Filial Piety (spring) - New (field) - Total (hing Games) Areas Would Be Of Clay Minerals In The Xujiahe Sandstone Reservoir

The clay minerals samples of reservoir sandstones that collected from Xujiahe Formation II and IV in the Xiao(quan)-Xin(chang)-He(xingchang) Area of the middle section of Western Sichuan Sag are analysed with the help of X-ray Difrraction(XRD),Scanning electron microscope(SEM),Thin-section analysis, Electronic probe microscopy (EPM) and so on; The experiments prove that the reservoir sandstones of the area have a characteristic of more abundant lithic fragments whereas are short of feldspars ,which are the material resources of the clay minerals diagenesis there. Three main clay mierals can be identified in Xujiahe Foramation reservoir sandstones in this area, they are illite ,chlorite and kaolinite. Among them ,the content of illite is at the utmost and chlorite has the secondary content. The waning and waxing of the main clay minerals(illite and chlorite) nearly represent the whole clay distribution pattern character in the Xujiahe Foramation II and IV vertically ; The authigenic clay minerals has the second place in content in the reservoir sandstones ,with the authigenic carbonate mineral has the first place in content., The authigenic chlorite appears mainly in Xujiahe Foramation II however , the authigenic kaolinite appears in the upper Xujiahe Foramation IV vertically. Because of the narrowness of the target area ,the sub-tectonic belts in the area have not play the important role of the distribution pattern horizontally; The type assemblages and distributing characteristics of the terrigenous (heterogenous) clay minerals are controlled by the transfer of marine and terrestrial facies, palaeoclimate and palaeoenvironment, however, we must have the prudential attitude in the deciphering work on the above aspects because of the violent alteration in the diagenesis stages in the case of the buried depth in target formations have already reached 5000m.The authigenic chlorite in Xujiahe Foramation II that exists prevalently in grain-coatings(or pore-linings) mainly precipitated during early diagenesis stage and the dominating material resources of chlorite are the prehydration and decompound of neutral and basic volcanic rock fragment(VRF), dark-colored ferromagnesian and the metasomatic replacement of the precursory clay minerals.The authigenic chlorite existing in this member(Xujiahe Foramation II) has revegetation, the potential main material resources are the Mg-rich flow in the underlying strata that has full-bodied marine characteristic ,the transfer passages are probably the abundant fissure system...