泥质夹层的三维预测与地质模型的等效粗化表征——以加拿大麦凯河油砂储集层为例

Muddy interlayer forecasting and an equivalent upscaling method based on tortuous paths:A case study of Mackay River oil sand reservoirs in Canada

根据加拿大麦凯河油砂储集层岩心观察统计泥质夹层终止频率,采用排队理论模型预测泥质夹层延伸范围,进而建立了岩心泥质夹层厚度与延伸长度的定量关系;提出了基于泥质夹层影响下流体迂曲路径计算的地质模型等效粗化方法。采用地质连通体追踪算法,实现每个粗化网格体内单一夹层的追踪识别,确定粗化网格内夹层平均长度、宽度以及占比;计算粗化网格内在泥质夹层影响下的流体流动平均路径长度等参数;以达西定律为基础,推导出粗化网格内平均渗透率计算公式,实现等效粗化网格渗透率的计算。麦凯河油砂实际地质模型的粗化结果及开发指标对比证实泥质夹层迂曲路径计算等效粗化方法可以很好体现泥质夹层的遮挡属性,更能代表实际地质条件对开发效果的影响。

Based on the abundant core data of oil sands in the Mackay river in Canada,the termination frequency of muddy interlayers was counted to predict the extension range of interlayers using a queuing theory model,and then the quantitative relationship between the thickness and extension length of muddy interlayer was established.An equivalent upscaling method of geologic model based on tortuous paths under the effects of muddy interlayer has been proposed.Single muddy interlayers in each coarse grid are tracked and identified,and the average length,width and proportion of muddy interlayer in each coarse grid are determined by using the geological connectivity tracing algorithm.The average fluid flow length of tortuous path under the influence of muddy interlayer is calculated.Based on the Darcy formula,the formula calculating average permeability in the coarsened grid is deduced to work out the permeability of equivalent coarsened grid.The comparison of coarsening results of the oil sand reservoir of Mackay River with actual development indexes shows that the equivalent upscaling method of muddy interlayer by tortuous path calculation can reflect the blocking effect of muddy interlayer very well,and better reflect the effects of geological condition on production.