Santos has agreed to sell its entire working interest in the Evans Shoal gas field in the Bonaparte Basin offshore northern Australia for up to $US350 million ($A327 million).

Santos said it would sell its 40 per cent stake to a major international exploration and production company already operating in Australia.

It will receive a cash consideration of $US250 million on completion and a contingent future cash payment of up to $US100 million, subject to a positive final investment decision (FID) for the development of Evans Shoal and the level of proved and probable reserves at FID.

The deal is targeted to be completed by the end of 2011.

Santos is Evans Shoal’s operator. The other participants are entities of PETRONAS (25 per cent), Shell (25 per cent) and Osaka Gas (10 per cent).