Talos Energy made history in late July 2017 when it made the first ever private sector discovery of a new structure offshore Mexico. Its Zama 1 wildcat, located on Block 7 (Contracto CNH-R01-L01-A7/2015) in 166m of water, approximately 60 km from the Mexican Gulf port of Dos Bocas, spudded on May 21, 2017.
It found a contiguous gross oil-bearing interval of over 335m, with 170m–200m of net oil pay in Upper Miocene sandstones with no water contact. Drilling using the Ensco 8503 semi-submersible continued to a TD of 4,108m into a secondary target, Zama Deep, but no additional hydrocarbons were encountered. The logging results confirmed the base of the reservoir section to be 3,380m, and initial tests of hydrocarbon samples recovered to the surface suggest light oil, with API gravities between 28° and 30°, and some associated gas.
The well has been suspended as a potential producer, and operator Talos, together with partners Sierra (40%) and Premier (25%), are analyzing the data to evaluate the best way to appraise and develop the discovery. Initial gross original oil-in-place estimates for the Zama-1 well range from 1.4 Bbo to 2 Bbo, exceeding pre-drill estimates, and some of the resource could extend into a neighboring block.
As reported earlier this year Eni made the first offshore oil discovery in Mexico since energy sector reforms enabled foreign companies to explore in the country, but this was part of an appraisal program. Zama is significant in that it found a completely new structure and field and can thus be considered a true exploration well.