Both oil and gas projects are on schedule, but are "experiencing some cost pressure", the company said.
The US$600 million Stybarrow project is due on stream in the first quarter of 2008 with peak production of 80,000 barrels of oil per day.
Partners in block WA-255-P(2) are operator BHP (50%) and Woodside (50%).
BHP said two injection wells have been completed and three development wells drilled by the semi-submersible Atwood Eagle.
