The development of large-scale shale gas production has been described as a game-changer for the U.S. energy market and has generated interest in expanding the usage of natural gas (NG) in sectors such as electricity generation and transportation. This development has been made possible by improvements in drilling technologies, specifically utilizing hydraulic fracturing in conjunction with horizontal drilling. However, the environmental implications of NG production and its use have been called into question. One of the major concerns is the amount methane (CH4) leakage from production activities and its impact on the life-cycle greenhouse gas (GHG) emissions of NG.