当储集层非均质性较强时,利用J函数(毛管压力函数)计算的含油饱和度存在较大误差。针对这一问题,以珠江口盆地某油田为例,通过实验测定和数值模拟研究,根据储集层质量系数对平均压汞曲线进行分类,建立能反映储集层非均质性的储集层质量系数模型,并在此基础上建立原始含油饱和度模型。结果表明,用此方法计算的含油饱和度与测井解释结果吻合较好,能够表征强非均质性油藏的含油性。综合利用压汞、退汞曲线拟合J函数,建立束缚水、可动水、残余油、可动油等流体的饱和度模型。此外,考虑到储集层质量系数、黏土含量等对退汞效率的影响,用"退汞指数"对退汞曲线进行分类,并建立可动油饱和度模型,为油田计算可采储量及研究剩余油分布提供依据。
When reservoir heterogeneity is strong,there is a great error between the calculated oil saturation based on the J-function and the actual oil saturation interpreted by logging.Aimed at this problem,a reservoir quality index is proposed to classify the average mercury curves,and the reservoir quality index model and original oil saturation model are established,by experimental measurement and numerical simulation with an illustration of an oilfield in the Pearl River Mouth Basin.The oil saturation calculated with this method accords closely with that interpreted by logging,it is a reliable method to show the properties of strongly heterogeneous reservoirs.In addition,this paper proposes a comprehensive utilization of mercury curve and mercury-ejection curve fitting J-function in establishing the saturation model of bound water,movable water,residual oil,movable oil.Considering the influences of such factors as reservoir quality index and clay content on mercury-ejection efficiency,"mercury-ejection index" is used to classify the average mercury-ejection curves and a movable oil saturation model is established,which provides basis for the calculation of recoverable reserves and the research of residual oil distribution.