白云凹陷珠海组碎屑砂岩粒度特征分析

Analysis of Particle Size Characteristics of Detrital Sandstone in Zhuhai Formation of Baiyun Sag

白云凹陷珠海组是目前深层勘探的优质目标,通过大量钻井资料、薄片资料的统计分析,对珠海组储层碎屑粒度特征进行分析研究.结果表明:(1)白云凹陷珠海组储层砂岩岩性以粉-细砂岩为主,含少量中-粗砂岩.(2)粒度纵向分布特征,凹陷珠海组储层砂岩砂地比与岩石组构具有显著差异,揭示了番禺低隆起为中粗粒砂岩的发育区,且以恩平组—珠海组五段为优势发育层位,这为有效储层的发育提供了有利条件.(3)三类砂岩粒度类型中,中粗粒砂岩的物性最好,且对储层的物性起到促进作用,同时沉积微相对储层物性也具有明显的控制作用,(水下)分流河道和河口坝为有利储集相带.

Zhuhai Formation in Baiyun Sag is the high-quality target of deep exploration at present.Through the statistical analysis of a large number of drilling data and thin section data,the particle size characteristics of reservoir clastic in Zhuhai Formation are analyzed and studied.The results show that:(1)The sandstone lithology of Zhuhai Formation in Baiyun Sag is mainly siltstone-fine sandstone,containing a small amount of medium-coarse sandstone.(2)In terms of the vertical distribution characteristics of particle size,the sand-land ratio of the reservoir sandstone of Zhuhai Formation in the depression is significantly different from that of the rock fabric.It is revealed that Panyu low uplift is the development area of medium-coarse sandstone,and the fifth member of Enping Formation–Zhuhai Formation is the dominant development horizon,which provides favorable conditions for the development of effective reservoirs.(3)Among the three types of sandstone particle size,the medium-coarse sandstone has the best physical properties,and plays a promoting role in the physical properties of the reservoir.At the same time,the sedimentary microfacies also have a significant control over the physical properties of the reservoir.(Underwater)distributary channels and mouth bars are favorable reservoir facies.