A Study on the Production and Reservoir Performance of the Germencik Geothermal Field

Abstract

The Germencik geothermal field is located in the western part of the Buyuk Menderes Graben (Western Anatolia). The field was discovered by MTA (General Directorate of Mineral Research and Exploration) in 1967 and more than 38 wells were drilled since then. It is a liquid dominated reservoir, with a temperature close to 240 oC, whose main feature is the high noncondensable gas (mainly CO2) content as much as 2.5% by weight. GURIS Construction and Engineering Co. Inc. is the operator of the field and constructed a 47.4 MWe double-flash power plant in 2009. The early production performance of the field clearly indicates a great potential for further developments. GURIS intends to develop the field and to extend the power plant capacity in the near future. In this study, the results of temperature profiles, well tests, and chemical analysis to characterize the Germencik geothermal reservoir are evaluated and presented. Based on static temperature measurements obtained from the wells throughout the field, a 3-D temperature distribution map was constructed. The reservoir limits are studied, and the volume of water in place and stored heat are estimated by various methods. About 80% of the produced fluid has been reinjected into the reservoir without any cooling and injectivity problems so far. The modeling study to assess the impacts of the further developments on the reservoir is underway. Our in-house lumped paramater model is utilized to model the production rate-reservoir pressure history and an almost perfect match is obtained. Results of the proper model obtained from the match are used to estimate the production performance of the field under several production scenarios.