Multiphase Modeling of Geologic Carbon Sequestration in Saline Aquifers   总被引：1，自引：0，他引：1       下载免费PDF全文

Karl W. Bandilla  Michael A. Celia  Jens T. Birkholzer  Abdullah Cihan  Evan C. Leister 《Ground water》2015,53(3):362-377

Geologic carbon sequestration (GCS) is being considered as a climate change mitigation option in many future energy scenarios. Mathematical modeling is routinely used to predict subsurface CO₂ and resident brine migration for the design of injection operations, to demonstrate the permanence of CO₂ storage, and to show that other subsurface resources will not be degraded. Many processes impact the migration of CO₂ and brine, including multiphase flow dynamics, geochemistry, and geomechanics, along with the spatial distribution of parameters such as porosity and permeability. In this article, we review a set of multiphase modeling approaches with different levels of conceptual complexity that have been used to model GCS. Model complexity ranges from coupled multiprocess models to simplified vertical equilibrium (VE) models and macroscopic invasion percolation models. The goal of this article is to give a framework of conceptual model complexity, and to show the types of modeling approaches that have been used to address specific GCS questions. Application of the modeling approaches is shown using five ongoing or proposed CO₂ injection sites. For the selected sites, the majority of GCS models follow a simplified multiphase approach, especially for questions related to injection and local‐scale heterogeneity. Coupled multiprocess models are only applied in one case where geomechanics have a strong impact on the flow. Owing to their computational efficiency, VE models tend to be applied at large scales. A macroscopic invasion percolation approach was used to predict the CO₂ migration at one site to examine details of CO₂ migration under the caprock.  相似文献   

The contribution of the IGM and minihaloes to the 21-cm signal of reionization     

Bin Yue  Benedetta Ciardi  Evan Scannapieco  Xuelei Chen 《Monthly notices of the Royal Astronomical Society》2009,398(4):2122-2133

We study the statistical properties of the cosmological 21-cm signal from both the intergalactic medium (IGM) and minihaloes, using a reionization simulation that includes a self-consistent treatment of minihalo photoevaporation. We consider two models for minihalo formation and three typical thermal states of the IGM – heating purely by ionization, heating from both ionizing and Lyα photons and a maximal 'strong heating' model. We find that the signal from the IGM is almost always dominant over that from minihaloes. In our calculation, the differential brightness temperature,  δ T _b,  of minihaloes is never larger than 2 mK. Although there are indeed some differences in the signals from the minihaloes and from the IGM, even with the planned generation of radio telescopes it will be unfeasible to detect them. However, minihaloes significantly affect the ionization state of the IGM and the corresponding 21-cm flux.  相似文献   

Evolution of X-ray cavities     

Marcus Brüggen  Evan Scannapieco  Sebastian Heinz 《Monthly notices of the Royal Astronomical Society》2009,395(4):2210-2220

A wide range of recent observations have shown that active galactic nuclei (AGN) driven cavities may provide the energy source that balances the cooling observed in the centres of 'cool-core' galaxy clusters. One tool for better understanding the physics of these cavities is their observed morphological evolution, which is dependent on such poorly understood properties as the turbulent density field and the impact of magnetic fields. Here, we combine numerical simulations that include subgrid turbulence and software that produces synthetic X-ray observations to examine the evolution of X-ray cavities in the absence of magnetic fields. Our results reveal an anisotropic size evolution of the cavities that is dramatically different from simplified, analytical predictions. These differences highlight some of the key issues that must be accurately quantified when studying AGN-driven cavities, and help to explain why the inferred pV energy in these regions appears to be correlated with their distance from the cluster centre. Interpreting that X-ray observations will require detailed modelling of effects, including mass entrainment, distortion by drag forces and projection. Current limitations do not allow a discrimination between purely hydrodynamic and magnetically dominated models for X-ray cavities.  相似文献   

Phytoremediation     

Evan K. Nyer  Edward G. Gatliff 《Ground Water Monitoring & Remediation》1996,16(1):58-62

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Practical Remediation Technologies     

Evan K. Nyer 《Ground Water Monitoring & Remediation》1996,16(4):54-57

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Structural succession in a late palaeozoic slate belt and its tectonic significance     

Evan C. Leitch 《Tectonophysics》1978,47(3-4)

Five deformational “episodes” (D₁-D₅) during which folds and associated cleavages formed, and a later period of faulting dominated by strike-slip movements, comprise the structural sequence in the Nambucca slate belt. D₁ structures are most widespread and involved greatest strain; D₂-D₄ structures have affected progressively smaller areas and indicate progressively smaller strains. Strong compressive stresses during D₁ produced horizontal shortening and vertical extension, and the D₂-D₄ structures result from adjustments to this initial strain. Regional metamorphism accompanied D₁, and D₁ strain is greatest in the more highly metamorphosed rocks. Some granitic bodies were probably emplaced at this time, but most plutons rose only after folding had ceased. Orogenesis, as indicated by folding and regional metamorphism lasted less than 10 m.y., but faulting continued for at least another 30 m.y.The slate belt accumulated close to a consuming plate margin, but deformation commenced only after subduction ceased, with compressive stresses generated by coupling across the former plate boundary. The development of a wrench regime during D₅, and its continued existence during a long period of faulting, suggests either that the consuming plate boundary was replaced by a transform fault, or that subduction stepped oceanward and underthrusting was obliquely directed.  相似文献   

Opening of the red sea with two poles of rotation     

Evan S. Richardson  C.G.A. Harrison 《Earth and Planetary Science Letters》1976,30(1):135-142

Previous studies have shown that the Red Sea was formed by two stages of sea-floor spreading, with a quiescent period in between. We suggest that these two phases have occurred in different directions. The shape of the central trough indicates that the present-day motion is almost E-W, whereas the total opening, deduced from the shape of the coastlines, is NE-SW. If the axial trough has opened in an E-W direction, the earlier stage of opening was in a direction which made the Dead Sea Rift fall along a small circle to the pole of early opening, and hence suggests that the Dead Sea Rift was a transform fault during this early stage. The later movement gives almost pure extension along the Dead Sea Rift, and this should be seen by normal faulting. Available first-motion studies are not precise enough to confirm or deny this hypothesis.  相似文献   

Bahamian carbonate platform development in response to sea-level changes and the closure of the Isthmus of Panama   总被引：1，自引：0，他引：1  

John?J.?ReijmerEmail author  Christian?Betzler  Dick?Kroon  Ralf?Tiedemann  Gregor?P.?Eberli 《International Journal of Earth Sciences》2002,91(3):482-489

In this paper we show that the development of the sediment architecture at the leeward toe-of-slope of Great Bahama Bank (Ocean Drilling Project Leg 166, Bahama Transect) during the last 6 Ma is not only a response to sea-level fluctuations, but also to major paleo-oceanographic and climatic changes. A major sequence boundary close to the Miocene/Pliocene boundary (dated at 5.6-5.4 Ma) is interpreted to reflect a major sea-level drop that was followed by a sea-level rise, which led to the re-flooding of the Mediterranean Sea at the end of the Messinian and increasing sea-surface temperatures at Great Bahama Bank. Distinct erosional horizons occurred during the Pliocene (dated at 4.6 and 3.3-3.6 Ma) related to sea-level change and the intensification of the Gulf Stream when the emergence of the Isthmus of Panama reached a critical threshold. The Gulf Stream brings warm, saline and nutrient-poor waters to the Bahamas. Starting at the Early-Late Pliocene boundary at 3.6 Ma this paleo-oceanographic reorganization in combination with enhanced sea-level fluctuations associated with the Late Pliocene main intensification in Northern Hemisphere Glaciation (since 3.2 Ma) led to (1) a gradual change from a ramp-type to a flat-topped type morphology, and (2) a change from a skeletal to a non-skeletal-dominated sedimentary system (mainly peloidal). Increased sea-level fluctuations during the second half of the Pleistocene led to an intensified high stand-shedding depositional pattern within the surrounding basins.  相似文献   

Genetic sequence stratigraphy of cool water slope carbonates (Pleistocene Eucla Shelf, southern Australia)     

Sabine Saxena  Christian Betzler 《International Journal of Earth Sciences》2003,92(4):482-493

The south Australian Eucla Shelf belongs to the world's largest cool-water carbonate sedimentary system. During the Pleistocene, it exported large amounts of sediment to the shelf edge and upper slope resulting in an expanded sedimentary wedge. Wedge-internal clinoforming seismic reflectors suggest a stacking of the deposits into genetic sequences. High-resolution stable oxygen and carbon isotope, point counting, grain size, and carbonate mineralogical XRD analyses were carried out to characterize these genetic sequences along a dip-parallel transect of three ODP Leg 182 drill holes located between the shelf edge and upper slope. Oxygen and carbon isotope fluctuations show that the genetic sequences formed as a response to sea level fluctuations. Within the genetic sequences, facies differentiation and sediment volume partitioning occur along the transect. Lowstand deposits are fine grained and contain more sponge spicules and micrite. Highstand deposits are coarse grained with tunicate spicules, brown bioclasts, as well as bryozoan and corallinacean debris. Boundaries separating highstand and lowstand deposits are triggered by sea level fall, and are expressed as abrupt grain size changes or as turning points in grain-size trends. Analyzed components vary in abundance along the transect. Genetic sequences show dip-parallel variations in thickness combined with changing relative proportions of lowstand versus highstand deposits.  相似文献   

Aboveground Treatment Equipment: Back in Fashion     

Evan K. Nyer  James M. Bedessem  P.E.   《Ground Water Monitoring & Remediation》2003,23(4):28-34

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