Flow assurance issues in deep-water gas well testing and mitigation strategies with respect to gas hydrates deposition in flowlines—A review

Abstract

Gas hydrate formation and deposition in deepwater subsea flowlines has been a major concern to flow assurance engineers as oil and gas exploration moves towards offshore developments in deeper water and may cause operational safety hazards in subsea and cold regions. This challenge can be addressed through adequate knowledge of the mechanisms of formation and deposition of hydrates as well as predictive tools for their deposition in flowlines. This paper reviews various predictive models to study hydrate formation and deposition mechanisms based on the current publications on the gas-dominated flowloop investigations. The review also provides an overview of various gas hydrate mitigation and management strategies used in offshore production system. Important methods such as chemical injection and depressurization that have been used for mitigating hydrate formation are reviewed in this paper. These mitigation strategies assist in avoiding any form of casualties/hazards and ensure safe production operations. This review suggests that the management of gas hydrate risk in flowlines is the best solution to maintaining hazard-free operations, prevent causes of the loss of production and derive economic benefits from the use of huge deposits of natural gas hydrate as a source of methane gas.