Exxon-Mobil says it’s conducting studies and making plans to wind down Nova Scotia’s first offshore natural gas development near Sable Island.

A spokesperson for the company says no date has been set for when decommissioning will begin, or how many years the process could take.

The lifespan of the Sable natural gas fields has been the subject of speculation as output from its five offshore wellheads has gradually lessened in recent years. When it went into production in late 1999, a 25-year lifespan was projected.

For the first five years of the project the facility pumped more than 400 million cubic feet a day, but Exxon announced in 2010 it would wind down Sable.

The offshore facility was producing 200 million cubic feet of natural gas a day before it decreased to 65 per cent capacity after problems with a subsea flow line were discovered last fall.

Exxon, the majority owner, said it's working to get production back to that level later this year. Over the past 13 years, the Sable Gas project has contributed more than $1.7 billion in royalties to provincial coffers.