Modeling of the dynamics of the movement of hydrate formation inhibitors in an extensional pipeline

Abstract

The dynamics of the movement of the hydrate formation inhibitors (methanol and monoethylene glycol) in an extensional hilly terrain field pipeline transporting a multiphase fluid is studied. The concentration distribution of inhibitors along the pipeline length is obtained by means of the hydrodynamic modeling using OLGA software for a wide range of the gas flow rates. The influence of liquid accumulation on the time of the pipeline filling by an inhibitor is analyzed. It is shown that the time of the inhibitor propagation through the pipeline is governed by the average velocity of the aqueous phase. It is demonstrated that the time of the pipeline filling by methanol can be significantly less than that by monoethylene glycol. It is shown that after the required equilibrium concentration of the inhibitor is reached along the entire length of the pipeline, the pressure drop in the liquid accumulation mode is less when methanol is used. The results obtained can be used to optimize the methods of the inhibition of extensional hilly terrain field pipelines. Keywords: hilly terrain pipeline; hydrodynamic modeling; multiphase flow; liquid accumulation; hydrate inhibitor.