| Keywords |
Tuzla, exploration, fractured marble, development, well testing, fluid chemistry, production-injection strategy, electric submersible pumps, scale inhibition |
| Abstract |
Yerka Elektrik Üretim A.Ş. (Yerka) is developing the Mt. Ida geothermal project near the village of Tuzla, Çanakkale Province, Turkey. Exploration began in 2013, with the drilling of two intermediate-depth wells, followed by geological and geophysical surveying in 2014-2015. In 2016 and 2017, Yerka successfully drilled six deep wells. Four wells in the eastern part of the lease are planned for production, and two wells in the west are planned for injection, with a separation of about 1 kilometer (km) between production and injection areas. Well testing has indicated sufficient production and injection capacity for a binary geothermal plant with a capacity of 12 MW gross. As of July 2019, the plant and gathering system are under construction, with a planned commercial operation date in the summer of 2020. Development wells have been drilled to 2,300- 2,500 meters measured depth (mMD). The main permeable intervals are in fractured marbles at depths typically in the range of 1,500 to 2,200 mMD. Bottom-hole temperatures have ranged up to 157 °C, but temperatures in the production zones are about 126-127 °C. The salinity of produced fluids is relatively high (about 50,000 ppm), while concentrations of non-condensable gas are relatively low (0.5% to 0.7% by weight in total flow). The wells have shown significant benefits from acid stimulations through coiled tubing, with Productivity Indices post-acid ranging from 21 to 139 tons/hour per bar. Pressure-interference testing shows that the entire well-field is interconnected, which is beneficial from the perspective of maintaining pressure support by injection. However, the interference is low enough that thermal breakthrough by injection should not be a concern. Yerka plans to use electric submersible pump (ESP) technology to maintain steady production rates and provide a greater measure of operational control. The produced fluid will be allowed to boil in the column pipe above the ESPs. The ESP design incorporates the use of downhole scale inhibitor to avoid scaling above the pumps and in the surface facilities. |