ارزیابی خطر شکستگی هیدرولیکی مواد شیمیایی با استفاده از روش نمایه سازی Hazard assessment of hydraulic fracturing chemicals using an indexing method

1. Introduction Unconventional natural gas production has significantly expanded in North America, owing to combined use of horizontal drilling and hydraulic fracturing (HF) techniques. These technical advances have enabled exploitation of unconventional natural gas reservoirs, such as low-permeability organic-rich shale formations and “tight-gas” reservoirs, redrawing the domestic energy landscape in Canada (Rivard et al., 2014). In 2012, Canada was the third largest producer of natural gas in the world and exported $15.6 billion worth of natural gas. The unconventional gas industry was responsible for about 15% of total natural gas production. By 2025, Canadian natural gas production is projected to be at least 25% greater than current levels, and the increase will be primarily attributed to unconventional natural gas production (NEB, 2013). In Canada, unconventional natural gas production has been distributed within several major shale plays, the most important plays include the Muskwa-Otter Park shale members of the Horn River Basin of Northern British Columbia (BC) and the adjacent Montney Basin, spanning the BC and Alberta border, as well as the Duvernay Formation in West-central Alberta (NRC, 2016). As a major natural gas producing province, BC is particularly well poised to benefit from the recent overhaul of the natural gas industry. As of 2014, over a thousand wells have been drilled for shale gas exploration or production in BC, and in most cases, completion processes have involved HF (FracFocus, 2014). The HF process involves the pumping of large volumes of fracturing fluid, consisting of a base fluid (primarily water), proppants (typically quartz sand), and various additives, under high pressure into a perforated wellbore to initiate and expand fractures within the adjacent geological formation (Vidic et al., 2013). The fractures increase the permeability of the formations, allowing for the previously trapped natural gas to flow through the formations into the wellbore (Ferrer and Thurman, 2015).