前第三系烃源岩埋藏史与生、排烃史研究—以南黄海南部坳陷为例

A STUDY ON THE HISTORY OF BURIAL AND HYDROCARBON GENERATION AND EXPULSION FOR PRE-TERTIARY SOURCE ROCKS-A CASE OF SOUTH DEPRESSION IN THE SOUTHERN YELLOW SEA

以现有盆地模拟软件为手段,结合钻井资料,采用大面积分凹陷已钻井或人工井与二维地震解释资料相结合的模拟分析技术,在开展部分已钻井剥蚀厚度恢复与校正以及多模式模拟对比试验的基础上,对南黄海南部坳陷前第三系烃源岩的埋藏史和生、排烃史进行了模拟分析.结果表明:剥蚀厚度恢复与校正的准确与否,严重影响前第三系主力生烃凹陷埋藏史和生、排烃史模拟的精度;南黄海南部坳陷普遍存在多期抬升剥蚀,其古生界生烃潜力优于中生界,以生气为主;南黄海南部坳陷烃源岩存在二次生烃,具有2个生、排烃高峰期,排气作用可持续至今.

The history of burial and hydrocarbon generation and expulsion has been modelled and analysed for the pre_Tertiary source rocks in South depression, the southern Yellow Sea, by means of basin modelling softwares and well data. For the drilled wells widely scattered in individual sags and pseudo_wells, the modelling analysis is combined with 2D seismic interpretation. Meanwhile, a restoration and correction of denudation thickness and a comparative test of multiple models are conducted for some wells. The modelling results indicate that the restoration accuracy of denudation thickness has a strong control on the modelling history of burial and hydrocarbon generation and expulsion for the pre_Tertiary source rocks; that in the South depression of the southern Yellow Sea, the hydrocarbon generating potential of Palaeozoic source rocks is higher than that of Mesozoic due to multiple periods of uplifting and erosion, with gas generation dominant; and that there are two times of hydrocarbon generation and two expulsion peaks, with gas expulsion lasting up to now, in South depression.