Abstract: In the Ordovician reservoirs covered by salt formation in the south of Tahe Oil Field,the rela-tionship between oil and water is complicated.Water flows actively.Oil and gas accumulate regionally.Oil reservoir thickness and single well production are obviously different between different fractured andvuggy belts.Theoretical forward model was used to analyze the formation mechanism of stringed-beadreflection.Combined with seismic reflection studies,the relationship between reflection features andsingle well production was discussed.The principle of hydrocarbon accumulation in regions covered bysalt was also talked about.The relationship between seismic reflection features and oil-gas-water wasfound out.The complicated relationship between oil and water as well as the controlling factors werefocused on,helping to avoid water-active regions.