British energy firm BG Group on Thursday said it along with its partners state-owned Oil and Natural Gas Corp and Reliance Industries Ltd will invest $140 million in Panna oil and gas fields, offshore Mumbai, to target new reserves and expand current production.

The development plan comprises construction and installation of two new wellhead platforms and associated infield pipelines to connect to the existing processing and compression platform. The drilling schedule, to begin in the second quarter of 2005, includes six horizontal wells from one platform and five horizontal wells from the other.

"Implementation of the expansion programme is expected to result in gross incremental recovery of 18 million barrels of oil and 74 billion cubic feet of gas. First production is expected in the third quarter of 2005," a company press release said in New Delhi.

BG holds 30 per cent stake in Panna-Mukta oil and gas and Tapti gas fields in the Arabian sea while ONGC has 40 per cent and the remaining is with RIL.

BG India CEO Nigel Shaw said, "BG India and partners are proceeding with investment plans to target undeveloped areas of the Panna field."

The two platforms are being designed to allow future infill drilling to maximise the field's full potential.