Melbourne-headquartered BHP has begun the approvals process for an infill development drilling campaign to boost oil production at its Pyrenees field offshore Western Australia.

The earliest possible start date for the drilling is the second quarter of 2022, but could be anytime in 2022 and 2023 based on the availability of a semi-submersible drilling rig and weather constraints, BHP said in a regulatory submission to Australian offshore petroleum regulator Nopsema.