Geothermal Potential Assessment of Edremit Geothermal Field (NW Turkey)

Abstract

Hot geothermal water from Edremit geothermal field is being used for district heating purposes since early 2000s. Geothermal water with an average wellhead temperature of 60 °C is produced from 12 wells located to a distance of 3 km SE of city center. Although the field has been producing for several years there is no resource assessment study for the field. There are plans to extend the operation into new areas in spite of the signs of a shortage of energy for the installed capacity. This study aims to estimate the recoverable heat energy of Edremit geothermal field with the limited data obtained from the wells. The method that was selected for resource estimation is volumetric method which requires the numerical values of parameters within the volumetric method equation. Almost all parameters of volume method exhibit uncertainties (especially reservoir volume, porosity and temperature) where a probabilistic approach is the common application to overcome these uncertainties. Monte Carlo method was utilized to assign numerical values for each parameter within the given constraints as distribution functions (i.e. triangular, Gaussian, uniform). Geological and geophysical studies, drilling reports, temperatures from geothermometer applications were the data sources to define the constraints of each parameter. In addition, parameters related to recovery of heat and specific to project (recovery factor, transformation yield, load factor, total project life) were assigned from literature. Estimates of recoverable heat resulted with 58.6 MWt, 26.8 MWt, and 9.1 MWt for 10%, 50% and 90% probability, respectively. Those heat recoveries correspond to 1500, 4300 and 9400 Residence Equivalent (RE) heating application where 1 RE means 100 m2 heated area. Municipality of Edremit has a target of 7500 RE heating which corresponds to heat energy with 19% probability.