Aspects of source rock and reservoir potential of the Port Campbell area, Otway Basin, Victoria

Sedimentary sequences in the Port Campbell area range from the Early Cretaceous to Pliocene in age. Two major groups are distinguished in the Cretaceous sequences. The Otway Group was deposited in a braided river fluviatile environment which is unconformable overlain by the fluvio-deltaic to shallow marine sequences of the Sherbrook Group. The Tertiary sequences are divided into Wangerrip Group (paralic to deltaic and shallow marine), Nirrandra Subgroup and Heytesbury Group (both marine environments)• The present study of organic petrology gives an assessment of organic matter type and abundance, and the rank of possible petroleum source rocks in the Port Campbell area. Organic matter in the Early Cretaceous-Tertiary sequences of the area is predominantly in a dispersed form but some thin coal seams also occur in the sequence.