WESTLAKE — Sasol said Tuesday that it will likely invest up to $10 billion in Calcasieu Parish to build the nation’s first gas-to-liquids plant by 2018 — a potential economic coup that Gov. Bobby Jindal said could trigger the creation of thousands of jobs.

The South African energy and chemical giant announced it would spent the next 18 months conducting a study to determine the feasibility of the proposed plant, including its size and production capabilities.

However, Jindal said he expects the company will ultimately choose to build the facility in the Lake Area and that it could become the largest economic development project in state history.

“If that analysis comes out the way they think it’s going to, if it verifies their assumptions, they will be building this project,” Jindal told reporters after joining Sasol officials to announce the study. “We’re confident they’ll build this complex right here in Calcasieu Parish.”

Sasol said the plant would create up to 850 permanent jobs. The company added that during peak periods of its five-year construction plan, the site could employ 5,500 people.

Still, Jindal said the plant’s effects could be far greater. He said state officials estimated that the complex could bring 5,000 permanent jobs to the region and have an annual economic impact of more than $900 million.

Ernst Oberholster, managing director of new business development for Sasol, said the company was excited about its plans in Louisiana.

“Louisiana has proven to be a place where research and next-generation technologies can thrive and grow,” he said. “We look forward to continuing to work with the people of Louisiana to make a long-term and sustainable contribution to the state.”

Jindal said state officials helped lure Sasol back to Louisiana with GIS mapping technology to help locate an appropriate site for the plant. State officials are developing a package of economic incentives for Sasol in exchange for the project.

One company official said that while Sasol has not made a final decision about where to build the complex, property is available at and near the company’s existing Westlake plant.

“We have some undeveloped land within our current plant fence line that is available for expansion, and we have an option to purchase more land next to our plant if needed,” Mike Thomas, president of Sasol North America, said through a spokeswoman.

The site could eventually produce up to 96,000 barrels daily of diesel, kerosene and other chemical feedstocks through a process that converts natural gas into liquids.

Sasol already runs gas-to-liquids plants in Malaysia and Qatar, with an additional site under construction in Nigeria.

Far closer to home, local leaders hailed the proposed project.

George Swift, president of the Southwest Louisiana Economic Development Alliance, said the project, the second Sasol has announced in Calcasieu Parish since December, is a significant boost.

“This one is really, truly overwhelming in its scope and what it will mean economically to Southwest Louisiana in terms of jobs and other benefits,” Swift said.

U.S. Rep. Charles Boustany, R-Lafayette, also praised Sasol’s plans.

“This is exactly the kind of job growth we need in south Louisiana,” Boustany said in a statement. “I am extremely pleased Sasol has decided to expand their company in Calcasieu Parish.”