--> ABSTRACT: A Regional Model for Deposition and Erosion of the Eocene Misoa Formation, Maracaibo Basin, Venezuela, by C. A. Knutson, L. E. Waite, and S. Kakizaki; #91021 (2010)

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A Regional Model for Deposition and Erosion of the Eocene Misoa Formation, Maracaibo Basin, Venezuela

KNUTSON, CRAIG A., LOWELL E. WAITE,and SATOSHI KAKIZAKI

The sandstones of the L-M Eocene Misoa Formation contain about 45% (24 Bbo) of the ultimate recoverable in the Maracaibo Basin. Extreme variations in formation thickness (0-15,000 ft) are a combination of depositional onlap and erosional truncation. Stratigraphic position within the Misoa, and hence reservoir behavior, can be difficult to predict. Traditionally the Eocene is subdivided into five litho-stratigraphic units: Misoa C Lower (C7-C4), C Upper (C3-C1), B Lower (B9-B6), B Upper (B5-B1), and Pauji. Correlations are not typically based on biostratigraphic data, which is limited. However, placing the traditional stratal units within a sequence stratigraphic framework helps constrain correlations. A sequence-based, genetic depositional model for the Misoa/Pauji succession was constructed using published literature and log motifs from 290 wells. The Misoa/Pauji comprises three second-order supersequences within the Tejas I/II supersequence set. The depositional sequences are interrupted and erosionally truncated by the intra-Misoa (49.5 mybp) and top-Pauji (39.5 mybp) unconformities, both tectonic in origin. The subcrop and depositional patterns vary considerably across major fault systems, indicating that large structural blocks within the basin behaved independently and have significantly different depositional and erosional Eocene histories. Recognizing these historical differences enhances the ability to predict reservoir occurrence and characteristics

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.