Organic and Nonorganic Characterization of the Bakken, Marcellus, Pierre, and Woodford

The development of effective strategies for hydrocarbon extraction through unconventional shales requires a comprehensive understanding of shale petrophysical properties – specifically the variability of fabric, composition, matrix, porosity, permeability, and thermal maturity/organic content [1-5]. Unconventional resource extraction from shale can involve the injection of carbon dioxide (CO2) to dissolve within crude oil lowering viscosity and improving recovery. In addition to their hydrocarbon resource value, depleted shale gas reservoirs are being considered for geologic carbon storage (GCS) [1,2,6]. Shale reservoirs are heterogeneous across multiple scales which can make it difficult to predict flow pathways for hydrocarbon migration. The aim of this study was to characterize shale from the Bakken, Marcellus, Pierre, and Woodford formations using different imaging techniques. High resolution computed tomography (CT) was performed to provide multiscale heterogeneity and structure. Correlative focused ion beam-scanning electron microscopy (FIB-SEM) was used to create high resolution images of total porosity, pore distribution, organic volume, and organic hosted porosity. The application of these imaging technologies will help to improve scientific understanding of shale petrophysical properties.