Table T5. Summary of 260 fluid hammer operation, Site 1182 (Mariana backarc).
|
Hole/test
|
Latitude
|
Longitude
|
Water
depth (m) |
Operating
time (min) |
Flow
rate (spm) |
Penetration
depth (m) |
Material
|
Lost
circulation |
Rotation
|
Heave
(m) |
Hammer/bit
|
ROP
(m/hr) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1182A | 12°57.0ŽN | 143°36.6ŽE | 2874 | 25 | 20-40 | 2 | Lava flows | Yes | No | 1-2 | 260 FH/DCUR | NA |
| 1182B | 12°57.0ŽN | 143°36.6ŽE | 2878 | 15 | 20-60 | 1.5 | Lava flows | Yes | No | 1-2 | 260 FH/DCUR | NA |
| 1182C | 12°57.0ŽN | 143°36.6ŽE | 2878 | 95 | 20-80 | 5 | Lava flows | Yes | Yes | 1-2 | 260 FH/DCUR | 3.16 |
| 1182D | 12°57.0ŽN | 143°36.6ŽE | 2878 | 45 | 20-80 | 3.5 | Lava flows | Yes | Yes | 1-2 | 260 FH/DCUR | 4.67 |
| 1182E | 12°57.0ŽN | 143°36.6ŽE | 2878 | 30 | 20-80 | 4.5 | Lava flows | Yes | Yes | 2.5-4 | 260 FH/FCUR | 9 |
| 1182F | 12°57.0ŽN | 143°36.6ŽE | 2872 | 145 | 20-90 | 7 | Lava flows | Yes | Yes | 2.5-4 | 260 FH/FCUR | 2.9 |
| 1182G | 12°57.0ŽN | 143°36.6ŽE | 2873 | 112 | 20-90 | 5 | Lava flows | Yes | Yes | 2.5-4 | 260 FH/FCUR | 2.68 |
| Totals: | 467 | 28.5 |
Notes: ROP = rate of penetration. spm = strokes per minute (~5 U.S. gal/stroke [i.e., 20 strokes equals 100 U.S. gal/min.]) NA = not applicable. DCUR = dual cam underreamer bit, FCUB = flat-face underreamer bit. Only 40% of the optimum flow rate through the hammer allows the hammer to jet into the seafloor while being observed by the VIT. The hammer fired only a few times because sufficient material strength to close the hammer to initiate operation was not present. Only the hammer and underreamer bits were being used, no casing installation was attempted.