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

水力压裂结合水平钻井是北美乃至世界范围内开采非常规石油储量的新兴技术。在加拿大，它正在艾伯塔省和不列颠哥伦比亚省得到广泛应用，而在其他司法管辖区，压裂正在考虑或暂时停止。水力压裂是一项水密集型技术，每次压裂需要数百万升水。此外，压裂后返回地面的回流废水可能含有高浓度的盐、重金属和有机物质，到目前为止还没有得到很好的表征。与Encana公司合作，这里提出的研究有两个主要目标：(1)确定在水力压裂中使用深层咸水地下水是否是使用新鲜地表或地下水的可行替代方案，以及(2)开始揭示有害物质是如何进入回流废水的。第一项研究将减少运营商对使用淡水资源的依赖，并可能减少由于用卡车将水输送到井垫而导致的水力压裂的碳足迹。第二项研究将确定回流废水中的哪一部分(S)可能是危险的，需要处理，哪些可以重复使用。这将提高井场的用水效率，减少淡水的总体使用量。在这项研究的最后几年，将在几个地质区域研究深部地层地质和地层水地球化学对排液化学的作用。最终，这将为利益相关者提供一个预测回流化学的框架，以便能够在现场实施适当处理、处置或再利用回流废水的计划。

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.