Pathways and Environmental Impacts of Methane Migration: Case Studies in the Marcellus Shale, USA

Figure 10

(A) Study area showing Lycoming County, Pennsylvania. (B) Expanded view of Sugar Run and Gregs Run sites. Shown are seep, outcrop and Harman, Lewis 1H gas well locations, and Gregs Run sample sites. (C) Expanded view of the study area showing homeowner water wells sampled and fugitive methane zone ( mg/L), sample locations in Sugar Run and Gregs Run, and outcrops. (D) Cross-section S-S defined in (B) roughly follows the plunge of the Nittany Anticlinorium to the east. Location of Gregs Run sample sites is projected along formation strike (green arrow) or along main joint direction (red arrow). One possible migration pathway (red dashed line) is up the gas wellbore, then laterally until intersecting vertical fractures connected to Sugar Run and a direct discharge to Gregs Run. Depths are measured relative to mean sea level. Fmn = formation.