Three holes were drilled at Site 1248 (Table T1), under good weather conditions. Wind speed was 8-24 kt, gusting to 28 kt; seas were 4-9 ft; swell was 6-10 ft and the prevailing sea-surface current was from the north at ~0.5 kt.
Hole 1248A was drilled without coring to obtain the initial LWD data for this site to a total depth (TD) of 194.0 mbsf. LWD operations began at 2130 on 20 July by spudding Hole 1248A at 832 m water depth. Drilling proceeded at reduced rates of penetration (ROP) of 15 m/hr and 15 spm circulation to moderate formation washout at shallow depths below seafloor. No real-time measurement-while-drilling (MWD) or nuclear magnetic resonance (NMR) data were recorded over this interval, as the pump rate was insufficient to activate the turbines in these tools. The penetration rate was increased to ~25 m/hr at a bit depth of 30 mbsf to TD (190 mbsf), and real-time MWD and NMR data were recorded (see "Downhole Logging"). The LWD tools were pulled to ~60 m above the seafloor at 0700 on 21 July. Total bit run took ~15 hr.
Hole 1248B was spudded at 0300 hr on 1 August. Three cores were collected with the APC, after which the hole was abandoned at 17 mbsf. Coring disturbance resulting from near-seafloor massive gas hydrates and a shattered liner during retrieval of Core 204-1248B-3H caused poor core recovery (44%). There was one APCT tool deployment in Hole 1248B. There were no other special tools deployed at this site.
Hole 1248C was spudded with the XCB in an attempt to increase core recovery. Cores were drilled to 48 mbsf. Recovery was poor (23%) in Cores 204-128C-1X to 5X, and then it increased in Cores 204-1248C-6H through 17X to 90% of the penetration. Cores 204-128C-6H to 16H were collected with the APC; these were followed by one XCB core to 149 mbsf. Five in situ temperature runs were made at this hole: two APCT tool, two DVTPP, and one DVTP runs (Table T13).