Tracer Simulation in Kamojang Geothermal Field, West Java, Indonesia

Abstract

In Kamojang field, reinjection activity has been carried out since 1983. Tracer injection tests were run to determine the interconnection between water reinjection and production wells.

Tracer of radioisotope tritium as tritiated water (HTO) was injected at KMJ-15 in 1983 and 1992 with activity 370 GBq respectively and at KMJ-46 in 2003 with activity 550 GBq . Tritium injected in KMJ-15 was monitored at production wells that lay at surround of reinjection well. By using TRINV and TRCOOL programs developed by Geoscience Division Orkus Tonum - Iceland , simulation of data could be interpreted to determine breakthrough time of water reinjection and cooling effect to the reservoir. The breakthrough time of water reinjection is about 5 to 7 years and mass recovery of all 7 wells of production is about 13.5%. The average of temperature decline rate in reservoir is about 0.21 ?C in 10 years.

The tritium that was injected at KMJ-46 in 2003 is already detected at six wells but the breakthrough time has not been reached yet and the monitoring is still underway. The simulation by using the same program is made in spite of the data not being complete yet. Simulation shows that the breakthrough time is faster than the 1992 injection, i.e. 1 to 3 years respectively.