Effect of Silica Nanoparticles to Span 80 and Cocamidopropyl Dimethylamine in Methane Hydrate Formation and Agglomeration in Water-Oil System

Hydrate control has raised great interest as it plays a crucial role for the flow assurance in oil and gas industry. In this work, the effect of silica nanoparticles to two antiagglomerants, Span 80 and cocamidopropyl dimethylamine, for hydrate formation and agglomeration was investigated by using high pressure stirring cell. At higher hydrate volume fraction (>= 12%) during the hydrate formation process, the abnormal reduction of hydrate volume fraction was detected, which may be local dissociation of hydrate by the frictional heat accompanied by the heterogeneous temperature distribution in the cell. For the system without AAs, the relative current curve exhibited the upward kinks due to the ongoing hydrate agglomeration, whereas downward kinks were observed in systems with hydrate AAs. It is suggested that the downward kinks in the relative current curves could be used as one of the signs for effective hydrate AAs in the partial dissociation system. An addition of 0.75 wt % hydrophobic silica nanoparticles to 0.5 wt % Span 80 system shows an equivalent antiagglomeration performance of 2 wt % Span 80. The nanoparticles could hinder the nucleation process, and the induction time can be prolonged by similar to 6.4 h with the addition of 0.5 wt % hydrophobic nanoparticles. For another AA, cocamidopropyl dimethylamine, the effective concentration of silica nanoparticles could be significantly reduced to 0.1 wt % at the higher hydrate volume fraction (similar to 30%). The new formulation was also found with kinetic inhibition effect, and the induction time can be prolonged to similar to 2.9 h with the addition of 0.1 wt % nanoparticles. The silica nanoparticle at the favorable low concentration exhibited great potential as an efficient synergist to hydrate AAs in oil-gas-water cotransportation system.