Abstract: Chang8¹ reservoir in Binchang block is one of the main targets for petroleum exploration and development at the southern margin of the Ordos Basin.Because of the strong reflector resulted from the Zhangjiatan shale at the bottom of the overlying Chang 7³ and the small thickness of the Chang8¹ reservoir, non-uniqueness exists when performing reservoir prediction by using conventional seismic data.On the basis of comparison and analysis of velocity and reflection intensity of the Zhangjiatan shale and the Chang8¹ reservoir and their combination patterns, reservoir prediction based on the 90 degree phase rotation technology of 3D seismic attribute is put forward for Chang8¹ reservoir in Binchang block.The main events of seismic reflection are well correlated with geological reservoirs by using the 90 degree phase rotation technology, so as to make the seismic phase having lithologic stratigraphic significance.Reservoir prediction was performed on the basis of the forward modeling, reflection structure comparison and multiple-window attribute optimization.It is believed that the reflection intensity and amplitude attribute within a certain time window under the 90 degree phase rotation can be used to more effectively predict Chang8¹ reservoir.

Key words: 90°, phase rotation, thin sand layer, reservoir prediction, Binchang block, Ordos Basin