高渗储层特高含水期渗流规律实验模拟及流场表征

以孤东油田七区西馆陶组Ng63+4砂层组地质特征为基础,设计二维平面物理模型进行水驱实验,组建压力、饱和度全程同时实时监测系统,并以绘制场图的形式表征模型内部压力及含水饱和度分布,系统地揭示了含水上升规律与压力、饱和度分布之间的关系。基于驱替过程中模型内部压力及含水饱和度分布的变化规律,推导出油水两相的速度分布及流线,通过调整注采关系改变流线,研究特高含水期供给边界及压力梯度的改变对储层油水两相饱和度分布的影响。建立质点迁移模型计算平面模型内部含水饱和度分布,并将预测值与实验测量值对比,认为长期注水冲刷及压力波动会导致储层的孔渗性及润湿性改变,进而导致油水两相相渗曲线改变。通过修正相渗曲线,预测得出与实验测量结论具有高相似度的含水饱和度分布,为高渗油藏特高含水期剩余油分布预测提供了一套新的思路。

Experimental Study on Seepage Law and Flow Field Description of High Permeability Reservoir at Extra High Water Cut Stage

Based on the geological characteristics of Ng63+4 sand group in the west 7th block of Gudong oilfield, two-dimensional flat areal models are designed for the water flooding experiment. A real-time monitoring system is set up to measure and represent the distribution of pressure and water saturation in the model, and the relationship between water cut increasing rate and distribution of pressure and saturation is revealed. According to the distribution of pressure and water saturation, the velocity distribution and flow line of oil-water two phases in the model are derived. By adjusting the flow line, the influence of supply boundary and pressure gradient on the distribution of water saturation at extra high water cut stage is studied. The distribution of water saturation predicted by the particle migration model is compared with the experimental results, and it is considered that long-term water flooding and pressure fluctuation will change the permeability and wettability of the reservoir, which will lead to the change of oil-water two-phase relative permeability curve. By revising the relative permeability curve, the water saturation distribution with high similarity to the experimental measurements is predicted, which provides a new way for predicting remaining oil distribution of high permeability reservoir at extra high water cut stage.