东营凹陷页岩油游离资源有利区预测

摘要

基于东营凹陷典型页岩油探井的有机地化参数,提出了一种页岩油有利区预测方法,即利用烃源岩游离烃量(S1)与总有机碳质量分数(TOC)关系的“三分性”、AlogR测井模型及烃指数(100S1/TOC)剖面,对东营凹陷古近系沙河街组进行页岩油资源分级评价、泥页岩有机非均质性研究及页岩油有利区预测.结果显示:东营凹陷古近系沙四上纯上次亚段-沙三下亚段页岩油,按富集程度分为饱和资源(Ⅰ级)、低效资源(Ⅱ级)和无效资源(Ⅲ级);游离烃主要来源于Ⅰ级和Ⅱ级资源,Ⅲ级资源基本不合游离烃;研究区页岩油游离资源赋存下限为100 mg/g,Ⅰ级游离资源强度在利津洼陷最高.综合分析认为,较高的有机质成熟度、较好的封存条件和纹层状泥页岩发育是页岩油Ⅰ级游离资源分布于利津洼陷的主要原因.%Based on the organic geochemical parameters of typical exploration well in Dongying Sag,a prediction method for favorable area of shale oil is presented.This method is synthesized by the characteristic of triple-division between the free hydrocarbon content (S1) and the total quality score of organic carbon (TOC) of source rock,the model of △log R and 100S1/TOC section classification of shale oil resources,the research on organic heterogeneity of shale,and the prediction for favorable area.The results show that shale oil from the upper section of Es4s to Es3x should be classified into three levels of resources in terms of enrichment degree:enriched resources (level Ⅰ),low efficient resources (level Ⅱ) and ineffective resources (level Ⅲ);free hydrocarbon mainly comes from the resources of level Ⅰ and level Ⅱ,little from level Ⅲ;the shale oil free resources floor level is identified as 100 mg/g TOC,and the highest intensity of free resources of level Ⅰ focuses on Lijin sub-sag.Furthermore,it is concluded that the higher organic matter maturity,good storage conditions and developed lamellar mudstone/shale are the main reasons for Lijin sub-sag to obtain free resources of level Ⅰ.