213 research outputs found
Recommended from our members
Assessing impacts to groundwater from CO2-flooding of SACROC and Claytonville oil fields in West Texas
Comparison of groundwater above two Permian Basin oil fields (SACROC Unit and
Claytonville Field) near Snyder, Texas should allow us to assess potential impacts of 30 years of
CO2-injection. CO2-flooding for enhanced oil recovery (EOR) has been active at SACROC in
Scurry County since 1972. Approximately 13.5 million tons per year (MtCO2/yr) are injected
with withdrawal/recycling amounting to ~7MtCO2/yr. It is estimated that the site has accumulated
more than 55MtCO2; however, no rigorous investigation of overlying groundwater has
demonstrated that CO2 is trapped in the subsurface. Mineralogy of reservoir rocks at the
Claytonville field in southwestern Fisher County is similar to SACROC. CO2-EOR is scheduled
to begin at Claytonville Field in Fisher County in early 2007. Here we have the opportunity to
characterize groundwater prior to CO2-injection and establish baseline conditions at Claytonville.
Methods of this study will include: (1) examination of existing analyses of saline to fresh
water samples collected within an eight-county area encompassing SACROC and Claytonville,
(2) additional groundwater sampling for analysis of general chemistry plus field-measured pH,
alkalinity, and temperature, stable isotopic ratios of hydrogen (D/H), oxygen (18O/16O), and
carbon (13C/12C), and (3) geochemical equilibrium and flowpath modeling. Existing groundwater
data are available from previous BEG studies, Texas Water Development Board, Kinder Morgan
CO2 Company, and the U. S. Geological Survey. By examining these data we will identify
regional groundwater variability and focus additional sampling efforts. The objective of this study
is to look for potential impacts to shallow groundwater from deep CO2-injection. In the absence
of conduit flow from depth, we don’t expect to see impacts to shallow groundwater, but
methodology to demonstrate this to regulators needs to be established.
This work is a subset of the Southwest Regional Partnership on Carbon Sequestration
Phase 2studies funded by the Department of Energy (DOE) in cooperation with industry and
government partners.Bureau of Economic Geolog
Recommended from our members
MUC16 Mutations and Prognosis in Gastric Cancer: A Little Goes a Long Way.
Gastric cancer is a global health problem; although incidence rates are declining, it remains the third most common cause of cancer death worldwide. Patients with advanced disease have limited treatment options, and most will live for less than 2 years. Therefore, exploration of gastric cancer disease biology is warranted to identify new targets for treatment. Recent comprehensive molecular analyses have identified distinct subgroups of gastric cancer that may have therapeutic relevance. With the exception of microsatellite-unstable tumors, however, the potential for genomically guided therapy has not been realized
Recommended from our members
Site Investigation and Evaluation of Remedial Alternatives for the Wharton County Site, East Bernard, Texas
The permitting process for salt-water injection wells mandates that oil companies or operators conduct an Area of Review (AOR) study within a 0.25-mile radius of a proposed well. The objective of such a study is to identify unplugged wells that could potentially allow injected fluids to migrate upward from the production zone, posing a threat to the overlying underground sources of drinking water (USDW).
The Bureau of Economic Geology (BEG) at the University of Texas at Austin, working in collaboration with the Railroad Commission of Texas (RRC), assessed oil fields across Texas to determine if any variations to the AOR permitting process were feasible based on the separation between production-zone fluid levels and the base of USDW. This evaluation aimed to provide the RRC and the industry with valuable data and methodology to facilitate AOR variance applications and the review of oil fields in Texas.Bureau of Economic Geolog
Assessing risk to fresh water resources from long term CO2 injection- laboratory and field studies
In developing a site for geologic sequestration, one must assess potential consequences of failure to adequately contain
injected carbon dioxide (CO2). Upward migration of CO2 or displacement of saline water because of increased pressure might
impact protected water resources 100s to 1000s of meters above a sequestration interval. Questions posed are: (1) Can changes in chemistry of fresh water aquifers provide evidence of CO2 leakage from deep injection/sequestration reservoirs containing brine and or hydrocarbons? (2) What parameters can we use to assess potential impacts to water quality? (3) If CO2 leakage to
freshwater aquifers occurs, will groundwater quality be degraded and if so, over what time period?
Modeling and reaction experiments plus known occurrences of naturally CO2-charged potable water show that the
common chemical reaction products from dissolution of CO2 into freshwater include rapid buffering of acidity by dissolution of
calcite and slower equilibrium by reaction with clays and feldspars. Results from a series of laboratory batch reactions of CO2
with diverse aquifer rocks show geochemical response within hours to days after introduction of CO2. Results included decreased
pH and increased concentrations of cations in CO2 experimental runs relative to control runs using argon (Ar). Some cation (Ba,
Ca, Fe, Mg, Mn, and Sr) concentrations increased over and an order of magnitude during CO2 runs. Results are aquifer dependant in that experimental vessels containing different aquifer rocks showed different magnitudes of increase in cation concentrations.
Field studies designed to improve understanding of risk to fresh water are underway in the vicinity of (1) SACROC
oilfield in Scurry County, Texas, USA where CO2 has been injected for enhanced oil recovery (EOR) since 1972 and (2) the
Cranfield unit in Adams County, Mississippi, USA where CO2 EOR is currently underway. Both field studies are funded by the
U.S. Department of Energy (DOE) regional carbon sequestration partnership programs and industrial sponsors. Preliminary
results of groundwater monitoring are currently available for the SACROC field study where researchers investigated 68 water
wells and one spring during five field excursions between June 2006 and July 2008. Results to date show no trend of preferential
degradation below drinking water standards in areas of CO2 injection (inside SACROC) as compared to areas outside of the
SACROC oil field.Bureau of Economic Geolog
Recommended from our members
Potential Sinks for Geologic Storage of CO2 Generated in the Carolinas
This document summarizes a scoping study of the current state of knowledge of carbon storage options for our geographic area.
The focus is on one aspect of carbon capture and storage—identification of deep saline aquifers in which carbon dioxide (CO2
) generated in the Carolinas might be stored. The study does not address other aspects of CO2 storage projects, such as capture and compression of the gas, well construction and development, or injection. Transport of CO2 is touched upon in this study but has not been fully addressed.
The information contained in this document is primarily from review of published geologic literature and unpublished data. No field data collection has been completed as part of this study. Further work will be necessary to increase confidence in the suitability of the potential CO2 storage sites identified in this report. This study does not address the regulatory, environmental, or public policy issues associated with carbon storage, which are under development at this time.Duke Energy, Progress Energy, Santee Cooper Power, South Carolina Electric and Gas, Electric Power Research Institute (EPRI), Southern States Energy Board (SSEB)Bureau of Economic Geolog
Recommended from our members
Transmissivity, Hydraulic Conductivity, and Storativity of the Carrizo-Wilcox Aquifer in Texas
Transmissivity, hydraulic conductivity, and storativity are crucial parameters for developing local and regional water plans and numerical groundwater flow models to predict the future availability of the water resource. To support this effort, we compiled and analyzed transmissivity, hydraulic conductivity, and storativity values from various sources for the entire Carrizo-Wilcox aquifer in Texas, resulting in a database of 7,402 estimates of hydraulic properties in 4,456 wells. Transmissivity and hydraulic conductivity results for all tests in the Carrizo-Wilcox aquifer follow a log-normal distribution. Transmissivity ranges from about 0.1 to 10,000 ft^2/day and has a geometric mean value of about 300 ft^2/day, while hydraulic conductivity ranges from about 0.01 to 4,000 ft/day and has a geometric mean value of about 6 ft/day. Transmissivity and hydraulic conductivity vary spatially, both vertically and laterally, within the Carrizo-Wilcox aquifer. The Simsboro Formation and Carrizo Sand portions of the aquifer exhibit transmissivity and hydraulic conductivity values that are 2.5 to 11 times higher and 2 to 6 times higher, respectively, than those of the Cypress aquifer, Calvert Bluff Formation, and undivided Wilcox Group.
Semivariograms demonstrate that transmissivity and hydraulic conductivity values in the Carrizo Sand and undivided Wilcox Group are spatially correlated over distances of about 17 and 25 miles, respectively. Large nuggets in the semivariograms suggest local-scale heterogeneity and measurement errors. Kriged maps of transmissivity and hydraulic conductivity reveal the highest values for the Carrizo Sand in the Winter Garden area and the greatest values for the Wilcox Group in the south-central and northeast parts of the aquifer. Storativity and specific storage values exhibit approximately log-normal distributions. Storativity ranges from about 10^-6 to 10^-1 with a geometric mean of 3.0 x 10^-4, while specific storage ranges from about 10^-7 to 10^-3 with a geometric mean of 4.5 x 10^-6. Lower values of storativity and specific storage tend to occur at shallow depths where the aquifer is unconfined.Bureau of Economic Geolog
Investigating the utility of combining Φ29 whole genome amplification and highly multiplexed single nucleotide polymorphism BeadArray™ genotyping
BACKGROUND: Sustainable DNA resources and reliable high-throughput genotyping methods are required for large-scale, long-term genetic association studies. In the genetic dissection of common disease it is now recognised that thousands of samples and hundreds of thousands of markers, mostly single nucleotide polymorphisms (SNPs), will have to be analysed. In order to achieve these aims, both an ability to boost quantities of archived DNA and to genotype at low costs are highly desirable. We have investigated Φ29 polymerase Multiple Displacement Amplification (MDA)-generated DNA product (MDA product), in combination with highly multiplexed BeadArray™ genotyping technology. As part of a large-scale BeadArray genotyping experiment we made a direct comparison of genotyping data generated from MDA product with that from genomic DNA (gDNA) templates. RESULTS: Eighty-six MDA product and the corresponding 86 gDNA samples were genotyped at 345 SNPs and a concordance rate of 98.8% was achieved. The BeadArray sample exclusion rate, blind to sample type, was 10.5% for MDA product compared to 5.8% for gDNA. CONCLUSIONS: We conclude that the BeadArray technology successfully produces high quality genotyping data from MDA product. The combination of these technologies improves the feasibility and efficiency of mapping common disease susceptibility genes despite limited stocks of gDNA samples
Recommended from our members
Assessment of Geological Storage Capacity of the Southeastern U.S. for CO2 in Brines and Economic Use for EOR
Bureau of Economic Geolog
Recommended from our members
Discovery, linkage disequilibrium and association analyses of polymorphisms of the immune complement inhibitor, decay-accelerating factor gene (DAF/CD55) in type 1 diabetes.
BACKGROUND: Type 1 diabetes (T1D) is a common autoimmune disease resulting from T-cell mediated destruction of pancreatic beta cells. Decay accelerating factor (DAF, CD55), a glycosylphosphatidylinositol-anchored membrane protein, is a candidate for autoimmune disease susceptibility based on its role in restricting complement activation and evidence that DAF expression modulates the phenotype of mice models for autoimmune disease. In this study, we adopt a linkage disequilibrium (LD) mapping approach to test for an association between the DAF gene and T1D. RESULTS: Initially, we used HapMap II genotype data to examine LD across the DAF region. Additional resequencing was required, identifying 16 novel polymorphisms. Combining both datasets, a LD mapping approach was adopted to test for association with T1D. Seven tag SNPs were selected and genotyped in case-control (3,523 cases and 3,817 controls) and family (725 families) collections. CONCLUSION: We obtained no evidence of association between T1D and the DAF region in two independent collections. In addition, we assessed the impact of using only HapMap II genotypes for the selection of tag SNPs and, based on this study, found that HapMap II genotypes may require additional SNP discovery for comprehensive LD mapping of some genes in common disease.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
- …