Choo Chiau Beng, head of the world’s biggest rig maker, doesn’t believe in quick returns.

Choo, who holds the top post at Singapore’s US$10 billion ($13.8 billion) Keppel Corp (KPLM.SI) had to work his way up after starting his career as a ship repair management in 1971.

As Keppel fights a slump in orders after a five-year boom that ended in 2008, the naval architect needs to steer the firm through difficult times.

Oilfield service firms face an uncertain outlook following BP’s massive oil spill that led to a halt in U.S. deepwater drilling.

Choo, also Singapore’s non-resident ambassador to Brazil, has to rely on his persuasion skills to help Keppel win big orders from the Latin American nation, where state firm Petrobras (PETR4.SA) wants to buy 28 rigs in the five years to 2018. The total order value is estimated at around US$20 billion.

Analysts said the 62-year old, who began his career with Keppel Group and is an avid art lover, must diversify the business, which is highly dependent on the offshore oil sector.

“Everyone will watch the Petrobras situation closely. That is an important agenda for the CEO,” said Kwok Chern Yeh, fund manager at Aberdeen Asset Management, which owns Keppel shares.

“Obviously there are other challenges such as the Gulf of Mexico spill, but from the company’s orderbook stand point Petrobras is a bigger issue at this point.”

Keppel, 21% owned by Singapore’s state investor Temasek Holdings, received $1.7 billion in new offshore and marine contracts last year. At the end of the first quarter, Keppel had new orders worth $1.6 billion and on Wednesday, it won an order valued at $170 million.

Last year, around half of the total orders came from Brazil related projects and the rest from Europe, Asia and other places.

The UK-educated Choo, took home as much as $11.75 million last year, earning more than Singapore’s top bank CEOs and making him one of the top paid CEOs in the city-state.

Choo pleased investors when he oversaw the sale of Keppel’s 45.5% stake in Singapore Petroleum Company to PetroChina (601857.SS) for $1.47 billion in 2009, a move that helped streamline Keppel’s portfolio.

But in the space of five quarters since Choo took office, Keppel’s order book has dropped by nearly half to $5.8 billion.

BP’s accident in the Gulf of Mexico prompted the US government to impose a moratorium on deepwater drilling and Keppel’s shares have since fallen in an industry wide selloff.

Choo, who also studied at Harvard Business School in 1982, has taken steps to diversify Keppel’s business into new areas such as wind farming and environmental engineering, while reducing reliance on the oil business.

“The environment has got a lot more competitive and the pricing is getting tighter, so they have to try to maintain the level of profitability and expanding to other businesses such as infrastructure,” said Kim Eng Securities’ analyst Rohan Suppiah.

Despite the turbulent times, Keppel posted a record profit of $1.27 billion in 2009 on a 4% rise in revenue to $12.2 billion.

In a recent interview with the Straits Times, Choo reiterated a robust outlook for the offshore marine business.

“We saw the opportunities in the future, we have the expertise and when there is upturn, we can hit the ground running,” Choo told the paper.

“If I was trained purely as a financial man. I could have sold Keppel FELS (offshore marine unit) and the shipyard business for a quick return.”