Depositional Facies Analysis of the Cotton Valley Group Sandstones of the Blackburn Field, Northern Louisiana using Well Logs and Cores; Implications for Carbon Sequestration

Author

Frederick Owusu, Stephen F Austin State UniversityFollow

Date of Award

Spring 5-11-2024

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 Mindy Faulkner

Fourth Advisor

Dr Robert Friedfeld

Abstract

The Cotton Valley Group (CVG) consists of tight sandstones with heterogeneous reservoir properties due to variations in depositional environments and diagenesis, spanning across eastern Texas through the Florida panhandle. It has served as a hydrocarbon target since the 1940s, and with recent technological advances, there is renewed exploration of the tight reservoirs within the group. Across northern Louisiana, the CVG has moderate to good reservoir properties, whereas those south extending westward across the Sabine uplift into east Texas decrease in porosity and permeability. With reservoir depletion coupled with its relatively simple mineralogy, these sandstone units may serve as good, localized carbon capture, utilization, and storage (CCUS) reservoirs or benefit from secondary gas recovery.

This research is focused on the depositional conditions and reservoir characteristics, within the CVG, Claiborne Parish, Louisiana to create a preliminary geologic assessment for carbon sequestration in the Blackburn Field. This research utilizes both geophysical and sedimentological analyses, centered on core from the Worley Estate 29H-1 well, particularly focusing on the lower sandstone units. A combination of core descriptions, thin section analysis, x-ray diffraction and x-ray fluorescence are used to characterize reservoir properties. The CVG was divided into six units based upon changes in lithology in the core, correlated to the well log, and extrapolated across the Blackburn Field, northwest Claiborne Parish.

Overall, this group represents deposition ranging from tidal flats to lagoon to reworked barrier islands and reefal slope environments. The lithologies are comprised of sequences of quartz wackes, thinly bedded silty mudstones, quartz arenites, and wackestones. Porosity within the CVG Sandstones was mostly secondary in origin caused by fractures, dissolution of cements and fossils (bivalves), and minor primary intergranular pores. The porosity and permeability vary throughout the reservoir, restricted mainly by detrital clays, carbonate cementation, or protected by chlorite pore coatings. The sandstones of the CVG in the Blackburn Field may not be regarded as ideal CO₂ storage reservoirs due to their low porosity-permeability characteristics resulting from the clays and extensive carbonate cementation restricting pore throats.

Repository Citation

Owusu, Frederick, "Depositional Facies Analysis of the Cotton Valley Group Sandstones of the Blackburn Field, Northern Louisiana using Well Logs and Cores; Implications for Carbon Sequestration" (2024). Electronic Theses and Dissertations. 533.
https://scholarworks.sfasu.edu/etds/533

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