Extent of gas hydrate filled fracture planes: Implications for in situ methanogenesis and resource potential

Abstract

High-angle gas hydrate filled fracture planes were idenified along a 31 m interval in logging while drilling images in two holes located ∼11 m apart drilled during the Indian National Gas Hydrate Program Expedition 01, offshore India. Using Monte Carlo simulations to account for uncertainty in hole location, hole deviation, strike and dip, we assert with 95% confidence that the fracture planes in the two holes are not the same. The gas hydrate filled fracture planes likely only extend a few meters laterally from each borehole and occur in an isolated interval in the middle of the gas hydrate stability zone. This suggests gas generated microbially within in the gas hydrate stability zone may have supplied the gas hydrate-filled fracture interval. Production of methane from these reservoirs using conventional methods may be quite challenging. Copyright 2008 by the American Geophysical Union.