Abstract:

The secondary pores and fractures constitute the major storage space and percolation path in muddy gravels in Kulongshan oilfield, Jiuquan Basin. A comprehensive evaluation on categories, types, scales, the attribute of parameters and formation mechanism shows that the secondary pores and corrosion fractures increase the permeability of reservoir, and the reservoir porosity. The nonhomogeneity of diagenesis and tectogenesis make the characteristic of physical property different obviously. The different parts of turbidities fan and the change of gravel size from a facies analysis are the main factors controlling the types and combinations of pores and fractures. The chief principle of improving the reservoir quality in the diagenetic stage is corrosion, including the mutual replacement and dissolution in muddy gravel, unstable debris particles of different (optional) solution. The structural evolution of reservoir indicates that the NW-striking reverse fault, which was formed by Himalayan orogenics, controls the formation of reservoir noticeably, and NE-striking adjustment fault leads to a different growth in fracture system.

Key words:

muddy gravel; reservoir feature and genesis; diagenesis; selective corrosion; Jiuquan basin

摘要：

酒泉盆地青西油田泥砾岩储层中发育的次生孔隙和裂缝系统构成了油藏主要储集空间和渗流通道。储层综合评价及成因分析表明，泥砾岩储层中的次生溶孔和裂缝不但对储层储集性能有较大程度的改善，而且显著改善了储层渗流能力。成岩及构造作用的不均性使得储层物性特征差异悬殊。浊积扇砾石成分和粒径的变化是控制储层孔缝类型及其组合的主要因素。自生胶结物的溶蚀、交代以及碎屑颗粒的差异（选择性）溶蚀是提高储层物性的主要成岩作用。喜山构造作用形成的北西向逆断层对油气成藏控制作用明显，北东向调节断层进一步造成裂缝系统差异性发育。

关键词: 泥砾岩；储层特征；成岩作用；选择性（差异）溶蚀；酒泉盆地