考虑应力敏感的缝洞型油藏三重介质试井分析理论模型

A Theoretical Model of Triple Medium Well Test Analysis for Fractured-vuggy Reservoirs Considering Stress Sensitivity

碳酸盐岩储藏资源潜力巨大,是当前研究的热点和难点领域。为了准确评价缝洞型油藏产能特征,以三重介质流体渗流方程为基础,考虑应力敏感对储层渗透率的伤害,建立基质-孔隙-裂缝的三重介质试井分析模型。研究结果表明:无量纲压力及压力导数曲线随应力敏感性增强而整体向上抬升,随着时间的增加,上升幅度逐渐增大;将无量纲压力导数曲线的水平段取值作为特征值,当其值大于0.5时应考虑应力敏感的影响,反之亦反;“双下凹”形态可作为判断三重介质缝洞型油藏的曲线特征。对于强应力敏感性储层,应力敏感的影响不可忽视,渗透率应力敏感的准确表征有利于提高产能预测精度。

Carbonate reservoir have great potential resources and it is a hot and difficult field of current research.To accurately evaluate the productivity characteristics of fracture-vuggy reservoirs,the damage of stress sensitivity to reservoir permeability was considered,and the triple medium well test model was established based on the seepage equation with matrix-pore-fracture medium.Results show that the dimensionless pressure and the pressure derivative curve rose with the increase in stress sensitivity.As time lasted,the rise increased.The horizontal section of the dimensionless pressure derivative curve was taken as the eigenvalue,and the influence of stress sensitivity should be considered when the value was greater than 0.5.The W-shape shown on the double logarithm curve of the bottom-hole pressure could be used to characterize the triple media fracture-cave reservoirs.Therefore,the influence of stress sensitivity cannot be ignored for the reservoir with strong stress sensitivity.The accurate characterization of permeability stress sensitivity is helpful to improve the accuracy of productivity prediction.