| Abstract |
Last year 238 production and 26 injection wells were operating in Mexico at the geothermal fields of Cerro Prieto, Los Azufres, Los Humeros and Las Tres Vírgenes, whose main data for 2011 are presented. Geothermal wells produced an average rate of 6882 tons per hour (t/h) of steam with an unitary production of 28.9 t/h. Between 1963 and 2011 almost 600 exploration, production and injection wells have been drilled in the country, at a national average depth of 2173 m. From a statistic view, it can be concluded that the mean life-cycle of a production well in the country goes from 12 years in Las Tres Vírgenes and 13 in Cerro Prieto, to 42 years in Los Azufres and 57 years in Los Humeros. The main factors affecting the production life-time of the wells can be related to the wells themselves (casing collapses, thermal stress, circulation losses) or to specific characteristics of the geothermal reservoir (mainly scaling and corrosion). To deal with these problems and get the mentioned life-cycle, some types of workovers, like mechanical and chemical cleaning, sleeves and sidetracks, must be done at variable intervals and with distinct results and success rates. |