New Insights on the Salt-Compressional Tectonics from the Hydrocarbon Rich Province of Southeastern Gulf of Mexico

Audemard, Felipe¹, Javier J. Meneses Rocha², Javier Villaseñor Hernández³, Jorge Varela Santamaría³, Andreas Suter¹, Nicolas Gonzalez Tovar³ (1) Schlumberger, Villahermosa, Tabasco, Mexico (2) Pemex Exploration and Production, Villahermosa, Mexico (3) Pemex Exploration and Production, DCS Mexico, Mexico

Reprocessed 3D seismic allows identifying at least two distinct regional autochthonous salt intervals. The shallower salt is currently assigned to the Oxfordian and is observed at 4-4.5 seconds and is interpreted as a belt of deformed salt rollers. A second, deeper salt inter-val is identified between 5.7-6.3 seconds. The salt pillows’ array shows different wave­lengths. The shallower unit shows pillows every 4 to 5 km apart and migrating towards the northwest whereas the deeper unit reflects a wavelength from 6 to 6.5 km, larger in size with a similar migrating pattern. The age of deeper section is undefined, but certainly older than Callovian and could be as old as Permian if it is correlated as a segment of the Permian Basin from south Texas or its equivalent in Guatemala - Southern Mexico. Both units are coupled to the Chiapas Neogene compression. The bases of these units define major detachment surfaces responsible for most of the prospective Mesozoic structures identified to date. An additional complexity is outlined within the basal shaly Paleogene unit on top of the Mesozoic carbonates and it corresponds to a major decoupling surface associated with gravitational gliding readjusting the deformation from underneath. This sequence is com­monly over pressured and show incipient shale diapirism associated with active normal faults. All three upper decoupling surfaces are linked together and define a complex raft sys­tem sliding towards the deeper Gulf of Mexico as salt evacuates basinwards continuously modified by the deeper effects of the Chiapas compression.