Fifteen Years of Reinjection in the Larderello-Valle Secolo Area: Analysis of the Production Data

Abstract

Intensive exploitation of the Larderello-Valle Secolo area has depleted the fluid inside the reservoir and caused the reservoir pressure to fall to about 0.5 although the reservoir temperature remains 240-250?C. Under these conditions a large fraction of themial energy remains stored in the reservoir rocks. Water injection tests in this "superheated" area started in 1979 and demonstrated that an enhancement of heat recovery through the boiling of injected water is feasible. Starting in 1984, reinjection of waters discharged from power plants became an important part of the exploitation strategy for this area. Analysis of the well production parameters the positive effects of reinjection with a significant increase in steam flow-rate and reservoir pressure. light of the positive results, a supplementary injection program was planned and put into operation in 1994 in order to increase secondary heat recovery in the Valle Secolo area.