Resource Potential of Natural Gas Hydrate Deposits Offshore Trinidad

Seismic data and gravity cores indicate that natural gas hydrate deposits are present in the Columbus Basin off the East Coast of Trinidad. These data led to the initiation of a research program aimed at delineating and characterizing this unconventional resource. Already the areal extents of deposits in two offshore blocks have been estimated. In this study, the theoretical thickness of the hydrate stability zone for one of the blocks was estimated and additional reservoir properties collated from globally located hydrate-bearing strata. These data were used to conduct a parametric study on the potential volume of natural gas in the block. Quantification of this unconventional gas resource is important since natural gas is a premium fuel and its use is likely to increase in the short and medium term. Factors contributing to this phenomenon are (i) the increasing global energy demand, (ii) natural gas is environmentally friendlier than oil and coal in terms of total emissions, and (iii) oil and coal, which are high carbon fuels, and greater contributors to global warming. In addition, international interest stems from the fact that gas hydrate deposits are affected by temperature and pressure, and release of methane from these deposits can occur if there are certain changes to these conditions. This could impact oceanic and atmospheric chemistry, and in due course climate. The data collated from the globally located hydrate-bearing strata indicated that porosities were generally greater than 16%, and hydrate saturations were as high as 80%. These data along with the theoretical thickness of the gas hydrate stability zone indicated that the potential volume of natural gas in situ may be greater than 1 TCF. This finding is significant since if the technical challenges associated with producing this unconventional resource are overcome, the natural gas stored in this hydrate deposit represents a potential additional source of gas which can be used to help meet Trinidad and Tobago‟s future energy needs.