2008 January Noon Luncheon
The Revitalization of
Prior to the formation of Greystone Petroleum
LLC and its development of Sligo Field, located in Bossier
Parish, Louisiana, Michael Geffert and Joe Bridges drilled and
completed over 200 wells in Lower Cretaceous and Upper Jurassic
reservoirs located in the Ark-La-Tex. Though these were
primarily Hosston wells located on turtle structures in the
North Louisiana Salt Basin, their experience in mapping,
drilling and completing the Rodessa, Pettit, Hosston, Cotton
Valley and Smackover reservoirs led them to the observation that
completion procedures followed by Pennzoil and other operators
at Sligo Field left many gas charged reservoirs either behind
pipe or bypassed below packers and cast iron bridge plugs.
April Noon Luncheon
The Global Warming
and fear associated with the global warming issue has become a
driving force behind many aspects of our daily life and work.
Government officials at all levels are making decisions that
affect business, environmental controls, international treaties,
taxes, political campaigns, and social policies based on “global
warming”. The Intergovernmental Panel on Climate Change (IPCC)
has just released the 2007 update of its “Physical Science Basis
Summary for Policy Makers”. Amid the hype, news agencies are
using the issue to create headlines designed to cause alarm (and
boost ratings). Yet, is the science sound? Is there consensus
that human activities are causing global climate change? Is
there an underlying agenda? What if the doomsayers are right?
What if they are wrong?
all questions that we as geoscientists are likely asking
ourselves. Yet, anyone who tries to figure out the answers may
quickly become overwhelmed with the flood of information
available on the internet or elsewhere in print. Because of all
the hype and distortion, it is difficult to get down to a simple
evaluation of the scientific facts. This presentation attempts
to provide a reasoned and balanced evaluation of the issue from
a geologist’s perspective. The presenter believes that
geologists are uniquely qualified to understand and lead the
debate on the global climate change issue, and it is our duty as
earth science professionals to be involved in advancing the
public understanding of the issue.
Ruckstuhl is a graduate of LSU and is a registered professional
geologist. He works in the Jackson office of Environmental
Management Services, Inc. He has worked in the environmental
consulting field for 25 years.
February Noon Luncheon
Petrophysical Evaluation of
Typically, geologists and engineers
work to develop a data set to define reservoir potential and
establish a drilling strategy that will provide optimum results.
The evaluation of shale reservoirs combines the evaluation of
several important parameters and includes petrophysical (core
and logs), petrographic, geochemical and mechanical property
data. All data types are important in defining reservoir
potential, targeting zones with the greatest potential and for
comparing shale reservoirs from different provinces. Unless all
key parameters are favorable, it is unlikely that economic
production can be achieved. This presentation will discuss
each key element’s importance in understanding productive
potential and outline evaluation efforts necessary to properly
characterize a gas-shale reservoir.
Chuck Segrest received his geology
degree from Baylor University.
He has over 25 years industry
experience in petrophysical evaluation of rock samples for the
purposes of improved reservoir characterization.
He is a senior partner in the
company GeoSystems, which is geological/petrophysics company
specializing in the integration of multiple data sets for the
purpose of improved reservoir characterization.
Recap - November
2006 Noon Luncheon
"Exploration Strategies for Thrombolite and
Associated Facies, Eastern Gulf Coastal Plain"
Ernest A. Mancini, Center for
Sedimentary Basin Studies and Department of Geological Sciences,
University of Alabama
In the eastern
Gulf Coastal Plain, Upper Jurassic Smackover inner ramp (shallow
water) thrombolite buildups have been documented as developing
on paleotopographic features (Paleozoic basement paleohighs or
Jurassic salt anticlines and ridges). Thrombolites dominated by
calcimicrobes grew in the eastern part of the Mississippi
Interior Salt Basin, the Manila Subbasin and the Conecuh
Subbasin. These thrombolites attained a thickness of 58 m and
are present in an area of up to 6.2 square km. Although these
buildups have been exploration targets for some 30 years, new
field discoveries continue to be made in this area indicating
that the development of these organosedimentary deposits is not
Recent hydrocarbon drilling in Little Cedar Creek Field, Conecuh
County, southwest Alabama has revealed that the productive
reservoir rocks are thrombolite boundstone and associated
nearshore grainstone and packstone that occur near the
depositional updip limit of the Upper Jurassic Smackover
Formation. These thrombolite buildups do not directly overlie
Paleozoic basement paleohighs.
By studying Upper
Jurassic thrombolite bioherms and reefs as preserved in outcrop,
the geometries, aerial extents, and facies relationships of
thrombolites can be better characterized, and this
characterization is useful in designing an effective exploration
strategy for delineating thrombolite buildups in the subsurface.
Thrombolites were best developed on a hard substrate during a
rise in sea level under initial zero to low background
sedimentation rates in low energy paleoenvironments, and their
occurrence was not restricted by water depth, salinity,
temperature, light penetration, oxygen content, or nutrient
supply. The keys to drilling a successful wildcat well in the
thrombolite reservoir play prior to the discovery of Little
Cedar Creek Field were to: 1) utilize three-dimensional seismic
reflection technology to find a paleohigh and to determine
whether potential thrombolite reservoir facies occur on the
crest and/or flanks of the feature and are above the oil-water
contact, 2) use the characteristics of thrombolite bioherms and
reefs as observed in outcrop to develop a three-dimensional
geologic model to reconstruct the growth of thrombolite buildups
on paleohighs for improved targeting of the preferred dendroidal
and chaotic thrombolite reservoir facies, and 3) utilize the
evaporative pumping mechanism, rather than the seepage reflux or
mixing zone models, as a means for assessing potential
dolomitization of the thrombolite boundstone.
The operative Smackover petroleum system at Little Cedar Creek
has shown that the current thrombolite exploration strategy
requires revision to include: consideration of a basin center
petroleum source in addition to a local source, the development
of potential reservoir facies in a broader array of
paleobathymetric settings other than restricted to inner to
middle ramp, inclusion of moldic and vuggy pore types to
intercrystalline dolomite pore types for a productive reservoir,
lime mudstone and shale as vertical and lateral seal rocks
rather than anhydrite, and stratigraphic traps in addition to
combination structural and stratigraphic traps.