一维井地电位模型建立与求解

井地电位法是研究水驱前缘以及剩余油分布较为实用的方法。首先建立一维油水两相渗流方程,基于电位与含水饱和度模型将渗流方程与电位微分方程相耦合,形成一维井地电位模型。对模型采用有限差分法,隐式求压力,显式求饱和度,再利用含水饱和度与电导率的关系,建立形成电位微分方程,隐式求电位;在此基础上建立计算机求解模型。对一维水驱油过程进行模拟计算,通过数值求解,模拟水驱油的完整过程,得到电位分布与含水饱和度变化的相关关系。该方法为井地电位法后期反演油水分布提供理论支持。

Establishing and solving of a one-dimensional well-ground potential model

The so-called well-ground potential method is a practical approach to study water flooding front and remaining oil distribution in oil reservoirs. In this paper, based on a one-dimensional equation of oil-water two-phase flow, a relationship between potential and water saturation in coupling with the flow and the electric differentiation equations was established to figure out a one-dimensional well-ground potential model. A finite difference approach was used to solve the model, in which the pressure distribution was computed implicitly, while the fluid saturation distribution was solved explicitly. The potential distribution was calculated implicitly based on the electric differentiation equation. The numerical model can be used to simulate the whole process of water flooding and reveal the variation of potential with the water saturation. The model can provide a useful theoretical basis for the inversion of oil and water distribution from potential field during water-flooding process.