Farmer, C. L.¹, R. M. Marksteiner², R. A. Clark²
(1) BP Venezuela Holdings, Ltd, Houston, TX (2) BP, Houston, TX

ABSTRACT: Modeling a Structurally Complex Reservoir - Boquerón Field - Eastern Venezuelan Thrust Belt

Boquerón Field is located along the El Furrial trend in the Eastern Venezuelan thrust belt. The trap is a structurally complex, thrust–faulted, ramp anticline cut by several strike slip faults. The main reservoir interval, locally termed “Naricual Inferior”, has a gross thickness of about 900 ft and consists of Cretaceous and Paleocene age fluvial and deltaic sandstones capped by a marine limestone.
A reservoir description and modeling study for Boquerón was conducted in order to identify gas injection and development well targets and to model field depletion. A coarse grid, deterministic approach was used to build the Boquerón reservoir model with the understanding that the model would be revised and rescaled if it did not adequately describe the reservoir. The model was constructed using a single seismic map at the top of the limestone. Intermediate horizons were generated using well thickness, and faults were assumed to be vertical through the reservoir. An excellent primary production history match was achieved from the model by adjusting fault transmissibility to segregate major pressure compartments.
Development drilling results indicated that additional velocity analysis and seismic mapping were necessary to better define the structural geometry and connectivity of reservoir sands. Boquerón Field was then re-mapped seismically with emphasis on actual fault plane geometries, and with addition of two seismic horizons to define the middle and base of the reservoir interval. The revised structural model more accurately reflects the fault plane and reservoir geometry of the field.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.