应用甲型水驱曲线的变液量产量预测方法

Production Prediction Method with Variable Liquid Production under A Type Water Drive Curve

产量预测是油田开发管理的重要任务之一。油井见水后产量开始递减,若生产制度不变,则产量递减一般会遵循Aprs递减规律,而实际会采取提液来保持油量稳定或升高,此时产量的变化规律无法用该递减模式去预测,但可借助于水驱曲线进行预测。常用的乙型、丙型和丁型等水驱曲线可直接得出累产液量与累产油量的关系,唯有甲型曲线无法直接得出。通过泰勒公式进行数学变换,得到累产液量和累产油量的"平方型"和"立方型"两种关系式。应用结果表明当Np/Lp越小,计算日产油量精度越高且两种方法计算结果相差越小;当Np/Lp小于0.6时,基本重合且精度较高;当Np/Lp大于0.6时,"立方型"公式精度较高。该方法将甲型曲线预测的技术可采储量转化为不同液量控制下的产油量指标,为液量优化提供科学依据,填补了这一经典方法的应用空白。

Production forecast is main task for field managers. After water breakthrough, oil production will de- crease. Generally, production decreases trend followed Aprs law when production system is stable. But when liquid production increases, oil production will be stable or raise. Then description of production decrease will become more difficult. Water drive curve provides us a reasonable ways to solve this problem. It＇ s easy to find relationship between Np and Lp for B, C, and D type curve. But it can＇ t obtain directly for A type water drive curve. After deri- vation of equation, we obtain square and cubic type equation for Np vs Lp. The result shows that Np/Lp value is less, theory result of daily oil more accurate and difference is less for two ways. When Np/Lp value is below 0.6, the result has some overlap. When Np/Lp value is above 0.6, cubic type equation is more accurate. This way translates technical recoverable reserve to oil production with variable liquid production. It provides scientific evi- dence for liquid production optimization. This way will fill in the using blank for classics reservoir engineer method.