The Artesa-Mundo Nuevo Platform of the Chiapas-Tabasco Region, South-East Basin, Mexico: An Enigma

Hugo L. Martinez-Kemp¹, Miguel Varela-Santamaria¹, Peter Bartok², and Santosh K. Ghosh^2
1PEMEX, Exploracion y Produccion, ARES, Villahermosa, Tabasco, Mexico
²Bartok Inc., PO Box 683002, Houston, Texas 77268

The detached Cretaceous carbonate Artesa-Mundo Nuevo Platform is unique in the Reforma region. It is a large platform measuring 50 × 20 km and located over 50 km north of the main Cretaceous carbonate shelf edge. Prior to the acquisition of 3D seismic data it was assumed that the high was similar to the series of basement highs extending from the southern United States and eastern Mexico that initiated carbonate platform build-ups during the Cretaceous. However, neither gravity nor magnetic surveys support the basement high hypothesis. Modern 3D seismic permits mapping of basement and though not clearly manifested in the seismic, there is evidence for its presence. In the region of the Artesa Mundo Nuevo Platform it is essentially a structural monocline dipping south with no influence on the carbonate platform.

Several problems concerning the platform require study: 1) during the Late Cretaceous the platform tilted south resulting in deep-water carbonate sediments along the trend of the Gaucho well, southern portion of the platform; 2) the northern section was uplifted and exposed, creating significant karsting; 3) the presence of Late Cretaceous debris breccias, south of the platform; and 4) the presence of a steep scarp facing north with possible Tamabra Formation style deep-water debris deposits. The following questions need answering: (1) What caused the tilting?, (2) What caused the scarp?, (3) What are sediments indicating?, and (4) What is the importance of the breccias?

This study first reviews the structure of the platform. Key core descriptions provide guidance as to the geologic development and a series of paleogeographic maps summarizes the observations. Several seismic surveys cover parts of the platform but none cover the entire system. For the purpose of the present study the seismic used in the study will be the eastern portion of the Caleton survey, covering the western third of the platform.

Given the abundance of literature on similar highs along the margin of the Gulf of Mexico during the early exploration of the platform it was assumed that the Artesa Mundo Nuevo platform was a basement high on which Middle Cretaceous shelf carbonates developed. In appearance and dimensions it is similar to the Sabine Uplift of the East Texas Basin (Halbouty and Halbouty, 1984). Similar conditions are present on the Artesa-Mundo Nuevo. The bulk of the production is from Middle to Late Cretaceous carbonates.

In the case of Artesa-Mundo Nuevo, seismic allows an interpretation of the general configuration of the platform. The sharp scarp is observed along the northern edge and the extent of the platform is evident. A more detailed view of the northern platform shows the characteristic of the northern margin and the proposed limit for the frontal debris apron. Once again the seismic line indicates that there is no particular basement high associated with the development of the platform. Salt has not been penetrated by any wells. However, many wells in the area report bottom hole waters with over 200,000 ppm chlorides. This suggests proximity to salt bodies. Modern 3D seismic indicate that salt is widespread beneath the platform. During the Lower and Middle Cretaceous  the platform underwent a construction phase. Either because of salt withdrawal or a tectonic event, in the Late Cretaceous the platform tilted south, was partly drowned, and exposed along its northernmost sections.

AAPG Search and Discovery Article #90080©2005 GCAGS 55th Annual Convention, New Orleans, Louisiana