论文详情
珠江口盆地L区块勘探程度相对较低, 而周缘已钻井证实文昌组发育半深—深湖相烃源岩, 此套烃源岩的发育规模是L区块资源潜力评价的关键。为了准确预测总有机碳(TOC)含量, 以研究区地化取心数据、测井数据和地震数据为基础, 利用ΔlogR法预测TOC曲线, 并建立TOC曲线与敏感弹性参数间的关系, 联合应用多属性约束的地震反演技术, 以提高少井区反演结果的可靠性, 最终将对地化参数TOC的预测转变为对弹性参数的预测。依次从点、线、面、体四方面逐步实现烃源岩的剖面预测到空间展布特征的雕刻, 并通过计算优质烃源岩的体积, 实现对烃源岩的定量刻画。该技术被称为"点-线-面-体"四步法定量预测烃源岩技术或四步法定量预测烃源岩技术。L区块的应用结果表明, 利用四步法定量预测烃源岩技术预测的TOC含量与已钻井处的TOC值吻合度高, 并且有效预测了文昌组优质烃源岩及中等烃源岩的发育规模及体积, 为L区块资源潜力评价提供了重要依据。
The degree of exploration is relatively low in Block L, the Pearl River Mouth Basin. Semi-deep to deep lacustrine source rocks in the Wenchang Formation, which have been proved by well drilling results in surrounding areas, are crucial to the evaluation of potential resources. The method in this paper contains four steps to accurately predict TOC content. The first step is to calculate total organic carbon curve by using the Passey formula; the second step is to establish the relationship between TOC content and its sensitive elastic parameters; the third step is to predict TOC content by using seismic inversion under multi-attribute constraints to reduce the uncertainties of inversion in the areas with a small number of wells; the last step is to do space carving and quantitative prediction of source rocks. Geochemical data of core samples, logging data, and seismic data should be analyzed before seismic prediction. This method gradually realizes the quantitative prediction of high-quality source rocks from 1D to 3D by four steps. The application in Block L shows predicted TOC contents consistent with calculated values at well sites; predicted volumes and distributions of high-quality and medium-quality source rocks offer support to resources assessment in Block L.