JSG Events

URS Corporation Externship 2013

URS hosts students from the Jackson School for a one-day one-site visit to their north Austin offices.

BEG Friday Seminar: William Ambrose, Research Scientist, BEG

Video Streaming NOT available for this seminar

TITLE: "Incised-Valley and Estuarine Deposits in the Pennsylvanian Cleveland Formation, Western Anadarko Basin"

William A. Ambrose and Tucker F. Hentz
Bureau of Economic Geology,
Jackson School of Geosciences
The University of Texas at Austin
University Station, Box X, Austin TX 78713-8924


Oil and gas production from the low-permeability (tight) Cleveland Formation in the northwest Anadarko Basin dates from the late1950’s, although relationships between productivity, sequence-stratigraphic origin, and facies controls on reservoir geometry have only been recently documented. Analysis of closely spaced log sections from a dataset containing ~1,130 wells from Ochiltree and Lipscomb Counties, Texas, and Ellis County, Oklahoma, and five (5) conventional cores comprising ~250 ft (~75 m) of total section indicates that the Cleveland Formation is a succession of highstand tidally modified shelf, lowstand incised-valley-fill, and transgressive deposits that accumulated on a broad shelf. Distribution of the greatest producing wells in the Cleveland Formation is controlled mainly by gross-sandstone thickness and facies geometry that varies within three systems tracts. Lower Cleveland production trends reflect northeast-trending, tidally modified shelf sandstones within highstand system tracts. These sandstones are eroded by an east-west trending, lowstand incised-valley and estuarine system. The greatest number of producing wells in the middle Cleveland Formation coincides strongly with this incised-valley-fill system. In contrast, upper Cleveland sandstone bodies deposited in a transgressive systems tract, are much thinner than those in the underlying middle Cleveland lowstand and lower Cleveland highstand intervals, and therefore are less favorable hydrocarbon reservoirs. Other controls on Cleveland productivity include the regional Lips fault, southeast-plunging anticlines, and structural noses presumed to be associated with fracture-enhanced permeability. Future development in the Cleveland Formation should take into account the depositional evolution and systematic variations in sandstone bodies in each systems tract that controls the orientation and distribution of maximum permeability pathways.

Soft Rock Seminar: Vivian Leung, University of Washington

"Wood, Sediment, and the Elwha River Restoration: How woody debris interacts with river morphology and dam removals"

BEG Friday Seminar: Dr. Art Saller, AAPG Distinguished Lecturer 2013

Video Streaming Link: http://mediasite.beg.utexas.edu/Media/Viewer/?peid=b75750a6612746adbce262ac57593347

Dr. Art Saller
Stratigrapher and Exploration Geologist
Cobalt International Energy, Houston

*AAPG Distinguished Lecturer 2013
http://www.aapg.org/education/dist_lect/saller.cfm

Title: “Diagenetic Evolution of Porosity in Carbonates during Burial”
Abstract:
The diagenetic evolution of porosity and permeability in carbonates is complex and involves a number of independent factors. Carbonate sediments start with 40-80% porosity and generally lose porosity with time and burial (Schmoker and Halley, 1982), however there are many factors that cause higher and lower porosity in carbonates of the same age and burial depth. Alteration of carbonate sediments during shallow burial is common and includes diagenesis in seawater shortly after deposition, freshwater diagenesis during subaerial exposure, and dolomitization in hypersaline waters. Marine (seawater) diagenesis varies with depth and carbonate saturation as is shown on Enewetak Atoll. Aragonite and Mg-calcite cementation dominate in shallow seawater; however aragonite is dissolved and radiaxial calcite precipitates in moderately deep seawater. In even deeper seawater, calcite dissolves and dolomite precipitates. Freshwater (meteoric) diagenesis and dolomitization commonly rearrange and decrease porosity, but they also impart strength to the rock that reduces porosity loss during deeper burial. Pennsylvanian limestones in west Texas show that prolonged subaerial exposure progressively decreases matrix porosity but increases conduit porosity (fractures and vugs), and hence, formation permeability. Reflux dolomitization is commonly associated with carbonates in arid climates like the Permian of the Permian Basin. The porosity and permeability of reflux dolomites varies according to position in the dolomitizing system with less porosity and permeability in proximal parts of the dolomitizing system. Dolomitization decreases rate of porosity loss with burial (Schmoker and Halley, 1982) allowing some porous dolomite reservoirs like the Smackover of south Alabama at depths of 16,000-18,000 feet. Deep burial dissolution increasing porosity is the exception, rather than the rule. In summary, unlike quartzose sandstones, a complex array of diagenetic factors generally affect the ultimate porosity, permeability and production of carbonate reservoirs.

UTIG Seminar Series: Steve May, Chief Geoscientist, ExxonMobil

"Detrital Zircon Geochronology from the Bighorn Basin, Wyoming, USA: Implications for Tectonostratigraphic Evolution and Paleogeography"

Abstract:

Tectonostratigraphic assemblages record phases of basin history during which the fundamental controls of tectonic setting, subsidence style, and basin geometry are relatively similar. Because these fundamental controls, in combination with climate and eustasy, influence paleogeography and sediment-dispersal patterns, they should also yield similar patterns or facies of detrital zircon age spectra. Reference curves for these patterns should be documented on the craton in order to make meaningful comparisons to sedimentary rocks from suspect terranes along continental margins. The Rocky Mountains of western North America provide excellent outcrops of sedimentary rocks that record > 500 million years of tectonostratigraphic evolution. One such Phanerozoic section is exposed along the margins of the Bighorn Basin in northwest Wyoming from which we report over 4,000 U/Th/Pb detrital zircon ages from 48 samples that span a stratigraphic interval from the middle Cambrian Flathead Sandstone through the Eocene Willwood Formation. These data provide one of the most complete records of detrital zircon age patterns from this portion of cratonic North America.

The stratigraphic record within the Bighorn Basin can be subdivided into four tectonostratigraphic assemblages. These assemblages record an initial passive margin history, followed by a transitional assemblage to a convergent margin, followed by a marine-dominated retroarc foreland assemblage, followed by a retroarc foreland segmented by local basement uplifts. This tectonostratigraphic architecture is expressed as four, first-order patterns within the detrital zircon age distributions that reflect fundamental changes in paleogeography and sediment dispersal at the 10 – 100 Ma time scale. Detrital zircon ages also provide evidence for linkages between convergent margin process like arc magmatism and sedimentation in the retroarc foreland. During these times of strong arc – retroarc linkage, detrital zircon geochronology provides a potentially useful tool for high resolution chronostratigraphy.

Tech Session

Ethan Lake: JGB 2.324
"TBA"

Kuldeep Chaudhary: JGB 3.222
"TBA"

Tech Session

John Vidale
"TBA"

BEG Friday Seminar: Dr. Bridget Scanlon, Sr. Res. Sci., BEG

Video Streaming Link: http://mediasite.beg.utexas.edu/Media/Viewer/?peid=6dcc0253255a43779b3243dacb39aa12

Dr. Bridget Scanlon
Senior Research Scientist
Bureau of Economic Geology, UT Austin
Email: bridget.scanlon@beg.utexas.edu

Title: "Drought and the Energy Water Nexus in Texas"

Bridget R. Scanlon, Robert C. Reedy, Ian Duncan, Nelun Fernando, Jon Paul Pierre, Alex Sun, and Michael Young
Bureau of Economic Geology, Jackson School of Geosciences, Univ. of Texas at Austin

Texas experienced the most extreme one year drought on record in 2011 with projections of 3000 MW of electricity shortages if drought extended another year. Lack of electricity storage results in the need to meet peak electricity demands during the hottest times (Aug 1 – 4, 2011) when water supplies are lowest (reservoir storage reduced to ~60% during drought), amplifying the water energy nexus problems. The objective of this study was to evaluate drought vulnerability of electricity generation in Texas. Water use for electricity generation was determined from federal (EIA) and state (TWDB and TCEQ) databases for 2010 and 2011. Most (86%) electricity generation required water for cooling, consuming 0.46 million acre feet (maf, 2011), and representing 3% of total water withdrawal in the state. Although ~19 maf is recirculated for cooling, 98% of this water is returned to the source. Drought vulnerability of electricity generation in Texas results from reliance mostly on surface water, with runoff reduced to < 1 percentile during 2011, reservoir storage for power plants decreasing to < 50% in a third of the monitored reservoirs, close to intake levels in only a couple of plants, and high temperature discharges in a few plants. Drought resilience can be increased by reducing electricity and water demands, increasing supplies, and storing more water. Recent trends towards combined cycle natural gas plants with towers has reduced water withdrawal and consumption rates since the late 1990s and is projected to further decrease to 2030. Understanding the controls on drought vulnerability of power plants and exploring various options to increase resilience is essential for continued reliable affordable electricity production in Texas.

UTIG Seminar Series: John Vidale, University of Washington

"West Coast Earthquake Early Warning - Issues and Imperatives"

Abstract:

The Cascadia subduction zone offers great utility from earthquake early warning for the Puget Sound, Portland, Vancouver, and the tsunami-vulnerable coast. So the UW and UC Berkeley, with the support of the Moore Foundation, are constructing a prototype early warning system.

The 1000-km length allows minutes of warning when a megaquake starts at a distance, as is likely. The 10,000-year record of the last several dozen great earthquakes from offshore turbidites allows good guessing of the chance of a big earthquake growing into a turbulent giant. We are far enough into the 500-year M9 cycle to have 150% of the long term odds - 1/300 odds each year. The southern stretch of Cascadia, which is prone to M8s as well as M9s, is even more primed for action.

Challenges are also outsized. Instrumentation is relatively sparse. Discrimination between a wide range of possible styles and depths of strong earthquakes will be difficult. Means of relaying warnings, discussions with potential users, and long-term funding are not yet mature.

Hydro Brown Bag: Dr. Sayed Bateni, UCLA

Soft Rock Seminar: Sarah Christian, DGS

Integrating surface and subsurface datasets to decipher the aeolian stratigraphic record on Earth and Mars

Tech Session

Ethan Lake (Boyd Auditorium)
"TBA"

Brian Kiel (JGB 3.222)
"TBA"

McCombs Undergraduate Career Fair

Open to other schools within UT at 3:00-5:00 PM. Event Link: http://www.mccombs.utexas.edu/career/~/~/~/link.aspx?_id=4D2268EAE683469DAE1E5FC4D231991C&_z=z

Strict dress code enforced.
Wear a suit – the material of the jacket must match the material of the slacks or skirt
Suit must be dark grey, navy or black (not a dark purple or other dark colors and we will not let in a light colored suit)
Professional shoes
No visible piercings
Hair color cannot be neon or bright colored

Tech Session

Julie Fosdick
"TBA"