Abstract: The Northwestern China had undergone three extensional and compressional cycles from Sinian to Devonian,Carboniferousto Triassic and Jurassic to Quaternary respectively,which caused a complex continental lithospheric block consisting mosaicallyof large or small cratons and orogenic belts.The sedimentary basins are characterized by superimposed geological structures,especially by the superimposition of foreland basins over the cratonic ones.The three periods of extension and transgression eventsof marine or lacustrine had resulted in three successions of regional source rocks,including the Cambrian to Ordovician,Carboniferous to Permian and Jurassic rocks,and constituted accordingly the lower,middle and upper assemblages of source-reservoirseals as a result.The three periods of compression,however,had formed large numbers of traps.The matching of the time ofmaturation of source rocks with the time of trap formation has controlled the four critical moments for oil and gas to accumulate.The NW China is famous for its rich petroleum resources,and favorable environments of foreland and cratonic basins for poolformation as well.The tectonic elements of the basins have played an important role in oil and gas pool formation and occurrencesof large-scaled oil and gas accumulations.The NW China shows broad prospects for hydrocarbon exploration,while the cratonicand foreland basins are the two predominant targets for the further exploration.

Key words: petroleum geology, extensional and compressional cycle, petroleum resources, prospects, northwestern region, China

摘要： 中国西北地区是在经历了震旦一泥盆纪、石炭─三叠纪与侏罗─第四纪三大伸展聚敛旋回的基础上,由大小不等的克拉通块体与造山带镶嵌形成的大陆岩石圈块体。沉积盆地具有以前陆与克拉通叠合为代表的叠加地质结构特点。三期伸展与海(湖)侵事件形成了寒武─奥陶系、石炭─二叠系与侏罗系三套区域性烃源岩,以其为基础构成了盆地上、中、下三套生储盖组合;三期聚敛作用形成了相应的圈闭组合,与源岩热成熟演化相匹配决定了西北地区四个成藏关键时刻。西北地区的油气资源潜力巨大,主要有克拉通盆地与前陆盆地两种油气成藏环境,盆地的地质结构单元决定了油气的成藏模式与大型油气田的分布。西北地区的油气勘探前景广阔,克拉通盆地与前陆盆地是主要的勘探领域。

关键词: 石油地质, 伸展聚敛旋回, 油气资源, 远景, 西北地区, 中国