Shale oil and gas are now a priority for Total SA (TOT) as it seeks to boost its reserves, Chief Executive Christophe de Margerie said Wednesday.

Less conventional resources like shale oil and gas are an option for international majors like Total as they fight for access to reserves even as national oil companies shore up their domination of much of the world's conventional reserves.

-By Adam Mitchell, Dow Jones Newswires, +33 1 40171756; adam.mitchell@dowjones.com