During farm-in discussions with Oil Co. of Australia relating to PEL 27, the PEL 62 joint venture partners viewed OCA's recent seismic mapping of the Killanoola oil discovery area, extending into adjoining PEL 62. They discovered a discrepancy between the results of Lakes' current structural mapping and those of OCA, hinging around the interpreted orientation and extent of major faults, as well as the inferred northern limit of the Cretaceous Sawpit Sandstone oil reservoir target. Naturally, they regarded the prompt resolution of this subsurface mapping disparity to be critically important to selecting the optimum location for their soon-to-be drilled PEL 62 licence Year 5 commitment well on the Porthos structure. Accordingly, they commissioned a consultant to undertake re-mapping of the SEG-Y digital format, relevant 2-D seismic data, using geophysical modelling software on a seismic workstation. The new work has essentially confirmed the spatial validity of the initial seismic mapping done for Lakes, and so it has been decided to drill the Porthos 1 well at the originally proposed location, V.P. 305 on line OHL86-110.