ABSTRACT: Identification and Revision of Reservoir Compartments in the Yarigui-Cantagallo Oil Field, Middle Magdalena Valley, Colombia: Integration of Geochemical, Geological, and Engineering Data

Talukdar, Suhas C.¹, Octavio Luna², Jimmy Ardila², and Robert Blake³
(1) Core Laboratories, Inc, Houston, TX
(2) ECOPETROL, Bogota, Colombia
(3) Core Laboratories, Inc, Carrollton, TX

In this study oil gas chromatography (GC) data is integrated with geologic and engineering information to define the reservoir compartments in the Yarigui-Cantagallo field. The trap (area 55 km2) is a southeast dipping, wedge shaped monocline bounded to the west by the northeast trending Cantagallo Fault. It is further dissected by secondary, longitudinal and transverse faults. The field produces heavy oils. The main producing horizons are the "Cantagallo" sands (alluvial and stacked braided channels) of the Eocene La Paz Formation. The overlying "C" sands (braided channels) of the La Paz Formation and the "B" sands (meandering channels) of the Oligocene Mugrosa Formation are secondary producers.

Comparison of GC fingerprints of oils produced from the "Cantagallo" sands in twenty four wells indicate lateral fluid continuity among the "Cantagallo" sands within and across the different fault blocks. GC data of oils from the "C" sands in six wells show they belong to isolated reservoirs. GC data from the commingled oils (ten from "Cantagallo" and "C", one from "C" and "B") have identified their real contributing zones. The oils were derived from the Cretaceous La Luna Formation and show similar thermal maturity. Differences in oil alteration in different reservoir compartments were responsible for their distinct oil fingerprints. Integration of the GC data with information on structure, reservoir distribution, oil-water contacts, initial pressure and pressure history, has led to modification of the structural interpretation, and has helped identify the reservoir compartments consistent with all data.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia