Date of Award
8-2026
Degree Type
Thesis
Degree Name
Master of Science - Geology
Department
Geology
First Advisor
Dr. Julie Bloxson
Second Advisor
Dr. R. LaRell Nielson
Third Advisor
Dr. Melinda Faulkner
Fourth Advisor
Dr. Jenny Rashall
Abstract
The Fort Trinidad and Alabama Ferry fields located in eastern Madison and southern Houston County, Texas, have produced approximately 100 million barrels of oil equivalent to date, with approximately 65% of this being oil. However, there has been considerable variation in production within this Cretaceous carbonate play of the Fort Trinidad field, despite similar well completions and perforated intervals. The Buda Limestone, a key producing formation in the Cretaceous interval, is described as under-pressurized and often has lost circulation problems during drilling due to sub-pressure vertical fractures. Within the producing interval, the mechanisms for water production versus oil production are poorly understood. Understanding reservoir properties and establishing a framework for reservoir quality could explain why the Buda Limestone shows production variability across the field.
This study utilizes core and well log data from the Fidelity Exploration Dawn T. Henry et al. #1 well, a relatively poor producer characterized by high water production and limited hydrocarbon recovery, to evaluate reservoir properties and establish a framework for reservoir quality. Detailed stratigraphic analysis integrating core description, petrography, mineralogy, routine core analysis, and petrophysical data identified seven lithofacies within the Georgetown Limestone, Del Rio Shale, Buda Limestone, and Maness Shale. The Buda and Georgetown limestones are dominated by heavily bioturbated calcisphere-rich wackestones and packstones deposited in low-energy, open marine carbonate environments. Diagenetic modification through compaction, cementation, fracturing, and localized dissolution significantly altered reservoir quality following deposition.
Routine core analysis indicates that both the Buda and Georgetown limestones possess low matrix porosity and permeability, with average porosity generally less than 5% and permeability commonly in the microdarcy range. Vertical fractures, fracture-associated secondary porosity, and hydrocarbon staining observed in core and thin section suggest that fracture systems provide the primary pathways for hydrocarbon migration and production. Original oil in place (OOIP) calculations demonstrate that matrix porosity alone cannot account for the cumulative production observed in the Dawn T. Henry et al. #1 well and require the presence of additional fracture-related storage and permeability. The high water-to-oil production ratio further suggests that fracture connectivity exerts a primary control on fluid flow behavior within the reservoir. These results indicate that hydrocarbon production within the Fort Trinidad Field is controlled primarily by fracture development, connectivity, and diagenetic modification rather than by matrix reservoir properties alone.
Repository Citation
Bridges, Jeffrey C., "Stratigraphic Analysis of the Buda Limestone with Implications on Hydrocarbon Production Constraints, Madison and Houston County, Texas" (2026). Electronic Theses and Dissertations. 679.
https://scholarworks.sfasu.edu/etds/679
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
