U.S., Sept. 28 -- Devon Energy and WPX Energy have entered into an all-stock merger which would result in a $12 billion enterprise and create one of the largest unconventional producers in the US with production of 277,000 barrels per day.

The combined company, to be named Devon Energy, will benefit from enhanced scale, improved margins, higher free cash flow and the financial strength to accelerate the return of cash to shareholders through an industry-first "fixed plus variable" dividend strategy, according to a statement.

Upon completion of the transaction, Devon shareholders will own approximately 57 percent of the combined company and WPX shareholders will own approximately 43 percent of the combined company on a fully diluted basi...