Characterization of a shale-gas reservoir based on a seismic amplitude variation with offset inversion for transverse isotropy with vertical axis of symmetry media and quantitative seismic interpretation

The Lower Silurian shale-gas formation in the south of the Sichuan Basin represents a strong transverse isotropy with vertical axis of symmetry (VTI) feature. Successful characterization of shale-gas formation requires handling the great influence of anisotropy in the seismic wave propagation. Seismic amplitude variation with offset (AVO) inversion for VTI media using PP-waves only is a difficult issue because more than three parameters need to be estimated and such an inverse problem is highly ill posed. We have applied an AVO inversion method for VTI media based on a modified approximation of the PP-wave reflection coefficient. This approximation consists of only three model parameters: the acoustic impedance (attribute A), shear modulus proportional to the anellipticity parameter (attribute B), and the approximated horizontal P-wave velocity (attribute C), which can be well-inverted and have great interpretation capability in shale-gas reservoir characterization. A statistical-rock-physics method was then applied to the inverted attributes for quantitative interpretation of the shale-gas reservoir. A Markov random field is combined with Bayesian rule to improve the continuity and accuracy of the interpretation results. Shales can be successfully discriminated from surrounding formations by using the attribute pair A-C, and the organic-rich gas-bearing shale can be successfully identified by using the attribute pair C-B . Comparison between the prediction results and well logs demonstrates the feasibility of the inversion and quantitative interpretation approaches

High-temperature protective coatings for C/SiC composites

AbstractCarbon fiber-reinforced silicon carbide (C/SiC) composites were well-established light weight materials combining high specific strength and damage tolerance. For high-temperature applications, protective coatings had to provide oxidation and corrosion resistance. The literature data introduced various technologies and materials, which were suitable for the application of coatings. Coating procedures and conditions, materials design limitations related to the reactivity of the components of C/SiC composites, new approaches and coating systems to the selection of protective coatings materials were examined. The focus of future work was on optimization by further multilayer coating systems and the anti-oxidation ability of C/SiC composites at temperatures up to 2073K or higher in water vapor

Comprehensive Evaluation of Environmental Policy for Water Pollutants and Greenhouse Gases Reduction in Jiaxing city, China

Recently, various environmental problems have been generated with the rapid economic development in China. That’s because China currently over-emphasized economic development beyond environmental issues; therefore, now it is important to enforce optimal environmental policies in order to achieve economic development as well as environmental improvement. In this study, we selected Jiaxing city as research area for that the environmental pollution problem has become prominent with economic high growth, and we constructed environmental system model and social economic model to establish the scenarios. Through computer simulation, we can evaluate the efficiency of the comprehensive environmental policies from both environmental preservation and social economic development aspects. While the social-economic model shows the socioeconomic activities which are vital events, fortune and service, such as production, finance and budget; the environmental system model shows the water pollutants and the greenhouse gas movement in the region. The dynamic optimization simulation is accomplished based on this environmental and socio-economic system model. In view of the restriction on water pollutants, greenhouse gas total exhausted amount, and economic activity in the catchment area, the simulation we practiced can provide concrete inner-generating optimal policies which can achieve the best economic and environment improvement with the consideration of policy, regional and timing choice in Jiaxing City, China.