Grant: Collaborative Research and Development Grants

Drilling for oil and gas involves the use of drilling fluids or muds, primarily to lubricate the drill bit and remove rock and rock fragments from the drilling well and transport them to the surface. There are two types of drilling fluids currently in use: water-based drilling fluids and non-aqueous drilling fluids. Non-aqueous drilling fluids are composed primarily of diesel oil, mineral oil or synthetic oil and additives while water-based fluids consist of a base of salt water or fresh water containing additives. Non-aqueous drilling fluids generally perform better than the water-based fluids, especially in the challenging drilling situations that are encountered in Canada, especially off-shore. However, despite their superior performance, non-aqueous fluids are not always used since they are considered less environmentally friendly due to the fact that they contain oil. During drilling, the rock fragments and drilling mud removed from the drilled well are brought to the surface and are considered a waste (termed drilling waste) that must be treated and disposed of. Examples of common treatment and disposal methods for oil-contaminated drilling wastes are land-treatment, land farming or land spreading, re-injection or landfilling. Supercritical fluid extraction (SFE) is a promising new technique that can effectively treat oil-contaminated drilling waste. SFE will remove oil from the drilling waste to below regulatory requirements and the drilling waste can be disposed of safely. As for the extracted oil, it can be quantitatively recovered and disposed of. In the case of valuable oils, the oil can be recycled or even sold, hence saving or making money for the drilling companies. For off-shore operations, SFE of oil-contaminated drilling waste could be performed on the drilling rig, thus eliminating the need for expensive and potentially dangerous transportation of offshore-generated cuttings to shore for treatment and disposal. Optimal application of this technology would substantially reduce drilling waste treatment times and costs, offering superior environmental protection and a potential economic benefit for drilling operations in Canada.