Characterization of the Marcellus Shale in the Appalachian Basin

Thomas H. Mroz¹, Dustin Crandall², Yael Tucker³, and Dustin McIntyre¹
¹U.S. DOE, NETL, Morgantown, WV, T[email protected], [email protected]
²URS Corporation, Morgantown, WV, [email protected]
³Oak Ridge Institute for Sceince and Education, Morgantown, WV, [email protected]

The goal of the project was to compile all of the historic DOE Eastern Gas Shale Project (EGSP) data and build a detailed geologic model of the Marcellus shale distribution across the basin. The tasks focused on developing a database of the geochemical analysis, well logs, core lithological and natural fracture descriptions, and reservoir parameter analyses that were done on the EGSP oriented core wells. The wells cover the basin from New York through Pennsylvania into West Virginia and eastern Ohio. Nine wells intercept the Marcellus from depths of 750 m (2500 ft) to 2500 m (8200 ft). In addition to the historic data, new analytical tools were employed to determine kerogen distribution, natural and induced fracture morphology, and porosity and permeability of the formation which is both a source and reservoir rock. The tools employed include several CT scanners with a range of resolution from 1 micron to .2 mm, to determine 3D spatial distribution of fractures and heavy minerals, optical microscopy to correlate CT images and lithology, and SEM to evaluate migration pathways for the fluids.

Other analytical methods applied to the samples include fluid inclusion analysis, source rock analysis, gas and water chemistry for a complete set of parameters for input to reservoir modeling tasks. Earthvision is utilized to display the distribution of data on both individual wells, small areas with several wells and on a regional basis. The results indicate that the lithology changes across the basin as well as the organic character and structural features influence reservoir gas potential. Drilling, completion and stimulation methods are affected by the current state of insitu stress and lithological changes control induced fracture geometries during stimulations. The geochemical data is currently being utilized at NETL to evaluate the environmental risk of developing and producing the resource. The data will be publically available through the USDOE, NETL website.

AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012