Numerical Simulation of a Laboratory-scale Experiment for the Hydrate Dissociation Process in Porous Media by Acid Injection

In this study, to enhance gas recovery from a methane hydrate reservoir, experimental and numerical studies that considered the acid injection process as a secondary gas recovery process after the depressurization operation were conducted. First, we experimentally analyzed the dissociation behavior of propane hydrate (PGH) in porous media by using acid injection and confirmed that the dissociation condition of PGH was shifted to the sides of low temperature and high pressure. This enabled the dissociation to proceed easily as the concentration of the injected acid increased. Then, on the basis of experimental observation, we conducted history matching for the temperature change and gas production behavior during PGH dissociation by acid injection, by varying the initial hydrate saturation, the reaction rate constant for acid consumption, and the intrinsic dissociation rate constant as the calculation parameters. Through history matching, we confirmed the validity of the developed numerical model targeting the dissociation of hydrates in porous media by acid injection.