Abstract: Integrated Reservoir Characterization to Define a Hydrodynamic Model in the Misoa Formation, Eocene, Center Lake Field, Maracaibo Basin, Venezuela

Vallez Azuaje, Jose Gil

The Center Lake Field is one of the most important light oil reservoirs in the Maracaibo Basin. Field production of "C" sandstones, Misoa formation, Eocene, started in 1968. Actual cumulative production is 630 MMBls, which represents 23% of the original oil in place. Flank water injection programs have been executed since 1976; however, reservoirs within this field still have shown pressure and production declination.

A multidisciplinary study has been conducted to produce an updated hydrodynamic model which matches the static and dynamic behavior of the reservoirs. An integrated interpretation team has merged geological, geophysical and engineering data and criteria to generate an updated and consistent interpretation of today's performance of reservoirs.

The integration of a 3D seismic survey with a sequence-stratigraphy analysis, petrophysical and production data allowed us to determine a new structural and stratigraphic framework. The first important conclusion is that active aquifer is not located at the flanks of the structure, as traditionally worked out. Instead, a water-bottom drive system was interpreted and validated with production data so a different strategy for water injection was recommended.

The latter interpretation restricted the injection to those areas where rock volume calculation, permeability, porosity and depositional environment make it suitable and profitable. A pattern injection program is going to be developed in C-4-X.46 reservoir and 21.6 MMBls additional recovery is expected in respect to the old production scheme.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela