(246f) Effects of Salt Species and Salinity On Gas Hydrate Anti-Agglomeration of An Effective Non-Ionic Surfactant

Gas hydrate formation often blocks flowlines in oil and gas production and may result in serious safety and environmental problems. Risk management of gas hydrate is a major challenge in offshore hydrocarbon production. Anti-agglomerant (AA) is an attractive option because of the effectiveness at low dosage and high subcooling. Hydrates particles are kept small and allow flow in slurry form, therefore avoiding plugging in flowlines. The thinking in the literature of anti-agglomeration is based on the need for the formation of water-in-oil emulsion. We have recently demonstrated that the process can occur without emulsion or through oil-in-water emulsion. We have shown anti-agglomeration in oil-free systems. Our newly developed AA shows high effectiveness over the entire watercut (volume fraction of water in the total liquid) range. In this work, we investigate the effects of salinity and salt species in the aqueous phase on anti-agglomeration in a rocking cell instrument. The thermodynamic inhibiting effect of electrolytes helps to lower the AA dosage and hydrate content, thus enhance the AA application in high salinity systems. However, the presence of ions also affects the surface adsorption of surfactant molecules on hydrate particle surface. We discuss both effects in this study. We further demonstrate that our AA is effective at the dosage as low as 0.1 wt% when the brine salinity varies from 0% to 11%.  Foaming phenomenon is observed in KCl and MgCl₂ brines. And clustering phenomenon is also observed in some tests prior to hydrate formation. Both are undesirable in anti-agglomeration applications. A small amount of oil results in effective anti-agglomeration. Our new findings have helped the way for the vast potential for our new surfactant formulation in hydrate flow assurance.