[PDF] Depositional Dynamics Of The Upper Eagle Ford Upper Cretaceous eBook

Author : Josie Danielle Brunick
Publisher :
Page : 298 pages
File Size : 27,85 MB
Release : 2017
Category : Geology, Stratigraphic
ISBN :

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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.

Author : Brett Huffman
Publisher :
Page : pages
File Size : 30,66 MB
Release : 2013
Category :
ISBN :

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The fine-grained organic-rich rocks of the Eagle Ford (Cenomanian-Turonian) were deposited during the Upper Cretaceous in the shallow waters of the Western Interior Seaway. Five drill cores recovered from two counties, four from Travis County, Texas and one from Frio County, Texas, have been scanned from between two foot and half foot intervals with a hand-held energy-dispersive x-ray fluorescence (HH-ED-XRF) spectrometer to acquire major (e.g. Ca, Si, Al) and trace (e.g. Mo, V, Ni) element data for quantitative analysis. Additionally, gamma ray logs have been analyzed for two of the cores. Major element geochemistry indicates the Eagle Ford deposited in South Texas is different from the Eagle Ford deposited in Central Texas. South Texas Eagle Ford is much more Ca (carbonate) rich, with a noticeably lower Al (clay) content. South Texas and Central Texas Eagle Ford both have low Si (quartz) content relative to the Al and Ca content, indicating a negligible siliciclastic contribution during deposition. Trace element analysis reveals the redox conditions of the bottom waters during deposition. Mn -- an element which becomes mobile and may be removed from an open system in reducing conditions -- levels are much higher in the Austin Chalk and Buda with notably lower values in the Eagle Ford in both Central Texas and South Texas. Mo, an element which tends to bind with organic matter or sulfides during reducing conditions, is notably higher in the Eagle Ford of both South Texas and Central Texas. The correlation of decreased Mn levels and increased Mo levels suggests that the Eagle Ford was deposited in reducing conditions in an open system capable of removing mobilized Mn. Geochemical analysis of major and trace elements obtained from ED-XRF may be used in the petroleum industry in concert with XRD, electric logs, and standard core analysis to give a more complete picture of the depositional environment, clay type and volume, geophysical rock properties, and areal extent of a potential unconventional shale reservoir for hydrocarbon extraction. XRF data offers insight about the rocks, leading to improved understanding of the depositional environment and chemical makeup. Applying these technologies to the Eagle Ford helps unlock the potential of this significant hydrocarbon source and reservoir.

Author : Brian Butler Hunt
Publisher : Geological Society of America
Page : 64 pages
File Size : 47,56 MB
Release : 2013-04-01
Category : Nature
ISBN : 0813700302

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"The four field trips in this volume focus on sedimentology and paleontology in Texas. All the trips can directly trace their roots to the work of early geologic explorers"--Provided by publisher.

Author : Adam Thomas Martin
Publisher :
Page : 144 pages
File Size : 33,37 MB
Release : 2014
Category : Geology
ISBN : 9781303858659

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First discovered in 1921, the Minerva-Rockdale Oil Field (MROF) has experienced a recent resurgence of drilling. The targeted Navarro Group is Upper Cretaceous (Maastrichtian) in age and ranges in depth from approximately 100 to 3000+ ft. (subsea). Several thin elongated sandy zones within the Kemp clay of the Corsicana (Navarro) Formation are the current targets for oil production. These sandy zones are informally divided into the Navarro 'A' and 'B' and their depositional morphology is described by the shelf plume model, as proposed by Patterson (1983). Despite the mature nature of the MROF and surrounding area, only a small number of published studies regarding the local strata exist. The purpose of this study is to: (1) produce a regional stratigraphic framework for the Eagle Ford though Navarro Group strata within Milam and surrounding counties, (2) document the sequence-stratigraphic framework for Campanian to Mastrichtian aged strata, (3) recreate and test the depositional shelf plume model developed by Patterson (1983). Donated well logs and one sidewall core report from a current operator in the Minerva-Rockdale Oil Field as well as raster logs obtained from the Drillinginfo.com aided in reconstructing and testing the shelf plume model. Findings from the correlation of 274 well logs and analysis of the modern sidewall core report challenge depositional proximity of the elongated sand bodies to a deltaic depocenter.