Da'anzai-1 submember reservoir body developed in high energy shelly limestone of shallow lake carbonate facies.Recrystallization and dissolution made the shelly limestone loose and easy to be break.Solution pores

cavities and fissures developed well in it.Two compressional movements resulted in two sets of conjugate shear fractures

and also formed retensional fissures and extensional fissures on the higher part and mutation part of the structure along the shear fractures.This thus considerably improved reservoir's physical property.It has been proved that intense amplitude and high wave impedance are important evidences for the identification of thick limestone;high mutation factor is an important parameter for distingushing porous reservoirs.This method was used to predict the distribution of porous reservoir in Da'anzai 1 submember in Baiya region of North Sichuan

the result has been proved by well drilling.