Publication Name: PESA's Eastern Australasian Basin Symposium II
Authors: N.C. Sharp and G.R. Wood
Date Published: December 2004
Number of Pages: 28
Reference Type: Book Section
Abstract:
The drilling of two wells on the Casino structure in the offshore Otway Basin, Victoria, in 2002 proved the presence of gas in two separate Cretaceous Waarre Formation sands, the Waarre A and C. Uncertainty regarding the pressure regime of the Waarre C prevented Casino being considered as a commercial gas discovery. Additional technical studies and an innovative commercial deal led to the drilling of an appraisal well on the field's northern flank in late 2003 . Casino-3, drilled in late 2003, established the pressure regime and GWC of the Waarre C and conducted a flow test. Planning for a two well, subsea development is ongoing, with first gas scheduled for the first quarter 2006.A working stratigraphic model for subdividing the Waarre reservoirs was developed by Santos during the Casino
drilling campaign. Three major sequence boundaries have controlled the present day distribution of the main Waarre Formation reservoir targets across the Mussel Platform. Palynological data has provided new insights into the Waarre stratigraphy and enabled a correlation to be established between the offshore wells and those in the onshore Port Campbell Embayment. An angular unconformity during the Late Santonian affects the preserved distribution of Waarre reservoir units across the Casino Field. The evidence from the Casino Field together with earlier records in surrounding wells supports the subdivision of the Sherbrook Group to incorporate these major sequence boundaries.