Preliminary evaluation of the economic potential of the technologies for gas hydrate exploitation

Several trial productions of natural gas hydrate (NGH) on onshore and offshore reservoirs have been implemented, signaling the start of the stage of technology development for its industrial exploitation. Several methods for NGH exploitation have been proposed, but none of them has been verified applicable to the commercial exploitation of NGH. The applicability of a technology to NGH exploitation is subject to the evaluation of its economic potential, but unfortunately few relevant studies have been conducted. In this research, each exploitation technology for NGH is evaluated for its economic potential as referring to the break-even production rate with energy return on investment (EROI) analysis. Sensitivity analysis is also performed to specify the effect of each key factor, such as gas production rate, gas-water ratio, efficiency of thermal stimulation, injection-production ratio for the methods of chemical injection or CO2 replacement, on the standard EROI. The results obtained indicate that depressurization is the most promising method, because on it the lowest critical production rate would be required for commercial exploitation of NGH, ranging from 0.16 to 0.25 million m3/day/well. Comparing with other unconventional oil and gas, the commercial exploitation of NGH still relies on further technological breakthroughs, especially those for the improvement of production rate.