The U.S. Geological Survey (USGS), under the World Petroleum Resources Project, assessed the potential for unconventional oil and gas resources (shale gas, shale oil, tight gas, and coalbed gas) in the Norte Basin of Uruguay. This is the southern extension of the Paraná Basin of Brazil, and is largely covered by volcanic rocks.
Using a performance-based geological assessment methodology, the U.S. Geological Survey estimated mean resources of 13,361 billion cubic feet of gas, 508 million barrels of oil, and 499 million barrels of natural gas liquids.
The Devonian Cordobes Formation is interpreted to be the principal petroleum source rock in the Norte Basin and possible reservoir for shale gas and shale oil accumulations. Thickness of the Cordobes ranges up to 160 meters (m), including as much as 60 m of organic-rich shale. Total organic carbon concentration ranges from 0.7 to 3.6 weight percent.
The geologic model used in the assessment of the Norte Basin assumes oil and gas to have been generated in organic-rich shales of the Devonian Cordobes Formation and to occupy matrix porosity and organic porosity in the same shales.
ANCAP has not yet declared any potential gas reserve that could be technically exploitable, according to ANCAP E&P manager Hector de Santa Ana. Currently ANCAP is negotiating an exploration contract with Shell for the Norte basin. Schuepbach Energy is proposing an exploration contract for 500 square kilometers in that region, including a 2D seismic study that will permit to assess with more precision the potential reserves. Also Schuepbach will be providing seismic studies for the area covered by ANCAP.
Although Uruguay is open to bid more onshore blocks for oil exploration to private companies, will maintain its monopoly on the areas of Pepe Nunez and La Paloma, where ANCAP considers that the potential for oil discovery is higher.