LEG 196 OPERATIONAL PLAN SUMMARYThe basic Leg 196 operational plan calls for LWD operations to be completed at all sites before the two ACORK installations (Table 2). This is required for a number of reasons. The most important being (1) the scientific and operational need for LWD data at the ACORK sites to fine-tune placement of the packers and screened monitoring zones and (2) the fiscal need to limit the time LWD tools are on the drillship. Hence, a brief midleg port call is scheduled in Osaka to off-load the LWD tools and allow a personnel transfer. This scenario implies that the time available for LWD must be defined to allow sufficient time to deploy two ACORKs after the tool and personnel transfer. The operational estimates were constructed with modest contingency time for the ACORK installations after the midleg port call. This leaves sufficient estimated time for full LWD operations at the three primary Leg 196 sites, but not for additional LWD sites.
If the LWD operations at the primary sites are completed ahead of schedule, LWD may be conducted at additional sites as described below up to the time of the scheduled midleg port call. As the Leg 196 ACORKs will be the first installed by ODP, it is quite possible that the time estimates may differ from actual installation times. Furthermore, the Kuroshio Current could present additional risk to assembling and deploying the ACORKs. If time becomes available during the ACORK phase, for whatever reasons, contingencies include the following: (1) packer permeability measurements in the basement section at Site 1173 (prior to final completion of the ACORK there), (2) Davis-Villinger termperature probe (DVTP) and water-sampling temperature probe (WSTP) measurements in the sediments at previously cored or alternate sites, (3) coring at alternate sites already approved for Leg 190, or (4) coming to port a day or two early if that time can be utilized for Legs 197 or 198.
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