川中—川南过渡带致密砂岩储层物性主控因素分析

Analysis on main controlling factors of physical property of tight sandstone reservoir

周康 彭军 耿梅

西南石油大学资源与环境学院，四川 成都 610500 新疆油田公司，新疆 克拉玛依 834000

四川盆地川中—川南过渡带须家河组为典型的致密化砂岩储层。为深入了解其致密化原因，综合大量岩心、薄片及扫描电镜观察分析辅之X射线衍射及各种分析化验资料详细分析了致密砂岩储层物性的影响因素。研究表明须家河组储层主要为水下分流河道砂体、河口坝砂体，属特低孔特低渗储层，其物性主控因素为沉积微相和成岩作用。沉积微相在宏观上控制着储层物性，石英和岩屑含量高是储层致密化的主要原因。强烈的压实作用、硅质胶结作用及钙质胶结作用是储层致密化的重要原因，而溶蚀作用和绿泥石环边胶结作用对储层有较好的改善作用。

Xujiahe Formation reservoir is the typical tight sandstone in transitional zone of middle-south Sichuan. In order to find out the
tightened reasons,this paper takes the Xujiahe Formation reservoir in the transitional zone as an example to study the controlling
factors of physical properties of tight sandstones by observation of the cores,slice and SEM combined with X-ray diffraction and test
data analysis. The study result shows that the reservoirs are mainly the distributary channel sand and river mouth bar sand which
belong to the low porosity and low permeability reservoirs. The main controlling factors are the sedimentary microfacies and
diagenesis. The sedimentary microfacies dominate the physical properties of reservoir on the macro and high quartz and lithic
fragment contents are the main tight reasons. The strong compaction,siliceous and calcareous cementations are the important
reasons of densification.The physical properties of reservoir can be improved by the denudation and chlorite rim cementation.