Evaluation of Mexico's Shale Oil and Gas Potential

Abstract

Abstract Mexico has significant oil and gas resource potential in Jurassic and Cretaceous age shale formations. These shale deposits -- which correlate with productive shale plays in the USA -- appear prospective but are still in the early stage of exploration and thus remain poorly characterized. Early shale exploration wells tested mostly low rates, but a recent oil well made 500 bopd while a shale gas well reached 10.9 MMcfd. The Mexican government plans to offer shale exploration blocks through an international auction. As part of a multi-client study, the authors have greatly expanded the geologic and reservoir data set we developed during an earlier scoping-level study conducted for the US Energy Information Administration (EIA). The additional geologic data support our initial view that Mexico has some of the largest and best quality shale potential outside the US and Canada. Risked, technically recoverable resources were estimated in the EIA/ARI study at 13.1 BBO of oil and 545 Tcf of natural gas. Detailed geologic mapping and analysis indicates the two most prospective liquids-rich shale areas in Mexico occur within onshore portions of the Burgos and Tampico-Misantla basins, which have transport infrastructure and well services. Significant potential also exists in the Veracruz, Macuspana, Sabinas, and other onshore basins, but those areas tend to be structurally more complex and/or are mostly in the dry gas window. The U. Cretaceous Eagle Ford Shale (in the Burgos) and correlative Agua Nueva Formation (in the Tampico-Misantla) have high TOC and brittle carbonate-rich mineralogy, but their net prospective area is reduced due to often shallow burial depth and low thermal maturity. A better target appears to be the U. Jurassic Pimienta and La Casita formations, which can be thick (~200 m), at prospective depth over much larger areas, are in the volatile oil to wet gas windows, and frequently overpressured, although TOC is lower than in the Agua Nueva.