南堡凹陷高柳地区古近系沉降史分析

Subsidence history analysis of the Paleogene in Gaoliu region of Nanpu Sag

以钻井资料标定的地震剖面的地质解释为基础,建立南堡凹陷的地层格架,根据沉降史回剥原理,应用EBM盆地模拟系统,定量的计算了该凹陷不同时期的沉降量和沉降速率,分析了它们在时空上的变化特征并勾绘了各个阶段的平面图。分析结果表明:南堡凹陷由断陷期到断坳期和坳陷期,沉降速率变化呈"幕"式特点;构造沉降速率占总沉降速率的份额由早期的大于1/2演变为近1/3,这表明凹陷产生的沉降的主导因素由早期的构造因素控制为主演变为非构造因素占主导控制地位。较大的岩石圈的拉伸系数β值(2.6)表现了南堡凹陷是一个好的富生烃凹陷。

Based on the geologic interpretation of the seismic profile demarcated by drilling data, this paper set up stratigraphic framework of Nanpu sag. According to subsidence back-stripping principle and by using EBM basin simulation system, this paper quantitatively calculated subsidence amount and subsidence rate of the sag at different periods, analyzed space-time variation features and drawed the plane graphs of different periods. Analysis results showed that： from fault to depression, the subsidence rate of Nanpu sag varied as ＇episode＇; the proportion that tectonic subsidence rate took up in total subsidence rate changed from more than 1/2 to approximate 1/3, indicating that the main factor leading to sag subsidence has changed from tectonic factor to non-tectonic factor. The big value of lithosphere extention coefficientβ（2.6） showed that Nanpu sag was rich in hydrocarbon.