Hydrate mitigation for subsea production multiphase pipeline by flow assurance approach

Abstract

Nowadays, gas and oil production through subsea pipeline are moving to deeper developments. It affects pressure and temperature conditions decrease within hydrate stability region. The composition of fluid, including mixed produced water, liquid, and gas also affects the formation of hydrate inside pipeline. It is potentially leads to serious operational and safety problems. The aim of this study is to predict the hydrate free zone in multiphase fluid, chemical inhibitor, and insulation designed for subsea production pipeline by flow assurance approach. This study was conduct using steady state multiphase simulation to build a model for predicting the hydrate free zone and build the sensitivity of chemical inhibitor and thermal insulation for optimizing the hydrate free zone. Data used for this study are gas rate, fluid composition includes 10% bbl/bbl water, pipeline data, and chemical hydrate inhibitors include Methanol, Monoethylene Glycol (MEG), Triethylene Glycol (TEG). This study yield sensitivity of gas flow rate, the composition of hydrate inhibitor, the effect of insulation thickness to shifting hydrate free zone. This study can be concluded that variation of gas rate could be more effective depends on fluid composition and injection of methanol inhibitor is the most effective methods to mitigate the hydrate formation.