Six Month Production Test at Momotombo, Nicaragua: Preliminary Results

Abstract

Results of a monitored six months production test carried out simultaneously on eight wells at the Momotombo geothermal field in Nicaragua indicate that its resource has a much smaller potential than previously believed. The resource potential is determined by the quantity of steam which emerges from a narrow source-fracture zone and move laterally into a secondary fracture system, where it is in contact with the cold waters underlying Lake Managua. Production from wells located off the source fracture zone resulted in gradual decrease of the pressure within the secondary fracture system, and, subsequently ,in intrusion of the cold water. Rapid precipitation of silica as the cold/hot water front advanced into the reservoir sealed off any fresh recharge. The vapor mixture gradually "dried out" and the production declined using the six months by 44% without stabilization. It is believe that the field can only produce about 35 MWe from the wells located at the source fracture zone.