为什么要根据原油粘度选择水驱特征曲线

WHY CHOOSING WATERDRIVE CURVE BY OIL VISCOSITY.

介绍了与水驱特征曲线对应的含水率ｆｗ与可采储量采出程度Ｒ＊关系的推导过程，并指出ｆｗ—Ｒ＊关系是代表水驱油田驱替特征实质的含水上升规律。以前推荐的４种水驱特征曲线，即纳札洛夫曲线、马克西莫夫—童宪章曲线、西帕切夫曲线和沙卓诺夫曲线的ｆｗ—Ｒ＊关系可以反映油田不同的含水上升规律。原油粘度是影响油田含水上升规律最主要的天然因素。选择油田适用的水驱特征曲线的原则是使水驱特征曲线与实际油田的含水上升规律相符，其目的是找出可以尽早地、准确地进行计算和预测的水驱曲线。根据原油粘度选择水驱曲线有助于这个目的的实现和避免水驱曲线应用的盲目性。最后介绍了应用伊万诺娃ｆｗ与Ｒ＊图版和我国油田在Ｒ＊＝１．０时的累积水油比（ＷＰ／ＮＰ）Ｒ＊＝１．０与μｏ的关系以及油藏数值模拟的结果，确定使用水驱曲线的原油粘度界限（３ｍＰａ·ｓ和３０ｍＰａ·ｓ）的方法。

The derived process of the relationships for water cut (fw) vs. recovery of recoverable reserves (R*) corresponded with waterdrive curve is recommended. It's shown that the relationships of fw vs. R* are a law of water cut raising being representative of essence of displacement characteristics in waterflooding reservoirs. The fw—R* relationships of previously recommended 4 waterdrive curves can reflect the different laws of water cut raising, i.e. Nazarov curve, Maksimov Tong curve, Sipachev curve and Sazonov curve. It's shown that oil viscosity is the most important natural control on the law of water cut raising in waterflooding reservoirs. The principle for choosing waterdrive curves suitable for the actual reservoir is the agreement between the choosed waterdrive curves and water cut raising trend actual reservoirs. The purpose is to look for a waterdrive curve which can make calculation and prediction as early and accurate as possible in a reservoir. It's demonstrated that to choose waterdrive curves by oil viscosity is helpful to realize this purpose and can avoid blindness in use of waterdrive curves. Finally, the method for determining the limits of oil viscosity(3 and 30 mPa·s) by which the waterdrive curve is choosed by using the Ivanova's fw—R* chart and the relationship between cumulative water oil ratio (Wp/Np) at R*=1.0 and μo used in China is recommended.