Application of Soap Sticks for Enhanced Stimulation in Geothermal Wells: Case Study of Lahendong Field, Indonesia

Abstract

The use of soap sticks for well stimulation in the geothermal industry is limited, yet they demonstrate promising potential for improving well discharge efficiency. Reducing the surface tension of water in the wellbore makes it easier for brine to flash into steam. While this method has been successfully employed in inducing eruptions at geyser manifestation, its application in geothermal well stimulation still needs to be explored. This study explores the application of soap sticks as a surfactant-based stimulation method in three non-self-discharging wells in the Tompaso Prospect, Lahendong Geothermal Field, Indonesia. Field trials in wells TPS-1, TPS-2, and TPS-3 demonstrated that combining soap sticks with air compression significantly enhanced discharge potential. TPS-1, with a bottom-hole temperature of 298°C and a feed zone at 2,100 meters, failed to discharge despite multiple air compression attempts up to 95 barg. Notably, TPS-2 and TPS-3 achieved sustained flow at a reduced air compression pressure, lowering the required pressure by up to 25% (22.5 barg lower) compared to targeted stimulation pressure from the Sta Ana method (Af/Ac). These findings validate the effectiveness of soap-assisted stimulation in geothermal wells, particularly in liquid-dominated reservoirs with deep feed zones where conventional high-pressure stimulation methods fall short. Further empirical research is essential to validate the broader applicability of soap sticks and explore additional innovative approaches for effective geothermal well stimulation across varying conditions and fields.