106 research outputs found

    Environmental Chemistry and Cycling Processes.. D.C. Adriano and I.L. Brisbin, Jr.

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    The organization of a library for the John Gill Elementary School, Redwood City, California

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    Statement of the Problem: The objectives of this thesis are to set forth the detailed procedures and methods essential to organize, from the instructional point of view, a library for John Gill School, a kindergarten through sixth grade school

    Do SiC grains in Orgueil differ from those in Murchison?

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    Studies of individual presolar SiC grains have shown that most are enriched in Si-29, Si-30, and C-13, and depleted in N-15, compared to solar-system abundances and that many have large excesses of Mg-26, most plausibly from in situ decay of Al-26. Stone et al., observed that Si from a family of platy SiC grains define a linear array on a 3-isotope plot that does not pass through normal solar-system Si. In contrast, Si-isotope data from over 100 3-4 micron SiC grains from Murchison from an elongate ellipse enclosing the Stone et al. linear array but also including 'normal' solar-system Si. To investigate whether this difference in Si isotopes indicates different populations of SiC in the two meteorites and to improve the characterization of Orgueil SiC, we used the PANURGE ion microprobe to measure Si, C, N, and Mg isotopes and Al and Na concentrations in a suite of 2-5 micron SiC grains from a new sample of Orgueil

    Monitoring the reservoir geochemistry of the Pembina Cardium CO2 monitoring project, Drayton Valley, Alberta

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    AbstractThe Pembina Cardium CO2 Monitoring Project in central Alberta was built to assess the Cardium formation’s storage potential for CO2 and stimulate oil production. Three baseline trips and 28 monitoring trips were undertaken over a three year period from February 2005 to March 2008 to collect fluids and gas from eight producing wells. Chemical and isotope analyses were conducted on the fluid and gas samples to determine the changes in the geochemistry of the pilot area and to assess the fate of the injected CO2. It was found that within 67 days after commencement of CO2 injection, injection CO2 break-through occurred in four of the eight monitoring wells. Further, CO2 dissolution was observed in three of the four monitoring wells in this time frame and in one well, 12–12, both CO2 dissolution and calcite mineral dissolution were observed within 67 days of the onset of CO2 injection. Within 18 months siderite dissolution and calcite dissolution were observed in all four of these wells. In the remaining four wells, CO2 dissolution was observed, indicated by a slow decreased in pH from 7.5 to 7.2 with no significant change in total alkalinity or calcium concentration in the water. Inter-well communications were observed between wells 08–11 and 12–12 by means of residual “kill fluid” migration occurring from well 12–12 to well 08–11

    Interactions of CO2 with Formation Waters, Oil and Minerals and CO2 storage at the Weyburn IEA EOR site, Saskatchewan, Canada

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    The Weyburn oil field in Saskatchewan, Canada, is hosted in Mississippian carbonates and has been subject to injection of CO2 since 2000. A detailed mineralogy study was completed as the basis for modeling of mineral storage of injected CO2. Combining the mineralogy with kinetic reaction path models and water chemistry allows estimates of mineral storage of CO2 over 50 years of injection. These results, combined with estimates of pore volume, solubility of CO2 in oil and saline formation waters, and the initial and final pore volume saturation with respect to oil, saline water and gas/supercritical fluid allow an estimate of CO2 stored in saline water, oil and minerals over 50 years of CO2 injection. Most injected CO2 is stored in oil (6.5•106 to 1.3•107 tonnes), followed closely by storage in supercritical CO2 (7.2•106 tonnes) with saline formation water (1.5 - 2•106 tonnes) and mineral storage (2 - 6•105 tonnes) being the smallest sinks. If the mineral dawsonite forms, as modeling suggests, the majority of CO2 dissolved in oil and salineformation water will be redistributed into minerals over a period of approximately 5000 years. The composition of produced fluids from a baseline sampling program, when compared to produced fluids taken three years after injection commenced, suggest that dawsonite is increasingly stable as pH decreases due to CO2 injection. The results suggest that hydrocarbon reservoirs that contain low gravity oil and little or no initial gas saturation prior to CO2 injection, may store the majority of injected CO2 solubilized in oil, making such reservoirs the preferred targets for combined enhanced oil recovery-CO2 storage projects

    Quantifying CO2 pore-space saturation at the Pembina Cardium CO2 monitoring pilot (Alberta, Canada) using oxygen isotopes of reservoir fluids and gases

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    Geochemical and isotopic monitoring allows determination of CO2 presence in the subsurface through the sampling of produced fluids and gases at production and/or monitoring wells. This is demonstrated by data from 22 months of monitoring at the Pembina Cardium CO2 Monitoring Pilot in central Alberta, Canada. Eight wells centered around two CO2 injectors were sampled monthly between February 2005 and February 2007. Stable isotope analyses of the samples revealed that changes in the δ13CCO2 values in produced gas as well as changes in the δ18O values of the produced fluids indicate CO2 presence and identify trapping mechanisms at select production wells. Using equilibrium isotope exchange relationships and CO2 solubility calculations, fluid and gas saturations in the pore space in excess of that occupied by oil were calculated. We demonstrate that stable isotope measurements on produced fluids and gases at the Pembina Cardium CO2 storage site can be used to determine both qualitatively and quantitatively the presence of CO2 around the observation well, given that the injected CO2 is isotopically distinct

    Carbon and nitrogen fixation and metabolite exchange in and between individual cells of Anabaena oscillarioides

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    Filamentous nitrogen fixing cyanobacteria are key players in global nutrient cycling, but the relationship between CO"2- and N"2-fixation and intercellular exchange of these elements remains poorly understood in many genera. Using high-resolution nanometer-scale secondary ion mass spectrometry (NanoSIMS) in conjunction with enriched H13CO"3- and 15N"2 incubations of Anabaena oscillarioides, we imaged the cellular distributions of C, N and P and 13C and 15N enrichments at multiple time points during a diurnal cycle as proxies for C and N assimilation. The temporal and spatial distributions of the newly fixed C and N were highly heterogeneous at both the intra- and inter-cellular scale, and indicative of regions performing active assimilation and biosynthesis. Subcellular components such as the neck region of heterocycts, cell division septae and putative cyanophycin granules were clearly identifiable by their elemental composition. Newly fixed nitrogen was rapidly exported from heterocysts and was evenly allocated among vegetative cells, with the exception of the most remote vegetative cells between heterocysts, which were N limited based on lower 15N enrichment. Preexisting functional heterocysts had the lowest levels of 13C and 15N enrichment, while heterocysts that were inferred to have differentiated during the experiment had higher levels of enrichment. This innovative approach, combining stable isotope labeling and NanoSIMS elemental and isotopic imaging, allows characterization of cellular development (division, heterocyst differentiation), changes in individual cell composition and cellular roles in metabolite exchange

    The use of stable isotope measurements for monitoring and verification of CO2 storage

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    Stable isotope data can assist in successful monitoring of the fate of injected CO2 in enhanced oil recovery and geological storage projects. This is demonstrated for the International Energy Agency Greenhouse Gas Weyburn-Midale CO2 Monitoring and Storage Project (Saskatchewan) and the Pembina Cardium CO2 Monitoring Project (Alberta) where fluid and gas samples from multiple wells were collected and analyzed for geochemical and isotopic compositions. In both projects, C and O isotope values of injected CO2 were sufficiently distinct from those of background CO2 in the reservoir. Consequently C and O isotope ratios constitute a suitable ‘fingerprint’ for tracing the fate of injected CO2 in the respective reservoirs
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