Natural Gas Hydrate in India: Prospect Identification, Production Technologies and Associated Challenges

This article outlines the prospect of natural gas hydrate in India, its identification, resource estimation and production technologies, and vital challenges associated with the viable production of natural gas from gas hydrates. It contains a brief review of petro-physical and chemical properties of gas hydrate, geological conditions, formation processes, morphology and accumulation of gas hydrate, geophysical, geochemical and microbiological indicators of gas hydrate accumulation, potential locales of gas hydrate, role of geophysical as well as well logging techniques for prospect investigation, conventional production technologies and theirs limitations, production scenario and the environmental issues related with commercial production of gas hydrate in India. The seismic studies for investigation of gas hydrate in Mahanadi and Andaman deepwater basins are depicted to exemplify the scenario of gas hydrate in India. Analysis of seismic data (Bottom simulating reflector (BSR), Coherency inversion and Amplitude-versus-offset (AVO) studies) in combination with geological preconditions (such as high rate of sedimentation, adequate depth and temperature coinciding with the BSR) indicate a large area of the order of 250 km2 in the central part of the basin as a probable gas hydrate accumulation area in Mahanadi deepwater basin. The analysis of AVO anomaly of BSR and seismic signatures of the study area in Andaman deep water basin reveal a pool of free gas beneath the hydrate layer which has been corroborated by drilling results of a well in the area.