Assessment of flow assurance issues for methane hydrate production in the ulleung basin : hydrate inhibition and slugging suppression = 울릉분지에서 메탄 하이드레이트 생산을 위한 유동 안정성 평가 : 하이드레이트 방지 및 슬러깅 저감hydrate inhibition and slugging suppression
This study presents a methodology to assess flow assurance issues for methane hydrate production in the Ulleung Basin. The explorations conducted near the Ulleung Basin confirmed the existence of hydrates, but many studies have focused on geological issues. Because of the high cost of producing methane hydrates, a production system must be designed to safely transport methane gas to the platform. A typical flow assurance issues are the hydrates reformation. The dissociated methane gas and water easily reform hydrate, and the excessive amounts of thermodynamic inhibitor are injected to prevent the reformation. The kinetic inhibitor may be used along with the thermodynamic hydrate inhibitor to reduce the injection amounts of inhibitor. This study suggests the methodology to estimate the optimized injection amounts of kinetic inhibitor. The second observed flow assurance issue is slugging. As the amount of inhibitor injected decreases, the liquid velocity slows down and the probability of slugging occurrence increases. Slugging can affect piping and topside facility. Among the many ways to eliminate slugging, we have established an active slug control design methodology that is easily controllable even with minimal facility changes. Two established methodologies were verified through simulation and experiments and applied to the methane hydrate production system of the Ulleung Basin. The economic benefits to the production system design from each methodology were analyzed.