Ömer-Gecek (Afyonkarahisar) Jeotermal Sahası Rezervuar Kayaçlarının Mineropetrografik ve Jeokimyasal Özellikleri

Authors : Metin BAĞCI, Ahmet YILDIZ, Can BAŞARAN

Pages : 506-517

Doi:10.35414/akufemubid.703597

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Publication Date : 2020-06-30

Article Type : Research Paper

Abstract :The most important elements of the geothermal system are fluid, reservoir-cover rock, heat source, and fault lines. In geothermal basins, it is necessary to have a reservoir rock of sufficient thickness with high porosity and permeability. The aim of this study is to determine the mineralogic-petrographic and geochemical features of the marbles, which are the reservoir rocks of Omer-Gecek geothermal region. In this scope, the samples taken from both the outcrops and the geothermal drillings made in the region were investigated and the possible effects of water-rock interaction were determined. There are low and medium temperature (45-128ºC) fluids produced from Omer-Gecek region, the most important geothermal field in Afyonkarahisar (Western Turkey). Afyon metamorphics, which are composed of Bayramgazi schists and Oyuklu Tepe marbles, are the basement rocks of the study area and the marble lenses/bands form the reservoir rock. As a result of the analyses, it has been determined that the samples are mainly composed of calcite and dolomite minerals, and these minerals are accompanied by quartz and mica minerals with secondary minerals and kaolinite minerals as alteration minerals. The granoblastic textured outcrop marble samples gained breccia texture due to alteration and secondary manganese and iron-rich solutions were deposited into the pores and micro-cracks. According to the geochemical analysis results, while the CaO is the most important component in outcrop samples, it is significantly depleted in drilling samples, while MgO, Al2O3, and SiO2 levels are enriched.
Keywords : Reservoir rock, Marble, Mineralogy petrography, Geochemistry, Afyonkarahisar