东濮凹陷热演化史研究

Thermal evolution of Dongpu Sag

采用多种方法研究东濮凹陷不同构造单元的热演化史发现,中央隆起、东部次凹和西部次凹在石炭-二叠系顶面的Ro值比白庙地区和西部斜坡的Ro值高,并且古今地温接近。东部次凹和西部次凹的古生界在三叠纪沉降幅度大,地层沉降增温;中生代晚期未沉积侏罗系—白垩系,处于抬升降温过程;新生代以来沉降幅度较大,随着埋深不断增加,古生界烃源岩温度不断升高并开始生烃,因此,东部次凹和西部次凹为有利的二次生烃区。而从白庙地区和西部斜坡带的Ro值与埋藏深度的关系判定,白庙地区新近系、古近系之间为欠补偿接触,并且该区的古地温明显高于今地温,说明新近纪以来地层抬升剥蚀较大,烃源岩热演化程度受古地温控制,新近纪以来无二次生烃过程。

The vitrinite reflectivities of the eastern subsag, western subsag and central uplift are higher than those of the Baimiao region and western slope belt on the Carboniferous-Permian upper surface. The palaeo-temperature and present temperature of the eastern and western subsags are close, which means that the two subsags have a great sedimentation since Cainozoic era and the geo-temperature keeps rising. So the Upper Paleozoic source rocks are controlled by present temperature and the area belongs to the area of secondary hydrocarbon generation. According to the relationship between the vitrinite reflectivity and burial depth in the Baimiao region and in the western slope belt, the Neogene system and Eogene system are lack of compensation and the palaeotemperature is higher than the present temperature, which means this area has a great denudation since the Neogene period and the source rocks are controlled by the palaeotemperature, and the area hasn＇t the process of secondary hydrocarbon generation since the Neogene period.