Abstract: In the areas that are characterized by intense tectonic activities and active hydrodynamic conditions, the distributive location of an oil/gas pool does not coincide with structural trap, and there is a displacement between them. In 1982, Dahlherg proposed an oil/pool exploration method of hydrodynamic trap, using the data of oil, gas and water available. The paper introduces its principles and application to Es³⁽⁵⁾ Formation in Liuzan oilfield, Nanbu depression, in which case it not only predicted the distributive location of oil pools, but gave reasonable explanation for the phenomenon of waterflushed layers.