Regional Mapping and Reservoir Analysis of the Upper Devonian Shale in Pennsylvania

Jared M. VanMeter
Range Resources - Appalachia, LLC, Canonsburg, PA, [email protected]

Although the Devonian Shale of the Appalachian Basin has been producing gas since the early 1800s, only recently has it become a giant play. In 2004, Range Resources, using analogues with geology and completion techniques in the Barnett Shale, began producing gas from a Marcellus Shale well in Washington County, Pennsylvania. Since then other organic shale packages both above and below the Marcellus have also attracted industry interest considerably. The Upper Devonian Shale in Pennsylvania is one of these viable plays and is the centerfold for this research.

The main purpose of this investigation is to define the distribution of the organic-rich facies of various Upper Devonian Shale intervals above the Tully Limestone within Pennsylvania. The analysis is based on well log data, primarily gamma-ray logs, which are the most common and well calibrated, plus bulk density logs, where available. Extensive stratigraphic correlations have been conducted to trace key formation tops across the study area. Detailed log analysis has been performed to normalize the logs and define key reservoir quality indicators.

The following maps were generated over the study area.

• Gross Thickness Isopachs of the Rhinestreet Shale, Cashaqua Shale, Middlesex Shale, Genesee Shale, and Burkett Shale


• 200 API Gamma-ray Net Pay maps of the Rhinestreet Shale, Cashaqua Shale, Middlesex Shale, Genesee Shale, and the Burkett Shale


• 160 API Gamma-ray Net Pay maps of the Rhinestreet Shale, Cashaqua Shale, Middlesex Shale, Genesee Shale, and the Burkett Shale

These observations and others portrayed on this new series of maps provide a better understanding of the development of the Upper Devonian Shale in the Appalachian Basin. Refining our knowledge of the geology with this series of geologic maps will allow the flexibility of relatively easy revisions and rapid dissemination of continuously evolving geologic knowledge, while further advancing industry exploration of the Upper Devonian Shale within Pennsylvania.

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