Deep aquifer systems of geothermal and petroleum reservoirs in Mexico

摘要

Evaporated seawater and meteoric water infiltrated into the Activo Luna and Activo Samaria-Sitio Grande oil field reservoirs at the Mexican Gulf coast during Late Pleistocene to Early Holocene. On a local scale, secondary processes such as the mixing of both water types, water-rock interaction with limestone host rocks, the formation of methane, and vertical zonation of the fluids with increasing salinity towards lower parts of the common aquifer were encountered. In none of the studied reservoirs, the extreme salinity of the brines is caused by dissolution of halite from adjacent salt domes. The geothermal fluids from Las Tres Virgenes and Los Azufres indicate the mixing of a "fossil" meteoric component (70%) with mag-matic water (30%). The recent composition of Cerro Prieto fluids is caused by mixing of Colorado river water with evaporated seawater. The influence of recent meteoric water was not proven in any of the deep reservoirs.