摘要
泥页岩中裂缝识别是一个难题,制约了济阳坳陷页岩油的发现。为了较为精确预测泥页岩裂缝,利用岩心、薄片、测井、数理统计等多种方法综合判识济阳坳陷泥页岩裂缝,预测构造缝、层理缝和超压缝在东营、沾化凹陷的分布范围。构造缝主要分布在断距大于100 m,距离断层上盘小于1.2 km的区域;层理缝主要发育在纹层状岩相内地层倾角大于6˚的区域;超压缝主要发育在压力系数 】1.38和TOC 】2的叠合区域。通过构造缝、层理缝和超压缝分布范围进行叠合,把裂缝发育区分为I类,II类发育区,为下一步寻找页岩油甜点打下基础。泥页岩裂缝是常规油藏、页岩油气形成的中转站;泥页岩裂缝是济阳坳陷页岩油富集高产的关键因素;泥页岩裂缝的存在有利于泥页岩储层的压裂。该成果对东部陆相断陷盆地页岩油勘探开发有一定指导作用。
Fracture identification in shale is a difficult problem and restricts the discovery of shaleoil in Jiyang depression. By means of core, thin slice, logging, mathematical statistics methods, fractures are identified, and the distribution of structural fractures, interlayer fractures and overpressure fractures in Dongying and Zhanhua sag is predicted. The structural fractures are mainly distributed in the area where fault throw is more than 100 m and distance away from the fault is less than 1.2 km, the interlayer fractures develop mainly in the areas where the dip angle of layer is greater than 60 in the laminated lithofacies, and the overpressure fractures develop mainly in the superimposed areas with pressure coefficients >1.38 and TOC >2. According to the superimposed distribution range of structural fractures, interlayer fractures and overpressure fractures, the fracture development areas are divided into I grade, II grade, which lay the foundation for finding the shale oil sweetspots. Shale fractures are a transit station for conventional reservoir and shale oil and gas formation;shale fractures are key factor for the enrichment and high output of shale oil in Jiyang depression;the existence of shale fractures is beneficial to fracturing of shale reservoir.
