特低渗透储层相渗类型及递减规律研究

Study of Permeability Ratio Curve Types and Production Decline Law of Extra-Low Permeability Oil Reservoirs

根据长庆特低渗透储层相渗曲线形态首次将其划分为上凹型、水相直线型和油相直线型3种类型；并首次将相渗和产量递减规律相结合，建立基于相渗、考虑裂缝与启动压力梯度的含水与含水上升率、含水与自然递减的数学模型。研究表明储层递减类型与油相渗透率和含水饱和度之间的关系式密切相关，且不同含水阶段上凹型储层含水上升率和递减均为最小，水相直线型均中等，油相直线型均最大。

According to the relative permeability curve shapes of extral-low permeability Changqing oilfield, it can be divided into three types： up-concavlty, aqueous phase linearity and oil phase linearity. Based on relative permeability, we have builded up the mathematical model between water cut and water cut escalating rate, between water cut and natural decline in view of fracture and actuating pressure gradient. Research shows that decrease types are connected to the relations between oleic permeability and Sw. The water cut escalating rate and natural decline of the up-concavity is the minimum, aqueous phase linearity is moderate and the oil phase linearity is the maximum.