EPP 24 covering an area of 134 graticular blocks (approximately 8980 square km) in the northern offshore Otway Basin of South Australia was granted to a consortium comprising Cultus Petroleum NL (55%) and SAGASCO Resources Ltd (45%) for six years from 25/1/89, with Cultus as operator. The guaranteed minimum work programme proposed for the first three years involved 1100 km of seismic surveying, substantial reprocessing of older seismic data and a thorough data review, for an estimated expenditure of $1.7 million. In the second half of the permit term, the consortium planned to undertake a continuing work programme of 300 km of seismic surveying, 2 wells and a review of the data obtained, for an estimated expenditure of $13.93 million. During early 1990 Cultus diluted its stake in the permit by minor interest farmouts to Drakar Holdings Pty Ltd and Fay Richwhite Australia Ltd, then in late 1990 transferred operatorship to BHP Petroleum Pty Ltd who farmed in to a 60% interest proportionately divested by Cultus and SAGASCO. In August 1991 BHP Petroleum withdrew from the farmout arrangement, and Cultus resumed operatorship, then in December 1991 that company negotiated with SAGASCO to reduce its exposure to the upcoming permit Year 4 drilling commitment, such that SAGASCO became the major permittee and therefore operator. Finally, in January 1992 BHP Petroleum re-entered the permit consortium to take charge of drilling its preferred Year 4 well, resuming a 60% interest that has remained unchanged to the present time. Exploration activities carried out by the EPP 24 consortium up until February 1993 include the following: - reprocessing of over 2000 line km of Chevron's ex-EPP 22 1985 and 1986 seismic data, to identify and rank prospective features on the Crayfish Platform; - acquisition and processing of the semi-detailed and detailed 1990 Rhonda 'C' Seismic Survey of 701.675 line km on 30 lines during 27 July - 3 August, to delineate existing leads and prospects in the vicinity of Trumpet 1 and Chama 1a; - acquisition, processing and interpretation of the detailed 1991 Otway OH91 Seismc Survey of 405.849 line km on 17 lines during 3-6 May, to define a drilling location for the Year 4 commitment well; - preparation of rigorous Environmental Management and Oil Spill Contingency Plans for the permit area, to accompany the technical application to drill the Year 4 well on the Troas Prospect; - acquisition, processing and interpretation of the 1992 Troas Site Survey on a tight grid of 33 lines above the Troas Prospect during 9-19 May, to search for seafloor and shallow sub-seabed section drilling and anchoring hazards, including possible shallow gas pockets; - completion of a comprehensive EPP 24 Seismic Interpretation Report embracing all exploration seismic data acquired to date; and - drilling of the Troas 1/ST1 wildcat well to 3507 metres KB total depth during the period 17/11/92 - 16/1/93. This well made a non-commercial gas discovery, the first significant petroleum occurrence in the SA offshore Otway Basin, within multiple thin pre-rift sandstone reservoirs of the Crayfish Sub-group lying below 2350 metres depth KB. RFT pressure analyses and fluid sample recoveries suggest that most of the gas sands may be laterally discontinuous, and contain only limited volumes of relatively dry gas. Consequently the well was plugged and abandoned on economic grounds, but evaluation of the source of the gas and the discovery's significance is ongoing via detailed drilling post-mortem studies in petroleum geochemistry, palynology and petrology of numerous sidewall cores taken for the purpose.