Exploration and Discovery of the Gumuskoy Geothermal Reservoir in Aydin, Turkey

摘要

This paper outlines the exploration and development effort to discover a geothermal reservoir that is suitable for power generation in the Gumuskoy Area, Aydin, Turkey. The area, located on the western end of the Buyuk Menderes Graben (BMG), adjacent to the Germencik Geothermal Site (232 deg C), was originally discarded by Mineral Research & Exploration General Directorate (MTA) owing to very limited surface manifestations and failed shallow exploration attempts. Exploration efforts were taken over by BM in early 2004, as Turkey's first private sector medium/high enthalpy geothermal exploration initiative. The usual geothermal exploration tasks were this time supported by deep exploration methods, and especially a comprehensive 3D Magnetotellurics and TDEM study conducted in a total of 3 stages and 393 measurement stations. Joint analysis of all results using a GIS database revealed that there exists a deep geothermal system at greater depths (from 1000 to 1500 meters). Three gradient wells were drilled in the area, with the latter having an unexpected blowout at 120m depth. Wildcat exploration well GK-1 was completed on 28 May 2009 at a total depth of 2100 meters, where flow tests confirmed the presence of a geothermal resource in the Gumuskoy formation, yielding a flow rate of 230 tons/hour and a maximum reservoir temperature of 178 deg C. Reservoir modeling, volumetric assessment and feasibility studies were initiated immediately thereafter for development of the 12 - 20 MW Gumuskoy Geothermal Power Plant Project, with expected commissioning in mid 2012. Exploration drilling was likewise continued with ORT-4 at 2330m and GK-3a at 2000m depth, albeit with varied degrees of conformity with the MT measurements.