ExxonMobil won government approval Feb. 20 to acquire an unconventional Canadian exploration company for C$3 billion, giving it 650,000 net acres in the Montney and Duvernay shales.

Exxon’s interest in Calgary-based Celtic Exploration Ltd. stretches back nearly a year to Feb. 23, 2012, when Exxon first explored working with Celtic. Those discussions ultimately evolved into the takeover bid, which is expected to be completed by Feb. 26.

For Exxon, the acquisition adds significant liquids-rich resources to its North American unconventional portfolio, Andrew Barry, president of ExxonMobil Canada, said in October. ...