To date, Devon has repurchased 144 million shares or nearly 30% outstanding shares at a total cost of $4.8 billion. (Read more Devon to Exit Barnett, Transforms to US Oil-Focused Company ) 3. ExxonMobil ( XOM - Free Report ) recently announced the commencement of production from the deepwater Liza field, located offshore Guyana in the Stabroek Block, well ahead of schedule. Following its first discovery of oil and gas, the company brought the field online in less than five years.