【摘要】 在合理设定热模拟边界条件前提下,模拟分析鄂尔多斯盆地热演化过程,结果表明:在中、晚侏罗世,盆地大部分地区中生界地热梯度为4.3~4.6℃/100m,但在庆阳、西峰及其西南部分地区达到5.7℃/100m。结合热流与地壳厚度关系及地震、重力、磁法方面证据,认为造成鄂尔多斯盆地中生代地温异常的最可能的热事件模式是全盆范围的地壳减薄与局部地区隐伏岩浆体加热的叠加。在热异常背景下,三叠系延长组烃源岩层在侏罗纪埋深达到1600m便可成熟排烃,大规模生烃期在早白垩世。较长的排烃期与埋藏过程中构造的调整是造成油气多期充注的主要原因。图5表2参21更多还原

【Abstract】 Based on the logical boundary conditions defined,the results of thermal evolution modeling of the Ordos Basin show that the temperature gradient of the Mesozoic Erathem during middle-late Jurassic is mainly from 43℃/km to 46℃/km,and locally(at Xifeng,Qingyang and their southwestern areas) beyond 57℃/km.Combining the relationship between heat flow and lithospheric thickness with the evidence of seismic,gravity and magnetics,this paper concludes that the pattern leading to the Mesozoic thermal anomaly of this basin may be the stacking of crustal thinning regionally and concealed magma heating locally.In the context of thermal anomaly,hydrocarbons would be generated from the Triassic Yanchang Formation source rock when its burial depth reached 1600 meters in the Jurassic period.The mass hydrocarbon generation occured in the early Cretaceous epoch.Multiple-phase hydrocarbon-fillings are due to long expulsion process and tectonic adjustment.更多还原