Exxon Mobil Corp said on Tuesday it has made another discovery offshore Guyana, as the largest US oil producer continues to develop one of the world's most important new oil and gas blocks in the last decade.

Exxon said that the 18th discovery, made at the Redtail-1 well, will add to its previous estimate of over 8 billion barrels of total oil and gas resources on the Stabroek Block offshore Guyana.

However, the company did not specify how much it estimates would be recoverable from this well and did not outline development plans for it.

Exxon operates the Stabroek block as part of a consortium with Hess Corp and China's CNOOC Ltd and began production on it ahead of schedule in December.

The new find continues the Exxon-led consortium's long string of discoveries in Latin America's newest crude producing nation and underscores the importance of Guyana to Exxon for increasing its future oil output.

In addition to the Redtail-1 discovery, drilling at Yellowtail-2 encountered high quality oil bearing reservoirs, Exxon said, which is currently being evaluated for development along with nearby discoveries.