低渗透砂岩储层可动流体赋存特征及影响因素研究——以姬塬油田长6储层为例

为了评价姬塬地区长6致密砂岩储层,综合应用恒速压汞及核磁共振等实验对储层样品进行了测试,探讨了储层微观孔喉与可动流体的赋存特征及影响因素。研究结果表明,孔喉半径比大、分布范围宽、主流喉道半径小是导致低渗透储层物性差、孔隙结构复杂、可动流体含量低的关键因素,从而使低渗透储层表现出排驱压力高、小喉道发育、可动流体动用程度低等特点;可动流体的充注以及驱替受到孔喉特征与配置关系的影响,流体可动用程度低是致密砂岩储层开发效果较差的重要因素;储层的开发效果可以通过可动流体的赋存特征来预测。

Characteristics and influencing factors of movable fluid in low permeability sandstone reservoir-by taking Chang-6 reservoir in Jiyuan oilfield of Ordos basin as an example

In order to evaluate Chang-6 tight sandstone reservoir in Jiyuan area,advanced experimental testing methods such as constant-rate mercury intrusion and nuclear magnetic resonance were carried out to test reservoir samples,the micro pore throat and the distribution of movable fluid and its affecting factors were discussed.The research results show the saturation of movable fluid in Chang 6 reservoir is low.Larger pore throat radius ratio,narrower distribution range and smaller mainstream throat radius are key factors which lead to poor reservoir property,complicated pore structure and low movable fluid content in Chang 6 low-permeability reservoir,thus some characteristics such as high displacement pressure,developed small throat and low degree of movable fluid.Movable fluid filling and displacement is affected by the relationship between pore throat characteristics and configuration.Low degree of movable fluid is an important factor that leads to poorer development effect of tight sandstone reservoir,the reservoir development by the occurrence characteristics of movable fluid can be predicted.