The transit to the Guam pilot station covered the 90-nmi distance in just 7.25 hr at an average speed of 12.4 kt. At 0945 hr on 29 March 2001, the Shamrock was alongside for a personnel exchange. By 1015 hr, the transfer of all personnel and cargo had been completed and the ship was underway for Site 1201 (proposed Site WP-1B).
During transit in international waters on 30 March at 1900 hr, a poetry reading was held in conjunction with a program sponsored by the United Nations, "Dialogue Among Civilizations." Marine Laboratory Technician Anastasia Ledwon read the poem "Planet Earth" by Marilyn Hacker.
The vessel covered the 652-nmi distance at an average speed of 11.8 kt and arrived at Site 1201 at 1600 hr on 31 March.
An APC/XCB bottom-hole assembly (BHA) was assembled, and the vibration-isolated television (VIT) camera was deployed to observe the jet-in test. The seafloor was tagged at 5722.0 meters below rig floor (mbrf) at 0750 hr on 1 April, and jetting continued to a depth of 5762.0 mbrf (40.0 mbsf), where a hard layer prevented further advancement of the jetting assembly. The drill string was pulled out of the hole, and the seafloor was cleared at 1045 hr, ending the jet-in test (see Table T1).
At 1500 hr on 1 April, Hole 1201A was spudded with the APC/XCB. However, the APC shear pins failed prematurely, causing the barrel to fall out under its own weight. With only 1.49 m of recovery, it was decided that another hole should be initiated. Hole 1201A was ended at 1545 hr on 1 April.
A problem with the spooling of the coaxial (coax) cable on the winch became apparent during the operations in >5700-m-deep water. Because of the high loads imposed by the deepwater operations at Site 1201, the coax cable was squeezing into the underlying cable wrap at isolated points. This led to uneven spooling and was destined to become further aggravated by each successive layer. Because improper spooling of the cable could lead to internal cable damage and ultimate cable failure, we tried to correct the spooling problem before it became further aggravated.
In an attempt to correct or at least improve the cable spooling situation and avoid or minimize the potential for cable damage, the VIT sleeve was lowered until it came to rest on the drill bit at the end of the BHA. With the core bit ~7 m above the seafloor, the drill ship was offset in dynamic positioning (DP) mode in a constant direction at ~1 kt. Simultaneously, the winch operator played out an additional 125 m of coax cable, letting the cable belly out aft of the ship and then spooled it back on. Cable spooling after this operation was significantly improved; however, the problem still existed to some extent because we were unable to get far enough into the underlying wraps to properly retension the cable.
The vessel was repositioned over the drill site, and Hole 1201B was spudded at 1905 hr on 1 April, establishing a seafloor depth of 5721.3 mbrf. APC coring was initiated and continued through Core 195-1201B-6H to a depth of 46.7 mbsf, where an incomplete stroke on a hard layer signaled the end of piston coring. The XCB core barrel was deployed, and coring continued through Core 195-1201B-11X to a depth of 90.3 mbsf, where coring was terminated because alternating hard and soft turbiditic layers tended to cause jamming in the XCB cutting shoe. Hole 1201B was ended when the drill string cleared the seafloor at 1815 hr on 2 April.
The vessel was offset 15 m to the west, and Hole 1201C was spudded at 1935 hr on 2 April. APC coring continued through Core 195-1201C-6H to a depth of 46.7 mbsf. Tensor tool-oriented measurements were taken on Cores 195-1201C-3H through 6H, and Adara temperature measurements were taken on Cores 3H and 5H. The temperature measurement taken on Core 195-1201C-5H was successful; however, the Core 3H measurement recovered no data. The drill string was pulled clear of the seafloor at 0720 hr and was recovered back to the drill ship. The rig floor was cleared, and the vessel was secured for transit by 1715 hr on 3 April.
Because of the critical need for the subsea television to achieve the Leg 195 objectives, it was necessary to take steps to correct the deepwater spooling problem. We decided to transit northwest in search of a deepwater pocket on the otherwise relatively flat seafloor. At 1715 hr on 3 April, the ship was under way for a deepwater location identified on the admiralty charts. After failing to locate the desired water depth of >6100 m at our first target location, we continued in a westerly direction to a second target location identified on Japanese hydrographic charts. After traveling a total of 204 nmi from Site 1201, we located a water depth of 6235.4 mbrf based on a corrected precision depth recorder reading at 20°59.9´N latitude and 133°27.5´E longitude. Deployment of the coax cable to a depth of 6183 m allowed the spooling problems to be corrected and left the coax cable in good condition.
At 1715 hr on 4 April, the vessel was in transit back to the drilling location at Site 1201. At 0718 hr on 5 April, the thrusters and hydrophones were lowered and the drill string was tripped to the seafloor. Hole 1201D was spudded at 1630 hr, and a seafloor depth of 5720.0 mbrf was determined. The hole was drilled with a center bit to a depth of 80.4 mbsf where RCB coring was initiated. Coring continued without incident through Core 195-1201D-44R to a depth of 503.3 mbsf. The basement contact was encountered on 9 April while Core 195-1201D-45R was cut at ~510 mbsf. Coring continued in basaltic basement through Core 195-1201D-55R to a depth of 600.0 mbsf.
A wiper trip in preparation for logging up to 80 mbsf and back was uneventful except for a couple of ledges encountered in the basement section of the hole. The hole was displaced with 30 bbl of sepiolite mud, and the pipe was pulled to the logging depth of 80.0 mbsf.
The first run with the triple combo (Lamont-Doherty Earth Observatory temperature/acceleration/pressure [TAP] tool/dual laterolog [DLL]/hostile-environment lithodensity tool/accelerator porosity sonde/hostile-environment natural gamma sonde) reached a depth of 599.0 mbsf. Logging continued up from TD to 450.0 mbsf, where the caliper had to be closed to get through a tight section of hole. When the caliper was closed, current to the DLL tool was lost and logging had to be stopped. Logging was restarted and continued from 415.0 to 120.0 mbsf, where a tight spot directly below the pipe was encountered. The interval from 180.0 to 96.0 mbsf was repeated without incident. The first run was completed and rigged down by 0200 hr on 13 April.
The second tool string run in the hole was the FMS-sonic (micro-electrical scanner tool/long-spaced sonic tool/natural gamma ray spectrometry tool). The tool was lowered until an obstruction that could not be passed was encountered at 355.0 mbsf. Logging continued up to 120.0 mbsf, where the tool was lowered for a second pass. The second pass reached the obstruction at 355.0 mbsf and took another 30 min of working to reach 370.0 mbsf, a gain of 15 m. Logging was then conducted up to the drill pipe at 80.0 mbsf. With the second tool string recovered, rig-down was completed and wireline logging operations were ended at 1330 hr on 13 April.
After completing the wireline logging effort, the pipe could only be lowered an additional 10 m to a depth of 90.0 mbsf before encountering an impassable bridge. At that point, a 15-bbl (50 m) plug of 15.8-pound per gallon (ppg) cement was set to prevent possible future communication with the cased reentry hole and seismometer installation. Upon completion of the cementing operation, the drill string was pulled out of the hole, clearing the seafloor at 1610 hr on 13 April.
The upper guide horn was laid out, and the reentry cone was moved into position on the moonpool doors. Three joints of 16-in casing were made up with the 16-in casing hanger and latched into the reentry cone. The reentry cone-casing assembly was then lowered to the seafloor, and at 1600 hr on 14 April, Hole 1201E was spudded at 5721.0 mbrf. Ultimately, the reentry cone base was landed at the seafloor and the Drill-Quip (DQ) running tool was released without difficulty at 1830 hr. The 16-in casing shoe was placed at 39.1 mbsf.
At 1945 hr on 15 April, Hole 1201E was reentered and drilling of the 14.75-in hole commenced. Drilling proceeded without incident, and at 0845 hr on 17 April, basement was contacted at a depth of 512.0 mbsf. Basement drilling continued at a slower rate but without difficulty. At 2100 hr on 17 April, drilling was terminated at a depth of 543.0 mbsf (31.0 m into basement).
A wiper trip back to the 16-in casing shoe at 39.1 mbsf was performed. There was no fill identified on the bottom, and the hole was judged to be in excellent condition. The top drive was set back, and the drill string was pulled clear of the reentry cone at 0300 hr on 18 April. Rig-up and running of the 10.75-in casing string went exceptionally well. A total of 43 joints of casing was made up to the casing hanger by 1700 hr on 18 April.
Hole 1201E was reentered for the second time at 0624 hr on 19 April, and the casing string was washed to a depth of 528.7 mbsf, where it landed on the casing hanger. Fifty barrels of 15.8-ppg cement was mixed up and displaced downhole with the mud pumps. The cementing operation was completed, and by 1112 hr the DQ running tool was released. Hole 1201E was reentered again at 1052 hr on 20 April. It took 3.5 hr to drill out the cement and wash to the bottom of the 14.75-in hole at 543.0 mbsf.
At 1645 hr, drilling of the 9.875-in ION installation hole began, and by 1600 hr on 21 April, the hole had reached a total depth of 580.0 mbsf. At 1945 hr on 21 April, the pipe cleared the reentry cone/seafloor, ending the reentry cone/casing/drilling operations at Hole 1201E.
After laying out the upper guide horn, preparations for deployment of the ION seismometer package began. The instrument carrier was made up to a joint of 4.5-in casing. At 0930 hr on 22 April, the 4.5-in casing and cable deployment operation began. Each joint of 4.5-in casing was run with two electrical cables strapped to the outside and secured with tie wraps and duct tape. Approximately every 1.5 m, a 4.5-in casing centralizer (measuring ~9 in outside diameter [OD]) was attached. A total of 23 additional joints of casing were run, making the total string length ~279 m. A circulating sub (~0.3 m) was then installed, followed by another 23 joints (~268 m) of casing. This was followed by the riser/hanger assembly.
At this point, electrical continuity checks were made, and the long and tedious cable terminating process was begun at 1915 hr on 22 April. By 1230 hr on 23 April, the instrument string was assembled and final electrical integrity checks were completed. Hole 1201E was reentered for the fourth and final time, and the instrument package was lowered into the hole without incident. The riser/hanger was landed at 0100 hr on 24 April, and a 50-bbl slurry of 15.8-ppg cement was mixed and displaced using the rig pumps. The instrument string was cemented in place with the end of the stinger located at a depth of 568.4 mbsf, or 56.4 m into basaltic basement. The top of the uppermost seismometer was placed at ~558.4 mbsf, or ~46.4 m below the basement contact. Using theoretical hole volumes and displacements, the top of the cement slurry should have reached a level of 142.6 m above the 10.75-in casing shoe (384.4 mbsf).
Preparations for deployment of the battery frame included bolting and tack welding the frame structure and rigging the deployment bridle, the glass balls for cable retraction, the redundant acoustic release package, and the wire cables for transferring the weight of the platform to the logging line. Lowering the platform through the moonpool was a complicated procedure in which the deployment of cables or the platform could snag on the open lower guide-horn structure. At 0830 hr on 24 April, once the final rig-up of the logging line had been completed and all final electrical checks had been performed, the platform was lowered through the moonpool and started on its descent to the seafloor. The 5.5-hr trip ended at 1400 hr when the platform landed in the reentry cone. A handheld acoustic command transducer was deployed, and within 10 min the release confirmation signal was received. At the same time, the winch operator reported losing ~700 lb of weight. Slowly raising the logging line confirmed that a satisfactory platform release had been achieved. The VIT system was lowered to survey the platform installation and observe the J-tool release from the riser/hanger. By 2010 hr on 24 April, the camera reached the seafloor, proper platform installation was verified, and in <5 min, the J-type running tool was released.
By 1100 hr on 25 April, the ship was secured for transit and underway for alternate Site 1202 (proposed Site KS-1).