Three carbonate reservoir intervals are found in the Ordovician in south Tahe: the Lower-Middle Ordovician Yingshan Formation

the Middle Ordovician Yijianfang Formation

and the Upper Ordovician Lianglitage Formation.The Yijianfang Formation is the main pay zone in the reservoir in south Tahe

and the Yingshan Formation is mainly aqueous layer

while the Lianglitage Formation is seldom tested due to its unfavorable physical properties.The spectral analysis based on wavelet transform mainly reflects various frequency parameters and energy parameters of frequency domain in relation to formation liquid.In view of the depositional characteristics of reservoirs in the study area

different oil and gas prediction technologies are studied.The oil-gas-water distribution characteristics of the Yijianfang and Yingshan formations can be well described by using the attenuation gradient attribute of high frequency absorption-attenuation

while oil & gas distribution of the Lianglitage Formation can be well predicted by using the frequency attribution parameter that relates to 85% of high frequency energy.The attenuation gradient attribute technology is employed to detect oil and gas in over 70 wells.The prediction results show that it can effectively recognize dry layer and differentiate hydrocarbon layers from water layers with coincidence rate as high as 70%.