Print this pagePaleothermometry Techniques Applied to Burial History and Hydrocarbon Migration Analyses, Tampico-Misantla Basin, Mexico
POTTORF, ROBERT J., GARY G. GRAY, MICHAEL G. KOZAR, WILLIAM M. FITCHEN, MARK RICHARDSON, RICHARD J. CHUCHLA, and DONALD A. YUREWICZ
To constrain the complex burial and migration history of the Tampico segment of the Sierra Madre Oriental fold-thrust belt, we applied integrated paleothermometry, including smectite/illite transformation, illite age analysis, fluid inclusion thermometry, vitrinite reflectance, kerogen maturation, and apatite fission track analysis. Our efforts were focused on a large, exhumed oil field, located in the Sierra de El Abra along the leading edge of the fold-thrust belt. The reservoir El Abra Formation is exposed in several quarries where it is heavily stained with bitumen. Fluid inclusion homogenization temperatures show that the El Abra reached maximum temperatures of 170 degrees C during burial of approximately 5km of Lower Tertiary sediments. Apatite fission track data suggest that the Sierra de El Abra was uplifted between 30-60Ma. Uplift timing and the formation of a free gas cap within the paleo-oil field is also confirmed by immiscible trapping of hydrocarbon inclusions. Our integrated study demonstrates that large volumes of hydrocarbons were generated within the fold-thrust belt during the Paleocene and migrated eastward where they were trapped within the Sierra de El Abra. A second, smaller charge of hydrocarbons was trapped in the same structure during Eo-Oligocene uplift of the frontal part of the fold-thrust belt and the foreland. Relatively recent regional uplift and erosion were responsible for the breaching of the large hydrocarbon accumulation.