Upper Jurassic Stratigraphy (Oxfordian and Kimmeridgian) in petroleum wells of Campeche Shelf, Gulf of Mexico

The original definitions of the Upper Jurassic Akimpech Formation and Ek-Balam Group of Campeche Shelf (southern Gulf of Mexico) as proposed by AngelesAquino and Cantu-Chapa did not incorporate the gamma-ray log responses of these units. Studies of new material from petroleum wells from the southern Gulf of Mexico permit their redefinition as important stratigraphic units for petroleum exploration and production. Additionally, this chapter defines the middle Oxfordian Bacab Formation and its upper member, the Tson anhydrite member. The middle Oxfordian ammonites Ochetoceras rioslopezi n. sp., Glochiceras sp., and Perisphinctidae ind. recovered from the oil wells of the southern region of the Gulf of Mexico are described.