Abstract

The Tertiary Basin of Comalcalco is located in the southeastern part of the Mexican Republic, on the Coastal Plain of the Gulf of Mexico, in the state of Tabasco. It was developed during the Neogene as a result of the interaction between large volumes of siliciclastic sediments and the withdrawal of allochthonous salt masses originally displaced as a large canopy in lower and middle Miocene sediments.

This study came about due to the need for a depositional model of the basin to generate a detailed inventory of producing plays.

The basin analysis was performed under the genetic sequence approach and allowed for the definition of the stratigraphic framework of the Miocene and Pliocene in 13 seismic-stratigraphic sequences separated by maximum flooding surfaces (MFS) correlatable throughout the basin. Under this stratigraphic framework, 12 depositional facies distribution maps were plotted, describing a prograding sedimentary evolution in the basin with sedimentary fill varying between deep marine to continental environments from the middle Miocene (13.15 Ma) to the late Pliocene (2.55 Ma).

Depositional systems representative of the Miocene are submarine channels and levees facies complexes with turbiditic basin floor fans, and composed shelf-slope systems with submarine intraslope fan complexes and river-dominated deltas, while for the Pliocene they are wide coastal plains with braided channels, shorezone, wave-dominated deltas, and slope fan complexes.

One characteristic of this basin is the presence of extensive delta systems established since the lower section of the late Miocene, the extension of which was controlled by growth faults with a southwest-northeast preferential orientation dipping to the northwest and counter-regional faults dipping to the southeast, associated to “roll-over” anticlines. The presence of these faults is reflected in the fill control and the existence of main depocenters whose origin is related to salt withdrawal in a Roho system.