The Tithonian (Upper Jurassic) Edzna Formation, an important hydrocarbon reservoir of the campeche shelf, Gulf of Mexico

The Upper Jurassic (Tithonian) Edzna Formation is considered to be the most important source rock in the southeastern Mexico Campeche shelf, Gulf of Mexico. The formation is penetrated by a number of wells, in which cumulative and test production show that the Edzna Formation also is an important hydrocarbon reservoir. The formation is composed of a condensed section of mudstone and bentonitic shale. Thicknesses vary between 62 m and 120 m in the northeastern area, thickening to 393 m in the central marine area. The structural top commonly reaches depths of 6100 m in the southwestern and western areas, with a minimum depth of 1600 m in the northeast. There is a distance of approximately 120 km between deepest and shallowest burial areas. There are three important structures in the Campeche shelf: the Ceeh-Cantarell anticlinorium in the northeast, the Sinan-Mison syncline in the central area, and the May-Oktan anticlinorium in the southern area of the marine region. The northeast-southwest-trending Edzna Formation reservoir is about 150 km long by 50 km wide. To date, cumulative oil production is about 45 million barrels.