Geologic factors controlling CO₂ storage capacity and permanence: case studies based on experience with heterogeneity in oil and gas reservoirs applied to CO₂ storage     

W. A. Ambrose  S. Lakshminarasimhan  M. H. Holtz  V. Nú?ez-López  S. D. Hovorka  I. Duncan 《Environmental Geology》2008,54(8):1619-1633

A variety of structural and stratigraphic factors control geological heterogeneity, inferred to influence both sequestration capacity and effectiveness, as well as seal capacity. Structural heterogeneity factors include faults, folds, and fracture intensity. Stratigraphic heterogeneity is primarily controlled by the geometry of depositional facies and sandbody continuity, which controls permeability structure. The permeability structure, in turn, has implications for CO₂ injectivity and near-term migration pathways, whereas the long-term sequestration capacity can be inferred from the production history. Examples of Gulf Coast oil and gas reservoirs with differing styles of stratigraphic heterogeneity demonstrate the impact of facies variability on fluid flow and CO₂ sequestration potential. Beach and barrier-island deposits in West Ranch field in southeast Texas are homogeneous and continuous. In contrast, Seeligson and Stratton fields in south Texas, examples of major heterogeneity in fluvial systems, are composed of discontinuous, channel-fill sandstones confined to narrow, sinuous belts. These heterogeneous deposits contain limited compartments for potential CO₂ storage, although CO₂ sequestration effectiveness may be enhanced by the high number of intraformational shale beds. These field examples demonstrate that areas for CO₂ storage can be optimized by assessing sites for enhanced oil and gas recovery in mature hydrocarbon provinces.  相似文献   

Assessment of Planetary-Boundary-Layer Schemes in the Weather Research and Forecasting Model Within and Above an Urban Canopy Layer     

Enrico Ferrero  Stefano Alessandrini  Francois Vandenberghe 《Boundary-Layer Meteorology》2018,168(2):289-319

We tested several planetary-boundary-layer (PBL) schemes available in the Weather Research and Forecasting (WRF) model against measured wind speed and direction, temperature and turbulent kinetic energy (TKE) at three levels (5, 9, 25 m). The Urban Turbulence Project dataset, gathered from the outskirts of Turin, Italy and used for the comparison, provides measurements made by sonic anemometers for more than 1 year. In contrast to other similar studies, which have mainly focused on short-time periods, we considered 2 months of measurements (January and July) representing both the seasonal and the daily variabilities. To understand how the WRF-model PBL schemes perform in an urban environment, often characterized by low wind-speed conditions, we first compared six PBL schemes against observations taken by the highest anemometer located in the inertial sub-layer. The availability of the TKE measurements allows us to directly evaluate the performances of the model; results of the model evaluation are presented in terms of quantile versus quantile plots and statistical indices. Secondly, we considered WRF-model PBL schemes that can be coupled to the urban-surface exchange parametrizations and compared the simulation results with measurements from the two lower anemometers located inside the canopy layer. We find that the PBL schemes accounting for TKE are more accurate and the model representation of the roughness sub-layer improves when the urban model is coupled to each PBL scheme.  相似文献   

A numerical study of the influence from pre‐existing cracks on granite rock fragmentation at percussive drilling          下载免费PDF全文

Mahdi Saadati  Pascal Forquin  Kenneth Weddfelt  Per‐Lennart Larsson  Francois Hild 《国际地质力学数值与分析法杂志》2015,39(5):558-570

The aim of this study is to investigate the effect of pre‐existing, or structural, cracks on dynamic fragmentation of granite. Because of the complex behavior of rock materials, a continuum approach is employed relying upon a plasticity model with yield surface locus as a quadratic function of the mean pressure in the principal stress space coupled with an anisotropic damage model. In particular, Bohus granite rock is investigated, and the material parameters are chosen based on previous experiments. The equation of motion is discretized using a finite element approach, and the explicit time integration method is employed. The pre‐existing cracks are introduced in the model by considering sets of elements with negligible tensile strength that leads to their immediate failure when loaded in tension even though they still carry compressive loads as crack closure occurs because of compressive stresses. Previously performed edge‐on impact tests are reconsidered here to validate the numerical model. Percussive drilling is simulated, and the influence of the presence of pre‐existing cracks is studied. The results from the analysis with different crack lengths and orientations are compared in terms of penetration stiffness and fracture pattern. It is shown that pre‐existing cracks in all investigated cases facilitate the drilling process. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Tracing the evolution and distribution of F and Cl in plutonic systems from volatile-bearing minerals: a case study from the Liujiawa pluton (Dabie orogen, China)   总被引：2，自引：1，他引：1  

Chao Zhang  Francois Holtz  Changqian Ma  Paul Eric Wolff  Xiaoyan Li 《Contributions to Mineralogy and Petrology》2012,164(5):859-879

Fluorine and chlorine play an important role in magmatic differentiation, hydrothermal alteration, and related mineralization processes, but tracing their evolution in magmatic and especially plutonic systems is not an easy task. The F and Cl in melts can be estimated from F and Cl concentrations in minerals, provided that partitioning between minerals and melts are constrained. Based on available partitioning models between mineral/melt, mineral/fluid, and melt/fluid, a set of equations has been derived to determine F and Cl concentrations in melts from the compositions of amphibole, biotite, and apatite. The new calculation procedure has been applied to a plutonic system, the Liujiawa pluton, eastern Dabie orogen (China). Cl and F concentrations in amphiboles, biotites, and apatites from different rock types (gabbronorite, two-pyroxene diorite, clinopyroxene diorite, and hornblende gabbro) have been determined by electron microprobe. Most amphiboles show a negative correlation between log(Cl/OH) and Mg-number and a positive correlation between log(F/OH) and A-site occupation. Biotites from the gabbronorite and two-pyroxene diorite show a slight positive correlation between log(Cl/OH) and Mg, which is however not the case for the clinopyroxene diorite. Apatites from all the samples are rich in F and show negative correlations between Cl and F concentrations. In our case study, we demonstrate that the Cl concentration in melt remains approximately constant at 1,000–2,000?ppm over the major crystallization interval, but decreases strongly at near solidus temperatures as a result of fluid exsolution. The F concentration in melt remains nearly constant at ca. 2,000–3,000?ppm at high temperatures as well as near solidus conditions, indicating that it is not largely affected by fluid exsolution because of its strongly preferred incorporation into melt. Interestingly, the evolution of Cl and F concentrations in melt with magmatic differentiation is similar to that determined in volcanic systems, suggesting that the evolution of Cl and F in melts during crystallization and late magmatic stages at depth (plutonic systems) is similar to that observed in volcanic systems during decompression and degassing.  相似文献   

Experimental study into the petrogenesis of crystal-rich basaltic to andesitic magmas at Arenal volcano   总被引：1，自引：1，他引：0  

F. Parat  M. J. Streck  F. Holtz  R. Almeev 《Contributions to Mineralogy and Petrology》2014,168(2):1-18

Arenal volcano is nearly unique among arc volcanoes with its 42 year long (1968–2010) continuous, small-scale activity erupting compositionally monotonous basaltic andesites that also dominate the entire, ~7000 year long, eruptive history. Only mineral zoning records reveal that basaltic andesites are the result of complex, open-system processes deriving minerals from a variety of crystallization environments and including the episodic injections of basalt. The condition of the mafic input as well as the generation of crystal-rich basaltic andesites of the recent, 1968–2010, and earlier eruptions were addressed by an experimental study at 200 MPa, 900–1,050 °C, oxidizing and fluid-saturated conditions with various fluid compositions [H₂O/(H₂O + CO₂) = 0.3–1]. Phase equilibria were determined using a phenocryst-poor (~3 vol%) Arenal-like basalt (50.5?wt% SiO₂) from a nearby scoria cone containing olivine (Fo₉₂), plagioclase (An₈₆), clinopyroxene (Mg# = 82) and magnetite (X_ulvö = 0.13). Experimental melts generally reproduce observed compositional trends among Arenal samples. Small differences between experimental melts and natural rocks can be explained by open-system processes. At low pressure (200 MPa), the mineral assemblage as well as the mineral compositions of the natural basalt were reproduced at 1,000 °C and high water activity. The residual melt at these conditions is basaltic andesitic (55 wt% SiO₂) with 5 wt% H₂O. The evolution to more evolved magmas observed at Arenal occurred under fluid-saturated conditions but variable fluid compositions. At 1,000 °C and 200 MPa, a decrease of water content by approximately 1 wt% induces significant changes of the mineral assemblage from olivine + clinopyroxene + plagioclase (5 wt% H₂O in the melt) to clinopyroxene + plagioclase + orthopyroxene (4 wt% H₂O in the melt). Both assemblages are observed in crystal-rich basalt (15 vol%) and basaltic andesites. Experimental data indicate that the lack of orthopyroxene and the presence of amphibole, also observed in basaltic andesitic tephra units, is due to crystallization at nearly water-saturated conditions and temperatures lower than 950 °C. The enigmatic two compositional groups previously known as low- and high-Al₂O₃ samples at Arenal volcano may be explained by low- and high-pressure crystallization, respectively. Using high-Al as signal of deeper crystallization, first magmas of the 1968–2010 eruption evolved deep in the crust and ascent was relatively fast leaving little time for significant compositional overprint by shallower level crystallization.  相似文献   

The effect of alkalis and polymerization on the solubility of H<Subscript>2</Subscript>O and CO<Subscript>2</Subscript> in alkali-rich silicate melts     

Francesco?VetereEmail author  Francois?Holtz  Harald?Behrens  Roman?E.?Botcharnikov  Sara?Fanara 《Contributions to Mineralogy and Petrology》2014,167(5):1014

The effect of alkalis on the solubility of H₂O and CO₂ in alkali-rich silicate melts was investigated at 500 MPa and 1,250 °C in the systems with H₂O/(H₂O + CO₂) ratio varying from 0 to 1. Using a synthetic analog of phonotephritic magma from Alban Hills (AH1) as a base composition, the Na/(Na + K) ratio was varied from 0.28 (AH1) to 0.60 (AH2) and 0.85 (AH3) at roughly constant total alkali content. The obtained results were compared with the data for shoshonitic and latitic melts having similar total alkali content but different structural characteristics, e.g., NBO/T parameter (the ratio of non-bridging oxygens over tetrahedrally coordinated cations), as those of the AH compositions. Little variation was observed in H₂O solubility (melt equilibrated with pure H₂O fluid) for the whole compositional range in this study with values ranging between 9.7 and 10.2 wt. As previously shown, the maximum CO₂ content in melts equilibrated with CO₂-rich fluids increases strongly with the NBO/T from 0.29 wt % for latite (NBO/T = 0.17) to 0.45 wt % for shoshonite (NBO/T = 0.38) to 0.90 wt % for AH2 (NBO/T = 0.55). The highest CO₂ contents determined for AH3 and AH1 are 1.18 ± 0.05 wt % and 0.86 ± 0.12 wt %, respectively, indicating that Na is promoting carbonate incorporation stronger than potassium. At near constant NBO/T, CO₂ solubility increases from 0.86 ± 0.12 wt % in AH1 [Na/(Na + K)] = 0.28, to 1.18 ± 0.05 wt % in AH3 [Na/(Na + K)] = 0.85, suggesting that Na favors CO₂ solubility on an equimolar basis. An empirical equation is proposed to predict the maximum CO₂ solubility at 500 MPa and 1,100–1,300 °C in various silicate melts as a function of the NBO/T, (Na + K)/∑cations and Na/(Na + K) parameters: \({\text{wt}}\% \;{\text{CO}}_{2} = - 0.246 + 0.014\exp \left( {6.995 \cdot \frac{\text{NBO}}{T}} \right) + 3.150 \cdot \frac{{{\text{Na}} + {\text{K}}}}{{\varSigma {\text{cations}}}} + 0.222 \cdot \frac{\text{Na}}{{{\text{Na}} + {\text{K}}}}.\) This model is valid for melt compositions with NBO/T between 0.0 and 0.6, (Na + K)/∑cation between 0.08 and 0.36 and Na/(Na + K) ratio from 0.25 to 0.95 at oxygen fugacities around the quartz–fayalite–magnetite buffer and above.  相似文献   

How light affect the magnetotactic behavior and reproduction of ellipsoidal multicellular magnetoglobules?     

Qian  Xinxin  Zhao  Yicong  Santini  Claire-Lise  Pan  Hongmiao  Xiao  Tian  Chen  Haitao  Song  Tao  Li  Jinhua  Alberto  Francois  Brustlein  Sophie  Wu  Long-Fei 《中国海洋湖沼学报》2021,39(6):2005-2014

Journal of Oceanology and Limnology - Magnetotactic bacteria (MTB) synthesize intracellular magnetic organelles, magnetosomes, which consist of magnetic crystals that are enveloped in a membrane....  相似文献   

The post-outburst photometric behaviour of V838 Mon     

Lisa A. Crause  Warrick A. Lawson  David Kilkenny  Francois van Wyk  Fred Marang  Albert F. Jones 《Monthly notices of the Royal Astronomical Society》2003,341(3):785-791

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GMRT and VLA observations at 49 cm and 20 cm of the HII region near <Emphasis Type="Italic">l</Emphasis> = 24.8°, <Emphasis Type="Italic">b</Emphasis> = 0.1°     

N. G. Kantharia  W. M. Goss  D. Anish Roshi  Niruj R. Mohan  Francois Viallefond 《Journal of Astrophysics and Astronomy》2007,28(1):41-53

We report multi-frequency radio continuum and hydrogen radio recombination line observations of HII regions near l = 24.8°, b = 0.1° using the Giant Metrewave Radio Telescope (GMRT) at 1.28 GHz (n = 172), 0.61 GHz (n = 220) and the Very Large Array (VLA) at 1.42 GHz (n = 166). The region consists of a large number of resolved HII regions and a few compact HII regions as seen in our continuum maps, many of which have associated infrared (IR) point sources. The largest HII region at l = 24.83° and b = 0.1° is a few arcmins in size and has a shell-type morphology. It is a massive HII region enclosing ∼550 M_⊙ with a linear size of 7 pc and an rms electron density of ∼110 cm⁻³ at a kinematic distance of 6 kpc. The required ionization can be provided by a single star of spectral type O5.5. We also report detection of hydrogen recombination lines from the HII region at l = 24.83° and b = 0.1° at all observed frequencies near V _lsr = 100 km s⁻¹. We model the observed integrated line flux density as arising in the diffuse HII region and find that the best fitting model has an electron density comparable to that derived from the continuum. We also report detection of hydrogen recombination lines from two other HII regions in the field.  相似文献   

First Lunar Flashes Observed from Morocco (ILIAD Network): Implications for Lunar Seismology     

Mamoun Ait Moulay Larbi  Ahmed Daassou  David Baratoux  Sylvain Bouley  Zouhair Benkhaldoun  Mohamed Lazrek  Raphael Garcia  Francois Colas 《Earth, Moon, and Planets》2015,115(1-4):1-21

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