Abstract: Tongnan area is located at a transition region from Central Sichuan to Southern Sichuan Basin.Its exploration result reveals a great hydrocarbon potential.In this area,the reservoir is characterized by heterogeneity,thin single layer,low permeability and porosity,in addition,the seismic wave velocity of the reservoir is the same as that of shale.Therefore,it is a little difficult to predict reservoir quantitatively.In this research,the geological feature and geophysical property are analyzed at first according to data of geology,seismic,well-logging and well testing;and then,the lithology is predicted by means of the natural gamma-ray inversion;thirdly,the effective reservoir is identified by both velocity and porosity inversion after wiping out the shale;finally,hydrocarbon abundance is detected by the dual-phase medium theory in order to provide a favorable prospect.In fact,the result of reservoir prediction is basically consistent with the drilling result.The research shows that the multi-well constrained inversion and the abundance detection should be adopted in clastic rocks to predict the lithological and reservoir distribution with a relatively high accuracy,which guides to a further exploration and development in Tongnan area.

Key words: Sichuan Basin, synthetic record, inversion, reservoir prediction, oil and gas detection