川西北地区须二段储层成岩作用及其对气水分布的影响

Study on Diagenesis and Its Effectiveness of Gas-water Distribution of Xu'er Fomation in Northern Part of West Sichuan Basin

川西北部地区须二段为致密砂岩,成岩作用对有效储层的发育具有控制作用。根据薄片、扫描电镜、X-衍射以及包裹体特征分析,对川西北部地区须二段砂岩储层的成岩作用及其对气水分布的影响进行了研究。结果表明,该区主要成岩作用类型有压实作用、胶结作用和压溶作用,成岩演化已达到晚成岩阶段;储层成岩致密带的形成是导致气藏复杂气水分布关系的主要因素。

In the second member of Xujiahe Formation in northwest Sichuan Basin,reservoirs are make up of tight sandstone,diagenesis has a control function on reservoir development.For this purpose,by means of thin slices, scanning alectron microscopy observation,X ray diffraction analysis as well as fluid inclusion characteristic anlysis, diagenesis anlysis is carried out in Xu'er formation in northern part of west Sichuan Basin.The results show that the main diagenesis typeS include compaction,cementation and denudation,and at late diagenesis stage.The results show that the formation of the tight belt is the most important factor including complicated gas-water distribution combined with the structural characteristics.