川西坳陷中段丰谷—合兴场地区须家河组四段钙屑砂岩储层为典型的致密化砂岩储层。为深入了 解其致密化原因，综合大量岩心、薄片资料，并辅之以各种分析化验资料详细分析了其储层特征及物性影 响因素。研究表明：钙屑砂岩储层以细—中粒碳酸盐岩岩屑含量高为典型特征，分选性以中等—好为主， 磨圆度中等，多呈次圆—次棱角状，颗粒间以点—线接触为主，胶结方式以孔隙-接触式为主；次生孔隙是 主要的储集空间，储层物性差，属特低渗、致密储层。储层物性主要受沉积作用和成岩作用等综合影响：沉 积作用在宏观上控制着储层物性，水下分流河道是形成有利储层的主要相带；强烈的压实作用和钙质胶 结作用是导致储层致密化的重要原因，而高岭石胶结作用对储层有一定的建设性作用，溶蚀作用是使储 集物性改善的主要原因；裂缝对改善储层物性有着积极意义。

The calcarenaceous sandstone in Fenggu-Hexingchang area is typical tight sandstone reservoir. In order to find out the reasons, this paper studied the reservoir characteristics and the influencing factors of physical properties based on analyses of cores, slice and test data. The result shows that the calcarenaceous sandstone reservoir has high contents of carbonate debris, with medium-well sorting, medium psephicity, point-line contact forms and pore-contact cementation among rock grains. The calcarenaceous sandstone reservoir belongs to the lowporosity and lowpermeability reservoirs, and secondary pores are the main reservoir spaces. The reservoir properties are affected by deposition and diagenesis. The deposition dominated the reservoir properties on the macro and underwater distributary channel is the main favorable microfacie. Furthermore，the strong compaction and cementation are the main factors resulting in the low porosity and low permeability of the reservoir, while kaolinite is the main clay mineral，which has constructive effect on keeping the pore space of reservoir. The dissolution is the main factor improving the reservoir properties.