Geothermal Exploration in Hululais Geothermal Field, Lebong Regency, using a 1D Magnetotelluric Approach to Estimate The Depth of Reservoir Rocks

Abstract

Indonesia continues to rely heavily on hydrocarbon energy sources. However, in order to ensure the country’s long-term economic growth, it must diversify its energy investments and use renewable energy sources. Through tapping into the country’s vast untapped geothermal resources, the country can meet its rising energy needs in a sustainable and effective manner, all while contributing to mitigating climate change’s worst effects. Lebong Regency, Bengkulu, Indonesia, is the site of the Hululais Geothermal Field. Geothermal energy could be extracted from the area’s hydrothermal systems, as evidenced by the existence of surface hot springs and sulfur craters. In order to determine how deep the geothermal reservoir rocks at Hululais go, a thorough investigation of the area has been carried out using the magnetotelluric (MT) technique to probe the underlying lithological conditions. More than 10 kilometers of MT data were collected across 4 different survey stations for this study’s 1D inversion. The information was gathered with the help of a Metronix ADU-07e MT instrument. The 1D occam inversion results explain the resistive zone connected to the flow of thermal fluid. Hot springs and sulfur craters can be seen on Hululais’s surface, indicating the fluid flows beneath the island’s crust. 1D Occam inversion of MT data measured in the Lebong District can identify geothermal reservoir, where the depth of the geothermal reservoir is 400 meters in subsurface, which is indicated by a high resistivity value (> 500 Ω.m).