UPDATE FLUID FLOW MODEL FOR THE CP1 AREA OF THE CERRO PRIETO GEOTHERMAL FIELD

Abstract

A fluid flow model for the Cerro Prieto 1 area (CP1) has been updated, on the basis of reservoir engineering and production data collected since 1973. Two reservoirs have been identified in the CP1 area, the shallow alpha and the deeper beta reservoir which extends over the entire field.

Due to 28 years of continuous exploitation and the existence of hydraulic communication between the reservoir zones and the surrounding groundwater aquifers, inflow of cold water into the CP1 reservoirs has occurred. This recharge has been intense in the beta reservoir in the northern part of CP1, and in the alpha reservoir in the southern part. The cold water inflow into the CP1 area has been induced not only by production in CP1, but also by that in the eastern areas of the field (CP2 and CP3).

At present, the most stable productive zone in CP1 is the northern part of the alpha reservoir. The production zone with highest steam quality is in the southern beta reservoir, next to the CP2 area.