鄂尔多斯盆地富县地区马家沟组沉积了一套以蒸发潮坪相为主的白云岩、含膏云岩等碳酸盐岩沉积物。利用宏观岩心、微观常规薄片、铸体薄片、X-射线衍射、氧碳同位素等资料，并结合物性资料，系统研究了富县地区马五段碳酸盐岩的成岩作用类型和成岩环境。结果表明：马五段碳酸盐岩在成岩过程中经历了海水、混合水和大气淡水成岩环境；成岩作用复杂多样，其中溶蚀作用和回流渗透白云石化作用对储层孔隙发育有利，各种矿物的充填作用、去白云石化作用、去膏化作用和压实-压溶作用对储层孔隙发育不利。

The Majiagou Formation in Fuxian area, Ordos Basin mainly deposited evaporation and tidal flat carbonate consisting of dolomites and gypsum-dolomite. The core observation, conventional thin section and casting thin section, X diffraction, carbon and oxygen isotope analysis combining with reservoir properties are used to study the carbonate diagenesis types and diagenetic environment of the fifth member ofMajiagou Formation in Fuxian area. The result shows that the carbonate rocks of the fifth member ofMajiagou Formation experienced the diagenetic environment of sea water, mixed water and fresh water. Dissolution and reflux dolomitization are constructive to the reservoir pore development, while mineral filling, dedolomitization and compaction-pressure solution are destructive.