关键词: 石油地质特征, 油气潜力, 西北地区, 中国

Abstract: The basic tectonic framework of NW China is an assemblage of several cratonic blocks pieced together with orogenic belts.Most of the major sedimentary basins occurring in the region developed three-layered architecture characterized by Paleozoic marine sequence,Mesozoic non-marine sequence and Cenozoic molasse facies.During the evolutional process,three extensional periods and four compressional phases alternately appeared in the region and three suites of soure rock,reservoir and caprock assemblage were therefore formed in some successive basins.The study made by the authors shows that the region underwent four main periods of hydrocarbon generation and pools formation due to the coincidence of hydrocarbon generation processes of different source beds superimposed on each other and the several tectonic compressions happening in coincidence with or a bit later than the hydrocarbon generations,dominantly in the end of Early Paleozoic,Permian and Late Jurassic to Cretaceous as well as Late Tertiary.The petroleum exploration done in the region in the past decades indicates that the two suites of marine and nonmarine sequences have rich oil/gas resources,but different exploratory countermeasures should be taken into practice owing to their different characteristics of petroleum geology.Three types of sedimentary basins are classified and the craton and foreland basins have been verified to be the largest potentialities of petroleum resources for the further exploration.

Key words: feature of petroleum geology, oil/gas resources potentiality, northwest region, China