Dillon Worley

Graduation Semester and Year




Document Type


Degree Name

Master of Science in Earth and Environmental Science


Earth and Environmental Sciences

First Advisor

Max Hu


Being more extensive than the Marcellus Play, the Utica Play covers from New York state in the north to northeastern Kentucky and Tennessee in the south. The Utica Play is a stacked play consisting of organic-rich mudstones from upper Ordovician units of Utica Shale, Point Pleasant, and the Logana member of the Lexington/Trenton Limestone. This study will focus on the pore structure and rock-fluid interaction and with relation to the rocks geochemical properties to assess the Utica Play. To achieve this research purpose, 7 core samples and 16 cuttings, with different maturities were collected from various wells, to study rocks from Utica Shale, Point Pleasant, and Lexington Limestone, as well as the Kope Formation which is immediately above the Utica Shale. The research investigated the nano-petrophysics by the means of mercury injection capillary pressure (MICP), helium porosity and permeability, low-pressure nitrogen gas physisorption, contact angle, and spontaneous imbibition. The geochemistry of rocks was analyzed by pyrolysis and total organic content (TOC) measurements, while mineralogy was determined by X-ray diffraction (XRD). MICP results indicate that clay-rich formations have more intra-clay, organic-matter, and intragranular pores (2.8-50 nm in pore throats), while the more carbonate-rich samples possess a more prevalent amount of intragranular and intergranular pores (~ 100 nm in pore throats). Mineralogically speaking, carbonate and clay have an inverse relationship, as clay increases carbonate decreases. Samples have a low connectivity for the hydrophilic pore network but high for the hydrophobic pore network. From pyrolysis, S1 shows a positive correlation with MICP porosity. However, the Utica Shale and Point Pleasant Formation show a negative correlation suggesting OM may play a negative role in porosity development. Carbonate is not a controlling factor but influences overall porosity. When compared to other unconventional reservoirs, the Utica Play shows similar traits of hardness, brittleness, organic richness, porosity and permeability as other successful unconventional plays. For the Utica Play, this study provides a better understanding of pore structure and how thermal maturity can reduce porosity in mature samples due to the infilling of bitumen and mineralogy, specifically carbonate, influence porosity. Our mineralogy, petrophysical, and geochemical results support the Point Pleasant Formation being the target of the Utica Play. The better sustain production rate of Well B compared to Well A could be due to the more favorable petrophysical and geochemical properties of the Point Pleasant Formation. Knowing the petrophysical and geochemical characteristics of the Utica Play could aid in well placement, well design, and hydraulic fracture design and optimization.


Petrophysics, Geochemistry, Unconventional reservoir, Utica Play


Earth Sciences | Physical Sciences and Mathematics


Degree granted by The University of Texas at Arlington