【摘要】 薄互层具有砂泥交互、储层平面各向同性、纵向非均质严重的特点,压裂裂缝在纵向上扩展呈非平面特征.考虑薄互层净总厚度比、纵向非均质性及压裂裂缝非平面特征,将压裂裸眼水平井周围流场划分为两个渗流区域,建立裸眼水平井多级压裂开发薄互层的稳态渗流数学模型,并推导出解析解.通过模型计算分析了净总厚度比、非平面系数、裂缝半长、启动压力梯度、应力敏感系数等因素对裸眼水平井多级压裂产能的影响.研究结果表明,薄互层的储层特性对产能有很大的影响,考虑薄互层特性计算的产能要明显小于不考虑薄互层特性的产能;净总厚度比越小、纵向非均质性越强、裂缝非平面性越强,多级压裂水平井产能越小;应力敏感系数越大,多级压裂水平井产能越小;启动压力梯度越大,多级压裂水平井产能越小.更多还原

【Abstract】 Thin inter-bedded low permeability reservoir is sand layer alternating with mud layer,areal isotropic formation and seriously longitudinal heterogeneous. Induced hydraulic fractures are non-planar fractures in thin inter-bedded reservoirs because of these characteristics. The flow field was divided into two regions with different flow mechanisms for multi-fractured open-hole horizontal well. A mathematical model was established for multi-fractured horizontal well in thin inter-bedded low permeability reservoirs,considering factors such as ratio of thickness of sand layers to total reservoir thickness,longitudinal heterogeneity and non-planar artificial fractures.According to the analytical solutions derived,productivity equation was presented. Numerical analysis was carried out to investigate influence of thickness ratio of sand layer,non-planar coefficient,fracture half-lengths,threshold pressure gradient and deformation coefficient. The results show that productivity considering characteristics of thin inter-bedded reservoirs is smaller than that without considering characteristics. Smaller thickness ratio of sand layer and thin inter-bed,more serious longitudinal heterogeneity and more serious non-planarity of fractures lead to smaller productivity of multi-fractured horizontal well. Productivity decreases with increasing deformation coefficient. The larger the threshold pressure gradient,the smaller productivity.更多还原