临兴气田致密砂岩储层可动流体分布特征及主控因素

Distribution Characteristics and Main Controlling Factors of Movable Fluid in Tight Sandstone Reservoir of Linxing Gasfield

针对鄂尔多斯盆地临兴地区储层微观孔隙结构复杂、可动流体分布特征及控制因素不明等问题,综合利用低场核磁共振、场发射扫描电镜、X射线衍射分析、核磁共振成像以及CT扫描等手段,对临兴气田上石盒子组和太原组可动流体饱和度特征进行定量刻画,分析了孔隙度、渗透率、岩石矿物组成、微观孔隙连通性与可动流体饱和度之间的关系。结果表明:临兴地区石盒子组储层平均可动流体饱和度为58.05%,太原组储层平均流体饱和度为48.60%,石盒子组储层平均流体饱和度明显高于太原组;渗透率及孔隙连通百分比是影响致密砂岩储层可动流体饱和度的重要因素。研究结果可为临兴致密砂岩储层渗流规律认识及开发方案编制提供有力支撑。

To address the problem of complex microporous structure and unknown distribution characteristics and control factors of movable fluid in the reservoirs of Linxing Area in the Ordos Basin,by comprehensively utilizing low-field nuclear magnetic resonance(NMR),field emission scanning electron microscopy(FESEM),X-ray diffraction(XRD)analysis,nuclear magnetic resonance(NMR)imaging,and CT scanning,we quantitatively portrayed the saturation characteristics of the moveable fluids of the Upper Shihezi Formation and the Taiyuan Formation of the Linxing Gasfield,and analyzed the relations among the porosity,permeability,mineralogical composition of the rocks,microscopic porosity connectivity and the saturation of the moveable fluids.The results show that the average movable fluid saturation of the reservoirs of the Shihezi Formation in Linxing Area is 58.05%,and the average fluid saturation of the reservoirs of the Taiyuan Formation is 48.60%,and the average fluid saturation of the reservoirs of the Shihezi Formation is significantly higher than that of the Taiyuan Formation;the permeability and the percentage of porosity connectivity are the important factors influencing the movable fluid saturation of the dense sandstone reservoirs.The results of the study can provide a strong support for the understanding of permeability rules and the preparation of the development plan for dense sandstone reservoirs in Linxing Area.