Petrological Characteristics and Rock Nomenclature of Sedimentary Bauxite Gas Reservoir: A Case Study of Bauxite in Taiyuan Formation of Ordos Basin

With the great breakthrough in natural gas exploration of Paleozoic Taiyuan formation Longdong exploratory area southwestern part Ordos Basin, it is urgent to solve petrological nomenclature sedimentary bauxite, so as further study pore mechanism, distribution law, and controlling factors bauxite reservoirs. In this paper, X-ray diffraction, polarizing microscope, scanning electron other methods are used analyze mineral composition structure rocks give appropriate names. The results show that sequence can be divided into five sections: A, B, C, D, E. main components diaspore (C section content more than 90%), illite, kaolinite, chlorite; accessory include anatase pyrite; trace quartz, feldspar, rutile, hematite, rock salt; some pores filled with calcite, siderite, (iron) dolomite. mainly bedding massive structure, them have geopetal structure. texture consists granular texture, grain (powder crystal) gel algal bonding texture. Considering special lithology A~C lack existing method, based on fabric, a triangulation classification method established, which adopts structure+texture secondary name diaspore-mud-pyrite three end-member primary name. It not only highlight assemblage characteristics but also reflect lithologic reservoir development influencing formation, effectively reflecting reservoir. Among them, granular, bean-oolitic, lithologies forming space area. naming feasible reliable for rocks, lays good foundation reservoir, law area, southwest basin.