Abstract:

Sand-gravel rock body in Yanjia oilfield of Dongying sag is a kind of nearshore sub-sea apron deposit with characteristics of close source, quick accumulation, heavy thickness and rapid lateral variation. The technology for correct division and comparison of the strata was inadequate and immature in the past, the subdivision and comparison of the inside of the thick sand-gravel rock body is a difficulty for oil geologic research of such reservoirs. According to sedimentary characteristics of sand-gravel rock body of Yan 22 block in Yanjia oilfield, firstly, sand-gravel rock intervals and mudstone intervals are subdivided by logs reconstruction method, which can get rid of the sharp nonreservoirs. Secondly, lithologic constituent of sand-gravel rock intervals is identified by cluster analysis method. Compared with core and FMI, the match rate of the results of reconstructive logs and cluster analysis is 96.6% and 96.2% respectively, which provides a geologic foundation for the subdivision and comparison of such reservoirs.

Key words: Dongying sag, Yanjia oilfield, sand-gravel rock body, logs reconstruction, cluster analysis, lithologic identification, stratigraphic division