Schlumberger Ltd. (NYSE: SLB) CFO Simon Ayat plans to retire this year and a company insider has emerged as the top candidate to replace him at the world's largest oil services firm, three people familiar with the matter told Reuters.

Stephane Biguet, currently vice president of finance, is the frontrunner to replace Ayat, according to the people who declined to be named because the matter is not yet public.

Schlumberger declined to comment.

The CFO change would come as rising oil prices and dwindling producer reserves are helping lift demand for oil services, which were hit hard by the 2014 oil price crash.

Schlumberger executives have said oil companies will have to increase spending to overcome declining output from existing fields and meet future demand.

Ayat's successor will face pressure from investors concerned about past investments by the company's Schlumberger Production Management, or SPM business, which takes direct stakes in oil projects.

"It's something that investors don't like. You buy Schlumberger because it is an oil services company, not a producer," said Cowen & Co. analyst Marc Bianchi. The new CFO would have to continue selling assets from the unit, Bianchi said.

Last year, Schlumberger launched a reorganization to simplify its business structure. The company also has said it was slowing investments in the SPM business.

Schlumberger shares were off 1.3% at $67.20 on July 16, and are down about 16% over the last two years.

Improving Schlumberger's share price will hinge on exceeding revenue and profit expectations, Bianchi said. "They just need to start beating some quarters."

Schlumberger reports second-quarter results on July 20. Revenues should move higher and the company should have a solid second half of 2018, James West, a senior managing director for Evercore ISI, wrote in a note on July 16.

Biguet previously held positions as Schlumberger's treasurer and as controller of operations, according to its financial filings. He has worked at Schlumberger since 1995 with roles in Venezuela, Canada and France before taking on his current position in December 2017, according to his LinkedIn profile.

Biguet "is very skilled in managing the organization," said one person familiar with proposed changes. "Now, he needs to manage the Street."

Ayat started at Schlumberger in 1982, serving in several roles, including treasurer before becoming CFO in 2007. As of January 2018, he was 63 years old, according to a regulatory filing. The company declined to confirm his age.