Acceleration of Novel Technology Development for Stabilized Emulsion Treatment in EOR Applications

Abstract

Separation of stable emulsions produced from chemical enhanced oil recovery (CEOR) in a brownfield production system using conventional 3-phase separators is almost impossible, requiring large quantities of chemical demulsifiers to meet oil production specifications. A new and novel high-voltage high-frequency (HVHF) electro-coalescence (EC) technology has been identified as potential method to enhance separation of EOR produced fluid for improving CEOR implementation feasibility. This paper aims to present results and findings from the recent EC technology development against success criteria and parameters associated for fast-track field application. Electrostatic coalescers are used as an emulsion breaker, crude dehydrator or desalter in production systems and refineries. However, significant developments are required to use this EC technology as a potential treatment technology for tight emulsions/rag layers in CEOR applications. A new prototype of Inline EC was developed and tested in a batch test setup to evaluate the separation efficiency using real crude-brine samples and a cocktail of alkaline-surfactant-polymer (ASP) chemicals. The sensitivities of separation efficiency to different water cut, demulsifier concentration, EC voltage/exposure time, concentrations of alkaline, surfactant and polymer in the brine were measured and optimal process conditions were assessed. The results and findings were evaluated based on defined success criteria and parameters associated with separation efficiency such as volume fractions of the emulsion, oil-in-water (OIW) and water-in-oil concentrations (WIO), respectively. On one of PETRONAS CEOR field case study, the test results show that EC reduced 90% of the tight emulsion. In conclusion, EC leads to a substantial improvement in separation efficiency relative to the case without EC for water cuts below the inversion point. It is also found that the EC treatment without added demulsifier is equally effective in breaking the emulsion as adding a demulsifier without EC treatment, and that EC can potentially minimise or eliminate the application of demulsifiers in the production system.