This article summarizes what is known of the nature of the limestone reservoir rocks in the Mexican oil fields, and discusses the probable source of the oil. Porosity in the Northern fields (Pánuco area) is due to faulting and fracturing of the compact Tamaulipas, the Agua Nueva, and the San Felipe limestones, of Cretaceous age. Some porosity in the limestones is due to jointing. Oil accumulation in the Northern fields occurs on the top, or on the flanks, of anticlinal structures. The basal Agua Nueva beds, of Eagle Ford age, are considered to have furnished the main source of the oil.
In the Southern fields (Dos Bocas-Alamo) the oil occurs in the El Abra limestone, a porous rock representing a reef facies, of Cretaceous age. Production is found at the top of asymmetric anticlines. The El Abra limestone reservoir rock of the Southern fields is considered to be the source of the oil which it contains.
Figures & Tables
The AAPG volumes of Structure of Typical American Oil Fields preceed this book, which was written as a sequel to those, and at first conceived as a third volume of the earlier work. This book is designed to review, modify and, if possible, clarify ideas with regard to the fundamental concepts of oil geology, utilizing, for this purpose, the material presented in the two earlier data-based volumes. To conform to the original standard set for it, this book has been kept relatively free from factual data and has been compiled rather as a summation, based upon the best available evidence, of present knowledge of the science. This volume does not include a discussion of the technique of field or laboratory geology, but does include papers divided into 7 parts: History; Origin and evolution of petroleum; Migration and accumulation of petroleum; Relations of petroleum accumulation to structure; Porosity, permeability, compaction; Oil-field waters; and Subsurface temperature gradients.