An Outcrop Based Study of the Weches Formation in Sabine County, Texas: Investigating Its Unconventional Resource Potential through the Study of Stratigraphy, Sedimentology, Petrology, and Geochemistry

<p>Fresh Weches Formation (Middle Eocene) exposures found in aggregate quarries in Sabine County, Texas, were sampled, measured, and logged with gamma-ray spectrometry (GRS). Sedimentology and petrology characteristics of Weches samples were analyzed through thin section, scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and GRS Th/K ratios analyses. The source rock quality of the Weches was evaluated with geochemical techniques involving total organic carbon (TOC), Rock-Eval pyrolysis, and GRS Th/U ratios.</p> <p>The Weches, in the study area, is 27.4 meters thick, and delineated into three major stratigraphic facies: an upper marginal marine prodeltaic facies (Therrill Member) comprised of silty claystones and two lower marginal marine to inner-shelf facies (Viesca and Tyus Members) of primarily pelleted, fossiliferous claystones and pelleted, fossiliferous packstones that form a stacked condensed section. The Viesca and Tyus Members are comprised of predominantly iron-rich serpentine and kaolinite clays. Conversely, the Therrill Member contains mostly smectite clays. The Viesca and Tyus Members had TOC values < 0.50 weight % and Th/U ratios > 7 ppm, indicating no hydrocarbon generative potential and an oxic environment. Whereas the Therrill Member had TOC values ranging from 0.46–2.85 weight % and Th/U ratios between 2 and 7 ppm, indicating some hydrocarbon generative potential and an intermittent suboxic to oxic environment. Rock-Eval pyrolysis analysis for the Therrill Member identified Type III kerogens (dry gas prone) but poor source rock quality based on S1 values < 0.5 and S2 values < 2.5.</p> <p>Results from this study indicate that all three members of the Weches would be poor candidates to target as an unconventional resource. However, the Therrill Member may warrant further investigation in other regions where it may have more desirable unconventional resource characteristics.</p>

Name thesis:degree_name

Master of Science - Geology

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Geology

Year dc:date.available

2018

Author dc:creator

• Kantala, Talban

Contributors dc:contributor

• Dr. LaRell Nielson
• Dr. Wesley Brown
• Dr. Melinda Faulkner

• Sabine Uplift
• structural geology
• paleocurrent
• Claiborne Group
• biostratigraphy
• petroleum
• Geology

Repository record dc:identifier

https://scholarworks.sfasu.edu/etds/214

OAI identifier oai:identifier

oai:scholarworks.sfasu.edu:etds-1231