P642 IMPROVED MAPPING OF BASEMENT USING TWO TYPES OF LOG ESTIMATION PAUL DE BEUKELAAR 1 MARK BROWNE 2 BRUCE FINLAYSON 2 PETER STRAUSS 2 and PAUL TARABBIA 2 1 Solegeo Sarl Reservoir Characterization Studies 28 rue des Tartres 92500 Rueil-Malmaison France 2 Santos Ltd. Australia Introduction Picking the top of basement beneath the thick fluvial/deltaic sediments of the Cooper/Eromanga Basins in South Australia has proven to be difficult in recent years. Firstly it was important to implement a set of criteria to recognise basement lithologies on wireline logs from similar log character responses obtained for overlying sediments. Of great assistance