Oil dispersant preparation and mechanisms for waste oil-based drilling fluids



Waste oil-based drilling fluids (WOBDF) contain oil, heavy metals, organic matter, and other pollutants and are classified as hazardous wastes in China and other countries. WOBDF produce harmful effects on the ecological environment and are often difficult to treat. At present, WOBDF are generally subject to landfills or re-injection in formulations, which not only waste valuable land resources but also produce severe environmental pollution. On the basis of numerous laboratory and field studies, oil dispersant ELO-1 was developed to recover oil from WOBDF. The components of oil dispersant ELO-1 are the following: 30% composite demulsifier FPR-1, 1.5% coagulant CC, and 2% flocculant PAM (0.1%). The corresponding temperature range is 40–60°C. This article combines the use of oil dispersant ELO-1 with centrifugal separation to recover oil from Daqing Oilfield WOBDF. The average recovery rate was 89.7% with water and sand content <0.1%. The residual mud slag was treated to control its hazardous components and was then used as a material for cofferdam building and road paving. Therefore, the harmless treatment and utilization of WOBDF objectives were achieved. © 2011 American Institute of Chemical Engineers Environ Prog, 2011