BP PLC (BP, BP.LN) said Tuesday its first-quarter profit nearly tripled from a year earlier, as proceeds from the $27.5 billion sale of Russian joint venture TNK-BP offset falling oil and gas production.

BP said net profit almost tripled to $16.86 billion from $5.77 billion. But that figure includes $12.5 billion of profit from the sale of TNK-BP to OAO Rosneft (ROSN.RS), which closed in March. Excluding the TNK sale and other extraordinary items, BP's profit was $4.22 billion for the quarter ended March 31.

That's down 9.4% from a year earlier, but well above the average of $3.25 billion projected by nine analysts polled by Dow Jones Newswires. Even though overall oil and gas production declined, thanks to asset sales, the company benefited from new higher-margin oil projects.

The results "demonstrate the progress BP is making" in a plan to improve profit in the wake of the 2010 Gulf of Mexico oil spill, BP Chief Executive Bob Dudley said in a statement.

They also show the company's ongoing challenges. BP said it expects production to drop in the current quarter from the prior one due to maintenance-related shutdowns in the
Gulf of Mexico and North Sea and projected cost increases. Much of the unexpected first-quarter profit boost came from one-time gains.

"The first quarter is one where a number of the more variable factors all went in BP's favor," said RBC Capital Markets analyst Peter Hutton.

Factoring out gains from its gas-trading business, BP made about $15 in profit per barrel of oil or natural-gas equivalent it produced in the first quarter, said Iain Pyle, an analyst with Bernstein Research. That falls far short of Chevron Corp.'s (CVX) $28 per barrel and Exxon Mobil Corp.'s (XOM) $21 per barrel, Mr. Pyle said.

BP also did not provide guidance on whether or when it may settle ongoing litigation over the 2010 Gulf spill, an area of uncertainty that continues to weigh on the stock, Mr. Pyle said.

BP on March 21 concluded its sale of TNK-BP to OAO Rosneft for a total of $27.5 billion in cash and Rosneft shares. BP now holds a 19.75% interest in Rosneft. The gain on the sale was $15.5 billion, of which $12.5 billion was recognized in the first quarter. The rest of the proceeds will be recorded over time, BP said. The 11 days of earnings from Rosneft attributable to BP in the first quarter were estimated at $85 million.

Excluding TNK and Rosneft results, BP's total oil and gas production last quarter was 2.33 million barrels of oil equivalent per day, a 5% decrease from a year earlier due mostly to other asset sales, and slightly above analyst expectations of 2.322 million barrels.

The company announced a quarterly dividend of 9 cents a share to be paid in June. Group revenues were $107.21 billion, compared with $97.42 billion in the first quarter of 2012. Diluted earnings per share were 87.61 cents, compared with 29.97 cents the previous year.

BP said that including the TNK deal, its replacement cost profit, a figure that excludes gains or losses in the value of inventories and is therefore equivalent to the net profit figure reported by
U.S. oil companies, was $16.6 billion in the three months ended March 31, compared with $4.78 billion in the first quarter of 2012.