Origin of Petroleum in the "Sureste" Basin, Mexico

Mario A. Guzman-Vega, Marcio Rocha Mello, Noel Holguin, Cristobal G. Leon

The "Sureste" basin comprises the most important petroleum provinces from Mexico, as Chiapas-Tabasco and Sonda de Campeche areas. Geochemical and biological marker analyses of oil and rock samples have identified successfully four age source-related oil families: Oxfordian, Tithonian, Lower Cretaceous and Miocene.

Distinct marine organic-rich depositional regimes can be genetically related to the "Sureste" basin oils using differences in isotopic signatures, key specific molecular compounds and biomarker ratios. The Oxfordian oil family is linked to an anoxic carbonate environment associated with a narrow and shallow semi-restricted sea. Diagnostic criteria allow to differentiate three carbonate depositional settings as the source of the Tithonian oil family: 1) an anoxic environment associated with a sill basin geometry, 2) an anoxic environment and 3) a clay-rich suboxic/anoxic environment, both related to isolated intraplatform depressions. The Lower Cretaceous oil family is linked with an anoxic marine evaporitic environment. The Miocene oil family is derived from terrigenous and marine sou ce materials deposited in a marine deltaic environment.

Tithonian oils are accumulated in siliciclastic and carbonate reservoirs, onshore and offshore and throughout the stratigraphic column from Kimmeridgian up to Pliocene. Some compositional differences in these oils can be explained by thermal and post-filling alteration processes.

This study confirms the Tithonian marine calcareous-shaly facies as the most important oil-prone source-rocks in the southeastern of Mexico.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995