Separation and Recycling of Used Oil-Based Drilling Fluids

A novel approach has been taken to separating, recovering and recycling the oil-continuous phase from used oil-based<br>drilling fluids. The method is based on destabilizing and aggregating the suspended solids and brine droplets through the<br>application of polymers and surfactants in a controlled mixing device. The aggregated material may then be centrifugally<br>separated using traditional solids-control equipment. This allows recovery of the oil-continuous phase, which may then be<br>recycled into another oil-based drilling fluid. Laboratory data and field case studies will be presented that substantiate the<br>efficacy of this solid-liquid separation method. Microscopic analyses of the aggregated solids support a proposed mechanism<br>based on preferential wettability.