have resulted in the complete loss of our mission-critical reentry system. The decision not to deploy the camera system again at this site also meant that we were unable to locate the lost logging tool or Hole U1403B, which compromised our ability to follow the abandonment guidelines of an irretrievable well-logging source given to us by the onsite Schlumberger engineer. The requirement to immobilize and seal the sources into place with a cement plug was impossible to accomplish because it was impossible to find either the tool string or the hole. The drill string with the damaged VIT was recovered at ~1400 h on 19 June. A total of 2.7 days was spent for the attempt to log. The drill floor was secured at 1415 h, ending Site U1403 and Hole U1403B. The vessel then proceeded under way to Site U1404. Site U1404Hole U1404A summary
Hole U1404B summary
Hole U1404C summary
DescriptionThe vessel arrived at Site U1404 (proposed Site JA-13A) after a 4.2 nmi transit from Site U1403 and stabilized over Site U1404 at 1455 h (UTC – 2.5 h) on 19 June 2012. The plan for this site called for drilling three holes to a depth of ~250 m DSF. After completion of Holes U1404A and U1404B to 308.8 and 228.7 m DSF, respectively, Hole U1404C was drilled to 16 m DSF and then cored to 44.5 m DSF in an attempt to recapture a zone hypothesized to contain gas hydrate. The total time spent at Site U1404 was 124.75 h (5.2 days). The XCB was deployed 4 times and the APC was deployed 62 times. The XCB-cored interval was 37.8 m with a recovery of 23.05 m (61.0% recovery). The APC-cored interval was 528 m with a recovery of 515 m (97.5% recovery). The overall recovery for Site U1403 was 95.1%. Hole U1404A coringThe drill bit was spaced out to 4715 m DRF for the first attempt at a mudline core. The calculated PDR depth for the site was 4718.4 m DRF. A mistake in the pipe tally resulted in an APC wireline run to ~4705 m DRF. The depth of the bit was repeatedly lowered until mudline was established at 4753.8 m DRF (4742.3 mbsl), which was 35.4 m below the PDR depth. Hole U1404A was spudded at 1030 h on 20 June. Two possible explanations for the discrepancy between the PDR depth and the drill pipe depth were offered: (1) strong currents were causing the drill pipe to bend in an S-shape and (2) the acoustic signal was significantly affected by thermal or current layering in the water column. The second explanation is supported by the poor quality of the acoustic signal received from the acoustic beacon on the seafloor. Cores 342-U1404A-1H through 32H were recovered using nonmagnetic core barrels and the FlexIt core orientation tool. The liner of Core 4H shattered, presumably from hitting a manganese nodule. Nodules as long as 10 cm were recovered in Core 1H, and others, perhaps even larger ones, may have been washed into the bottom of the hole. In Core 22H, the formation began to firm up and the first partial stroke was recorded. Cores 22H through 32H were partial strokes, and the hole was advanced by recovery. The XCB was deployed for Cores 33X through 36X to a final depth of 308.8 m DSF. The drill bit cleared the seafloor at 2040 h on 22 June, ending Hole U1404A. Overall core recovery for Hole U1404A was 281.02 m for the 308.8 m interval cored (91% recovery). The total time spent on Hole U1404A was 77.75 h. Hole U1404B coringThe vessel was offset 20 m east. The bit was spaced out to 4752.0 m DRF in an attempt to recover ~7–8 m on the mudline core. Hole U1404B was spudded at 2255 h on 22 June, and a 2.48 m mudline core established the seafloor depth at 4759.1 m DRF (4747.6 mbsl). Cores 342-U1404B-1H through 27H were recovered to a depth of 228.7 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. The liner of Core 7H returned shattered and collapsed for unknown reasons. Cores 21H through 27H were partial stroke, and the hole was advanced by recovery. Eight core liners were either collapsed or broken and three of those had to be pumped out of the core barrel with a high-pressure pump. The bit cleared the seafloor at 1310 h on 24 June, ending Hole U1404B. A total of 27 piston cores were taken over a 228.7 m interval with a total recovery of 228.04 m (100% recovery). The total time spent on Hole U1404B was 40.5 h. Hole U1404C coringThe vessel was offset 20 m south. Hole U1404C was spudded at 1445 h on 24 June and was drilled to a depth of 16 m DSF. The seafloor depth was assumed to be the same as that for Hole U1404B (4759.1 m DRF; 4747.6 mbsl). Cores 342-U1404C-2H through 4H were recovered to a final depth of 44.5 m DSF. The total advance was 28.5 m, with 28.98 m of core recovered (102% recovery). The bit cleared the seafloor at 1945 h on 24 June, ending Hole U1404C. The drill floor was secured and the vessel began moving to Site U1405 in dynamic positioning mode at a speed of 0.9 kt. The total time spent on Hole U1404C was 6.5 h. Site U1405Hole U1405A summary
Hole U1405B summary
Hole U1405C summary
DescriptionThe vessel arrived at Site U1405 (proposed Site JA-14A) after a 7.5 nmi transit from Site U1404. The transit was made in dynamic positioning mode at a speed of 0.8 kt with the drill pipe suspended below the vessel. The vessel stabilized over Site U1405 at 0745 h (UTC – 2.5 h) on 25 June 2012. The plan for this site called for drilling three holes to a depth of ~250 m DSF. Holes U1405A–U1405C were successfully cored to depths of 308.6, 223.5, and 232.0 m DSF, respectively, without any significant problems. Hole U1405A coringHole U1405A was spudded at 1140 h on the 25 June and a 6.2 m mudline core established seafloor depth at 4297.3 m DRF (4285.8 mbsl). Cores 342-U1405A-1H through 26H were recovered from the seafloor to 241.9 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. APCT-3 temperature measurements were taken on Cores 4H, 7H, and 10H with good results. The first partial stroke was experienced with Core 26H, and the liner and core had to be pumped out of the core barrel. The XCB was deployed for Cores 27X through 33X to a total depth of 308.6 m DSF. The seafloor was cleared at 1120 h on 27 June, ending Hole U1405A. Overall core recovery for Hole U1405A was 270.34 m for the 308.6 m interval cored (88% recovery). Total time spent on Hole U1405A was 51.6 h (2.1 days). Hole U1405B coringThe vessel was offset 20 m east, and Hole U1405B was spudded at 1305 h on 27 June. A 9.5 m mudline core established seafloor depth at 4296.0 m DRF (4284.5 mbsl). Cores 342-U1405B-1H through 24H were recovered from the seafloor to 218.5 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. An interval of 5 m was drilled without coring in an attempt to cover coring gaps in Hole U1405A. The seafloor was cleared at 1610 h on 28 June, ending Hole U1405B. Coring the 218.5 m interval yielded 219.60 m of core (101% recovery). The total time spent on Hole U1405B was 29.0 h. Hole U1405C coringThe vessel was offset 20 m south. Hole U1405C was spudded at 1915 h on 28 June and a 6.7 m mudline core established seafloor depth at 4298.8 m DRF (4287.3 mbsl). Cores 342-U1405C-1H through 25H were recovered to a total depth of 232.0 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. The cored interval of 232.0 m yielded 227.77 m of core (98% recovery). The total time spent on Hole U1405C was 33.75 h. The seafloor was cleared at 0200 h on 30 June, ending Hole U1405C. After clearing the seafloor, the drill string was tripped to ~3500 m DRF and the vessel began moving in dynamic positioning mode to the next site at a speed of 1.5 kt. The positioning beacon was left on-site to minimize the risk of losing it during recovery in difficult weather conditions. The beacon was recovered after operations at Site U1406 were complete. The total time spent at Site U1405 was 114.25 h (4.8 days). Site U1406Hole U1406A summary
Hole U1406B summary
Hole U1406C summary
DescriptionThe vessel arrived at Site U1406 (proposed Site JA-6A) after a 14.9 nmi transit from Site U1405, which was made in dynamic positioning mode at a speed of 1.4 kt with the drill pipe suspended below the vessel. The vessel stabilized over Site U1406 at 1435 h (UTC – 2.5 h) on 30 June 2012. The plan for this site called for drilling three holes to a depth of ~250 m DSF. Holes U1406A–U1406C were successfully cored to a depth of 283.3, 253.6, and 241.4 m DSF, respectively, without any significant problems. The total time spent at Site U1406 was 145.5 h (6.1 days). Hole U1406A coringThe calculated PDR depth for the site was 3810.4 m DRF. Two water cores were shot before the mudline was recovered, establishing seafloor depth at 3826.3 m DRF (3814.8 mbsl). Hole U1406A was spudded at 1950 h on the 30 June and Cores 342-U1406A-1H through 25H were retrieved using nonmagnetic core barrels for all cores and the FlexIt core orientation tool on the first 17 cores. The first partial stroke was experienced with Core 16H, and the APC was advanced by recovery for this and subsequent cores. The XCB was deployed for Cores 26X through 34X to a total depth of 283.3 m DSF. The seafloor was cleared at 1920 h on 2 July, ending Hole U1406A. Overall core recovery for Hole U1406A was 267.30 m for the 283.3 m interval cored (94% recovery). The total time spent on Hole U1406A was 52.75 h. Hole U1406B coringThe vessel was offset 20 m east. Hole U1406B was spudded at 2055 h on 2 July, and a 6.5 m mudline core established seafloor depth at 3825.2 m DRF (3813.7 mbsl). Cores 342-U1406B-1H through 22H were retrieved from the seafloor to 188.8 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. The XCB was deployed for Cores 23X through 30X to a total depth of 253.6 m DSF. The seafloor was cleared at 1435 h on 4 July, ending Hole U1406B. Recovery for Hole U1406B was 241.34 m over the 253.6 m cored (95% recovery). The total time spent on Hole U1406B was 43.25 h. Hole U1406C coringThe vessel was offset 20 m south. Hole U1406C was spudded at 1630 h on 4 July and a 9.4 m mudline core established seafloor depth at 3824.6 m DRF (3813.0 mbsl). Cores 342-U1406C-1H through18H were recovered from the seafloor to 161.4 m DSF using nonmagnetic core barrels. Core orientation was not performed in Hole U1406C. The XCB was deployed to a final depth at 241.4 m DSF. Two intervals were drilled without coring (2 and 3 m) in an attempt to cover coring gaps in the previous two holes. The seafloor was cleared at 0500 h on 6 July. After clearing the seafloor, the drill string was tripped to the surface. The BHA was set back in the derrick with the exception of the lower seal bore drill collar plus subs. Schlumberger logging tools were then rigged up to conduct a pass-through check on the lower portion of the BHA. At the conclusion of the test, the remaining BHA components were secured. The drill floor was secured at 1600 h on 6 July, ending Hole U1406C. The acoustic positioning beacon was recovered and the vessel began the move to Site U1405 to recover the beacon left behind there. The total time spent on Hole U1406C was 49.5 h. Site U1407Hole U1407A summary
Hole U1407B summary
Hole U1407C summary
DescriptionAfter a 120 nmi, 11 h transit from Site U1406 at a speed of 10.9 kt, the vessel arrived at Site U1407 (proposed Site SENR-20A) at 0800 h (UTC – 2.5 h) on 7 July 2012. The plan for Site U1407 called for drilling three holes to a depth of ~250 m DSF. Holes U1407A–U1407C were successfully cored to 308.7, 276.3, and 261.6 m DSF, respectively, without any significant problems. Recovery was mediocre in the first hole because of weather but improved in the second and third holes. Overall recovery for Site U1407 was 86.9%. The total time spent at Site U1407 was 107.25 h (4.5 days). Hole U1407A coringThe second attempt at a mudline core recovered 6.81 m, establishing Hole U1407A at 1655 h on the 7 July at a seafloor depth of 3084.7 m DRF (3073.1 mbsl). Cores 342-U1407A-1H through 15H were retrieved using nonmagnetic core barrels and the FlexIt core orientation tool. The first partial stroke was experienced with Core 11H, and the APC was advanced by recovery to Core 15H (121.9 m DSF). The XCB was deployed for Cores 16X through 35X to a final depth of 308.7 m DSF. The seafloor was cleared at 1005 h on 9 July, ending Hole U1407A. Overall core recovery for Hole U1407A was 205.64 m for the 308.7 m cored (66.6% recovery). This relatively low APC recovery can most likely be attributed to the high heave and large pitch and roll of the vessel during coring operations as well as low recovery in cherts and reef sediments. The total time spent on Hole U1407A was 50.00 h. Hole U1407B coringThe vessel was offset 20 m east. Hole U1407B was spudded at 1200 h on 9 July, and an 8.4 m mudline core established the seafloor at 3085.1 m DRF (3073.5 mbsl). Cores 342-U1407B-1H through 11H were recovered using nonmagnetic core barrels and the FlexIt core orientation tool. A 3 m interval (27.4–30.4 m DSF) was drilled without coring in an attempt to cover a coring gap in Hole U1407A. Based on the recovery of an interval of chert layers in Hole U1407A, the interval from 95 to 127 m DSF was drilled without coring using the XCB. Cores 13X through 28X were then recovered to a final depth of 276.3 m DSF. The seafloor was cleared at 1340 h on 10 July, ending Hole U1407B. The recovery for Hole U1407B was 234.54 m over the 241.3 m cored (97% recovery). The total time spent on Hole U1407B was 27.75 h. Hole U1407C coringThe vessel was offset 40 m west. Hole U1407C was spudded at 1510 h on 10 July and a 7.7 m mudline core established the seafloor at 3086.8 m DRF (3075.2 mbsl). Cores 342-U1407C-1H through 11H (0–93.0 m DSF) were recovered using nonmagnetic core barrels. No core orientation was performed in Hole U1407C. A 3 m interval was drilled without coring to optimize core overlap in multiple holes. Once again, a 21 m interval (96–117 m DSF) was drilled without coring through the chert layers using the XCB. Cores 13X through 29X were then recovered to a final depth of 261.6 m DSF. The seafloor was cleared at 1805 h on 11 July. The drill string was pulled up to 2792 m DRF and the rig was secured for a dynamic positioning move to the next site at 1915 h on 11 July, ending Hole U1407C. Overall recovery for Hole U1407C was 244.4 m from the 237.6 m interval cored (103% recovery). The total time spent on Hole U1407C was 29.5 h. Site U1408Hole U1408A summary
Hole U1408B summary
Hole U1408C summary
DescriptionThe vessel arrived at Site U1408 (proposed Site SENR-21B) after a 1.46 nmi dynamic positioning move from Site U1407, which took 1.75 h at 0.83 kt. The vessel stabilized over Site U1408 at 2045 h (UTC – 2.5 h) on 11 July 2012. The plan for Site U1408 called for drilling three holes to a depth of ~250 m DSF. Holes U1408A–U1408C were successfully cored to 246.5, 217.5, and 187.5 m DSF, respectively. The total time spent at Site U1408 was 106.5 h (4.4 days). Hole U1403A coringA mudline core of 4.3 m determined seafloor depth at 3033.2 m DRF) (3021.6 mbsl). Hole U1408A was spudded at 2335 h on 11 July, and Cores 342-U1408A-1H through 20H were retrieved using nonmagnetic core barrels and the FlexIt core orientation tool. Core 14H experienced the first partial stroke and the APC was advanced by recovery to the APC total depth of 182.9 m DSF. The XCB was deployed for Cores 21X through 27X to the final depth of 246.5 m DSF. The seafloor was cleared at 1045 h on 13 July, ending Hole U1408A. Overall core recovery for Hole U1408A was 243.92 m for the 246.5 m interval cored (99.0% recovery). The total time spent on Hole U1408A was 38.00 h. Hole U1408B coringThe vessel was offset 20 m east. Hole U1408B was spudded at 1230 h on 13 July, and the 6.74 m long mudline core established the seafloor at 3033.8 m DRF (3022.1 mbsl). Cores 342-U1408B-1H through 18H were retrieved using nonmagnetic core barrels and the FlexIt core orientation tool. A 3 m long interval (25.7–28.7 m DSF) was drilled without recovery to optimize coverage of coring gaps in Hole U1408A. Coring was slowed when the FlexIt tool housing sheared at the overshot connection above the core barrel three times in the APC section of Hole U1408B. Total advance including the drilled interval with the APC was 154.5 m. The XCB was deployed for Cores 342-U1408B-19X through 26X to a final depth of 217.5 m DSF. The seafloor was cleared at 1700 h on 14 July, ending Hole U1408B. The recovery for Hole U1408B was 224.09 m over the 214.5 m cored (104.5% recovery). The total time spent on Hole U1408B was 30.25 h. Hole U1408C coringThe vessel was offset 20 m south, and Hole U1408C was spudded at 1905 h on 14 July. Cores 342-U1408C-1H through 19H (0–165.1 m DSF) were retrieved using nonmagnetic core barrels. Core orientation was performed with Cores 6H through 8H. A 3 m long interval (8.8–11.8 m DSF) was drilled without recovery to optimize coverage of coring gaps in the previous holes. Again, the FlexIt tool was held responsible for mechanical trouble, including one mechanical shear at the overshot and one mechanical shear of the APC shear pins. During APC operations, an intermittent electrical fault developed, and coring operations were suspended for 6.5 h while the problem was located and fixed. The XCB was deployed for Cores 20X through 23X to a final depth of 187.5 m DSF. The drill string was pulled to the surface and the drill floor was secured at 0715 h on 16 July, ending Hole U1408C. The vessel began the transit to Site U1409. The recovery for Hole U1408C was 181.52 m over the 184.5 m cored (98.4% recovery). The total time spent on Hole U1408C was 38.25 h. Site U1409Hole U1409A summary
Hole U1409B summary
Hole U1409C summary
DescriptionThe vessel arrived at Site U1409 (proposed Site SENR-22A) at 1010 h (UTC – 2.5 h) on 16 July 2012 after a 26.3 nmi transit from Site U1408 that took 3.0 h at 8.8 kt. The plan for Site U1409 called for three holes to a depth of ~250 m DSF. In addition, the VIT camera system was to be deployed and tested for the repairs done after the damage sustained at Site U1403. The test was aborted because of the risks to the camera system from strong ocean currents. Holes U1409A–U1409C were successfully cored to 200.1, 170.5, and 160.8 m DSF, respectively. Overall recovery for Site U1409 was 96.2%. The total time spent at Site U1409 was 101.0 h (4.2 days). Hole U1409A coringThe pipe trip to the seafloor was interrupted at 2863.3 m DRF to install the VIT with subsea camera system. The plan was to deploy the camera near the seafloor and record the shooting of the APC. After installing the VIT, it was determined that the surface currents posed a serious risk to the equipment, and the VIT frame was pulled back on board. After completing the pipe trip, a 1.07 m long mudline core defined the seafloor depth at 3514.9 m DRF (3503.2 mbsl). Hole U1409A was spudded at 2200 h on 16 July and Cores 342-U1409A-1H through 16H were recovered to 127.0 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. Core 15H experienced the first partial stroke and the APC was advanced by recovery to Core 16H. The XCB was deployed for Cores 17X through 26X to 200.1 m DSF. The seafloor was cleared at 0550 h on 18 July, ending Hole U1409A. Overall core recovery for Hole U1409A was 183.33 m for the 200.1 m interval cored (91.6% recovery). The total time spent on Hole U1409A was 43.5 h. Hole U1409B coringThe vessel was offset 20 m east. The mudline recovery was 8.36 m and established the seafloor depth at 3512.7 m DRF (3501.0 mbsl). Hole U1409B was spudded at 0800 h on 18 July and Cores 342-U1409B-1H through 14H were retrieved to 122.5 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. The XCB was deployed for Cores 15X through 19X to 170.5 m DSF. The seafloor was cleared at 0340 h on 19 July, ending Hole U1409B. The recovery for Hole U1409B was 167.09 m over the 170.5 m cored (98.0% recovery). The total time spent on Hole U1409B was 22.00 h. Hole U1409C coringThe vessel was offset 20 m south, and Hole U1409C was spudded at 0800 h on 19 July. After the mudline core, which established the seafloor at 3512.2 m DRF (3500.5 mbsl), the wireline blow-out preventer (BOP) was observed to be leaking around one of the bonnets. The top drive had to be set back, and an attempt was made to tighten the leaking connection. The top drive was then reinstalled, and a core barrel was run to bottom to take Core 342-U1409C-2H. The wireline BOP was still leaking, and the top drive had to be set back again. This time the entire BOP bonnet assembly was changed out. The top drive was again reinstalled, and APC coring resumed to Core 14H (124.2 m DSF). Nonmagnetic core barrels were used for all APC cores. Core orientation was not performed on cores from Hole U1409C. XCB coring continued from Core 15X through 21X to the final depth of 160.8 m DSF. The seafloor was cleared at 1315 h on 20 July. The recovery for Hole U1409C was 160.98 m over the 160.8 m cored (100.1% recovery). The drill string was pulled to ~3200 m DRF and the rig prepared for a transit in dynamic positioning mode to Site U1410. Although the beacon was tracked during its ascent after being released from the seafloor, it was never sighted at the surface because of poor weather conditions and strong surface currents. The drill floor was secured for transit, and the beacon recovery operations concluded at 1515 h on 20 July, ending Hole U1409C. The total time spent on Hole U1409C was 35.50 h. Site U1410Hole U1410A summary
Hole U1410B summary
Hole U1410C summary
DescriptionThe vessel arrived at Site U1410 (proposed Site SENR-23A) at 1845 h (UTC – 2.5 h) on 20 July 2012 after a 3.46 nmi transit from Site U1409 in dynamic positioning mode that took 3.5 h at 1.0 kt. The plan for Site U1410 called for three holes to a depth of ~250 m DSF. Holes U1410A–U1410C were successfully cored to 259.8, 245.2, and 243.8 m DSF. The total time spent on Site U1410 was 110.5 h (4.6 days). Hole U1410A coringA 8.53 m long mudline core established seafloor depth at 3399.0 m DRF (3387.3 mbsl). Hole U1410A was spudded at 2125 h on 20 July. Cores 342-U1410A-1H through 16H were recovered to 151.0 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. Core 16H experienced the first partial stroke. The XCB was deployed for Cores 17X through 28X to the final depth of 259.8 m DSF. The seafloor was cleared at 0500 h on 22 July, ending Hole U1410A. Overall core recovery for Hole U1410A was 256.88 m for the 259.8 m interval cored (98.9% recovery). The total time spent on Hole U1410A was 34.25 h. Hole U1410B coringThe vessel was offset 20 m east. A 3.8 m long mudline core established the seafloor at 3398.7 m DRF (3386.9 mbsl). Hole U1410B was spudded at 0650 h on 22 July. Cores 342-U1410B-1H through 18H were recovered to 153.8 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. The XCB was deployed for Cores 19X through 28X to a final depth of 245.2 m DSF. The seafloor was cleared at 1620 h on 23 July, ending Hole U1410B. The overall recovery for Hole U1410B was 244.84 m over the 245.2 m cored (99.9% recovery). The total time spent on Hole U1410B was 35.25 h. Hole U1410CThe vessel was offset 20 m south, and Hole U1410C was spudded at 1825 h on 23 July. A 6.82 m long mudline core established the water depth at 3398.7 m DRF (3386.9 mbsl). Cores 342-U1410C-1H through 16H were recovered to 146.8 m DSF using nonmagnetic core barrels. No core orientation was performed in Hole U1410C. The XCB was deployed for Cores 17X through 27X to a final depth of 243.8 m DSF. Overall recovery for Hole U1410C was 238.81 m out of 243.8 m cored (98.0% recovery). The seafloor was cleared and the vessel was secured for transit at 0915 h on 25 July, ending Hole U1410C. The total time spent on Hole U1410C was 41.00 h. Site U1411Hole U1411A summary
Hole U1411B summary
Hole U1411C summary
DescriptionThe vessel arrived at Site U1411 (proposed Site SENR-11A) at 1115 h (UTC – 2.5 h) on 25 July 2012 after a 19.0 nmi transit from Site U1410 that took 2.0 h at 9.5 kt. The plan for Site U1411 called for three holes to a depth of ~250 m DSF. The first core for Hole U1411A failed to capture the mudline and the hole was terminated after Core 342-U1411A-1H. The second hole was successfully cored to 254.2 m DSF. The third hole was APC-cored to 9.2 m DSF, advanced by drilling 90.8 m, and then cored to a total depth of 223.9 m DSF. Because of a medical emergency, the decision was made to terminate coring operations rather than coring a further, last hole at this site. Overall recovery for Site U1411 was 91.3%. The total time spent at Site U1411 was 89.75 h (3.7 days). Hole U1411A coringAfter arriving at Site U1411, a short test was performed during the BHA assembly to determine if the APC core barrel was in fact landing on the landing seat in the BHA. During the test it was discovered that the core barrel was landing prematurely in the modified top sub. The modified top sub was changed out and the test was performed again to the satisfaction of all concerned. The remainder of the drill string was tripped to just above mudline and Hole U1411A was spudded at 2320 h on 25 July. Core 342-U1411A-1H was 9.87 m long and therefor did not recover the mudline. Without confirmation of the mudline, it was decided to abandon Hole U1411A. The seafloor and water depths for Hole U1411A were adopted from Hole U1411B (seafloor at 3310.6 m DRF; 3298.8 mbsl). The seafloor was cleared at 2320 h on 25 July, ending Hole U1411A. Overall core recovery for Hole U1411A was 9.87 m for the 9.5 m interval recovered (103.9% recovery). The total time spent on Hole U1411A was 12.00 h. Hole U1411B coringThe vessel was offset 20 m east. Hole U1411B was spudded at 0035 h on 26 July and recovered a 0.93 m long mudline core, establishing seafloor depth at 3310.6 m DRF (3298.8 mbsl). Cores 342-U1411B-1H through 20H were recovered to 177.4 m DSF using nonmagnetic core barrels and the FlexIt core orientation tool. The XCB was deployed for Cores 21X through 28X to a final depth of 254.2 m DSF. The seafloor was cleared at 1310 h on 27 July, ending Hole U1411B. The recovery for Hole U1411B was 233.94 m over the 254.2 m cored (92.0% recovery). The total time spent on Hole U1411B was 38.00 h. Hole U1411C coringThe vessel was offset 20 m south. Hole U1411C was spudded at 1505 h on 27 July and recovered a 3.2 m long mudline core, establishing the seafloor depth at 3312.0 m DRF (3300.18 mbsl). Cores 342-U1411C-1H through 2H were recovered to 9.2 m DSF. After Core 2H, the hole was advanced by drilling without coring from 9.2 to 100.0 m DSF in order to save operational time for deeper objectives. After the drilling advance, APC coring continued with Cores 4H through 9H (100.0–152.2 m DSF). All APC cores were oriented with the FlexIt core orientation tool and recovered using nonmagnetic core barrels. The XCB was deployed for Cores 10X through 17X to a final depth of 223.9 m DSF. After recovery of Core 17X, a medical emergency terminated operations. The seafloor was cleared and the vessel was secured for transit at 0500 h on 29 July, ending Hole U1411C. The recovery for Hole U1411C was 118.62 m over the 133.1 m cored (89.1% recovery). The total time spent on Hole U1411C was 39.75 h. |
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inch APC/XCB bit with 126.58 m BHA