Abstract Of all the countries in the world considered to be oil rich, Mexico is the only one that consistently has been losing production and reserves in the last ten years. Even though Mexico has five major producing provinces: two for oil (the Southeast and the Tampico–Misantla basins) and three for gas (the Sabinas, Burgos and Veracruz basins), and has seven more with potential, (California, Gulf of Cortès, Chihuahua, Sierra Madre Oriental, Sierra de Chiapas, Progreso shelf, and the deep Gulf of Mèxico), its output and reserves have declined consistently. Many reasons can be attributed for these results, and as this note proves, least of them is the country’s endowment of oil and gas resources. The problem is that Mexico, since 1938, has had only one oil company responsible for all of its upstream activities and even though Pemex’s performance is comparable with that of most of the majors’ (it is world’s third largest in terms of production), it is impossible that all the remaining potential of the entire country can be found and produced with only one company, no matter how large, wealthy, efficient, technologically advanced, and successful it can be. The good news is that once the country opens up for third-party participation in exploration, which will eventually take place, results are going to be spectacular. So far there has only been a timid opening for development and exploitation opportunities.

Abstract The Mexican portion of the Gulf of Mexico Basin (MGOM) extends onshore into several oil- and/or gas-producing basins: Burgos, Tampico-Misantla, Veracruz, and Sureste (the Sureste Basin includes the Salina del Istmo, Comalcalco-Chiapas-Tabasco, Macuspana, Sonda de Campeche, and Litoral de Tabasco provinces). To the east, the MGOM includes the nonproducing Plataforma de Yucatán. The deep-water Gulf of Mexico has been subdivided into eight provinces: Franja Distensiva, Delta del Río Bravo, Franja de Sal Alóctona, Cinturón Plegado de Perdido, Cordilleras Mexicanas, Canon de Veracruz, Salina del Golfo Profundo, and Planicie Abisal. Based on the petroleum systems and exploration history of these provinces, most undiscovered reserves are likely to be found in the deep water of the MGOM.

Abstract Most of Mexico’s oil has come from Cretaceous and Jurassic carbonate rocks, but, in southeastern Mexico, these formations were not productive until the significant 1972 Pemex discoveries. By the end of 1977, 15 to 20 onshore and 3 offshore Mesozoic producing sites had been drilled in the Reforma area and Campeche Bay. Eight of these pools were productive, and several have been recognized as giant fields. Conservatively, proved reserves exceed 5 billion bbl of liquid hydrocarbons and 7 Tcf of gas. Because of the extent and number of favorable structures, the additional potential is enormous. Daily production in January, 1978, was 810,000 bbl of oil and condensate, and about 900 MMcf of gas. Cumulative production at the end of 1977 was about 580 million bbl of oil, approximately 60 million bbl of condensate, and 840 Bcf of gas. Of the 249 wells drilled at that time (three of them offshore), 202 were successful. New reservoirs are mainly Cretaceous and Jurassic dolomites and microfractured limestones, at an average depth of 12,500 ft (3,810 m). Trapping is in complexly faulted rocks and overthrusted anticlines covered by a thick Tertiary shale and sandstone sequence. Salt tectonics are also involved. Miocene sandstones have produced in the area since 1960, but Mesozoic discoveries had to await development of more sophisticated geophysical and drilling techniques. In northwestern Mexico, the Baja California peninsula area has received renewed interest with the establishment of dry gas production from Upper Cretaceous marine clastic rocks in the Sebastian Vizcaino basin. Geologic studies started early in this century. Between 1944 and 1960, geologic, gravity, and seismic surveys led to the drilling of 11 unsuccessful wildcats, In 1972, more modern geophysical and geologic studies justified the drilling of six additional wells, two of which are gas producers. At present, two rigs, one onshore and one offshore, are continuing exploration.