Date of Graduation

5-2017

Document Type

Thesis

Degree Name

Master of Science in Geology (MS)

Degree Level

Graduate

Department

Geosciences

Advisor/Mentor

Manger, Walter L.

Committee Member

McGilvery, T.A. "Mac"

Second Committee Member

Potra, Adriana

Keywords

Earth sciencs; Cenomanian; Deposition; Eagle ford; Turonian; Unconventional; Upper cretaceous

Abstract

The mixed siliciclastic/carbonate late Cretaceous Eagle Ford Formation is commonly divided into the lower Eagle Ford and the upper Eagle Ford. The lower Eagle Ford is arguably the most obvious organic rich interval highlighted with wireline log data; however, the upper Eagle Ford may have just as much potential for hydrocarbon production success as the lower Eagle Ford has had. A better understanding of the upper Eagle Ford will allow a more thorough and educated assessment into its full potential as an unconventional reservoir, and allow its sweet spots for oil or gas to be found and exploited.

This study is based on the description and interpretation of four cores of the upper Eagle Ford located within Karnes and Gonzales counties, Texas, thin sections, and key XRF data in an effort to better understand its sediment sources and depositional regime.

Seven lithofacies were identified in the upper Eagle Ford are as follows:

1) Bioturbated Wackestone/Packstone; 2) Deformed Wackestone/Packstone; 3) Wavy Laminated Wackestone/Packstone; 4) Massive Mudstone/Wackestone; 5) Coarsely to Finely Laminated Wackestone/Packstone; 6) Massive packstone/grainstone; 7) Volcanic Ash.

The highest Total Organic Carbon (TOC) percent relative to each core always occurred within the base of the upper Eagle Ford. In fact, the highest TOC percentage recorded was 4.5% within the base of the upper Eagle Ford in the most distally located core.

Thorium to Uranium ratios of the upper Eagle Ford were on average less than 1 indicating that the upper Eagle Ford contains very little terrigenous sourced material. Nickel, copper, vanadium, molybdenum, and uranium concentrations were also analyzed and correlated to relative organic matter influx and Paleoredox levels within the upper Eagle Ford in each core.

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