Penn West Petroleum Ltd. (Penn West), formerly Penn West Energy Trust, is a Canadian exploration and production company. Penn West is engaged in the business of acquiring, exploring, developing, exploiting and holding interests in petroleum and natural gas properties and related assets. Penn West participates in the exploration for, and the development and production of, oil and natural gas principally in western Canada. The majority of the Company's proved plus probable reserves are located in Canada in Alberta, British Columbia, Saskatchewan, Manitoba and the Northwest Territories. On January 1, 2011, Penn West completed its plan of arrangement and converted from an income trust (Penn West Energy Trust) to a conventional corporation operating under the trade name of Penn West Exploration. In December 2012, the Company closed its previously announced divestment of non-core assets.