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Early Eocene Outcrop Analogue in the Chicontepec Formation, Hidalgo State, Mexico

Diaz, Gustavo E.1; Cossey, Stephen P.2; Slatt, Roger M.1
1 Geology and Geophysics, The University of Oklahoma, Norman, OK.
2 Cossey and Associates, Inc., Durango, CO.

The complex Paleocene-Eocene sedimentary succession of the Chicontepec Formation is extensively exposed within the western margin of the Tampico-Misantla Basin in east-central Mexico. This complex clastic sequence records deposition in a deep-marine foredeep developed in response to the onset of the Sierra Madre Oriental fold and thrust belt.

The Chicontepec formation represents the main reservoir for the Chicontepec Play. In order to establish an analogue for the reservoir elements interpreted in the subsurface, 75m of an outcrop section were measured and described at bed-scale, and in addition to this, an outcrop gamma ray (GR) log was acquired.

The outcrop represents an early Eocene deepwater sequence deposited above the Paleocene-Eocene unconformity. The sequence is composed of mass-transport deposits (MTC’s) at the base, sitting on the unconformity, overlain mainly by layered and amalgamated sheet sandstones with some distributary channels sandstones (basin floor fans). The upper part of the sequence corresponds to channel-levee deposits. This high net to gross facies succession overlying a regional unconformity is also observed in correlative core/well logs and seismic data with implications to the identification of good reservoir intervals in the subsurface. Sedimentary features such as bed geometry, shale intercalations, bioturbations and mass transport complexes (MTC’s), indicate that sub-seismic scale features can certainly affect reservoir performance in the Chicontepec Formation

Although not representative of the common stratigraphic expression of Chicontepec Fm. in the outcrop belt, this outcrop provides a unique opportunity to study the detailed stratigraphic characteristics of an equivalent to a prospective reservoir interval in the Eocene sequences of Chicontepec Formation.


AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009