INEOS bought the Grangemouth plant from BP in 2005
A Chinese state-owned oil firm has completed "preliminary work" on a possible bid to buy a stake in the giant oil refinery at Grangemouth.
Ineos, who bought the plant from BP in 2005, is currently in talks to sell at least part of the plant to PetroChina.
The Grangemouth plant, which is Scotland's only refinery, processes about 200,000 barrels of crude oil a day.
There are currently about 1,300 workers employed at the Grangemouth site.
In a statement Ineos said it was in talks with "a number of parties" about the future of the Grangemouth plant.
It added: "The discussions with interested parties are exploratory and it would be premature to speculate on whether any might lead to investment in the site.
"The Grangemouth petrochemical and refining facility remains a strategic part of the Ineos Group and the company is committed to its long-term development."
PetroChina's acquisition strategy has involved buying a number of refineries and oil-related business across the globe, include in Canada, Singapore, Argentina and Japan.
News of any move on the Grangemouth plant by PetroChina was given a cautious welcome by local SNP councillor Angus MacDonald.
He said: "While there may be some who are concerned at such aggressive expansion plans, we have to accept that we live in a global economy and must welcome any inward investment locally as we drag ourselves out of one of the worst recessions this country has seen."
In a highly controversial move, Ineos, owned by billionaire businessman Jim Ratcliffe, has also unveiled plans to move its UK headquarters to Switzerland to save on tax.
The news comes after the company reported high debt levels last year.