Portfolio acquired from Total E&P UK Ltd
The portfolio includes seven producing fields in Central North Sea, including Greater Armada, the Alba field and the Mungo and Monan cluster.
Centrica's share in these fields is estimated to amount to 22 million barrels of oil equivalent, based on estimates comprising 36 per cent gas and 64 per cent oil.
The deal will increase Centrica's overall reserves by five per cent, the company said.
Final agreement is subject to UK Government approval and other closing conditions, including various pre-emption rights linked to Totals existing joint venture partners.
The deal is expected to close around July 2012.
Mark Hanafin, managing director of Centrica Energy, said: "Today's announcement marks another step in the growth of our upstream oil and gas business.
"This acquisition in the North Sea provides a good fit with our existing portfolio and strategy,bringing strong cash flow and adding value for Centrica. It underlines our commitment to invest where we see attractive opportunities, securing future energy supplies for the UK."
Centrica announced a s13 billion,10-year deal last November with Norwegian state-owned oil and gas producer Statoil to secure gas supply for up to 3.5 million UK homes, starting in 2015.
That deal took the total value of future gas supplies secured by Centrica for the UK to more than s50billion.
In a separate deal last November,Centrica also acquired Norwegian North Sea assets from Statoil -in the Kvitebjorn field - for $1,525 million (s965 million).
Centrica said that deal would increase its overall production by around 25 per cent, or 34,000 barrels of oil per day.
The utility firm also agreed a s2billion supply deal last year with Quatargas for 2.4 million tonnes of liquefied natural gas.