Low Environmental Impact Non-Silicone Defoamers for use in Oil/Gas Separators

Abstract Significant quantities of water are produced alongside crude oil production which, following treatment on the platform, are then discharged into the marine environment. This water contains residues of treatment chemicals including separator additives intended to aid in oil/water/gas separation and improve operational efficiency. Silicone products have been widely used as defoamers for oil/water/gas separators due to availability and performance. However, silicones are known to foul catalyst activity in downstream upgrading refineries and present unfavorable environmental profiles. As environmental regulations tighten, alternative chemistries will be needed to take the place of traditional additives such as silicone. Simulated produced waters of low (0%), medium (7%), and high salinity (14%) were evaluated in combination with untreated crude oil at 0, 30, and 80% ratios to replicate typical compositions of produced fluids. Experimental data were obtained based on separator operating pressure and temperature. Sodium Sulfosuccinates have shown promise in previous evaluations and case studies of oil/water/gas separators (Wylde, 2010). The dioctyl sodium sulfoccunate (DOSS) chemistries evaluated by the above methods present valid alternatives to silicone systems, minimize environmental impact, and maintain or improve operational performance. Several benefits and drawback to DOSS usage as a silicone alternative were realized during this study. DOSS was found to be a sufficient defoamer and antifoamer at low water ratios, though not as immediately effective as silicone. DOSS was also found to antifoam more efficiently than silicones at low water ratios and remain as effective as silicone at high water ratios. Increasing salt content was found to negatively affect DOSS defoaming and antifoaming performance. In high salt content and high water content conditions, DOSS generates more foam than the blank solution and thus may be more effectively used as a foam assisted lift (FAL) agent or during enhanced oil recovery (EOR).