Informing best practices for hydraulic fracturing in Alberta: water sources and characterizing the toxicity of produced facturing fluids

点击翻译按钮获取中文摘要

Hydraulic fracturing combined with horizontal drilling is an emerging technology for the recovery of unconventional petroleum reserves throughout North America and worldwide. In Canada it is being extensively utilized in the provinces of Alberta and British Columbia, while in other jurisdictions fracturing is under consideration or temporary moratorium. Hydraulic fracturing is a water-intensive technology, requiring millions of litres of water per fracture. Further, the flowback wastewaters that return to the surface following a fracturing episode can contain high concentrations of salts, heavy metals, and organic substances, and have not been well-characterized to date. In collaboration with the Encana Corporation, the studies proposed here have two primary aims: (1) to determine if using deep saline groundwater is a feasible alternative to using fresh surface or groundwater in hydraulic fracturing, and (2) to begin to unravel how hazardous substances enter into flowback wastewaters. The first study will decrease the dependence of operators on using freshwater resources, and may mitigate the carbon footprint of hydraulic fracturing due to trucking water to well pads. The second study will determine which fraction(s) of flowback wastewater may be hazardous and require treatment, and which can be reused. This will increase the efficiency of water use at the well site and decrease the overall use of fresh water. In the final years of the study, the roles of deep formation geology and formation water geochemistry on flowback chemistry will be studied across several geologic regions. Ultimately this will provide stakeholders with a framework to predict flowback chemistry, so that plans for proper treatment, disposal, or reuse of flowback wastewater can be implemented on site.