Abstract:

According to the characteristics of the unconformity and depositional conversion surface, the oil layers of Tongbomiao and Nantun Formations in the Sudeerte Oil Field are divided into three longterm base level cycles and thirteen mediumterm base level cycles, and the main oil formationsⅠand Ⅱ are further divided into twenty six shortterm base level cycles (layers). The oil formations are well corresponding to the mediumterm cycles. In the framework of the multigrade base level cycles, the reservoir heterogeneity characteristics show obvious regularity: the structural patterns of different shortterm cycles determine the four modes of intralayer physical property changes; the medium cycles and their positions control the interlayer reservoir heterogeneity and the plane reservoir heterogeneity; and in the early period of the base level rise, in the late period of the base level fall and in the lowest position of the base level, the sandstone monolayer has large thickness, good continuity and good reservoir physical properties; in the period of high base level, the sandstone reservoir condition is poor.

Key words: base level cycle, reservoir heterogeneity, Sudeerte Oil Field, Hailar Basin