July 30 (Bloomberg) -- Exxon Mobil Corp., the biggest U.S. oil company, may fail to meet its 2009 production target after output slid to the lowest for any second quarter since Exxon Corp. bought Mobil Corp. in 1999, Barclays Capital Inc. said.

Meeting Chief Executive Officer Rex Tillerson’s target of 2 percent growth in oil and natural-gas production will require Exxon Mobil to boost output by the equivalent of 390,000 barrels of crude a day in this year’s second half. That exceeds the output of Alaska’s Prudhoe Bay, the biggest U.S. oil field.

“I have some suspicion about whether they can do this,” Paul Cheng, an analyst at Barclay’s Capital in New York, said today in a telephone interview. “I’m not a big believer that they can do this.”

The company plans to accelerate its crude and natural-gas production during the third and fourth quarters as new projects come online, David Rosenthal, an Exxon Mobil spokesman, said today during a conference call with investors. Rosenthal didn’t change the company’s forecast for full-year production equivalent of 4 million barrels of oil a day.

Rosenthal’s comments came after Irving, Texas-based Exxon Mobil reported its lowest quarterly profit in more than five years. Second-quarter production fell 3.3 percent to the equivalent of 3.68 million barrels of oil a day.

Qatar, Norway

Four of the company’s nine major 2009 projects have already started production, Rosenthal said. Others expected to begin output later this year include liquefied natural-gas developments in Qatar and an oil project in the Norwegian sector of the North Sea.

Jason Gammel, an analyst at Macquarie Securities USA Inc., said in a note to clients that lower-than-expected second- quarter output probably will limit full-year growth to 1 percent, “significantly lagging the peer group.”

Gammel lowered his rating on Exxon Mobil to neutral from outperform and reduced his full-year profit estimates for this year and 2010 by 16 percent and 1.9 percent, respectively.

Exxon Mobil fell 71 cents, or 1 percent, to $70.72 in New York Stock Exchange composite trading. The shares have fallen 11 percent this year.

To contact the reporter on this story: Joe Carroll in Houston at jcarroll8@bloomberg.net.

Last Updated: July 30, 2009 16:08 EDT