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Zhang W.,Jilin University | Zhang W.,Geoscience Documentation Center
Journal of Earth System Science | Year: 2013

Geological storage of CO2 in deep saline formations is increasingly seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, possible leakage of injected CO2 from the storage formation through vertical pathways such as fractures, faults and abandoned wells is a huge challenge for CO2 geological storage projects. Thus, the density-driven fluid flow as a process that can accelerate the phase change of injected CO2 from supercritical phase into aqueous phase is receiving more and more attention. In this paper, we performed higher-resolution reactive transport simulations to investigate the possible density-driven fluid flow process under the 'real' condition of CO2 injection and storage. Simulation results indicated that during CO2 injection and geological storage in deep saline formations, the higher-density CO2-saturated aqueous phase within the lower CO2 gas plume migrates downward and moves horizontally along the bottom of the formation, and the higher-density fingers within the upper gas plume propagate downward. These density-driven fluid flow processes can significantly enhance the phase transition of injected CO2 from supercritical phase into aqueous phase, consequently enhancing the effective storage capacity and long-term storage security of injected CO2 in saline formations. © Indian Academy of Sciences.

Wang Y.,Chinese Academy of Geological Sciences | Xing S.,Chinese Academy of Geological Sciences | Zhang Y.,Chinese Academy of Geological Sciences | Zhang Z.,Chinese Academy of Geological Sciences | And 3 more authors.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2015

The mineral components, chemical composition, crystal chemistry and dissemination characteristics of the Jinlong bauxite deposit were systematically studied using a XRD, chemical analysis, microscopic identification and SEM analysis. The results show that the main minerals are diaspora (36.5%), gibbsite, clay minerals and hematite. The average grade of Al2O3 in the Jinlong bauxite deposit is 44%, and A/S is about 3.57. Jinlong bauxite deposit is defined as low-grade bauxite. Diaspora represents an orthorhombic dipyramidal class, and mainly have following three dissemination forms: euhedral and subhedral grain, bean and oolitic shaped, aphanitic and microcrystalline aggregates, and always accompanied by kaolinite and pyrophyllite. Kaolinite is a triclinic crystal layered silicate mineral, with implicit crystalline density or soil aggregates. Pyrophyllite is a monoclinic two-octahedral hydrous aluminum silicate mineral, with aphanitic small oolitic flake aggregates, accompanied by hematite, rutile, and so on. ©, 2015, China University of Mining and Technology. All right reserved.

Zhang W.,Geoscience Documentation Center | Xu S.,Geoscience Documentation Center | Lv P.,Geoscience Documentation Center
Energy Sources, Part A: Recovery, Utilization and Environmental Effects | Year: 2016

CO2 geological storage into deep saline aquifers is one of the most promising methods for reducing anthropogenic CO2 emissions into the atmosphere. During the CO2 geological storage, many factors may affect the final success of actual storage projects, including storability, injectivity, and seal security. In order to investigate the impact of the desiccation phenomenon on the physical and chemical behaviors around the injection well, a series of numerical simulations were performed. Simulation results demonstrated that the geochemical reactions play an important role in the CO2 injection stage, especially the dissolution of easily soluble minerals, such as carbonates and sulfate. © 2016 Taylor and Francis.

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