Abstract

The Tithonian-Cretaceous Petroleum System in offshore Campeche, Mexico, is the most important one in the country because of its reserves and oil production. It is in a mature stage of exploration. Despite this, the system underwent revitalization in 1999 as the result of the discovery of a new producing play in Upper Miocene sands. Also, a new oil and gas field in the autochthonous block of the mature Cantarell Field was discovered and new hydrocarbon prospects in the Pliocene and Pleistocene rocks have become evident. The great hydrocarbon volumes produced and still to be discovered in this system were expelled by calcareous shales, rich in Type II organic matter. These shales were deposited during the Tithonian on a clastic carbonate platform. The objective in the most important play is made up of Upper Cretaceous calcareous breccia and the traps basically correspond to anticline structures formed during Miocene Late-Pliocene overthrusting. Hydrocarbon expulsion ages range between 9 and 0 Ma. This suggests favorable timing for migration and accumulation when compared with the age of the last structural stage (11-3.4 Ma.) In the southern portion of the area, the traps are located within the hydrocarbon expulsion zones, whereas, in the north, source rocks are immature on the crests of producing structures and are charged by laterally located kitchens within their respective drainage areas.