The Laminaria and Corallina Fields were discovered in 1994 and 1995, within permit AC/P8 in the Timor Sea, and are currently being developed using subsea wells, manifolds, flowlines and a large Floating Production, Storage and Offloading (FPSO) vessel. Expected reserves for the combined fields ranges from 130 to 250 MMbbl and production is planned to commence in October 1999, five years after field discovery. In order to achieve this, subsurface development studies have been conducted in parallel with facility concept and engineering design studies. Due to the large range of reserves associated with the two fields, leading edge technology and rigorous uncertainty management techniques have been used to produce a robust development plan. Seismic imaging in this area is particularly difficult and has been enhanced by using Prestack Depth Migration. Even so, structural mapping remains the largest factor contributing to reserves uncertainty. P. 497