关键词: 鄂尔多斯盆地, 西部, 奥陶系, 成藏, 资源潜力

Abstract: The abundance of organic matter in Ordovician source rock of Pingliang Formation is rather high in western Ordos Basin. The organic matter is mainly typeⅠand at the stage of high to post maturity. Gas generation potential is large, total gas generation quantity is about 151 trillion cubic meters, and gas resource amount is up to 936.2 billion cubic meters. The rate of gas generation is fast in the western margin thrust zone of Ordos Basin and it is favorable for gas accumulation. In this area, the two intervals of carbonate reservoirs have been developed, dolomite reservoir in the 4th member of Majiagou Formation in Ordovician and Kelimoli Formation's weathering-crust reservoir. The direct seal and up-dip lower Carboniferous mudstone cover have the strong sealing ability. Therefore, the condition of gas accumulation is superior in this area, and it has the geological advantages to form large- and medium- sized gasfields. According to the relation among source, reservoir and cover,it is thought that Etuokeqi-Dingbian and Tianchi-Bulike areaswould be the favorable targets for natural gas exploration in the future.