Table 4. Volume of natural gas within the downhole log-inferred gas-hydrate occurrences at Sites 994, 995, and 997 on the Blake Ridge.
| Site | Depth of logging Unit 2 (mbsf) | Thickness
of hydrate-bearing zone (m) |
Sediment
porosity (%) |
Gas-hydrate
saturation (%) |
Volume
of hydrate/km2 (m3) |
Volume
of gas within hydrate/km2 (m3) |
|---|---|---|---|---|---|---|
994 |
212.0-428.8 |
216.8 |
57.0 |
3.3 |
4,083,577 |
669,970,673 |
995 |
193.0-450.0 |
257.0 |
58.0 |
5.2 |
7,731,352 |
1,267,941,673 |
997 |
186.4-450.9 |
264.5 |
58.1 |
5.8 |
8,839,915 |
1,449,746,073 |
Note: Gas volume calculation assumes a hydrate number of 6.325 (90% gas-filled clathrate), 1 m3 of gas hydrate = 164 m3 free gas at STP.