The distribution of weathering crust karst reservoirs of the Sinian Dengying Formation in Sichuan Basin is mainly controlled by palaeo-highlands and palaeo-slopes of unconformity produced by the Tongwan Movement.Based on the interpretation of the cross-basin seismic profile and drilling data

this paper restored the palaeogeomorphology of Tongwan unconformity by using printing method.The palaeogeomorphology features in a framework consisting of the northwes-tern high

central slope and southeastern sag.Outcrop

drilling and seismic data were integrated to study the development characteristics of the solution cavities and pores and predict favorable karst reservoirs in the Dengying Formation.It is concluded that solution cavities and pores are well developed in the karst weathering crust with three widely distributed karst belts.The karst is thick in the west and thin in the west.The favorable and fair karst belts occur on the palaeo-karst slopes

such as Zigong-Guangan-Daxian-Tongjiang.And the local karst belts occur on the palaeo-karst high and in the palaeo-karst sag

such as Chengdu-Ziyang

Mingyang-Guangyuan as well as the south-eastern part of Sichuan Basin.