Subsurface Geology of the North Sector Ulubelu Geothermal Field, Lampung, Indonesia
Hary KOESTONO, Imam M. PRASETYO, Vivi D.M. NUSANTARA, Marihot SILABAN, M. Husni THAMRIN
[Pertamina Geothermal Energy, Indonesia]
The Ulubelu Geothermal Field is located in the southern tip of Sumatera Island. The field currently generates 220 MW of electricity from 4 Units of single flash geothermal power plant. The earliest 2 Units were commissioned in 2012 and followed by the 3rd and 4th Units in 2016 and 2017 respectively. The 2017-2018 make-up wells program was to drill delineation well further north closer to the postulated upflow. Strong geoscientific rationales were made to justify the campaign. It covers the UBL-J well pad in an elevated terrain of Mt. Rendingan. The UBL-J wells were planned to target the reservoir beneath Mt. Rendingan. The UBL-J consists of three wells in a well pad. All the wells intersected the rhyolitic tuff reservoir which are starting from depth about 1350 to 2200 mMD. The maximum average temperature of the wells about 275oC.
|        Topic: Geology||Paper Number: 12161|