KUDRNA, ANTONIN J., Maraven, S.A., Caracas, Venezuela

ABSTRACT: Seismic Inversion of the Tertiary Reservoir in the Southeastern Part of Lake Maracaibo, Venezuela

Seismic inversion has been tested previously in the Lake Maracaibo by the Maraven Exploration and is now being applied by the Production group. Area 8 in the south-eastern part of the Ceuta Field was selected for the inversion study to improve parameters of the planned waterflood project. The reservoir is located in a monoclinal fault block bounded by north dipping east-west normal faults and the Ceuta High Structure to the west. The producing zones, Eocene Misoa Formation Sands B and C appear to have stratigraphic limits, that this study was intended to define and characterize. The methodology consists of two parts; Acoustic Petrophysics and Seismic Inversion. The results are integrated to achieve the final qualitative and quantitative reservoir model. In the Acoustic Petrophysics pa t the impedance computed from the well logs is compared with known petrophysical properties. The derived relationships are used for petrophysical predictions and their quantitization by transfer functions. In the Seismic Inversion part seismic data were inverted via a forward modeling technique with constraining parameters derived from wells. The resulting seismic acoustic impedance was tested and calibrated to well data.

The impedance displays, generated for a grid of seismic lines, were interpreted for stratigraphic definition and, in the reservoir zone, converted to selected petrophysical parameters. These parameters were mapped resulting in reservoir models that can be used in the waterflood planning.

AAPG Search and Discovery Article #90988©1993 AAPG/SVG International Congress and Exhibition, Caracas, Venezuela, March 14-17, 1993.