Abstract: The paper is divided into 5 parts.A brief presentation about the general characteristics of Renqiu buried hills is given in the introduction.Three types of reservoir space-pores,fissures and caverns are present in the dolomitic reservoir rocks.The algal dolomites with widespread and persistent distribution,formed in the lower part of the intertidal zone and the upper part of the undertidal zone under medium to high hydrodynamic environments,are the principal reservoir rocks of the oil field,while the micritic dolomites deposited in the low energy environment are not favourable for holding oil.Factors affecting reservoir properties are lithology,recrystallization,tectonic stress,dissolution etc.Based on their geometry,the pores are classified into 4 categories: (1)dissolution cavities interconnected by faults; (2)pores with short throat; (3)grid-like pores and(4) pores with tortuous and narrow throat.Identification and rating of reservoir rocks are made on the basis of connate water saturation.A preliminary study of the heterogeneity of the reservoir rocks reveals that there exist a macroscopic pore system and a microscopic pore system in the carbonate rocks and that the algal dolomites mostly with primary porosity have excellent reservoir properties.The paper points out that in the development of the field,measures should be taken to regulate and balance production in the different parts of the pool to ensure uniform advance of the oil-water interface.