任丘古潜山油田碳酸盐岩储层研究

前言任丘潜山带高产油气藏由四个走向北东的古潜山高点组成,自北而南呈雁行式斜列,其西侧被大断层切割,坡度较陡,东坡较缓。据钻探揭示,有两大套沉积建造,上为新生界第三系陆相碎屑岩沉积,厚约3000米;下为古生界和震旦亚界海相碳酸盐岩为主的沉积,厚3000余米。

A STUDY ON THE CARBONATE RESERVOIR ROCKS OF RENQIU BURIED-HILL OILFIELD

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.