Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Fluid-CO2 Injection in a Hypersaline Volcanic Systems: A Reactive Transport and Experimental Evaluation with Application to the Tuzla Geothermal Field, Turkiye(Springer, 2026) Tonkul, Serhat; Erol, Selcuk; Baba, Alper; Regenspurg, SimonaThis study evaluates the CO2 sequestration capability of the Tuzla Geothermal Field (TGF) in northwest T & uuml;rkiye under reservoir conditions (200 degrees C and 4.4 MPa). While ongoing studies at TGF have investigated CO2 co-injection primarily for geothermal heat extraction, the present study focuses on the associated potential for long-term CO2 storage. To this end, CO2-brine-rock interactions were examined through batch reactor experiments and reaction path modeling using the PhreeqC geochemical tool. The experiments revealed complex dissolution/precipitation reactions that altered reservoir properties, with mineralogical analyses (XRD, XRF, SEM, and EDS) showing the formation of secondary phases such as calcite, kaolinite, and Ca-rich aluminosilicates. These results indicate that the Tuzla reservoir rocks provide sufficient divalent cations to support mineral trapping under reservoir conditions. Overall, our findings highlight that, in addition to its promise for heat extraction, CO2 co-injection at TGF offers an opportunity for permanent geological storage, thereby strengthening the dual benefits of this approach.Article Development and Validation of Regression Model via Machine Learning to Estimate Thermal Conductivity and Heat Flow Using Igneous Rocks from the Dikili-Bergama Geothermal Region, Western Anatolia(Pergamon-Elsevier Science Ltd, 2026) Ayzit, Tolga; Sahin, Onur Gungor; Erol, Selcuk; Baba, AlperThermal conductivity is a fundamental parameter that significantly influences the thermal regime of the lithosphere. It plays a crucial role in a variety of geological applications, including geothermal energy exploration, igneous system assessment, and tectonic modeling. In this study, a machine learning approach is used to predict the thermal conductivity of igneous rocks based on the composition of major oxides. A total of 488 samples from different regions of the world were analyzed. The thermal conductivity values ranged from 1.20 to 3.74 Wm(-1) K-1 and the mean value was 2.61 Wm(-1) K-1. The Random Forest (RF) algorithm was used, resulting in a high coefficient of determination (R-2 = 0.913 for training and R-2 = 0.794 for testing) and a root mean square error (RMSE) of 0.112 and 0.179, respectively. Significance analysis of the traits identified SiO2 (>40 %), Na2O (>15 %) and Al2O3 (>10 %) as the most influential predictors. The study presented results from the Western Anatolia region, where felsic rocks had the highest thermal conductivity (mean = 2.69 Wm(-)(1)K(-)(1)) compared to mafic (mean = 2.34 Wm(-)(1)K(-)(1)) and ultramafic rocks (mean = 2.39 Wm(-)(1)K(-)(1)). In addition, the study evaluated the predictive capabilities of machine learning models for the igneous rocks of the Dikili-Bergama region and compared the results with those of saturated models. Using these data, we calculated heat flow values of up to 400 mWm(-2) under saturated conditions in western Anatolia. These results highlight the value of integrating geochemical data with machine learning to improve geothermal resource exploration and lithospheric modeling.Article Citation - WoS: 1Citation - Scopus: 1Petrogenesis and Comprehensive Thermal Assessment of the Dikili-Bergama Region, Western Anatolia(Pergamon-elsevier Science Ltd, 2025) Ayzit, Tolga; Erol, Selcuk; Baba, AlperVarious methods are available to evaluate the thermal properties and energy potential of geothermal fields. The heat flow method is crucial for thermal modeling and understanding geological evolution. It helps to assess the impact of geological formations on various processes, including hydrocarbon generation and structural modeling. This study focuses on the Dikili-Bergama geothermal region and presents heat flow trends based on thermal modeling. The analysis of volcanic rock petrogenesis data and a thermal model are presented based on data from deep and shallow boreholes. The geothermal gradient is found to vary between 66.28 degrees C km-1 and 121.68 degrees C km-1, according to the interpolated data. Additionally, the study investigates the geochemical and lithological properties of magmatic rocks in the Dikili-Bergama region. The Kozak pluton group's has been measured to have radioactive heat production of up to 7.4 mu Wm-3. Thermal conductivity properties and correlations, along with heat flow assessment, contribute to the understanding of geothermal potential. The mean dry thermal conductivity of the rocks in the study area is 2.33 Wm-1K-1. The data for the terrestrial heat flow and the radioactive heat flow values are up to 200 mWm-2. The integration of 3D geological models and thermal models has highlighted the south western area of the study as a promising location for unconventional geothermal operations.Article Citation - WoS: 2Citation - Scopus: 2Bayesian Uncertainty Quantification in Temperature Simulation of Borehole Heat Exchanger Fields for Geothermal Energy Supply(Pergamon-Elsevier Science Ltd, 2025) Mohammadi, Hesam Soltan; Ringel, Lisa Maria; Bott, Christoph; Erol, Selcuk; Bayer, PeterAccurate temperature prediction is crucial for optimizing the performance of borehole heat exchanger (BHE) fields. This study introduces an efficient Bayesian approach for improving the forecast of temperature changes in the ground caused by the operation of BHEs. The framework addresses the complexities of multi-layer subsurface structures and groundwater flow. By utilizing an affine invariant ensemble sampler, the framework estimates the distribution of key parameters, including heat extraction rate, thermal conductivity, and Darcy velocity. Validation of the proposed methodology is conducted through a synthetic case involving four active and one inactive BHE over five years, using monthly temperature changes around BHEs from a detailed numerical model as a reference. The moving finite line source model with anisotropy is employed as the forward model for efficient temperature approximations. Applying the proposed methodology at a monthly resolution for less than three years reduces uncertainty in long-term predictions by over 90%. Additionally, it enhances the applicability of the employed analytical forward model in real field conditions. Thus, this advancement offers a robust tool for stochastic prediction of thermal behavior and decision-making in BHE systems, particularly in scenarios with complex subsurface conditions and limited prior knowledge.Article Citation - WoS: 16Citation - Scopus: 17Experimental Study and Kinetic Modeling of High Temperature and Pressure Co2 Mineralization(Elsevier Sci Ltd, 2024) Berndsen, Maximilian; Erol, Selcuk; Akin, Taylan; Akin, Serhat; Nardini, Isabella; Immenhauser, Adrian; Nehler, MathiasThe potential for in-situ CO2 sequestration was analyzed experimentally for one basaltic hyaloclastite sample from the Nesjavellir geothermal reservoir in Iceland and three metasedimentary rock samples from the K & imath;z & imath;ldere geothermal field in Turkey. Based on batch reaction experiments, this paper demonstrates the interaction between a CO2 gas-charged fluid and rock samples from these reservoirs. The experiments were conducted at 260 degrees C and 0.8 MPa, and 105 degrees C and 17 MPa for the basaltic and metasedimentary rocks, respectively. The experimental results indicate that CO2 sequestration within the glassy basaltic rocks is hampered by zeolite, chlorite, and anhydrite, which compete with carbonate minerals to uptake divalent cations at the P-T conditions applied. In contrast, the carbonation process for the metasedimentary rocks is inhibited by their mineralogical composition. Generally, these rocks are less reactive and provide an insufficient supply of divalent cations. The batch reactor experiments were numerically simulated with the PHREEQC geochemical modeling program. The simulations indicate that CO2 sequestration is feasible at the tested P-T conditions, provided that silicate and SO4 mineralization is suppressed for the basaltic rocks and that there is an effective source of divalent cations for the metasedimentary rocks.