Geothermometer, Geoindicator and Isotope Monitoring in Lahendong Wells During 2010-2012

Abstract

Pertamina Geothermal Energy (PGE) Lahendong area has been developed since 2001. Since then, scientific research were always performed to obtain reservoir's performance information. Hence, Geochemical monitoring is essential to maintain and improve production from reservoir. In this paper geochemical monitoring was performed to gain subsurface and well behaviour during production. Data from PGE well were processed to Geothermometer, geoindicator, isotope and entalphy to monitor changes within the reservoir. Well XXX showed significant change from chloride to chloride- sulphate water. Boiling occured then mixing with meteoric water in well XXX-2. Well XXX-3 showed Chloride and entalphy decline indicating water injection influx. Writer recommends to perform tracer test intensively for injection well to provide hidrogeological pattern. MEQ investigation can also provide data to confirm the event in wells.