Through the analysis of casting thin sections, 3D geological modeling, special logging series and micro seismic monitoring, reservoir stress characteristics of Jing’an area were studied. The results show that: 1) the distribution of the direction of micro pore and throat would cause the stress anisotropy; 2) differences in each layer of Chang 4+5₂ sandstone are big, the lateral superposition characteristics of multi-periods channels have the major influence on stress distribution; 3) the stress difference in the study area is generally not large with the value of 3?6 MPa, with the development of water flooding development, the variation of the two main stress varies in the reservoir, resulting in the multi-directional development of fractures in the process of repeated fracturing. The results can provide a scientific basis for improving oil recovery in the middle and late development of low permeability reservoirs.

Through the core observation, inter-well tracer test and water flooding front test, the fracture development characteristics of Chang-7 tight sandstone reservoir in Xin’anbian area of Ordos Basin are studied. The results show that maximum horizontal principal stress direction of Chang-7 tight sandstone oil reservoir in Xin’anbian area is NE60°?80°. The fracture type is mainly high angle fractures or vertical fracture, and fracture direction is NE75°?85°, the dip angle is 70°?85°. Dynamic monitoring data analysis shows that the micro fracture research area of tight sandstone oil reservoir developed widely and plays an important role in increasing the seepage channel and improving the permeability of matrix, water channeling easily along the fracture formation, resulting in the production of well water is fast. 3D geological modeling results show a high degree between oil saturation of tight sandstone oil reservoir in the study area and the degree of fracture development, which can effectively support the fracture of oil and gas reservoir and accumulation.

X-ray diffraction (XRD), laser Raman microprobe (LRM) and X-ray fluorescence(XRF) were used to study the mineral and elemental component of atmospheric inhalable particles (PM₁₀) collected during the periods of haze day, normal day and the day after precipitation respectively in 2008 winter in Beijing. The concentration of PM₁₀ collected during the haze periodis 262.7 μg/m³, and the pollution of PM₁₀ in the following day exceeds the national standard level Ⅱ. The results of XRD phase analysis indicates that the concentration of chloride of haze day is higher than that in the normal day, and the behavior of other crustal minerals are different from that of chloride. Thetotal concentration of secondary aerosols in the haze day is 37.9%, higher than 30.6% of normal day, which shows the enhancement effected by the haze weather condition. Especially ammoniumchloride, existing in all samples, its percentage decreased from9.6% (haze day) to 5.9% (normal day). Moreover, the LRM individual particle analysis shows that the organic matter and sulphate minerals cover other minerals in the PM₁₀ of haze day, which means the mineral particles in the atmosphere becomethe convenient carrier for the pollutant material. Besides, the results of XRF elemental quantitative analysis are consistent with the results of XRDphase analysis, and it shows the concentrations of Al and Si decrease in the haze day, and S and Cl enrich in the haze period.

Clay minerals are widely applied in reconstructing paleoclimate, and many analysis methods are involved. Among them the X-ray diffraction analysis(XRD) is mainly used to confirm clay mineral assemblages and their crystallinity; chemical analysis and electronic microscope are used to study the source, the genesis and the evolvement process of clay minerals; radioactive isotopes analysis can make up the relationship between the time and space which is based on the climate index and the chronology; Hydrogen and oxygen isotopes also provide important evidence for reconstructing paleoclimate. This paper summarizes what paleoclimate information is contained in clay minerals, and it is intent to use clay minerals synthetically as the means to reconstruct paleoclimate.