THE USE OF MICRO/ULTRAFILTRATION FOR THE REMOVAL OF OIL AND SUSPENDED-SOLIDS FROM OIL-FIELD BRINES

Brine generated at offshore and onshore oil recovery facilities is generally treated for removal of oil and suspended solids to meet process and regulatory requirements. Microfiltration (MF) and ultrafiltration (UF) have been proposed as effective and cost-competitive alternatives to conventional oil removal technology. Recent studies in this field were reviewed to identify current trends and technical obstacles to the implementation of MF/UF technology for oilfield brine treatment. The most extensively demonstrated membrane technology for oilfield brine treatment in North America is a tubular ceramic microfiltration system which employs backflushing and chemical pretreatment. Two commercial installations of this technology are now in place, however, long term viability is uncertain. Lack of an adequate database on both membrane/brine interaction and long term system operations have mitigated against the development of predictive models and correlations necessary to design membrane processes for removal of oil from oilfield brine. The key technical obstacles to cost effective application of membranes include low average flux rates, flux degradation and uncertain membrane life. Concerns regarding integration of membrane processes at oilfield brine treatment facilities include sensitivity to variations in flow and oilfield brine characteristics, handling of waste streams generated using chemical pretreatment and requirements for extensive prefiltration.