Abstract：The reservoirs in overlap zone of Songliao west slope are characteristic of shallow buried depth that generally is 300-600m and the lowest depth is 5-12m. On the basis of the conclusion studied by the predecessors that different type of reservoirs can produce relative negative gravitational anomaly,the paper studied in detail gravitational data of oil-sand mine drilled in Pu-36 well situated in Tumuji area. It is summarized that positive structural background can produce regional gravitational high and lithologic reservoir in that background also can produce local lower gravitational anomaly, which formed feature of "sag within uplift" on one-order gravitational derivative anomaly chart. The feature was predicted in the north area of Tu-9 well according to abovemen-tioned analysis, which became oil/gas-predicted zone that has been preliminarily proved by geologic, self-potential and drilling data. Afterwards, using this idea to implement similar analysis for gravitational data in adjacent Jiang-37 well area,which discovered gravitational anomaly feature of "sag within uplift" in gravitational data of Jiang-37 well area.
