Characterization of Marcellus Shale and Huntersville Chert before and after exposure to hydraulic fracturing fluid via feature relocation using field-emission scanning electron microscopy

Results indicate that in situ pressure promoted fracture growth along the sedimentological (horizontal) bedding plane of the Marcellus Shale samples. Moreover, calcium carbonate (CaCO3) dissolution was observed and gypsum (CaSO4 ∗ 2H2O) appeared to precipitate both on the surface and in the numerous fractures. Barite (BaSO4), strontianite (SrCO3), celestine (SrSO4), and apatite (CaPO4) formed a unique pattern of precipitates on the surface of the Huntersville Chert samples. Additionally, Rhenium and rare earth element (REE) Europium were identified in minerals which precipitated on the Huntersville Chert surface identified by FE-SEM spectral analysis.