Abstract:

Block Zhao 35 is a newly developed area of Songfangtun oilfield in Daqing, in which the main target horizon is Putaohua reservoir. According to various geological data and sedimentary facies analysis, it is recognized that delta front and shallow lake are main depositional facies in the study area, which are further divided into underwater distributary channel, mouth bar, sheet sand, interdistributary bay and shallow lake mudstone. A logging facies template was established. Mouth bar developed well in upper of Putaohua reservoir，and in which Layer PI2 was the main oil layer. Underwater distributary channel developed well in lower of Putaohua reservoir, and in which Layers PI51, PI52 and PI7 were the main oil layers. The deposits in the study area mainly came from northwest and north, and the sand body is thicker in the northwest than in the southeast. Underwater distributary channel was branched, and characterized by excellent connectivity along the channel direction. Sheet sand was thin and continually developed around the channel. Mouth bar distributed as lens at the end of the channel. Based on comprehensive study, three types of favorable facies zones were divided. TypeⅠis the underwater distributary channel which was distributed large in the study area; Type Ⅱis the mouth bar which was small and dispersed, Type Ⅲis sheet sand which only developed in south of the study area.

Key words: sedimentary micro-facies, favorable facies zone, Putaohua reservoir, Block Zhao 35