Shale-to-well energy use and air pollutant emissions of shale gas production in China

Tapping its large reserves of unconventional gas, China has launched shale gas exploration and started drilling wells in trial development zones. To better understand the potential energy and air pollution implications of shale gas production in China, this study developed a hybrid life cycle inventory (LCI) model that combines process and input–output (IO) based LCI methods for estimating “shale-to-well” energy use, resource use, and emissions of air pollutants. The model’s structure and inputs are based on data from the first shale gas horizontal well in China. The IO model was constructed using the 2007 benchmark IO table for China. Results suggest shale-to-well energy use of 59 TJ and shale-to-well greenhouse gas (GHG) emissions of 5500 metric tons of carbon dioxide equivalents (CO2e). Shale-to-well energy use and air emissions were dominated by the production and use of diesel fuel for oil-based drilling fluids and for on-site combustion, and by fugitive emissions and flaring from well completion. The results shed light on some potential energy and air pollutant emission impacts of a shift from coal to shale gas in China, and highlight opportunities for reducing these impacts moving forward.