中文摘要：

选择胜利油田惠民地区特低渗透砂岩样品,利用XRD和SEM分析样品的粘土矿物组成及产状,采用ZetaProbe电位仪测定粘土矿物在4种以地层水矿化度为参照的实验流体及不同pH值条件下的动电电位。结果显示,实验流体所含阳离子浓度均超过平衡粘土矿物表面负电荷需要的临界电解质浓度,达到阳离子过饱和状态,使其动电电位在较宽的pH值范围内保持正值。评价样品的盐敏损害程度,并与粘土矿物在实验流体中的动电电位数据进行比较分析,研究表明,对于以高岭石-绿泥石-伊利石、绿泥石-伊利石粘土矿物组合为主的特低渗透砂岩油层,盐敏损害主要由流体矿化度降低,水膜厚度增加,有效孔喉半径减小,流体渗流阻力增加而引起的。

英文摘要：

Core samples of sandstone with extra-low permeability from Huimin area in Shengli oil field were selected,and the shape and composition of clay mineral in core samples were analyzed by SEM and XRD.Electrokinetic potential of clay minerals in four experimental fluids was measured,under reference to formation water＇s salinity and different pH by means of Zeta Probe（potential measuring apparatus）.The results show that the positive ion concentration in these experimental fluids is higher than the critical value to balance the negative ions on the face of clay minerals.That makes the positive ion in the state of over-saturated and keeps the value of electrokinetic potential positive in a wide range of pH value.We have evaluated the salt sensitivity extent of the samples,and analysed the data with electrokinetic potential of clay minerals in experimental fluids.The results show that the salt sensitivity mechanism of extra-low permeability sandstone reservoirs,with kaolinite-chlorite-illite and chlorite-illite as the main clay mineral composition,is that with the formation salinity decreasing,the thickness of water film increases,which brings about decreasing of effective pore-throat and enhancement of permeative resistance.