RESERVOIR MODELLING OF LAHENDONG GEOTHERMAL FIELD, SULAWESI - INDONESIA

Abstract

Lahendong is a geothermal system in North Sulawesi, Indonesia, which has been generating electricity since 2001. Since this field is likely to be developed further, it is important to perform reservoir modelling of Lahendong to improve understanding of the characteristics of the field and to provide better estimates of its production capacity.
The model discussed here tries to improve on the previous numerical model that was developed by Yani (2006). The model is extended in area and depth, and the grid is refined. The surface of the model follows the topography and an air/water equation-of-state is used so that the shallow zone at Lahendong, including the vadose zone can be represented.
Model results from natural state simulations are compared to the actual temperature data from pre-production wells. Calibration to improve the model was performed by adjusting parameters in the model, such as permeability, flow rate and enthalpy of the deep inflow. After much iteration a good match to the temperature profiles was obtained, although there is still room for further improvements.