(174a) Novel Experimental Methods to Quantify Surfactant Adsorption to Hydrophilic-Lipophilic Interfaces

In conventional energy production, the formation of water- and hydrate-in-oil dispersions generates a strong degree of frictional pressure loss, and may enforce sizing requirements for downstream receiving facilities. Depending on the nature of the system’s chemistry, surfactants may be injected into the production system to manipulate or minimise this free energy and improve the ability of the system to flow. Conventionally, the performance of these surfactants is validated qualitatively through macroscopic benchtop methods, including rocking cells. In this study, we have deployed three experimental methods to quantify the competition between surfactants at hydrophilic-hydrophobic interfaces. First, pendant drop interfacial tensiometry (IFT) was adapted to quantify a matrix of adsorbed surfactant densities via Gibbs isotherm analysis, for surfactants exposed to water-oil interfaces over ten orders of magnitude in concentration. Second, micromechanical force (MMF) tests were deployed over a similar concentration range to quantify the adsorption of surfactants at the clathrate hydrate-oil interface. Third, Raman spectroscopy methods were adapted to quantify the extent of surfactant adsorption at the gas hydrate-oil interface above the dissolved concentration in the continuous phase. Comparison of IFT with MMF/Raman data provide an attractive means by which to characterise the hydrate-philicity of surfactant molecules, where the size of the hydrophilic group is a critical differentiating factor; the results demonstrate that these experimental methods may be used to tune a new generation of hydrate-selective surfactant chemicals.