缝洞性碳酸盐岩油藏储渗模式及其开采特征

Storage-percolation modes and production performance of the karst reservoirs in Tahe Oilfield

塔里木盆地塔河油田的下奥陶统缝洞性碳酸盐岩储集层中的次生裂缝或溶蚀孔洞是其主要储集空间和渗流通道。为更好地认识此类油藏的开采特征,根据储集体内缝洞之间的组合关系,提出了6种储渗模式。从缝洞性储集体的类型角度分析油井的开采特征,结果表明:钻遇裂缝溶洞型储集体的油井一般见水前高产稳产,见水后递减幅度最大;钻遇溶洞裂缝型储集体的油井产量中等,见水后产量递减幅度较小;钻遇裂缝基质型储集体的油井对开发贡献很小。结合油井开采特征,用统计方法预测了储集体的平面分布,与储集层建模结果对比,二者的相关性较好。

The secondary fractures and solution cavities are the main storage spaces and percolation paths of the Lower Ordovician karst reservoir in Tahe Oilfield, Tarim Basin. Six storage-percolation modes are developed to better understand the producing performance of the reservoirs according to the combination of the fractures and solution cavities. The performance indicates the producers encountered the fracture-cavity reservoir yield high and stable production before water breakthrough but the output will sharply decline after water breakthrough, the producers encountered the cavity-fracture reservoir have a medium production rate before water breakthrough and a relatively low production decline rate after water breakthrough, the producers encountered the fracture-matrix reservoir may contribute little to development of the oil field.