Structure H hydrates: Implications for the petroleum industry

Abstract

Structure H (sH) hydrates are unique since their formation requires both a light gas such as methane and molecules typically present in oil and condensates. Several sH formers such as methylcyclopentane, methylcyclohexane, neohexane, and adamantane, are indigenous to petroleum. Phase equilibrium measurements indicate that the temperature and pressure conditions, under which sH hydrates form as a stable phase are consistent with those in hydrocarbon production, processing, and transportation facilities. The stable occurrence of sH hydrates calls into question existing hydrate prediction programs and suggests that the hydrate phase itself should be measured, in contrast to previous experimental practice. In this work, we provide a brief overview of the current state-of-the-art on sH hydrates, with an emphasis on its implications for the petroleum industry.