Mezgit formasyonu (Şereflikoçhisar güneydoğusu) jeolojisi ve petrol hazne kaya özelliklerinin incelenmesi
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Date
2001
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Fen Bilimleri Enstitüsü
Abstract
Study area is located in east of Tuz Gölü Basin and southeast o Şereflikoçhisar in the central Anatolia. Basement rocks in north an< northeastern parts of the Tuz Gölü Basin are represented with Temirözü anı Mollaresul Formations and units of Ankara Complex and Kırşehi Crystalline Complex; east and southeastern parts of the region ar characterized by the units of Kırşehir Crystalline Complex while west am southwestern parts are represented with low-degree metamorphites. L accordance with transgressive and regressive character of the sea betweei upper Cretaceous and recent time interval, horizontal and vertical lithofacie changes are observed within the units. During this time interval, flysch typ sediments were deposited in deeper parts of the basin while terrestrial an shallow marine units were accumulated in the margins. It was observed ths all these units are laterally and vertically transitional with each othei During the upper Cretaceous and recent time interval, from oldest to th youngest, Kartal, Haymana, Çaldağ, Karapınaryaylası, Çayraz, Mezgit an Cihanbeyli Formations were deposited in east and southeastern parts of th Tuz Gölü Basin. Upper Eocene-Miocene Mezgit Formation under investigation is compose of terrestrial deposits that start with pebbles at the basement and continu with pebbly sandstone, pebbly mudstone and are comprised by massivi laminated, claret-greenish colored, organic material-bearing gypsiferoi mudstone at the top. Organic material-bearing mudstones in the Mezgit Formation are thought to be bedrock. Sandstones in the unit are evaluated as reservoir rock and, the aim of this study is to investigate the reservoir rock characteristics of sandstones. Porosity and permeability values of samples from sandstone levels in the region are below the limit values in some localities (Pamukdere and Değirmenüstüdölektepe). Depending on diagenetic processes, porosity values in other areas are changeable. With epocxy thin section determinations and SEM studies performed in sandstone samples from the formation, primary mtergranular - intraconstituent and secondary intergranular - grain fracture porosity were determined. Some diagenetic processes, such as compaction, fracture development, cementation, fracture fill, argillization of feldspars and development of secondary porosity in the carbonate cement were found in the Mezgit Formation. These diagenetic processes have a negative effect on the reservoir. On the other hand, formation of fracture and secondary porosity have a positive effect on the reservoir. However, filling of these space and fractures with carbonate and argillization of feldspars lowered the porosity and permeability. On the basis of results of porosity, permeability and grain density tests together with diagenetic investigations, a reservoir rock potential was determined in Araliksenirtepe and around Kayalıboğazı. 108 pages.KEY WORDS: Tuz Gölü Basin, Mezgit Formation, reservoir rock, porosity, permeability, sandstone, diagenesis.
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Jeoloji Mühendisliği