FROZEN HEAT | Volume 2

Ulleung basin

(a)

4000 Shot-point:

3900

3800

3700

3600

3500

3400

2.7

Figure 2.11: Drilling expeditions and results, Ulleung Basin. Scientific drilling expeditions evaluated gas hydrates in the Ulleung basin off the eastern coast of South Korea in 2007 and in 2010. The drilling confirmed that the basin contains a wide array of gas hydrate occurrence types, including a multitude of gas- hydrate-bearing “gas chimneys”. Above: Location of Ulleung basin Right: Geophysical data showing typical Ulleung basin gas chimneys (vertical features with anomalous physical properties) (with permission from Ryu et al. , 2009). Drilling has confirmed high concentrations of gas hydrates in the centres of these chimneys.

2.8

2.9

3.0

Depth in TWT (s)

o 140 C/km

3.1

o 80 C/km o 100 C/km

3.2

“Blanking zone” with pull-up structure Shot-point: 5600 5700 5800

Shot-point:

(c)

(b)

5700

5750

5800

W

E

E

W

500 m

2.7

2.8

2.9

Depth in TWT (s)

3.0

Interval velocity (m/s)

1000 m

3.1

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