特高含水期油田新型水驱特征曲线公式推导

目前国内部分水驱油藏都进入了特高含水阶段，对于特高含水油藏来说，相对渗透率比值与含水饱和度的关系曲线会发生上翘的现象，这也导致推导出的水驱特征曲线在油田特高含水期产生上翘，使得运用常规水驱特征曲线对实际油田生产进行预测会产生较大的偏差。基于实际油田的数据资料，通过对不同油田区块多条相对渗透率比值与含水饱和度关系曲线上翘后的部分进行拟合分析，给出了新的相对渗透率比值与含水饱和度关系表达式；同时，根据新的相对渗透率比值与含水饱和度关系表达式推导出新型水驱特征曲线，并将其运用于实际油田的生产。结果表明，新型水驱特征曲线能够很好地预测常规水驱特征曲线产生上翘后的油田生产动态，对特高含水阶段的预测具有较好的适用性。

New equations for characterizing water flooding in ultra-high water-cut oilfields

Many oil reservoirs stimulated by water flooding in China have entered the ultra-high water-cut stage.Using the relative permeability ratio versus water saturation curve in the performance prediction of these reservoirs often yields up-warping curves and misleading results.Based on a fitting analysis of the up-warping curves of different oilfields, this study obtained a new expression for the relationship between relative permeability ratio and water saturation.New equations were then deduced to characterize the performance of high water-cut reservoirs.Applications of the equations to oilfields verified their effectiveness in the production prediction of ultra-high water-cut reservoirs.