Thermo-hydro-mechanical modeling of carbon dioxide injection for enhanced gas-recovery (CO2-EGR): a benchmarking study for code comparison   总被引：2，自引：1，他引：1  

Zhengmeng Hou  Yang Gou  Joshua Taron  Uwe Jens Gorke  Olaf Kolditz 《Environmental Earth Sciences》2012,67(2):549-561

The objective of this paper was to investigate the THM-coupled responses of the storage formation and caprock, induced by gas production, CO₂-EGR (enhanced gas recovery), and CO₂-storage. A generic 3D planer model (20,000?×?3,000?×?100?m, consisting of 1,200?m overburden, 100?m caprock, 200?m gas reservoir, and 1,500?m base rock) is adopted for the simulation process using the integrated code TOUGH2/EOS7C-FLAC3D and the multi-purpose simulator OpenGeoSys. Both simulators agree that the CO₂-EGR phase under a balanced injection rate (31,500?tons/year) will cause almost no change in the reservoir pressure. The gas recovery rate increases 1.4?% in the 5-year CO₂-EGR phase, and a better EGR effect could be achieved by increasing the distance between injection and production wells (e.g., 5.83?% for 5?km distance, instead of 1.2?km in this study). Under the considered conditions there is no evidence of plastic deformation and both reservoir and caprock behave elastically at all operation stages. The stress path could be predicted analytically and the results show that the isotropic and extensional stress regime will switch to the compressional stress regime, when the pore pressure rises to a specific level. Both simulators agree regarding modification of the reservoir stress state. With further CO₂-injection tension failure in reservoir could occur, but shear failure will never happen under these conditions. Using TOUGH-FLAC, a scenario case is also analyzed with the assumption that the reservoir is naturally fractured. The specific analysis shows that the maximal storage pressure is 13.6?MPa which is determined by the penetration criterion of the caprock.  相似文献   

Discrimination between different water bodies from a multilayered aquifer (Kaluvelly watershed,India): Trace element signature     

Nathalie Gassama  Haino Uwe Kasper  Aline Dia  Constantin Cocirta  Martine Bouhnik-LeCoz 《Applied Geochemistry》2012

In the multilayered aquifer of Kaluvelly (India), comprising various sedimentary layers overlying a charnockitic basement, concentrations of trace elements were measured in aquifer formations and in groundwaters to identify geochemical tracers for water bodies. The two main sandstones (Cuddalore and Vanur) originate from the charnockites and the Cuddalore sandstone has experienced lateritization. In the studied area, two charnockite end-members were identified: a dioritic and a granitic one. Mineralogical composition and whole-rock Ti concentrations confirmed the charnockite which displayed the granitic composition as the parent rock of the two sandstones. Titanium distribution indicates that the Cuddalore sandstone originates from a more intense weathering of the parent material than the Vanur sandstone. Despite extensive differences in trace element contents recorded in aquifer formations, only a few trace elements were suitable to distinguish the water bodies. Among soluble elements, Li (in the Vanur aquifer) and Ba (in the charnockite and carbonaceous aquifers) can be used as tracers. As the input of these elements in solution is mainly regulated by the available stock, for a given mineralogical origin there is a direct link between the aquifer formation composition and water signature. With the exception of As, concentrations of redox-sensitive elements were not preserved during pumping because of oxidation, preventing their use as tracers. Low-mobility elements such as La, Ce, Th, Zr, Nb, Hf, or Ta were too insoluble to be detected in waters and/or to record the aquifer formation signature. Their input in solution was not regulated by the available stock but by the dissolution rate of rock-forming minerals. Only Ti can be used to distinguish between two out of the three aquifers (charnockite and Vanur). The specific behavior of Ti recorded in these waters may be linked to rutile inclusions within plagioclases and to the influence of climate on Ti solubility.  相似文献   

The crystal structure of cualstibite-1M (formerly cyanophyllite), its revised chemical formula and its relation to cualstibite-1T     

Uwe Kolitsch  Gerald Giester  Thomas Pippinger 《Mineralogy and Petrology》2013,107(2):171-178

The crystal structure of the rare secondary mineral cualstibite-1M (formerly cyanophyllite), originally reported to have the chemical formula 10CuO·2Al₂O₃·3Sb₂O₃·25H₂O and orthorhombic symmetry, was solved from single-crystal intensity data (Mo-Kα X-radiation, CCD area detector, 293 K, 2θ_max?=?80) collected on a twinned crystal containing very minor Mg. The mineral is monoclinic, P2₁/c (no. 14), with a?=?9.938(1), b?=?8.890(1), c?=?5.493(1) Å, β?=?102.90(1)°, V?=?473.05(11) ų; R1(F)?=?0.0326. All crystals investigated turned out to be non-merohedric twins. The atomic arrangement has a distinctly layered character. Brucite-like sheets composed of two [4?+?2]-coordinated (Cu,Al,Mg) sites are linked by weak hydrogen-bonding (O···O?~?2.80 Å) to isolated regular Sb(OH)₆ octahedra (<Sb-O>?=?1.975 Å). The layered, pseudotrigonal character explains the perfect cleavage and the proneness to twinning. The Sb site is fully occupied and the two (Cu,Al,Mg) sites have occupancies of Cu_0.79Al_0.17Mg_0.04 and Cu_0.72Al_0.23Mg_0.05. The Cu-richer site shows a slightly stronger Jahn-Teller-distortion. The resulting empirical formula, which necessitates a H₂O-for-OH substitution to obtain charge balance, is (Cu_2.23Al_0.63Mg_0.14)(OH)_5.63(H₂O)_0.37[Sb⁵⁺(OH)₆]. The ideal chemical formula is (Cu,Al)₃(OH)₆[Sb⁵⁺(OH)₆], with Cu:Al = 2:1. The structure is closely related to those of trigonal cualstibite-1T [Cu₂AlSb(OH)₁₂, P-3, with ordered Cu-Al distribution in the brucite sheets], and its Zn analogue zincalstibite-1T [Zn₂AlSb(OH)₁₂]. Cualstibite-1M and cualstibite-1T are polytypes and, together with zincalstibite-1T, zincalstibite-9R and omsite, belong to the cualstibite group within the hydrotalcite supergroup, which comprises all natural members of the large family of layered double hydroxides (LDH).  相似文献   

Silicon-32 as a tool for dating the recent past   总被引：2，自引：2，他引：0  

L. Keith Fifield  Uwe Morgenstern 《Quaternary Geochronology》2009,4(5):400-405

Silicon-32, with a half-life of approximately 140 years, has the potential to fill the dating gap that lies between those chronologies based on the shorter-lived isotopes of ³H and ²¹⁰Pb, and those based on the longer-lived ¹⁴C. Silicon-32 is produced in the atmosphere by cosmic ray bombardment of argon, and falls out on the Earth's surface in precipitation. Silicon-32 methods may be used to date siliceous sediments and sponges, groundwater and glacier ice. Measurement of ³²Si concentrations in these archives is, however, not straightforward. Two methods are available: radioactive-decay counting of the activity of the daughter nucleus, ³²P, and accelerator mass spectrometry, but in both cases the detection of ³²Si pushes the boundaries of the technique. Even the half-life of ³²Si is not known to a precision of better than ±10%. In this paper, we review efforts to determine the isotope's half-life, survey the detection methods and discuss the applications of ³²Si chronology. We show that at least some of the chronometric potential of this radioisotope is close to being realised as a result of recent improvements in methods of measurement.  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2016          下载免费PDF全文

Ulrike Weis  Beate Schwager  Brigitte Stoll  Uwe Nohl  Patricia Karlowski  Isabelle Leisgang  Florentine Zwillich  Klaus Peter Jochum 《Geostandards and Geoanalytical Research》2017,41(4):487-491

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Reply to Lowe,D.J., Wilson,C.J.N., Newnham,R.M., Hogg,A.G. comment on Grapes, R., Rieser,U., Wang,N., 2010. Optical luminescence dating of a loess section containing a critical tephra marker horizon,SW North Island of New Zealand. Quaternary Geochronology 5, doi:10.1016/j.quageo.2009.01.004, 2010     

Rodney H. Grapes  Uwe Rieser  Ningsheng Wang 《Quaternary Geochronology》2010,5(4):497-501

The arguments presented by Lowe et al. [Lowe, D.J., Wilson, C.J.N., Newham, R.M., Hogg, A.G., 2010. Dating the Kawakawa/Oruanui eruption: comment on “optical luminescence dating of a loess section containing a critical tephra marker horizon, SW North Island of New Zealand” by R. Grapes et al. Quaternary Geochronology 5(4), 493–496] against our IRSL results, which suggested that the widespread Kawakawa tephra (KkT) could be considerably younger than the generally accepted 27.1 ka cal BP age, are unsustainable. We discuss the points raised by Lowe et al., in terms of: 1) Presentation and analysis of luminescence ages (comparison between reporting and error margins of luminescence and ¹⁴C ages, statistical treatment of age data); 2) Possible sources of error (“upbuilding pedogenesis” and its affect on U and Th distribution in loess, effect of biotubation, variation of K in loess, single grain luminescence dating of quartz, probability of luminescence age underestimation in dating tephra); 3) Stratigraphic and paleoenvironmental considerations (ages of tephras overlying KkT, timing of the end of Ohakea loess deposition and its distribution; 4) Radiocarbon-based ages of KkT (problems with the currently accepted ¹⁴C 27.1 ka cal BP age of KkT). We stress that our study was not to establish a new benchmark age for the KkT, but to open debate about the currently accepted benchmark age of the KkT, which we deem to be erroneous.  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2008     

Klaus Peter Jochum  Stefanie M. Brueckner  Uwe Nohl  Brigitte Stoll  Ulrike Weis 《Geostandards and Geoanalytical Research》2009,33(4):501-505

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Modelling the poroelasticity of rocks and ice   总被引：1，自引：0，他引：1  

Thomas Keller  Uwe Motschmann  & Ludwig Engelhard 《Geophysical Prospecting》1999,47(4):509-526

For many geophysical and astrophysical applications the relationship between physical bulk properties and porosity is needed. As part of the preparation for the 'Rosetta' comet rendezvous mission, a simple model for the porosity dependence of the elastic properties of granular media, i.e. the elastic moduli and the propagation velocities of elastic waves, has been developed based on textural properties and the contact stiffness of the constituent particles. It is shown that the derived relationships fit very well with sandstone data. The model is also consistent with data for snow and ice and is in agreement with the transformation mechanisms from snow to ice. A short review shows the relevance to another physical bulk property, the thermal conductivity.  相似文献   

Determination of the submerged macrophyte coverage of greifswalder bodden     

Solveig Bartels  Uwe Klüber   《Limnologica》1999,29(3):311

The extent to which a water body can support submerged macrophytic vegetation provides an indicator of its degree of eutrophication. Regular, quantitative assessment of macrophyte populations enables changes in the trophic state of the system to be observed. A combination of aerial photography and underwater videography has proved to be an efficient method for calculating macrophyte coverage of large coastal areas.  相似文献   

The Erbisberg drilling 2011: Implications for the structure and postimpact evolution of the inner ring of the Ries impact crater     

Gernot Arp  Andreas Reimer  Klaus Simon  Sebastian Sturm  Jakob Wilk  Corina Kruppa  Lutz Hecht  Bent T. Hansen  Jean Pohl  Wolf Uwe Reimold  Thomas Kenkmann  Dietmar Jung 《Meteoritics & planetary science》2019,54(10):2448-2482

The 26 km diameter Nördlinger Ries is a complex impact structure with a ring structure that resembles a peak ring. A first research drilling through this “inner crystalline ring” of the Ries was performed at the Erbisberg hill (SW Ries) to better understand the internal structure and lithology of this feature, and possibly reveal impact‐induced hydrothermal alteration. The drill core intersected the slope of a 22 m thick postimpact travertine mound, before entering 42 m of blocks and breccias of crystalline rocks excavated from the Variscan basement at >500 m depth. Weakly shocked gneiss blocks that show that shock pressure did not exceed 5 GPa occur above polymict lithic breccias of shock stage Ia (10–20 GPa), with planar fractures and planar deformation features (PDFs) in quartz. Only a narrow zone at 49.20–50.00 m core depth exhibits strong mosaicism in feldspar and {102} PDFs in quartz, which are indicative of shock stage Ib (20–35 GPa). Finally, 2 m of brecciated Keuper sediments at the base of the section point to an inverse layering of strata. While reverse grading of clast sizes in lithic breccias and gneiss blocks is consistent with lateral transport, the absence of diaplectic glass and melt products argues against dynamic overthrusting of material from a collapsing central peak, as seen in the much larger Chicxulub structure. Indeed, weakly shocked gneiss blocks are rather of local provenance (i.e., the transient crater wall), whereas moderately shocked polymict lithic breccias with geochemical composition and ⁸⁷Sr/⁸⁶Sr signature similar to Ries suevite were derived from a position closer to the impact center. Thus, the inner ring of the Ries is formed by moderately shocked polymict lithic breccias likely injected into the transient crater wall during the excavation stage and weakly shocked gneiss blocks of the collapsing transient crater wall that were emplaced during the modification stage. While the presence of an overturned flap is not evident from the Erbisberg drilling, a survey of all drillings at or near the inner ring point to inverted strata throughout its outer limb. Whether the central ring of the Ries represents remains of a collapsed central peak remains to be shown. Postimpact hydrothermal alteration along the Erbisberg section comprises chloritization, sulfide veinlets, and strong carbonatization. In addition, a narrow zone in the lower parts of the polymict lithic breccia sequence shows a positive Eu anomaly in its carbonate phase. The surface expression of this hydrothermal activity, i.e., the travertine mound, comprises subaerial as well as subaquatic growth phases. Intercalated lake sediments equivalent to the early parts of the evolution of the central crater basin succession confirm a persistent impact‐generated hydrothermal activity, although for less time than previously suggested.  相似文献