陆相页岩油有利岩相优选与压裂参数优化方法

Optimization method of favorable lithofacies and fracturing parameter for continental shale oil

综合高精度岩石物理实验、数字岩心以及测井新技术资料,系统描述了鄂尔多斯盆地三叠系延长组7段3亚段陆相页岩油的页岩岩相特征及其识别方法,根据每类页岩岩相的内幕特征确定了"油气甜点"有利岩相分布层段与平面展布规律。研究认为,高TOC含量页岩岩相是陆相页岩油的源岩基础,但不是产量的主控因素;孔隙结构良好和储集空间发育的页岩岩相是"油气甜点"的有利岩相;有利页岩岩相的可压性与脆性矿物的粒度、分布形式及其与柔性矿物间的接触关系密切相关;有利岩相以及良好的源-储配置关系是陆相页岩油产量的主控因素;基于储层品质、源岩品质和完井品质("三品质")的评价结果可优化压裂分级与射孔簇布置。研究成果与认识有效地支持了鄂尔多斯盆地C80井区2口水平井的风险勘探部署,并为其获得重大突破提供了有效的技术支撑。

Based on the new technical data of high-precision petrophysical experiment, digital core and logging, this paper systematically describes the shale lithofacies characteristics of continental shale oil from the submember 3 of Member 7 of Triassic Yanchang Formation in Ordos Basin, as well as its identification method. The favorable lithofacies interval and distribution of "oil and gas sweet spots" were determined according to the internal characteristics of each category of shale lithofacies. The research suggests that the shale lithofacies with high TOC content are foundational for the development of source rock of continental shale oil, but not the main controlling factor for the production. The shale lithofacies with good pore structure and developed reservoir space is deemed as favorable lithofacies for "oil and gas sweet spots". The compressibility of favorable shale lithofacies is closely related to the particle size and distribution pattern of brittle minerals, as well as its contact relation with flexible minerals. Favorable lithofacies and good source-reservoir configuration are the main controlling factors of continental shale oil production. Fracturing classification and perforation cluster layout can be optimized based on the evaluation results of the reservoir quality, source quality and engineering quality("three qualities"). The research results and understandings effectively supports the risk exploration and deployment of two horizontal wells in C80 well area of Ordos Basin, and provides effective technical support for making significant breakthroughs.