烃源岩TOC地球物理定量预测新技术及在珠江口盆地的应用

南海东部珠江口盆地富生烃洼陷内部的钻井极少,给烃源岩总有机碳含量(TOC)地球物理预测研究及洼陷的资源潜力评价带来了极大的困难。结合烃源岩测井及地震响应特征,从实测有机碳含量出发,应用测井预测TOC的方法建立虚拟井的TOC曲线,以此为因变量,选取的地震属性作为自变量,建立它们之间的最佳拟合方程,通过三维地震数据体中提取地震属性从而计算得到三维TOC数据体。将该方法应用到珠江口盆地富生烃洼陷惠州洼陷中,得到整体文昌组和恩平组的三维TOC数据体。HZ26洼陷边缘到洼陷深部,有机碳含量明显增大,反映了洼陷深部是优质烃源岩的发育场所,从南部隆起区到洼陷深部,再到北部洼陷边缘,先增大后又逐渐减小的变化特征。

Geophysical quantitative prediction technology about the total organic carbon in source rocks and application in Pearl River Mouth Basin, China

There are few or no drilled wells in the interior of the depression in Pearl River Mouth Basin.This brings great difficulty in the geophysical prediction of the total organic carbon(TOC) in source rocks and in the assessment of the resource potential in the depression.By combining hydrocarbon source rocks and seismic response characteristics,starting from measuring organic carbon content,using logging prediction method of TOC to build TOC curve of the virtual well,as dependent variables,and selecting seismic attributes as independent variables,the paper establishes the best fitting equation and extracts seismic attributes from 3-D seismic data to calculate the 3-D TOC data body.The method is applied to the rich-in hydrocarbon-generating Huizhou depression of Pearl River Mouth Basin in China,and calculates the 3-D TOC data body of the overall Wenchang group and Enping group.This provides important parameters for the correct evaluation of the sub sag hydrocarbon potential.