DISTRIBUTION PATTERN OF FLUVIAL RESERVOIRS IN QINHUANGDAO A OIL FIELD

The Qinhuangdao A Oil Field located in the center of Bohai Bay, is an oil field with the Minghuazhen Formation as the main reservoir. The lower member of the Minghuazhen Formation is dominated by a meandering river system. The deposits of the system are strongly heterogeneous, that may cause uneven water displacement. This paper systematically analyzed the texture of the sand body Ⅲ2 and ifs distribution pattern with the data from 40 wells and the 3-D seismic data covering the whole oilfield. Deposits of two point bars have been recognized so far, of which each consists of 4~5 single bars. The fine deposits between point bars make the reservoirs strongly heterogeneous and dominates the distribution of remaining oil. According to the latest production performance, there is close relationship between the injection water flow and the distribution pattern of sediments. The one-way flow of injected water and the low productivity of some wells are probably caused by the heterogeneity of the fluvial deposits.