Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences


Geology and Geography

Committee Chair

Richard Smosna

Committee Co-Chair

Kathy Bruner

Committee Member

Tim Carr.


The main purpose of this investigation is to define the distribution of organic-rich facies of the Middle Devonian Marcellus Shale in New York, Ohio, Pennsylvania, and West Virginia. The analysis is based on well-log data, primarily gamma-ray (the most common and best calibrated) and bulk-density logs (where available). Detailed log analysis has been performed to normalize the logs and define key indicators of reservoir quality. Stratigraphic correlations have been conducted to trace key formation across the study area.;The following maps were generated over the study area.;• Isopach maps of the Mahantango Shale, Marcellus Shale, Oatka Creek Member, Cherry Valley and Union Springs Member. These maps show the stratigraphic thicknesses of the various formations and members.;• Net thickness maps of the Marcellus Shale where the gamma-ray < 100 API and gamma-ray is between 100-180 API. The gamma-ray < 100 API map shows the thickness of the various limestone intervals within the Marcellus. The paleography of these intervals represents carbonate shoals along the basin margin (north and west) and over the peripheral bulge. The gamma-ray map between 100-180 API shows the net thickness of calcareous shale and gray shale. These intervals represent the shallow muddy sea above the thermocline.;• Net thickness maps of the Marcellus Shale where the gamma-ray >180 API, > 200 API, > 250 API, and > 300 API. These maps show the thickness and distribution of shale with different organic-richness within the Marcellus. The paleography of these shale intervals was the deep basin below the thermocline. These maps show the location of the better reservoir.;• Average gamma-ray over the Marcellus interval. This map shows the average gamma-ray value for the Marcellus Shale across the basin. The map can be used as an indication of the highest average organic-richness of the Marcellus Shale, and is best used in conjunction with the net thickness maps by comparing the thickest portion of the various maps and where they may overlap regionally.;• Net thickness maps of the Marcellus Shale where the bulk-density < 2.55 g/cc, < 2.4 g/cc, and < 2.35 g/cc. These maps show various reservoir quality grades of organic-richness (where lower density equals higher quality).;• Isopach Maps of stratigraphic sequences and their systems tracts in the Marcellus Shale. Thin Transgressive Systems Tracts equal a condensed section, whereas thick Regressive Systems Tracts equal a major clastic influx.;These observations and others portrayed on this new series of maps provide a better understanding of the exploratory development of the Marcellus Shale in the Appalachian Basin. By using all of these maps in conjunction, the best target areas for oil and gas exploration can be identified and exploited. The sequence stratigraphic maps can be used for regional correlations and to develop target zones within the Marcellus Shale.