Exxon Mobil Corp. confirmed Wednesday that it has made what it calls a “significant” oil discovery off Guyana in waters also claimed by Venezuelaas part of a long-running border dispute between the South American countries.

The company and Guyana’s government had said May 7 that the exploration was showing promise but provided no details. Exxon Mobil now says it is still working to determine the commercial viability of the find at a site within the 6.6 million-acre area known as the Stabroek Block but has reasons to be optimistic.

“I am encouraged by the results of the first well on the Stabroek Block,” said Stephen M. Greenlee, president of ExxonMobil Exploration Co.

The company says it encountered more than 295 feet (90 meters) of high-quality oil-bearing sandstone reservoirs in the drilling site about 120 miles (193 kilometers) off Guyana. It said the well was safely drilled to 17,825 feet (5,433 meters) in 5,719 feet (1,743 meters) of water.

This would be the first significant oil discovery following decades of exploration within the territory of Guyana, a largely undeveloped country of about 800,000 people.

Venezuela has long claimed about two-thirds of Guyana’s territory as well as the offshore area where Exxon Mobil began drilling in March.

In October 2013, the Venezuelan navy detained an oil research vessel operating under contract for U.S.-based Anadarko Petroleum Corp. Guyana Foreign Minister Carolyn Rodrigues-Birkett said in March that her country would push ahead with exploration in the area despite protests by Venezuela.

Source: Associate Press