Fusion Geographic Information System Data with State-of-the-art Atmospheric Systems: Application to Methane Source Mapping over the Marcellus Shale formation

Abstract:

Natural gas production from multiple shale formations has increased significantly in the last decade. More particularly, a growing number of unconventional wells is the result of intense drilling in the Marcellus shale area. The Marcellus shale production represents a third of the production of natural gas in the entire US. This unprecedented increase could lead to additional fugitive methane (CH₄) emissions at a level that remains highly uncertain. If natural gas is to replace less energy-efficient fossil fuels, the emissions during the production phase ought to be relatively small. However, the magnitude and the spatial distribution of CH₄ emissions from unconventional wells in the Marcellus shale remains poorly documented.

The novelty of this research consists in coupling various sources of information to map accurately the methane emissions, combining Geographical Information System (GIS) data, atmospheric measurements of greenhouse gases, and atmospheric modeling tools. We first collected various GIS data to estimate CH₄ emissions caused by the shale gas industry, such as wells, facilities, and pipelines, with the other major contributors such as wetlands, farming activities, and soils. We present our projection methods to generate model input in gridded format while preserving the distribution and magnitude of the emissions and assembling a diverse database.

The projection tools for GIS data are generalized to the use of GIS data in atmospheric modeling systems. We then present the atmospheric concentrations simulated by the Weather Research and Forecast (WRF) model, used to represent the transport and the dispersion of CH₄ emissions. We compare the WRF model results to aircraft measurements collected during a 3-week campaign to identify missing sources in our initial inventory. We finally propose a new approach to identify the area at the surface that could potentially influence the aircraft measurements using spatial analysis of particle footprints. This technique aims at identifying undocumented sources and unreported large emitters to quantify more rigorously the emissions of CH₄ over the Marcellus shale.