UPDATE 2-Exxon quarterly profit falls, output tumbles

* Quarterly refining profit more than doubles

* Oil and gas production down 7.5 percent

* Shares edge lower

Nov 1 (Reuters) - Exxon Mobil Corp, the world's largest publicly traded oil company, on Thursday reported a lower quarterly profit that topped expectations, as higher margins from its refining arm countered a 7.5 decline in oil and gas output.

Refining margins have improved as companies benefit from processing cheaper grades of crude oil from Canada as well as shale basins like the Eagle Ford in south Texas.

``The (earnings) beat definitely came from the refining side of the business,'' said Brian Youngberg, energy company analyst at Edward Jones in Saint Louis. ``The production decline was more than expected. It has been a recurring challenge for Exxon.''

Earnings from Exxon's global refining business more than doubled to $3.2 billion. The company's exploration and production business had a profit of $5.97 billion, down 29 percent.

The Irving, Texas, company said its third-quarter earnings had fallen to $9.57 billion, or $2.09 per share, from $10.33 billion, or $2.13 per share, a year earlier.

Analysts on average had expected a profit of $1.95 per share, according to Thomson Reuters I/B/E/S.

Oil and gas output declined 7.5 percent to 3.96 million barrels oil equivalent per day, Exxon said.

The company and other global oil producers are buying oil and gas assets in North America as they struggle to raise production in a sector where vast energy resources are tightly controlled by countries like Brazil.

Earlier this month, Exxon agreed to buy Celtic Exploration Ltd for $2.64 billion. That deal will give Exxon access to some of the most promising shale oil and gas region in Western Canada.

The company said it had bought back 58 million shares of its own stock for $5.1 billion in the third quarter.

Shares of Exxon edged down 0.8 percent to $90.41 in premarket trading.