Integrated Approach in Implementing Hydrate Management Strategies in Deepwater Gas Developments

Abstract

Hydrates have been a constant threat to subsea deepwater operations. Partial or total hydrate blockages usually occur after shutdown of a host facility, which invariably affects the resumption of production. The complexities of subsea production systems and extensiveness of deepwater fields present challenges in implementing hydrate management strategies. In the past, erroneous and ad-hoc strategies were implemented due to a lack of flow assurance (FA) awareness and understanding, resulting in production deferment caused by frequent hydrate formation/ blockages. Hydrate inhibition based on Mono-Ethylene Glycol (MEG) and Methanol (MeOH), if not properly understood and managed may lead to significant increases in a field's annual operating expenditure (OPEX). PETRONAS has gained a fair amount of experience in dealing with hydrates. The approaches taken in mitigating hydrate related issues in subsea developments have been exemplary and it is beneficial to be shared across the fraternities. These approaches will be discussed in detail throughout the article based on case studies from two subsea field developments: Field D Deepwater Gas Development and BG Gas Flowline at Field C