Determination of hydrate inhibitor concentrations by measuring electrical conductivity and acoustic velocity

Deployment of hydrate inhibitors is the most common measure to prevent hydrate blockage in oil and gas transport pipelines. There is an increasing demand for simple, quick, and reliable means for monitoring hydrate inhibitor concentrations in pipelines to optimize the injection rate of hydrate inhibitors, improve the economy and reliability, and reduce the potential negative impact on the environment and product quality. This paper reports a novel method for determining salt and inhibitor concentrations in aqueous solutions. This method was developed on the basis of measuring electrical conductivity and acoustic velocity of the aqueous solutions under examination. Artificial neural network (ANN) correlations were trained, validated, and tested using the measured conductivity and velocity data for monoethylene glycol (MEG)-salt solutions,
methanol (MeOH)-salt solutions, and kinetic hydrate inhibitor (KHI) Luvicap EG-salt solutions. The developed ANNs can simultaneously determine thermodynamic hydrate inhibitors (THIs) (MEG and MeOH) and salts or KHIs (Luvicap EG) and salts with good accuracy. This method can provide hydrate flow assurance operations with a simple, quick, and reliable means for monitoring hydrate inhibitor and salt concentrations in pipelines.