This paper describes the delimitation of oil reservoirs by induced polari-zation method in oil-bearing structures or fault blocks so far discovered in theDagang oil field for the purpose of directing the arrangement of oil wells;italso discusses the judgement of new oil-bearing horizons in demonstrated orexploited oil fields on the basis of sizes and values of anomalies and the geo-logic effectiveness of looking for oil-gas accumulation sectors in unknown areas.Of the 12 drilling holes expected to intersect oil-bearing horizon, 8 prove tobe correctly judged.IPlogging and sulfur analysis of heavy sand samples were performed wi-thin the depth of 0-1,000 m in20 wells in order to determine whether oil-bearing beds are present at depth, and it turns out that 13 of them are corre-ctly judged.