EOR requires detailed knowledge of permeability distribution in a reservoir. In reservoirs with a complex architecture, permeability distribution can be modelled with stochastic models which incorporate geological information such as width/thickness ratios of reservoir units and width/length ratios of shales layers. Reliable geological data can be derived frorn the reservoir itself or from analogue outcrops. This paper presents the preliminary results of an outcrop study of a turbidite channel sediment body, the Lower Ainsa Channel. The deposits are of Eocene age and outcrop near Ainsa, central Spanish Pyrenees. The sediment body is at least 375m wide, has a maximum thickness of 30m and consists mainly of interbedded conglomerate, sandstone and mudstone. Five li thofacies are recognized. Their spatial arrangement is related to rnass­transport processes. Data are presented on spatial distribution and geornetry of the sandstone and mudstone layers. A shale length distribu­tion curve is compiled from the outcrop data.