This well is a replacement for the Neptune-6 (OCS-G 08038 #1) well which had to be plugged and abandoned soon after spudding due to mechanical difficulties.

The well is being drilled by the GlobalSantaFe drillship Explorer in water depth of around 1,908 metres (6,260 feet). Planned total depth is approximately 5,745 metres (18,848 feet).

Previously the Neptune-5 sidetrack 1 and sidetrack 2 appraisal wells, in the Atwater Valley Block 574, encountered a gross oil column of around 1,200ft, with more than 500ft of net oil pay.

Sidetrack 1 was drilled to a target down-structure from the original Neptune-5 location and penetrated an oil water contact which extended the gross oil column by 100ft.

Good reservoir quality sands were encountered and the well was plugged back to enable drilling of a second sidetrack.

Sidetrack 2 was drilled to an up-structure location and encountered a net oil column that the company estimates to be around 120ft. The oil recovered was of similar quality to the oil encountered in the original Neptune-5 well.

Operations are currently being conducted to abandon the well as a potential producer in the event that Neptune is shown to be commercially viable.

Woodside has a 20% working interest in the leases containing the Neptune Field and BHPB 50%.