STUDY OF THE WEST-EAST TREND NATURAL GAS ACCUMULATION ZONE IN THE MIDDLE OF THE ORDOS BASIN, CHINA

The discovered industrial gas fields, like Liujiazhuang, Shenglijing, Changqing, Zhenchuanbu and Wubu in the Oudos Basin are all located in the west-east trend tectonic belt of the Middle. There are gas showings or a small amount of gas flows in only rare wells in the other regions of the basin. Their reservoirs are the Ordovician carbonate rock or sandstone and thin-bedded limestone in the Carboniferous and the Permian coal measures strata. The gas sources are pure gas pools and are all related to the Ordovician or the Carboniferous and the Permian hydrocarbon source rocks. They show good identity. Industrial gas fields zonally distributed in west-east trend in the middle of the basin is not accidental. It reflects the controlling action of the middle tectonic belt to the pool-formation and distribution of these fields. Taking the middle tectonic belt as setting and linking their same or similar genetic background together, theas fields can be included into the west-east trend natural gas accumulation zone of the Middle. Obviously, this zone is the most favorable target for natural gas exploration.