Chevron Corp.'s proposed $33-billion deal for Anadarko Petroleum Corp vaults the company into top ranks of the world's biggest oil companies and cements its chief executive, Mike Wirth, as a dealmaker.

The merger, the sixth largest energy acquisition by value, propels Chevron two spots to the second-largest major by oil output, behind Exxon Mobil Corp., according to research firms Drillinginfo and Wood Mackenzie.

The deal announced on April 12 comes less than three months after Wirth bought Pasadena Refining System Inc., the (PRSI) operator of a Texas oil refinery.

"My aspirations are for the company to be a strong performer," Wirth said in an interview on April 12. "We have always said and will still say that anything we do would have to make us even stronger."

Wirth, 58, took over as chief executive 14 months ago, with a reputation for keen attention to costs earned from running Chevron's pipeline and trading units, and nearly a decade in charge of its refining business.

The Anadarko deal was negotiated over the last few weeks, though Chevron has been thinking about the deal for some time, Wirth, a chemical engineer by training, said.

Chevron regularly evaluates potential deals and has a number of companies "that we’re watching," said Wirth. But completing the latest purchase is now his priority. "Executing it well is important, so that will be our focus," said Wirth.

The Chevron executive is detailed-oriented and a relentless worker, said Mike Sommers, president of industry group American Petroleum Institute, where Wirth is a member of the executive committee. After a recent dinner concluded at 10 p.m., Wirth headed off to make calls to staff overseas, Sommers said.

"He is not someone who enters into every conversation but when he engages on an issue, he has a way of bringing the room together," said Sommers.

His agreement with Anadarko marks the company's biggest expansion since its acquisition of Texaco in 2000. The purchase makes Chevron the top producer in the Permian Basin, the largest U.S. shale field. It also expands its oil and gas operations in the Gulf of Mexico and in liquefied natural gas.

"It wasn't that long ago you wouldn't have heard the word 'Permian' in anything from Chevron," said Rob Thummel, portfolio manager at energy investment firm Tortoise Capital.

Chevron's $350 million deal for PRSI, a Gulf Coast refinery business owned by Brazil's Petrobras, fits its Permian expansion. The unit will turn West Texas crude into gasoline and fuels for its retailing network.