鄂尔多斯盆地三叠系延长组陆相页岩测井评价

Log Evaluation of Continental Shale of Triassic Yanchang Formation in Ordos Basin

探究页岩的空间分布及有机质丰度特征是评价页岩气资源潜力的一项重要任务,但由于实验分析的局限性,需借助测井信息对页岩的空间分布进行精细刻画。总结前人提出的各种评价模型的基础上,应用这些方法对研究区长7、长9段页岩的有机碳含量(TOC)进行了拟合。通过将拟合结果与岩心样品实测TOC进行对比,发现大多数模型驱动方法具有经验性与局限性。结合研究区实际条件,优选出Δlog R作为该区陆相页岩评价的主要方法。评价结果显示长7段富有机质页岩(TOC>2.0%)在研究区西南部最为富集,厚度>80m,TOC主要分布在3.5%~6.5%;长9段分布中心位于研究区中部,富有机质页岩主要分布于长9段顶部,厚度范围在10~30m。

One of the most important tasks of evaluating the potential shale gas is to determine the spatial distribution and organic matter abundance of shale in the basin.As the limitations of experimental analysis,we utilized the logging information to make the fine spatial distribution of shale.On the basis of summarizing the proposed various evaluation models,we applied these methods to calculate the(TOC)of Chang 7&9shale formation of studied area.By comparing these calculated results with that obtained from the Rock-Eval pyrolysis,we found that most of the model-driven models are empirical and restrained.It was ultimately determined thatΔlog R method is the main method for the evaluation of the continental shale in the studied area based on their practical situation.The evaluation results indicated that the thickest part of organic-rich shales appears in the southwest,thickness is more than 80 m,and TOCis mainly in 3.5% ~6.5%.The distribution center of Chang 9strata located in the middle of the studied area,the organic-rich shales is mainly in the top of it,thickness ranges from 10~30m.