Simulating the gas hydrate behavior at equilibrium dissociation: A study from Mahanadi basin of eastern offshore, India

Abstract

A suitable model is developed by analyzing the effects of external stimuli such as changes in pressure and temperature on the gas production behavior for the multi-phase fluid system. Our ultimate goal was to assess and understand the response of the Mahanadi basin of eastern India, which is already identified as a prospective zone for gas hydrate exploration, while subjected to dissociation through numerical simulation. Further, a series of simulations were conducted to understand the spatial distributions of several key parameters including hydrate saturation, gas and aqueous phase velocities, heat flux, enthalpy changes, within the system. In this case, we have considered only the equilibrium reaction model to simulate the natural gas production during two vital hydrate dissociation mechanisms such as thermal stimulation and depressurization methods. Coupled equations of heat and mass balance were used in every subdomain of the simulation and the integral difference equations were used to model the hydrate-bearing geologic system of the studied region at different physicochemical environments. The simulation results suggest that the studied field has a great prospect for commercial gas production. Further, we identified that the speed of dissociation front varies with the boundary pressure, and depressurization is the suitable dissociation method to produce more gas from the studied field when compared to the thermal stimulation. The developed model can be used as an avenue for further detailed study of natural gas production from the hydrate reservoir of this region.