Organic Geochemical Investigations of the Tertiary Units in the Thrace Basin (Edirne, Turkey)

Abstract

Units in the Thrace basin with respect to petroleum geology can be divided into two parts: pre-Tertiary and Tertiary deposits. Pre-Tertiary units are generally represented with ophiolites, green schists, and magmatic rocks comprising the basement and upper Cretaceous sediments. The Oligocene Osmancık formation, the upper Eocene-lower Oligocene Mezardere formation, the Eocene Hamitabat, Soğucak, and Ceylan formations encountered in the Minnetler-1A and Karakavak-1 wells drilled in the Thrace basin, are composed of shale, limestone, and sandstone. On the basis of organic geochemical and organic petrographic observations in the Minnetler-1A and Karakavak-1 wells, organic components of the Eocene-Oligocene formations are generally terrestrial organic materials (Type II and Type III kerogens). In the Minnetler-1A and Karakavak-1 wells, organic material contents of units are between 0.08 and 2.48 wt%. On the basis of these values, the Eocene-Oligocene units in both wells show weak to good source rock potentials. According to maturity parameters, Eocene-Oligocene units in the Minnetler-1A and Karakavak-1 wells are at immature and mature oil zone.