Chemical Demulsification-Ultrasonic Recycle Oil from Oil-Based Drilling Fluid Using Response Surface Methodology

The abandoned oil-based drilling fluid is a kind of water-in-oil system with high oil content, which has a significant recovery value. The effects of demulsifier dosage, heating temperature, ultrasonic time and centrifuge speed on the oil recycle were investigated in the chemical demulsification-ultrasonic treatment of oil-based drilling fluid. From the results of the experiment, BSF-L62 was a suitable reagent with the highest oil removal rate among the selected demulsifiers. The main influencing factors were optimized using the Response Surface Methodology based on Box-Behnken design. The oil removal rate was up to 76.9% under the optimal conditions of demulsifier dosage of 250 mg/L, heating temperature of 70 °C, ultrasonic time of 12.5 min and centrifuge speed of 7000 r/min.