Abstract: Gaotaizi area has been a major target of Changyuan tectonic zone to submit reserves in recent years. Fuyu oil layer was dominated by terrigenous fluvial faces and delta at sedimentary stage. It has thin sandstone (less than 5m in general) and small sand bodies (300m~600m), which is far lower than the seismic limiting resolution. So it is difficult to identify river sand bodies. To solve the problem, taking accurate seismic identification of river sand bodies in the oil layer as the objective, a technique and procedure for seismic reservoir predicting is developed, which is based on high resolution of relative preservation of amplitude and waveform features and employs such means as the optimal stack identification of sand bodies, the prestack AVO prediction of effective reservoirs, and the inspection of oil layer by prestack elastic parameter inversion. It has been applied well in work area, and meandering river point bar sand bodies are described clearly, laying solid basis for the discovery of thin-bed lithologic oil and gas reservoirs in the area. There are 18 recommendation wells in total, all of which have obtained good oil and gas shows. 10 wells have been drilled and completed, 9 have been tested, 7 have got commercial oil, and 2 have produced less oil. Wildcat success rate reaches 77.8%, 1.78 times higher than the 43.9% before the research is conducted.

Key words: Changyuan tectonic zone, low porosity and low permeability reservoir, preservation of amplitude and wave form, AVO attribute, elastic parameter inversion