关于油藏含水上升规律的若干问题

Some topics about water cut rising rule in reservoirs

针对油藏含水上升规律研究的一些定量分析指标不够明确,及含水率上升与地质特征的对应关系尚未建立等问题,利用油藏地质模型和实例分析进行了研究,明确了含水率上升速度的定量分析指标,给出了水淹速度的评价指标及油井见水时间与底水类型的对应关系,并定义了2种非均质性,即离散型非均质和连续型非均质。离散型非均质性油藏和连续型非均质性油藏的含水率曲线分别呈阶跃式上升和连续上升。孔隙型介质的相渗曲线因高毛管压力而呈曲线形态,决定了其含水率上升曲线也呈曲线形态;缝洞型介质的相渗曲线因低毛管压力而呈对角直线,决定了其含水率上升曲线也呈直线形态。

Some quantifying parameters are so far unclear about water cut rising rule of reservoirs.The corresponding relationship between water cut rising features and geological features of reservoirs has not been established.Reservoir geological model and case analyses were used to define the quantifying parameters of water cut rising rate.The quantifying parameters of water flooding rate and the corresponding relationship between water breakthrough time in wells and bottom-water types were obtained.Two types of reservoir heterogeneity were defined：discrete heterogeneity and continuous heterogeneity.Discrete heterogeneous reservoirs have the step-type curve of water cut rising,while continuous heterogeneous reservoirs have the continuous curve of water cut rising.The relative permeability curves of porous media are not straight lines because of high capillary pressure,which results in the non-straight line type of water cut rising curves in such reservoirs.However,the relative permeability curves of fractured-vuggy media are straight lines because of low capillary pressure,which results in the straight line type of water cut rising curves in fractured-vuggy reservoirs.