Subsurface Temperature of Well B-02 and D-01 Tulehu Geothermal Field: Past and Present

Abstract

Abstract. Tulehu geothermal field is one of the geothermal potentials in Eastern Indonesia. This field is located in the eastern part of Ambon Island and is associated with a relatively old geothermal system, where the last volcanic activity is estimated to have occurred during the Pliocene. The subsurface temperatures of wells B-02 and D-01 were analyzed using drilling data, including well lithology data based on cutting analysis, laboratory analysis such as petrography, XRD, and fluid inclusion, as well as temperature and pressure measurements (PT Logging). The subsurface temperature of well D-01 shows a significant decrease, approximately 60-70°C, compared to its formation temperature in the past. Meanwhile, in well B-02, the current temperature is similar to its formation temperature based on fluid inclusion analysis, though the current temperature is slightly lower than its formation temperature when assessed through alteration mineral temperature analysis.