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位于西藏高原东北边缘的柴达木盆地是一个陆相含油气盆地。据报导,其潜在的烃源岩为第三系咸水湖沉积和侏罗系淡水湖(即陆相)地层。根据沉积体系、岩性、时代以及有机地化特征,该侏罗系烃源岩与中亚诸盆地(包括塔里木、准噶尔及其它重要的产油气盆地)的侏罗系陆相烃源岩相似,被认为是一套很有潜在价值的烃源岩。侏罗系烃源岩为早中侏罗世的内陆前陆盆地的淡水湖盆沉积体系。这些湖相地层与煤及煤系泥岩共生,后者构成次要的烃源岩。柴达木盆地北部的原油按沉积环境的分子指标和断代生物标志物可分为两组:一组来源于侏罗系淡水湖烃源岩,另一组则来源于第三系超咸水湖烃源岩。通过把部分柴达木原油与侏罗系烃源岩对比,建立了陆相侏罗系烃源岩含油气系统。该含油气系统中的原油产自东北部的背斜圈闭及与冲断有关的圈闭中的第三系和中生界储层。侏罗系烃源岩的成熟度模拟显示.柴达木盆地北部大部分地区在中上新世生成、运移油气。盆地的地质格架说明盆地内油气以垂向运移为主,最大可能是沿断层运移,直到遭遇上覆新生界的蒸发岩或超压泥岩盖层而停止。该含油气系统资料显示,柴达木盆地北部和西南部的其余勘探目标仍然被低估;另外,柴达木盆地北部含油气系统对资料不多的中亚地区其它盆地中的相似侏罗系烃源岩所起的作用方面,也是一种有用的参照。
The Qaidam Basin, located on the northeast edge of the Tibet Plateau, is a continental oil and gas basin. Its potential source rocks are reported to be Tertiary lagoon deposits and Jurassic freshwater lakes (ie, continental) formations. Based on the sedimentary system, lithology, age and organic characteristics, the Jurassic source rocks are similar to the Jurassic continental source rocks in Central Asia, including Tarim, Junggar and other important hydrocarbon-producing basins. It is considered as a set of potential source rocks. Jurassic source rocks are the freshwater lake basin sedimentary system of the Early Middle Jurassic inland foreland basin. These lacustrine strata co-occur with coal and coal-bearing mudstones, which constitute secondary source rocks. The molecular indicators and the dating biomarkers of crude oil in the northern Qaidam Basin can be divided into two groups: one sourced from the Jurassic freshwater lake source rock and the other from the Tertiary super-salt lake source rock. By comparing some Qaidam crude oil with Jurassic source rocks, a petroleum system of continental Jurassic source rocks was established. The oil in this petroleum system is derived from Tertiary anticline traps in the northeast and Tertiary and Mesozoic reservoirs in thrust-related traps. Simulation of the maturity of Jurassic source rocks shows that most of the northern Qaidam basin was formed and migrated in the Middle Pliocene. The geological framework of the basin shows that the oil and gas in the basin are mainly migrated vertically, most likely along the fault and stopped until it encounters the overlying Cenozoic evaporites or overpressured mudstone caprocks. The petroleum system data show that the remaining exploration targets in northern and southwestern Qaidam Basin are still underestimated. In addition, the petroleum systems in the northern Qaidam Basin are similar to those in other basins in Central Asia with few data The role played by the source rock is also a useful reference.