Reservoir Characteristics and Lateral Variability of the Marcellus Formation at the Allegheny Mountain Front
Date of Graduation
Eberly College of Arts and Sciences
Geology and Geography
The Marcellus Formation, a large shale gas reservoir located within in the Appalachian basin, produces the energy that fuels the economy across the United States. Well data and rock core for the Coastal 1H well, found in Fayette County, Pennsylvania, provides the basis to understand reservoir characteristics and depositional processes of the Marcellus Formation across the basin. The well is located near along the eastern edge of the productive fairway and adjacent to the Allegheny mountain front. We used characteristics, such as total organic carbon (TOC), geomechanical properties, and lithology, to integrate with ten other available wells across the basin. Specifically, MIP3H is the nearest well and used in conjunction with the Coastal 1H. The wells fall into 3 groups which are near, far, and outliers. The near group is comprised of the Coastal 1H, MIP3H, Boggess 17H, and the Poseidon 8M. The far group of wells encompasses the Dunham 4H, Armstrong 1, and Goff 5. Lastly, the outlier group utilizes the Tippens 6HS, St. Whipkey, and Coldstream 1MH.
The Marcellus Formation was divided into five informal units - three shale layers (upper, middle, and lower), separated by two limestone beds. Ternary diagrams visualize the mineralogical composition of the Marcellus Formation. Consistently they indicate that carbonate and silica content increase with depth and clay decreases. These minerals can indicate the quantity of organic content present. Total organic carbon, however, increases with depth in only certain wells. Geomechanical properties vary the most when looking at the individual units of a well and brittleness decrease upwards with increased clay content. Overall, the Marcellus Formation is weak, and brittle compared to adjacent units. The Coastal 1H shares similar lithological properties with the nearby wells, however, it is less organic rich and less brittle in comparison to the other study wells. In general, it seems that the lower Marcellus is the optimal unit for hydraulic fracturing, as it is the most brittle and organic rich.
Abersold, Bruno J., "Reservoir Characteristics and Lateral Variability of the Marcellus Formation at the Allegheny Mountain Front" (2021). Graduate Theses, Dissertations, and Problem Reports. 10188.