Nazan Yalcin Erik

Source-Rock Hydrocarbon Potential of the Middle Triassic—Lower Jurassic Cudi Group Units, Eastern Southeast Turkey

The southern part of Southeast Turkey constitutes the northern margin of the Arabian plate. The region contains rock units ranging in age from Paleozoic to Mesozoic. The source-rock potential of the Middle Triassic-Lower Jurassic Cudi Group in the eastern part of Southeast Turkey was investigated. Samples were obtained from six wells (çilesiz-1, B. Yolaçan-1, G. Dinçer-1, çamurlu-101, çamurlu-102, and Yolaçan-3). The source-rock potential of these units was evaluated by organicgeochemical and petrographic analyses. Sediments have an average of 0.15% total organic carbon (TOC). Commonly, TOC is higher in carbonate-rich facies than in evaporitic deposits. TOC analyses of the Cudi Group shows that these formations are poor to moderate in organic matter. The S1 (average 0.25 mgHC/gTOC), S2 (0.40 mgHC/gTOC), hydrogen index (HI) (average 235 mgHC/gTOC), oxygen index (OI) (average 231 mgCO2/gTOC), and Tmax (average 422°C) values from the Rock-Eval pyrolysis indicate that the dominant organic matter consists of types II and III kerogen, which have gas generative potential. Production index (PI) values indicate samples containing secondarily migrated hydrocarbons. Optical investigation demonstrates that the organic matter is mainly amorphous (70-90%) and of marine origin, but includes small amounts of terrigenous organic matter (10-30%). Results suggest that these beds probably do not constitute a source of liquid hydrocarbons but may represent a source of gas.

On the Use of Conventional and Soft Computing Models for Prediction of Gross Calorific Value (GCV) of Coal

Gross calorific value (GCV) is an important characteristic of coal and organic shale; the determination of GCV, however, is difficult, time-consuming, and expensive and is also a destructive analysis. In this article, the use of some soft computing techniques such as ANNs (artificial neural networks) and ANFIS (adaptive neuro-fuzzy inference system) for predicting GCV (gross calorific value) of coals is described and compared with the traditional statistical model of MR (multiple regression). This article shows that the constructed ANFIS models exhibit high performance for predicting GCV. The use of soft computing techniques will provide new approaches and methodologies in prediction of some parameters in investigations about the fuel.

Organic Geochemical Characterization and Hydrocarbon Potential of Tertiary Coals of the Tokat Province (Central Anatolia, Turkey)

The aim of this study is to provide geochemical and petrological data to characterize coals and carbonaceous shales of the Tokat Province in terms of both compositional and thermal-maturity parameters. The samples, collected from outcrops, belong to the Pliocene Kemerkaş Formation. Geochemical results are based on total organic carbon content, Rock-Eval pyrolysis and GC, and GC-MS analyses. Generally, there is good agreement between the acquired optical and geochemical data, and between organic and inorganic changes. All parameters indicate low-grade transformation, a consequence of low lithostatic pressure. The coals of the Tokat Province are considered to have economic potential as gas (hydrocarbon) source rocks.

Organic‐geochemical characteristics of the Miocene Lycian Basin, western Taurides, Turkey

In the Lycian Basin (SW Turkey), the Miocene Karabayır and Karakuştepe formations consist of algal limestone, conglomerate, sandstone, shale and limestone. Total organic carbon (TOC) analysis of the Miocene units show that these formations are poor in organic matter. TOC values are generally between 0.02 and 0.51%, but reach 3.47% in the Karabayır Formation. Hydrogen indices (HI) are mostly below 600 mgHC/gTOC, increasing to 1200 mgHC/gTOC in the Karabayır Formation. S2 vs. TOC diagrams are used to evaluate the sedimentary environments and hydrocarbon potential of the Lower–Middle Miocene sediments (the Isparta, Bucak and Korkuteli‐Elmalı areas). The organic material contains about 63 (type I), 35 (type II) and 29 (type II/III) pyrolysable hydrocarbons, respectively. The dominant organic matter is type II kerogens, and hydrocarbon generating potential is quite low. A positive x‐intercept has been calculated in analysed samples according to S2 vs. TOC diagrams; this value shows a rock‐matrix effect. Clay is the main agent of adsorption. Biomarker characteristics also verify these results. Isoprenoid rates are Pr/Ph: 2, Pr/n‐C17: 1.9, and Pr/n‐C18: 0.5, and a high Pr/Ph ratio (pristane/phytane) indicates an oxic environment; the terpane C29 NH/C30 H ratio is >1 for the Karabayır Formation, and this value indicates a carbonate lithology. On the other hand, the C25 NH/C30 H ratio is <1 for the Karakuştepe Formation; this indicates that the hydrocarbons were derived from terrestrial organic matter. According to m/z 191 mass fragmentograms, the Miocene units contain oleanane, indicating a Tertiary age. The abundance of sterane C29>C28>C27 shows that the kerogens formed from algal organic matter.