Valero Energy Corp. is expected to have 3.3 million barrels of crude oil per day in a deal that will make the company the biggest crude-oil refiner in North America.

The company agreed to buy refiner Premcor for about $8 billion in an attempt to get the first place in refinery for North America overrunning its closest rival Exxon Mobile Corp.

"This transaction is one of the largest and most strategic acquisitions in Valero’s history. We are acquiring several very strategic refineries for significantly less than their combined replacement value, and we’ll be improving the profitability of these plants by capturing synergies, improving their reliability and yields, and increasing their capacities." according to Valero chairman and chief executive officer Bill Greehey.

Under the terms, Premcor’s shareholders will get either 0.99 share of Valero common stock, or $72.76 in cash for each Premcor share. The price give a 20% premium for the recent 30-day trading range of Premcor’s stock price.

The acquisition will make the company the biggest refiner for North America with 13% of the US market for refined products.