Abstract:

Low-sinuosity distributary channel reservoir is an important reservoir type of Xingbei oilfield and it is of great significance to further study its reservoir architecture characteristics for the adjustment and potential tapping. Based on the data of cores, wire-line logs and production performance from close well-spacing block, the reservoir architecture of low sinuosity distributary channel in Xingbei oilfield was finely analyzed by using “hierarchy analysis and depositional pattern guidance” with two primary hierarchies which were the determination of amalgamated channels and overbank sandstone bodies and the contact relationships among solitary channels. The 3-D reservoir architecture model was then established. Based on the static data of sealed coring wells and water-cut well-logging interpretation results and the production performance data, the waterflooding features of different periods and distribution of remaining oil were analyzed. Subsequently, the distribution of remaining oil was verified by numerical reservoir simulation based on 3-D reservoir architecture model. Finally, the distribution of remaining oil controlled by the reservoir architecture was summarized and demonstrated as follows: within the channel, the remaining oil volumes are enriched in the top and edge of the channel, the lower areas controlled by mud or calcareous interbeds between individual channels and undeveloped areas just connecting with low-permeability overbank sands. Outside the channel, they are mainly in low-permeability overbank sands, end of the overbank sands and the isolated sandstone bodies with imperfect injection-production systems.

Key words: low-sinuosity distributary channel, reservoir architecture, close well-spacing, 3-D reservoir architecture model, numerical reservoir simulation, distribution of remaining oil