M. A. Gutierrez and A. Nur

Rock Physics Laboratory, Geophysics Department, Stanford University, Stanford, CA

ABSTRACT: 3-D Seismic Structural Interpretation of the Mature Giant Oil Field La Cira-Infantas, Middle Magdalena Valley Basin (Colombia)

One of the current problems in oil recovery is the restricted knowledge of the reservoir's external geometry and the controls that geological heterogeneities exert on hydrocarbon flow.Generally, geological heterogeneities compartmentalize reservoirs into flow units, preventing efficient drainage and sweep of reservoirs. Understanding the three-dimensional geometry, spatial organization, genesis, and evolution of structures such as folds and faults is essential to providing a realistic conceptual model for flow studies. However, to date wireline log-based structural models of several mature giant oil fields, including La Cira-Infantas, do not provide a clear delineation of the field production boundaries and compartments. Moreover, particularly in La Cira-Infantas, the characteristics and evolution of its structural style are not completely well understood. Published interpretations show La Cira-Infantas structure, which is a complex combination of probably coeval folds, thrust faults, and a large number of normal faults, as the farthest west expression of a thrust belt that extends out into the Middle Magdalena Valley Basin from the Eastern Cordillera. However, these structural elements are not concordant with the characteristics of a typical compressive tectonic regime, as is generally claimed in the literature. In order to solve these uncertainties, we present in this paper a rigorous model of faulting for the La Cira-Infantas oil field. A very thorough and detailed description and documentation of the structural features, based on the interpretation of a specially acquired threedimensional seismic data set, support the model.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado