Purpose of study The initial findings of the chronostratigraphic studies undertaken near and within the PEL 115 permit were reported to the PEL 115 SA Cooper Basin Joint Venture at the JV Meeting held in Adelaide on 18th August, 2004. At the time of that meeting there was work in progress and in particular some key well data was missing. This well data, principally wells in the Bagundi Trough and the Dullingari-Burke High, has now been incorporated. Accordingly the interpretational maps have been amended. This report consolidates the results of the chronostratigraphic work. Cooper Basin exploration is now entering a mature phase of stratigraphic target definition, discovery & exploitation. The remaining undrilled structural closures are small and provide little upside unless there is the chance of multiple stacked reservoirs. The remaining prospectivity and upside within the Cooper Basin presides in the definition and discovery of stratigraphic plays. The Patchawarra Formation provides the bulk of these stratigraphic opportunities as it is the dominant Permian depositional unit both in thickness of sediments accumulated and in time duration of accumulation (refer Figure 2). Further it is the dominant source of hydrocarbon generation within the basin. As an auto-generative unit it therefore naturally provides abundant stratigraphic trap opportunities which involve only short path migration. It is therefore imperative that a workable Patchawarra stratigraphic framework be established in order to define and interpret the stratigraphic play potential of the permit. The Operator needs to establish the stratigraphic framework early in the exploration phase in order to avoid any mis-interpretations or potential “myopic vision”. Once established, the regional framework can be applied to the individual drilling prospects. The work has already contributed to the Hornet 1 Proposal to Drill and the development of the Airacobra-Canberra Stratigraphic play.