The Evidence Used in Targeting Wells in a Geothermal Reservoir Using Fracture Zones and Erratic Structure at Lumut Balai and Tompaso Geothermal Area, Indonesia

Abstract

The most useful surface and subsurface data would concentrate precision orientations to optimize future well design and development strategy. Abundant open fractures are concentrated in more brittle rock at the reservoir. A number of faults were identified through the fractures zone. This is the best evidence for the future development strategy for Lumut Balai at South Sumatra and Tompaso at North Sulawesi.
Three wells at Lumut Balai area and two at Tompaso area have been drilled successfully at a depth of 1,800-2,200 mMD. FMI logging and spinner logging have been done at both areas. Evaluation of spinner data from LMB well indicate an erratic structure at the depth of 800–1,000 mMD that showed the means of how some turbulent fluid flow through narrow fractures to the biggest fractures in reservoir during fluid injection in hole. The fracture zone has been separated at the interval 1,000–1,700 mMD for LHD well at Tompaso area and most of the fracture zones form potential production zones. Both data fully support the next targeting of wells in the surrounding areas.