Geochemical description and oil&gas generation potential of Mesozoic formations within the Gydan and Yenisei-Khatanga oil and gas bearing regions
The paper presents the results of geochemical studies of organic matter in the Mesozoic deposits of Gydan and Yenisei-Khatanga oil and gas bearing regions; the studies were conducted on the comprehensive collection of core material with the use of the Rock-Eval method. The detailed sampling was carried out in the intervals, where the previous investigations have identified the levels with predominance of sapropelic components in the organic matter. IT is shown that source rocks of the Yanovstansky (J3-K1jan) and the upper part of the Golchikhinsky (J2-K1gl) formations are of the major interest in the context of liquid hydrocarbons generation. 20 to 50 m thick members enriched in sapropelic-type organic matter and situated in the oil window were identified in the mentioned formations. It is found that in terms of generation features, source rocks of the Golchikhinsky intervals associated with its middle and upper parts do not differ from the Yanovstansky source rocks. Comparison of Rock-Eval results for stratigraphic levels of the lower parts of the Golchikhinsky and Sigovsky (J3sig) formations also shows their similarity. Inhomogeneity of the Golchikhinsky Fm in terms of geochemical parameters confirms the previously discussed assumptions that this sequence should be stratified into formations (Yanovstansky, Sigovsky, and, possibly, Tochinsky), while the Golchikhinsky formation should be considered as a group.