American oil giant ExxonMobil has signed a preliminary agreement to explore investment opportunities in Venezuela’s oil industry, nearly 20 years after leaving the country.

The agreement, signed on Monday, will allow the company to assess potential drilling projects and other opportunities in Venezuela’s petroleum sector.

The development signals a possible return for ExxonMobil, whose Chief Executive Officer, Darren Woods, described Venezuela as “uninvestable” during a meeting with US President Donald Trump in January.

Woods had raised concerns about the country’s investment climate, casting doubt on the prospects of American oil companies returning to its energy sector.

However, the latest agreement indicates that ExxonMobil is willing to reconsider opportunities in the country, although the deal does not amount to a final investment decision.

A potential return by the company could bring renewed foreign investment and technical expertise to Venezuela’s oil industry, which holds some of the world’s largest crude oil reserves.