Approaches to reducing injection rate of hydrate inhibitor based on risk management, operational scenario and life-cycle cost

Abstract

This study presents a framework for hydrate formation risk management and proposes a new methodology that estimates the acceptable injection rate of a hydrate inhibitor. The methodology provides risk-based information which presents the acceptable injection rate of a hydrate inhibitor considering the random failure and subsequent maintenance of the topside system followed by the cooldown of the flowlines and risers. Case studies are performed for several installations that have different extent of process configurations and insulation. With obtained risk-based information, a life-cycle cost (LCC) hydrate formation risk management methodology is proposed to determine the optimal injection rate of hydrate inhibitor. This study provides a realistic limit of the hydrate injection rate, which the conventional methodology cannot provide and establish the guidelines to prevent the over-sized design for offshore plant.