NUMERICAL SIMULATION UPDATE of DIENG GEOTHERMAL FIELD, CENTRAL JAVA, INDONESIA

Abstract

Dieng Geothermal Field has been operated for 17 years with installed capacity of 60 MW. Next target, Dieng field will be developed for additional 2x55 MW. For development purposes, numerical model is used to evaluate initial permeability and temperature distribution and to forecast future reservoir performance as well. After 2013, several geoscience surveys and well testing have been conducted in order to estimate the changes of reservoir behavior during production and to update the conceptual model. Several numerical models of Dieng have been developed in 2006 and 2013 by using single porosity approach. Generally, the single porosity models give more optimistic result in forecast simulation and to account this issue dual porosity approach were implemented in the model. The recent numerical model is built by using TOUGH2 with EOS1. This paper describes the possibility and sustainability for the next 2x55 MW development. Several PT shut-in surveys data and production well histories were used to validate the model. During forecast simulation, the model was also coupled with Excel based wellbore model.