WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Update for Reactive Transport Modeling of the Kızıldere Geothermal Field To Reduce Uncertainties in the Early Inspections
    (TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2023) Erol, Selçuk; Akın, Taylan; Akın, Serhat
    The development of carbon capture and storage techniques has become essential to reduce and mitigating CO2 emissions to the atmosphere. CarbFix1 and CarbFix2 projects carried out in Iceland demonstrated that the emissions of waste CO2 gas from geothermal power plants can be captured and mixed with the effluent geofluid and subsequently injected back into the geothermal reservoir. This experience gained in the CarbFix projects expanded into other geothermal fields around Europe, and one of the demonstration sites is the geothermal field in Turkey, Kızıldere. This paper focuses on the results of an updated study on early field evaluations with reactive transport simulations. In the new three-dimensional numerical model, the geological formations and fault zones were updated according to the well-logs data. Based on the tracer tests performed in the field, the anisotropic permeabilities between the wells were evaluated and imposed into the model. Geofluid chemistry, mineral components, and the volume fractions used as input in the simulations are modified depending on the performed laboratory experiments on the metamorphic schists taken from the geothermal site (i.e. X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning-electron microscope (SEM), and batch reactor tests). Different thermodynamic databases such as Lawrance Livermore National Laboratory (LLNL) and Thermoddem databases were tested using PHREEQC and TOUGHREACT programs for consistency with experiments. The thermodynamic conditions and the geofluid-rock-CO2 interactions prevent the mineralization of CO2 in the reservoir. This outcome differs from CarbFix projects in terms of the carbonization process, but the CO2 injection is still reliable with solubility-trapping in a geothermal reservoir to partially mitigate the emission. Roughly, 200 kt of CO2 in 10 years can be safely injected into the geothermal reservoir. According to the new analysis, the ratio of magnesium, sodium, and potassium varies in solid solution series of feldspars and clay minerals as albite end-member and montmorillonite/illite end-members, respectively. The evaluations of solid solution reactions are relatively limited in the law of mass action approach used by PHREEQC and TOUGHREACT. © TÜBİTAK.
  • Article
    Citation - WoS: 1
    Hydrogeochemical and Hydrogeological Investigation of the Can Geothermal Field
    (TMMOB Jeoloji Mühendisleri Odası, 2010) Deniz, Ozan; Baba, Alper; Tarcan, Gultekin
    The Can Geothermal Field is located on a central part of the Biga Peninsula in northwest Turkey. Volcanics are the dominant rock type in this region. Alteration zones and clay minerals are very common in these rocks. Sedimentary rocks, low-grade metamorphics and alluvium are other geological units observed around Can. These units include common fracture zones because of the tectonic activity in the region. Thermal waters have reached the surface via these fracture zones. Alluvium is the most productive aquifer in all geological units. Wells drilled in this unit yield between 5-30 L/s. The transmissibility and permeability coefficients of this unit are of 50-421 m(2)/day and of 1.01-16.8 m/day, respectively. In this aquifer, groundwater depth changes between 0.1 and 8.3m. According to the IAH (1979) water classification, these thermal waters are of the Na-Ca-SO4 type, the cold waters are of the Ca-Mg-HCO3 type and the snow samples are of a mixed water type. Geothermal waters have a meteoric origin. The mean temperature, electrical conductivity and pH of the thermal waters have values of 44.4 degrees C, 2941 mu S/cm and 6.9, respectively. Geothermometer equations were used for prediction of reservoir fluid temperatures of the geothermal system and temperature values were obtained between 46 and 203 degrees C. delta D, delta T and delta O-18 isotope analysis showes that thermal waters in the Can region have a meteoric origin and are a minimum of 45-50 years old.