Hydrate Management Strategy for Subsea Development in Gulf of Mexico

Abstract

Gas hydrate formation in natural gas systems and subsea infrastructure can block pipelines and instruments, restrict flow, and lead to safety and environmental hazards in production and/or transportation systems. These problems can lead to substantial economic and HSE risks. Therefore, understanding how, when and where hydrate formation occurs are important factors in developing the hydrate management strategies. This paper addresses the hydrate management strategy in one of the subsea developments in the Gulf of Mexico (GOM). The effects of salinity, water cut, and amount of methanol on hydrate formation and plugging risk were studied in this paper. The experimental results and modeling in advanced thermodynamics software showed that an increase in the concentration of methanol and salts in the autoclave cell leads to a shift of the equilibrium curves, reducing subcooling and hydrate volume fraction while increasing induction time. The results also show that for some under-inhibited systems, the volume fraction of the hydrate slurry is low enough to allow for safe transportation of fluids during various operational conditions.