Organic Geochemical Evidence of the Working Petroleum System in Beypazarı Neogene Basin and Potential Traps (Northwest Central Anatolia, Turkey)

Özdemir A., Palabıyık Y., Karataş A., Şahinoğlu A.

Turkish Journal of Geosciences, vol.1, no.2, pp.35-52, 2020 (Peer-Reviewed Journal)

  • Publication Type: Article / Article
  • Volume: 1 Issue: 2
  • Publication Date: 2020
  • Journal Name: Turkish Journal of Geosciences
  • Journal Indexes: Asos İndeks
  • Page Numbers: pp.35-52
  • Istanbul Technical University Affiliated: Yes


The Miocene units of the Beypazarı Neogene Basin extensively outcrop and prevalently include oil shale and coal. In the previous studies, it has been determined that the total organic carbon (TOC) values of bituminous shales in the basin are concentrated between 4-8% and algal organic matter (Type I-II kerogen) are dominant. It has also been determined that the bituminous shales have pyrolyzable hydrocarbon content of 83% and a potential source rock feature that can produce oil in a large quantity if exposed to high temperatures. Beypazarı Neogene Basin consists of volcano-sedimentary units. Therefore, as a result of the idea that the immature source rocks can be matured by young volcanics that exhibit widespread outcrops, it has been aimed to investigate the oil and gas potential especially in the northeastern part of the basin by TPH (Total Petroleum Hydrocarbons) analysis performed on the samples taken from the natural cold water resources located in the related part of the basin. As a consequence of the analyses conducted, hydrocarbons have been detected in all the water samples. The organic geochemical methods have been used to determine the source of hydrocarbons detected in the water resources. The detected n-alkane hydrocarbons are the mature petroleum hydrocarbons derived from peat/coal type organic matter (Type III kerogen, gas-prone). The presence of these mature petroleum hydrocarbons is regarded as evidence for the existence of a working petroleum system in the study area. Due to the presence of waters containing mature petroleum hydrocarbons, the anticlines in the depth of approximately 110 m in fault-propagation folds identified in the investigation area by gravity and magnetic data have a very high potential to become gas reservoirs. Keywords: Beypazarı Neogene basin, reservoir-targeted petroleum exploration, TPH in water analysis, hydrocarbon-rich water, oil shale, coal.