特高含水期剩余油受力状态方程及敏感分析

The Stress State Equation and Sensitive Analysis of Remaining Oil at the Ultra-High Water-Cut Stage

摘要: 特高含水开发阶段剩余油不再以连续态赋存于地层毛细管中，基于连续态的渗流状态方程无法指导特高含水期油田开发实践。以剩余油离散态分布特征为基础，结合流体力学微观力计算方法和受力平衡原理，建立特高含水期等径(不等径)毛细管油滴、油膜受力状态方程；引入敏感分析基本原理，设定敏感向量，以胜利油田某区块基础数据为例，对不同状态方程进行敏感分析，形成了特高含水期剩余油受力敏感分析图形。实践表明：注入水对剩余油的黏滞剪切力敏感性最强，其次是界面张力。结合受力状态及敏感分析原理，合理制定开采计划，改变微观作用力大小，可将离散态赋存于地层的剩余油有效、合理地开采出来。

Abstract: At the ultra-high water-cut development stage, remaining oil was no longer stored in formation capillary continuously. Therefore, the seepage state equation based on the continuous state could not guide the development practice of the oilfields at the ultra-high water-cut stage. By taking discrete distribution of remaining oil as the basis of study, combined with the macroscopic force calculation method of fluid mechanics and balance principle of force condition, the equations for equal diameter (unequal diameter) capillary oil droplet and oil film at the ultra-high water-cut stage were established. The principle of sensitivity analysis was introduced to set the vectors of sensitivity, by taking the basic data in a block from Shengli Oilfield for example, the sensitivity in the equations of different states was analyzed, by which a diagram was created for sensitivity analysis of remaining oil force condition at the ultra-high water-cut stage. The practice shows that the flooded water is the most sensitive to the viscous shear stress of remaining oil, and the interfacial tension is the second. Based on the principle of stress condition and sensitivity analysis, an oil development plan is reasonably made and the size of micro force is changed for the effective and rational development of discrete remaining oil stored in formation.