AIM: The principal objective of the OC81 Seismic Survey and a calculated, normal moveout velocity-based seismic reflection time stratigraphic well tie to North Renmark 1 was to determine the areal extent of the prospective Permian (and Devonian?) section found within the Renmark Trough, looking in a northwesterly direction across the Hamley Fault Zone onto the Canegrass Lobe. The primary objective of the OC83 Seismic Survey was to better define hydrocarbon plays along the western flank of the Renmark Trough. A loose 3 km x 4 km seismic grid was located over a small gravity low located to the immediate southwest of the previous OC81 Seismic Survey. This gravity low was predicted to indicate a small sedimentary re-entrant (post-Permian?) within the Canegrass Lobe.METHODS:OC81 - Survey dates: 1 December 1981 - 11 January 1982. Energy source: explosives. CDP coverage: 600%. Recording mode: 48 channel digital - Sercel 338HR recorder. SP interval: 160.0m; group interval: 40.0m.OC83 - Survey dates: 18 January - 11 February 1983. Energy source: explosives (Geoflex). CDP coverage: 600%. Recording mode: 96 channel digital - ? recorder. SP interval: 200.0m; group interval: 25.0m.The OC81 spread (9 lines totalling 129 line km) was recorded by WOWCO Exploration Services Pty Ltd (Party 1) and processed in Sydney by Seismic Data Processors (International) Pty Ltd (SDP), with the subsequent survey interpretation input including, from the same acquisition area, portions of 3 re-interpreted lines of poor quality analogue data from the 1965 Renmark Seismic Survey. The OC83 spread (12 lines totalling 128 line km) was recorded by South Eastern Exploration Pty Ltd and also processed in Sydney by SDP.RESULTS: The OC81 survey has better defined the stratigraphy and structure of the southeastern flank of the Canegrass Lobe. Seismic stratigraphic correlations from a synthetic velocity tie with the North Renmark 1 well indicate that the prospective Permian and Devonian(?) sedimentary sequence is unlikely to be present in the Canegrass Lobe to the north of line OC81-09. Several high and low-side structures are recognised adjacent to the Hamley Fault Zone, but are small and of uncertain closure, and are therefore regarded as high risk drilling targets. Following on from this, the OC83 survey refined the structural model for the southern Canegrass Lobe and the overlying western truncation edge of what is interpreted to be Permian strata. It successfully identified a basement re-entrant in the CanegrassLobe with a maximum thickness of approximately 1100 metres of what are interpreted to be Permian(?), Cretaceous and Tertiary sediments. Three structural leads are recognised within this re-entrant, varying in areal extent from 2 to 8 km 2 and 10 to 20 milliseconds relief (50 to 100 feet), and in age from Permian(?) to Cretaceous. Potential also exists for stratigraphic pinchout plays of the basal Permian(?) section onto old basement high blocks.