Polymer-Assisted Chemical Inhibitor Flooding: A Novel Approach for Energy Recovery from Hydrate-Bearing Sediments

Recent production technologies to extract methane from mysterious hydrate reservoirs are not effective and need additional efforts to develop novel technologies to improve methane production. Chemical inhibitor injection is appraised as an effective method due to ease in operation, improved energy efficiency, and reduced threat of hydrate reformation. In the current study, several experiments on methane recovery have been performed in a simulated laboratory-based hydrate reservoir by injecting chemical inhibitors and combinations of aqueous chemical inhibitor/polymer systems. Different combinations of inhibitors and polymers, viz., chemical inhibitors such as methanol, ethylene glycol, methanol + polyacrylamide, and so forth, with varying concentrations, have been explored. Polyacrylamide has been used as in our previous study, it was shown that it can act as a better kinetic hydrate inhibitor, and also, the same polymer is often used for the enhanced oil recovery process in the upstream oil industry. In total, seven different simultaneous hydrate formation and dissociation experiments were performed. The inhibitor + polymer aqueous solution was injected to produce methane by dissociating the hydrate. The gas production ratio and the effectiveness of inhibitor aqueous solution and pure inhibitor in terms of methane recovery from hydrate-bearing sediments have been discussed and analyzed. This study provides a good insight into the use of some of the conventional hydrate inhibitors along with the oilfield polymer for methane recovery from hydrate-bearing sediments.