Abstract: Application of Sequence Stratigraphy in an Integrated Reservoir Characterization of the Miocene Lower Lagunillas Member, Blocks III and IV, Lake Maricaibo, Venezuela

GAMERO DE VILLARROEL, H., C. M. COLL, Z. JIMENEZ, T. LOZADA, K. LEON, R. BRANDT, R. PADRON, L. RONDON, BRYANT, I. D., GOMEZ, E., M.A. MUNOZ, R. A., RIPPLE, AND B. A. LUNEAU

An integrated reservoir characterization has been conducted for the lower to middle Miocene Lower Lagunillas Member of blocks III and IV, Lake Maracaibo. This mature field was discovered in the 1950's and has produced over 1320 MMBO. The Lower Lagunillas had traditionally been subdivided into three homogeneous sandstones that were deposited on an upper to lower delta plain/alluvial plain. This geological model assumed that these sandstones were in communication. Subsequent engineering studies showed that this simplistic model did not adequately address the heterogeneities of the reservoir.

The reinterpretation of four (4) cored wells, using a sequence stratigraphic framework, led to the development of a new sedimentological model consisting of eleven (11) distinctive, correlatable units (II-XII) deposited on a fluvial-dominated upper to lower delta plain and delta front. The integration of this model with 35 well logs, 3D seismic data, petrophysical evaluations, production and pressure data resulted in a new, more detailed geological model. This model suggests that the interbedded thin shales associated with flooding events act as partial barriers to vertical communication resulting in reservoir compartments and increased complexity.

The development of a new reservoir model incorporating geological concepts has provided the basis for the identification of new opportunities to optimize through infill and horizontal drilling and recompletions. To date, three (3) new wells have been drilled in the field and have successfully validated the proposed model.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria