Celtic Exploration Ltd. says it has Ottawa's approval to be taken over by Houston energy heavyweight ExxonMobil Corp. for $3.1 billion.

The approval under the Investment Canada Act means that no further regulatory approvals are required.

The deal, announced last October, will see Exxon add lucrative natural gas liquids to its portfolio through the control of about 221,000 hectares in the Montney formation in B.C. and Alberta and 42,000 hectares in the emerging Duvernay shale in Alberta.

The deal is expected to be completed Feb. 26.

Imperial Oil Ltd., which is about 70 per cent owned by ExxonMobil, said in November it would exercise its option to invest $1.55 billion for a 50 per cent stake in Celtic.

Separately, Imperial and ExxonMobil have discussed building a liquefied natural gas export facility on Canada's West Coast to enable the fuel to reach more lucrative Asian markets.