致密砂岩有效储层形成演化的主控因素——以库车坳陷巴什基奇克组砂岩储层为例

Main controlling factors of formation and evolution of effective reservoir in tight sandstone:taking Bashijiqike Formation sandstone reservoir in Kuqa Depression as an example

致密砂岩气资源潜力巨大,已经成为全球范围内非常规天然气勘探的热点之一。致密砂岩储层形成机理是制约油气勘探的重要因素,因此依据岩心、铸体薄片、扫描电镜、阴极发光以及物性参数等资料,系统地分析了库车坳陷克深井区巴什基奇克组致密砂岩储层的岩石学特征、储集空间组合特征以及有效储层形成演化的主控因素。结果表明:高能沉积微相的叠合控制着有效储层的分布;压实作用和胶结作用是主要的破坏性成岩作用,溶蚀作用和构造裂缝的组合成为储层质量改善的主控因素;在异常高压和膏盐层的配合下,储层储集物性进一步保持和改善。沉积环境、成岩作用以及构造运动等多因素综合控制着库车坳陷巴什基奇克组有效储层的形成。

Tight sandstone gas regarded as the important potential resource has become a popular target of the global unconventional natural gas exploration. The formation mechanisms of tight sandstone reservoir have become the most important factors limiting the petroleum exploration. Based on core, thin section, scanning electronic microscope, cathodoluminescence and physical property parameters, this paper mainly focuses on studying the formation and evolution of effective reservoir. The results show that the superimposition of high-energy sedimentary microfacies controls the distribution of effective reservoir. Compaction and cementation are main destructive diagenetic processes, and the combination of dissolution and fracturing improves greatly reservoir quality. Besides, overpressure system and thick salt layer can further remain and improve reservoir physical property. Thus, the interaction of sedimentary environment, diagenesis and tectonic movement affects the formation and distribution of Bashijiqike Formation sandstone reservoir.