Deep CO Research Articles

Scenario analysis of hypothetical site conditions for geological CO2 sequestration in Japan

Abstract For the practical application of deep geological CO 2 sequestration in Japan, it is necessary to assure the safety of the sequestration method and technology to achieve public acceptance. For this purpose, it is also necessary to carry out risk assessments and scenario analysis taking into account typical Japanese geological conditions. A scenario analysis procedure was evaluated by using hypothetical geological information reflecting the actual geology in Japan. A new FEP database (RITE-DB) was created for application to Japanese geology because Japan has complicated geological structures which include folds, faults and fractures. FEPs are features, events and processes that are relevant to the long-term safety and performance of the sequestration system after injection of CO 2 . The scenario analysis with the RITE-DB identified important scenarios, i.e. a fault scenario, a seal failure scenario, etc. and many phenomena sequences in these scenarios. The process of identifying the scenarios and phenomena was judged to be exhaustive. The results will inform quantitative safety analysis and site design.

Soil gas ( 222Rn, CO 2, 4He) behaviour over a natural CO 2 accumulation, Montmiral area (Drôme, France): geographical, geological and temporal relationships

The south east basin of France shelters deep CO 2 reservoirs often studied with the aim of better constraining geological CO 2 storage operations. Here we present new soil gas data, completing an existing dataset (CO 2, 222Rn, 4He), together with mineralogical and physical characterisations of soil columns, in an attempt to better understand the spatial distribution of gas concentrations in the soils and to rule on the sealed character of the CO 2 reservoir at present time. Anomalous gas concentrations were found but did not appear to be clearly related to geological structures that may drain deep gases up to the surface, implying a dominant influence of near surface processes as indicated by carbon isotope ratios. Coarse grained, quartz-rich soils favoured the existence of high CO 2 concentrations. Fine grained clayey soils preferentially favoured the existence of 222Rn but not CO 2. Soil formations did not act as barriers preventing gas migrations in soils, either due to water content or due to mineralogical composition. No abundant leakage from the Montmiral reservoir can be highlighted by the measurements, even near the exploitation well. As good correlation between CO 2 and 222Rn concentrations still exist, it is suggested that 222Rn migration is also CO 2 dependent in non-leaking areas – diffusion dominated systems.

Potential Impacts of Leakage from Deep CO2 Geosequestration on Overlying Freshwater Aquifers

Carbon Capture and Storage may use deep saline aquifers for CO(2) sequestration, but small CO(2) leakage could pose a risk to overlying fresh groundwater. We performed laboratory incubations of CO(2) infiltration under oxidizing conditions for >300 days on samples from four freshwater aquifers to 1) understand how CO(2) leakage affects freshwater quality; 2) develop selection criteria for deep sequestration sites based on inorganic metal contamination caused by CO(2) leaks to shallow aquifers; and 3) identify geochemical signatures for early detection criteria. After exposure to CO(2), water pH declines of 1-2 units were apparent in all aquifer samples. CO(2) caused concentrations of the alkali and alkaline earths and manganese, cobalt, nickel, and iron to increase by more than 2 orders of magnitude. Potentially dangerous uranium and barium increased throughout the entire experiment in some samples. Solid-phase metal mobility, carbonate buffering capacity, and redox state in the shallow overlying aquifers influence the impact of CO(2) leakage and should be considered when selecting deep geosequestration sites. Manganese, iron, calcium, and pH could be used as geochemical markers of a CO(2) leak, as their concentrations increase within 2 weeks of exposure to CO(2).

Fluid Inclusion and Stable Isotope Study of the Buffalo Gold Deposit, Red Lake Greenstone Belt, Northwestern Ontario, Canada

The Buffalo gold deposit is a small deposit consisting of auriferous quartz-tourmaline veins within a granodiorite stock in the Red Lake greenstone belt. This study aims to characterize the mineralizing fluids through fluid inclusion and stable isotope analyses and to compare them with those of the world-class Campbell-Red Lake deposit. Four types of fluid inclusions were recognized, including carbonic, aqueous-carbonic, aqueous, and halite-bearing aqueous, with the carbonic type being the most abundant. Raman analyses indicate that the carbonic phase mainly consists of CO 2 , with minor amounts of N 2 and CH 4 , and rarely detectable H 2 S. The homogenization temperatures of the carbonic inclusions range from −41.7° to 30.9°C. The homogenization temperatures and salinities of the aqueous, halite-bearing aqueous, and aqueous-carbonic inclusions are 130° to 276°C and 9.7 to 23.6 wt.% NaCl equiv., 155° to 207°C and 32.9 to 42.3 wt.% NaCl equiv., and 215° to 357°C and 8.3 to 19.7 wt.% NaCl equiv., respectively. The δ 18 O VSMOW values of tourmaline range from 8.2‰ to 9.0‰, and those of quartz from 11.4‰ to 11.9‰, with estimated fluid temperatures from 323° to 399°C based on the quartz-tourmaline isotopic geothermometer. It is postulated that separate CO 2 -dominated and aqueous fluids intermittently invaded the fracture/vein system in response to fluid pressure fluctuations, with limited mixing. The CO 2 -dominated fluid, previously recognized in Campbell-Red Lake as the main mineralizing fluid, is inferred to have been derived from deeper parts of the crust. This deep CO 2 -dominated fluid reservoir might have been a common source for gold mineralization in the Red Lake greenstone belt.

Surface Gas Geochemistry above the Natural CO2Reservoir of Montmiral (Drôme, France), Source Tracking and Gas Exchange between the Soil, Biosphere and Atmosphere

One of the options considered to mitigate greenhouse gas concentrations in the atmosphere is underground storage of CO<sub>2<sub/>. There is a strong need for enhancing and developing methods that would help throughout the duration life of such underground storage, to ensure the safety and able to monitor the evolution of the injected CO<sub>2<sub/> plume. Among these, geochemical methods can play an important role. Here, we describe results acquired under the research programme “Géocarbone-Monitoring”, partially funded by the French National Research Agency, on the Montmiral natural analogue in South-Eastern France. Other results obtained under the same research programme in the French Massif Central are reported elsewhere in this volume.Spot sampling methods allowing a great geographical coverage and continuous measurements on selected points were undertaken in 2006 and 2007, in order to determine soil gas concentrations and fluxes as well as carbon isotope ratio determinations. One important result is that without any evidence of deep CO<sub>2<sub/> leakage, both CO<sub>2<sub/> concentrations and fluxes appear to be higher than can be explained only by biological activities. Further investigations are thus needed to understand the gas evolution better throughout the year.

Study of the sensitising potential of various textile dyes using a biphasic murine local lymph node assay

Disperse dyes, which are suitable for dyeing synthetic fibres, are responsible for the great majority of allergic contact dermatitis (ACD) cases to textile dyes. The aim of the present study was to investigate the sensitising potential of various disperse dyes using a biphasic protocol of the local lymph node assay (LLNA). Briefly, mice were shaved over a surface of approximately 2 cm(2) on their backs and treated using a "sensitisation-challenge protocol". The shaved surface was treated once daily on days 1-3 with 50 microl of the test solution. Animals remained untreated on days 4-14. On days 15-17, mice were treated with 25 microl of the test solution on the dorsum of both ears. Mice were killed on day 19 with deep CO(2) anaesthesia, the lymph nodes prepared and various end points, such as ear thickness, ear punch weight, lymph node weight, lymph node cell count and the proportion of various lymphocyte subpopulations, were determined by flow cytometry. The results were compared to control group treated with the vehicle alone. Our results showed that almost all of the tested textile dyes caused a significant increase in lymph node cell count and lymph node weight. We also observed an increase in ear thickness and ear punch weight in most of the concentrations tested for various textile dyes. We observed a decrease in CD4+ and CD8+ cells and an increase in CD19+, CD45+ and CD45+/1A+ cells in most of the cases, which is characteristic for allergens. The CD4+/CD69+ cells increased in only few experiments mainly with Disperse Blue 124 and Disperse Blue 106. Based on our results, the disperse dyes could be arranged in four groups on the basis of their sensitising potency in the following decreasing order (in parenthesis: lowest concentration causing a significant increase in lymph node cell number): group 1, strong: Disperse Blue 124 and Disperse Blue 106 (0.003%); group 2, moderate: Disperse Red 1 and Disperse Blue 1 (3%); group 3, weak: Disperse Orange 37 and Disperse Blue 35 (10%); and group 4, very weak: Disperse yellow 3 and Disperse Orange 3 (increase at 30% or no increase at 30%). In conclusion, our study shows that the biphasic LLNA protocol was proficient enough to study the sensitisation potential of tested textile dyes and provides data allowing to discriminate them according to their potency.

Dual-Depth Fractional Carbon Dioxide Laser Resurfacing for Periocular Rhytidosis

Laxity and rhytidosis of eyelid skin as a result of photoaging is a frequent cosmetic concern. Fine lines and deep wrinkles may not be optimally addressed with traditional ablative carbon dioxide (CO(2)) resurfacing. Modern devices allow for surface fractional ablation and deep fractional ablation with narrow treatment columns that target deep dermal layers. To examine the efficacy and safety of a combination of deep fractional CO(2) ablation and superficial fractional ablation of eyelid and periorbital skin for improvement of rhytidosis and redundancy. Fifteen patients underwent dual-depth fractional CO(2) resurfacing of eyelid and periorbital skin. Blinded, independent investigators evaluated rhytidosis and skin redundancy as evident in pretreatment and 6-month post-treatment digital images. Excellent post-treatment improvements were noted for eyelid skin rhytidosis and redundancy, which improved 53.1% and 42.0%, respectively. No serious complications were noted, and the recovery profile was favorable. Dual-depth fractional CO(2) resurfacing of eyelid and periorbital skin, including areas within the boundaries of the orbital rim, is safe and effective for the treatment of eyelid photoaging.

Pathways to a low-carbon economy for the UK with the macro-econometric E3MG model

This paper examines different carbon pathways for achieving deep CO 2 reduction targets for the UK using a macro-econometric hybrid model E3MG, which stands for Energy–Economy–Environment Model at the Global level. The E3MG, with the UK as one of its regions, combines a top-down approach for modeling the global economy and for estimating the aggregate and disaggregate energy demand and a bottom-up approach (Energy Technology subModel, ETM) for simulating the power sector, which then provides feedback to the energy demand equations and the whole economy. The ETM submodel uses a probabilistic approach and historical data for estimating the penetration levels of the different technologies, considering their economic, technical and environmental characteristics. Three pathway scenarios (CFH, CLC and CAM) simulate the CO 2 reduction by 40%, 60% and 80% by 2050 compared to 1990 levels respectively and are compared with a reference scenario (REF), with no reduction target. The targets are modeled as the UK contribution to an international mitigation effort, such as achieving the G8 reduction targets, which is a more realistic political framework for the UK to move towards deep reductions rather than moving alone. This paper aims to provide modeling evidence that deep reduction targets can be met through different carbon pathways while also assessing the macroeconomic effects of the pathways on GDP and investment.

GALACTIC CEPHEIDS WITHSPITZER. I. LEAVITT LAW AND COLORS

Classical Cepheid variable stars have been important indicators of extragalactic distance and Galactic evolution for over a century. The Spitzer Space Telescope has opened the possibility of extending the study of Cepheids into the mid- and far-infrared, where interstellar extinction is reduced. We have obtained photometry from images of a sample of Galactic Cepheids with the IRAC and MIPS instruments on Spitzer. Here we present the first mid-infrared period-luminosity relations for Classical Cepheids in the Galaxy, and the first ever Cepheid period-luminosity relations at 24 and 70 um. We compare these relations with theoretical predictions, and with period-luminosity relations obtained in recent studies of the Large Magellanic Cloud. We find a significant period-color relation for the [3.6]-[8.0] IRAC color. Other mid-infrared colors for both Cepheids and non-variable supergiants are strongly affected by variable molecular spectral features, in particular deep CO absorption bands. We do not find strong evidence for mid-infrared excess caused by warm (~500 K) circumstellar dust. We discuss the possibility that recent detections with near-infrared interferometers of circumstellar shells around delta Cep, l Car, Polaris, Y Oph and RS Pup may be a signature of shocked gas emission in a dust-poor wind associated to pulsation-driven mass loss.

HUBBLE SPACE TELESCOPE/NEAR-INFRARED CAMERA AND MULTI-OBJECT SPECTROMETER OBSERVATIONS OF THE GLIMPSE9 STELLAR CLUSTER

We present HST/NICMOS photometry, and low-resolution K-band spectra of the GLIMPSE9 stellar cluster. The newly obtained color-magnitude diagram shows a cluster sequence with H-Ks =1 mag, indicating an interstellar extinction Aks=1.6\pm0.2 mag. The spectra of the three brightest stars show deep CO band-heads, which indicate red supergiants with spectral type M1-M2. Two 09-B2 supergiants are also identified, which yield a spectrophotometric distance of 4.2\pm0.4 kpc. Presuming that the population is coeval, we derive an age between 15 and 27 Myr, and a total cluster mass of 1600\pm400 Msun, integrated down to 1 Msun. In the vicinity of GLIMPSE9 are several HII regions and SNRs, all of which (including GLIMPSE 9) are probably associated with a giant molecular cloud (GMC) in the inner galaxy. GLIMPSE9 probably represents one episode of massive star formation in this GMC. We have identified several other candidate stellar clusters of the same complex.

Was the lethal eruption of Lake Nyos related to a double CO 2/H 2O density inversion?

The 1986 lethal eruption of Lake Nyos (Cameroon) was caused by a sudden inversion between deep, CO 2-loaded bottom lake waters and denser, gas-free surface waters. A deep CO 2 source has been found in fluid inclusions which occur predominantly in clinopyroxenes from lherzolitic mantle xenoliths, brought to the surface by the last erupted alkali basalts. P–T conditions of CO 2 trapping correspond to a gas density equal (or higher) than that of liquid water. It is suggested that this dense CO 2, found in many ultrabasic mantle xenoliths worldwide, has accumulated at km depth, below a column of descending lake water. It may remain in a stable state for a long period, as long as the temperature is above the density inversion temperature for pure H 2O/CO 2 systems. At an estimated depth of about 3 km, cooling by descending waters (to about 30 °C) induces a density inversion for the upper part of the CO 2 reservoir. This causes a constant, regular upstream of low-density CO 2 which, in its turn, feeds the shallower lake density inversion.

Modeling crustal deformation and rupture processes related to upwelling of deep CO2‐rich fluids during the 1965–1967 Matsushiro earthquake swarm in Japan

In Matsushiro, central Japan, a series of more than 700,000 earthquakes occurred over a 2‐year period (1965–1967) associated with a strike‐slip faulting sequence. This swarm of earthquakes resulted in ground surface deformations, cracking of the topsoil, and enhanced spring outflows with changes in chemical compositions, as well as carbon dioxide (CO2) degassing. Previous investigations of the Matsushiro earthquake swarm have suggested that migration of underground water and/or magma may have had a strong influence on the swarm activity. In this study, employing coupled multiphase flow and geomechanical modeling, we show that observed crustal deformations and seismicity could have been driven by upwelling of deep CO2‐rich fluids around the intersection of two fault zones: the regional east Nagano earthquake fault and the conjugate Matsushiro fault. We show that the observed spatial evolution of seismicity along the two faults and magnitudes surface uplift are convincingly explained by a few megapascals of pressurization from the upwelling fluid within the critically stressed crust, a crust under a strike‐slip stress regime near the frictional strength limit. Our analysis indicates that the most important cause for triggering of seismicity during the Matsushiro swarm was the fluid pressurization with the associated reduction in effective stress and strength in fault segments that were initially near critically stressed for shear failure. Moreover, our analysis indicates that a 2‐order‐of‐magnitude permeability enhancement in ruptured fault segments may be necessary to match the observed time evolution of surface uplift. We conclude that our hydromechanical modeling study of the Matsushiro earthquake swarm shows a clear connection between earthquake rupture, deformation, stress, and permeability changes, as well as large‐scale fluid flow related to degassing of CO2 in the shallow seismogenic crust. Thus our study provides further evidence of the important role of deep fluid sources in earthquake fault dynamics and surface deformations.

The potential for increased atmospheric CO 2 emissions and accelerated consumption of deep geologic CO 2 storage resources resulting from the large-scale deployment of a CCS-enabled unconventional fossil fuels industry in the U.S.

Desires to enhance the energy security of the United States have spurred renewed interest in the development of abundant domestic heavy hydrocarbon resources including oil shale and coal to produce unconventional liquid fuels to supplement conventional oil supplies. However, the production processes for these unconventional fossil fuels create large quantities of carbon dioxide (CO 2) and this remains one of the key arguments against such development. Carbon dioxide capture and storage (CCS) technologies could reduce these emissions and preliminary analysis of regional CO 2 storage capacity in locations where such facilities might be sited within the U.S. indicates that there appears to be sufficient storage capacity, primarily in deep saline formations, to accommodate the CO 2 from these industries. Nevertheless, even assuming wide-scale availability of cost-effective CO 2 capture and geologic storage resources, the emergence of a domestic U.S. oil shale or coal-to-liquids (CTL) industry would be responsible for significant increases in CO 2 emissions to the atmosphere. The authors present modeling results of two future hypothetical climate policy scenarios that indicate that the oil shale production facilities required to produce 3 MMB/d from the Eocene Green River Formation of the western U.S. using an in situ retorting process would result in net emissions to the atmosphere of between 3000 and 7000 MtCO 2, in addition to storing potentially 900–5000 MtCO 2 in regional deep geologic formations via CCS in the period up to 2050. A similarly sized, but geographically more dispersed domestic CTL industry could result in 4000–5000 MtCO 2 emitted to the atmosphere in addition to potentially 21,000–22,000 MtCO 2 stored in regional deep geologic formations over the same period. While this analysis shows that there is likely adequate CO 2 storage capacity in the regions where these technologies are likely to deploy, the reliance by these industries on large-scale CCS could result in an accelerated rate of utilization of the nation's CO 2 storage resource, leaving less high-quality storage capacity for other carbon-producing industries including electric power generation.

Hydrogeochemical modeling of a thermal system and lessons learned for CO 2 geologic storage

Geological storage of carbon dioxide is presently considered to be one of the main strategies to mitigate the impact of the emissions of this gas on global warming. Among the various alternatives considered for CO 2 geological storage, one of the main geological candidates for hosting injected CO 2 in the long term are deep porous reservoir rock formations saturated with brackish or saline solutions. Although valuable information on the expected hydrogeochemical processes involved in the CO 2 storage in such deep saline aquifers can be obtained in laboratory or modeling studies, the only direct source of information about the long-term behavior of geological storages for CO 2 in deep aquifers is natural analogues. In this work, a classical and simple geochemical methodology is successfully applied to the study of the features and hydrogeochemical processes determining the evolution of a Spanish thermal system (the Alhama–Jaraba complex), which can be considered as a natural analogue for deep geological CO 2 storage in carbonate rocks. The geology, structure, depth and hydrogeochemistry of the Alhama–Jaraba thermal system are very similar to the expected features of a potential CO 2 reservoir in carbonate materials. The processes determining the hydrogeochemical evolution in the Alhama–Jaraba thermal system have been successfully identified and quantified with the assistance of ion–ion plots, speciation–solubility calculations and mass-balance calculations. Furthermore, the feasibility of the proposed conceptual hydrogeochemical model for this system has been verified by using reaction-path calculations. Mass-balance calculation results have indicated that the observed hydrogeochemical evolution between springs is mainly due to halite dissolution and dedolomitization triggered by gypsum or anhydrite dissolution. CO 2(g) mass transfer has been estimated to be negligible, which suggests that the main processes responsible for the variation in the TIC and the CO 2(g) pressure during deep circulation are dissolution and precipitation reactions for carbonate minerals. All the processes identified in the Alhama–Jaraba thermal system are relevant for the long-term evolution of a deep CO 2 storage site hosted by carbonate rocks. As shown in this study, the application of classical geochemical tools provides an excellent starting point for understanding the behavior of prospective storage systems. Moreover, the existence of dedolomitization is very relevant for the hydraulic properties of carbonate aquifers potentially used for CO 2 geological storage because of the effects on porosity and, therefore, permeability during the long-term evolution of such systems. Furthermore, dedolomitization may represent a mechanism of mineral trapping for CO 2 sequestration under certain conditions.

Isotope ( 14C and 13C) analysis of deep peat CO 2 using a passive sampling technique

We developed and tested a new method to collect CO 2 from the surface to deep layers of a peatland for radiocarbon analysis. The method comprises two components: i) a probe equipped with a hydrophobic filter that allows entry of peat gases by diffusion, whilst simultaneously excluding water, and, ii) a cartridge containing zeolite molecular sieve that traps CO 2 passively. We field tested the method by sampling at depths of between 0.25 and 4 m at duplicate sites within a temperate raised peat bog. CO 2 was trapped at a depth-dependent rate of between ∼0.2 and 0.8 ml d −1, enabling sufficient CO 2 for routine 14C analysis to be collected when left in place for several weeks. The age of peatland CO 2 increased with depth from modern to ∼170 BP for samples collected from 0.25 m, to ∼4000 BP at 4 m. The CO 2 was younger, but followed a similar trend to the age profile of bulk peat previously reported for the site ( Langdon and Barber, 2005). δ 13C values of recovered CO 2 increased with depth. CO 2 collected from the deepest sampling probes was considerably 13C-enriched (up to ∼+9‰) and agreed well with results reported for other peatlands where this phenomenon has been attributed to fermentation processes. CO 2 collected from plant-free static chambers at the surface of the mire was slightly 14C-enriched compared to the contemporary atmosphere, suggesting that surface CO 2 emissions were predominantly derived from carbon fixed during the post-bomb era. However, consistent trends of enriched 13C and depleted 14C in chamber CO 2 between autumn and winter samples were most likely explained by an increased contribution of deep peat CO 2 to the surface efflux in winter. The passive sampling technique is readily portable, easy to install and operate, causes minimal site disturbance, and can be reliably used to collect peatland CO 2 from a wide range of depths.

Operating Behavior and Scale-Up of an ECPrOx Unit for CO Removal from Reformate for PEM Fuel Cell Application

Recently, an approach involving electrochemical preferential oxidation (ECPrOx) of CO was suggested as having the potential to replace the PrOx concept for deep CO removal from reformate gas in proton exchange membrane (PEM) fuel cells. The first part of this paper deals with the characterization of such an ECPrOx unit from a reaction engineering point of view. Based on a spatially lumped, isothermal model, the qualitative selectivity-conversion behavior is discussed for varying feed flow rates and CO inlet mole fractions. A simple two-phase mechanism is suggested that explains the findings. The second part of the contribution considers qualitative questions on cascading of two ECPrOx reactors. The crucial importance of the configuration of their electrical connection is demonstrated and explained. While two cells connected electrically in parallel exhibit almost the same selectivity-conversion behavior in comparison with a single cell, an electrical series connection enables a considerable increase in the selectivity at the same CO conversion.

Carbon dioxide on the satellites of Saturn: Results from the Cassini VIMS investigation and revisions to the VIMS wavelength scale

Several of the icy satellites of Saturn show the spectroscopic signature of the asymmetric stretching mode of C–O in carbon dioxide (CO 2) at or near the nominal solid-phase laboratory wavelength of 4.2675 μm (2343.3 cm −1), discovered with the Visible-Infrared Mapping Spectrometer (VIMS) on the Cassini spacecraft. We report here on an analysis of the variation in wavelength and width of the CO 2 absorption band in the spectra of Phoebe, Iapetus, Hyperion, and Dione. Comparisons are made to laboratory spectra of pure CO 2, CO 2 clathrates, ternary mixtures of CO 2 with other volatiles, implanted and adsorbed CO 2 in non-volatile materials, and ab initio theoretical calculations of CO 2 * nH 2O. At the wavelength resolution of VIMS, the CO 2 on Phoebe is indistinguishable from pure CO 2 ice (each molecule’s nearby neighbors are also CO 2) or type II clathrate of CO 2 in H 2O. In contrast, the CO 2 band on Iapetus, Hyperion, and Dione is shifted to shorter wavelengths (typically ∼4.255 μm (∼2350.2 cm −1)) and broadened. These wavelengths are characteristic of complexes of CO 2 with different near-neighbor molecules that are encountered in other volatile mixtures such as with H 2O and CH 3OH, and non-volatile host materials like silicates, some clays, and zeolites. We suggest that Phoebe’s CO 2 is native to the body as part of the initial inventory of condensates and now exposed on the surface, while CO 2 on the other three satellites results at least in part from particle or UV irradiation of native H 2O plus a source of C, implantation or accretion from external sources, or redistribution of native CO 2 from the interior. The analysis presented here depends on an accurate VIMS wavelength scale. In preparation for this work, the baseline wavelength calibration for the Cassini VIMS was found to be distorted around 4.3 μm, apparently as a consequence of telluric CO 2 gas absorption in the pre-launch calibration. The effect can be reproduced by convolving a sequence of model detector response profiles with a deep atmospheric CO 2 absorption profile, producing distorted detector profile shapes and shifted central positions. In a laboratory blackbody spectrum used for radiance calibration, close examination of the CO 2 absorption profile shows a similar deviation from that expected from a model. These modeled effects appear to be sufficient to explain the distortion in the existing wavelength calibration now in use. A modification to the wavelength calibration for 13 adjacent bands is provided. The affected channels span about 0.2 μm centered on 4.28 μm. The maximum wavelength change is about 10 nm toward longer wavelength. This adjustment has implications for interpretation of some of the spectral features observed in the affected wavelength interval, such as from CO 2, as discussed in this paper.

Optimizing geologic CO 2 sequestration by injection in deep saline formations below oil reservoirs

The purpose of this research is to present a best-case paradigm for geologic CO 2 storage: CO 2 injection and sequestration in saline formations below oil reservoirs. This includes the saline-only section below the oil–water contact (OWC) in oil reservoirs, a storage target neglected in many current storage capacity assessments. This also includes saline aquifers (high porosity and permeability formations) immediately below oil-bearing formations. While this is a very specific injection target, we contend that most, if not all, oil-bearing basins in the US contain a great volume of such strata, and represent a rather large CO 2 storage capacity option. We hypothesize that these are the best storage targets in those basins. The purpose of this research is to evaluate this hypothesis. We quantitatively compared CO 2 behavior in oil reservoirs and brine formations by examining the thermophysical properties of CO 2, CO 2–brine, and CO 2–oil in various pressure, temperature, and salinity conditions. In addition, we compared the distribution of gravity number ( N), which characterizes a tendency towards buoyancy-driven CO 2 migration, and mobility ratio ( M), which characterizes the impeded CO 2 migration, in oil reservoirs and brine formations. Our research suggests competing advantages and disadvantages of CO 2 injection in oil reservoirs vs. brine formations: (1) CO 2 solubility in oil is significantly greater than in brine (over 30 times); (2) the tendency of buoyancy-driven CO 2 migration is smaller in oil reservoirs because density contrast between oil and CO 2 is smaller than it between brine and oil (the approximate density contrast between CO 2 and crude oil is ∼100 kg/m 3 and between CO 2 and brine is ∼350 kg/m 3); (3) the increased density of oil and brine due to the CO 2 dissolution is not significant (about 7–15 kg/m 3); (4) the viscosity reduction of oil due to CO 2 dissolution is significant (from 5790 to 98 mPa s). We compared these competing properties and processes by performing numerical simulations. Results suggest that deep saline CO 2 injection immediately below oil formations reduces buoyancy-driven CO 2 migration and, at the same time, minimizes the amount of mobile CO 2 compared to conventional deep saline CO 2 injection (i.e., CO 2 injection into brine formations not below oil-bearing strata). Finally, to investigate practical aspects and field applications of this injection paradigm, we characterized oil-bearing formations and their thickness (capacity) as a component of the Southwest Regional Partnership on Carbon Sequestration (SWP) field deployments. The field-testing program includes specific sites in Utah, New Mexico, Wyoming, and western Texas of the United States.

Degassing of mantle-derived CO2 and He from springs in the southern Colorado Plateau region—Neotectonic connections and implications for groundwater systems

Groundwaters of the southern Colorado Plateau–Arizona Transition Zone region are a heterogeneous mixture of chemically diverse waters including meteoric (epigenic) fluids, karst-aquifer waters, and deeply sourced (endogenic) fluids. We investigate the composition of travertine-depositing CO 2 -rich springs to determine the origin, transport, and mixing of these various components. The San Francisco Mountain recharge area has little surface flow. Instead, waters discharge through major springs hundreds of kilometers away. About 70% (9340 L/s) of the total recharge (13,500 L/s) discharges 100 km to the north in the incised aquifer system at Grand Canyon. Most of this water (85%; 8070 L/s) emerges through two travertine-depositing karst spring systems: Blue Springs (6230 L/s) and Havasu Springs (1840 L/s). About 30% of recharge (4150 L/s) flows to the south and discharges along NW-striking faults in the Arizona Transition Zone, forming the base flow for the Verde River. Geochemical data define regional mixing trends between meteoric recharge and different endogenic end members that range from bicarbonate waters to sulfate waters. Water quality in the region is dictated by the percentage and character of the endogenic inputs that cause a measurable degradation of groundwater quality for water supply. Sources for the high CO 2 include dissolution of limestone and dolostone (C carb ) and “external carbon” (C external ). C external is computed as the bicarbonate alkalinity (dissolved inorganic carbon [DIC]) minus the C carb (C external = DIC - C carb ). C external is deconvolved using carbon isotopes into biogenically derived sedimentary carbon (C organic ) and deep CO 2 inputs (C endogenic ). Measured δ 13 C values are −17‰ to +3‰ versus Pee Dee Belemnite (PDB). Assuming δ 13 C carb = +2‰, δ 13 C organic = −28‰, and δ 13 C endogenic = −5‰, water chemistry mixing models indicate that an average of 42% of the total DIC comes from dissolution of carbonate rocks, 25% from organic carbon, including soil-respired CO 2 ,and 33% from deep (endogenic) sources. Helium isotope values ( 3 He/ 4 He) in gases dissolved in spring waters in the southern Colorado Plateau region range from 0.10 to 1.16 R A (relative to air) indicating that a significant component of the deeply derived fluid is from the mantle (mean of 5% asthenospheric or 10% subcontinental lithospheric mantle source). Measured CO 2 / 3 He ratios of 2 × 10 9 to 1.4 × 10 13 are adjusted by removing the proportion of CO 2 from C carb and C organic to give values 10 for all but four samples. Various mixing models using CO 2 / 3 He suggest that the mantle-derived components of the CO 2 load are highly variable from spring to spring and may make up an average of ~10% of the total CO 2 load of the regional springs. Fluid-rock interactions involving endogenic fluids are suggested by 87 Sr/ 86 Sr, δ 18 O, and other tracers. The endogenic CO 2 component, multiplied by discharge for each spring, yields an integrated annual flux of deeply derived CO 2 to the groundwater system of ~1.4 × 10 9 mol/yr. This CO 2 emission from the Colorado Plateau region reflects a complex tectonic evolution involving Laramide hydration of the lithosphere above the Farallon slab, addition of fluids from mid-Tertiary mantle tectonism during slab removal, and ongoing fluid movement induced by neotectonic small-scale asthenospheric convection.

Production of intermetallic catalysts of deep CO and hydrocarbon oxidation

The possibility of producing (Ni, Co, Mn) Alx intermetallides using the technique of self-propagating high-temperature synthesis and their subsequent processing with the purpose of using them as catalysis in the process of complete oxidation of CO and hydrocarbons is considered. Phase composition, microstructure, and morphology of alloys and catalysts based on them are studied. Dependences of activity and stability on composition are determined. These catalysts are shown to possess high activity and their development is considered to be a promising direction in the catalysis of deep oxidation processes.