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ON THE NATURE OF HIGH CO2 CONTENTS IN THE KELORSKY PRODUCTIVE HORIZON (KEDERGINSKOYE GAS CONDENSATE FIELD)​

А. V. Svyashchenko 1, N. F. Chistyakova 2, А. I. Sivtsev 1,3

1 Taas-Yuryakh Neftegazodobycha LLC, Irkutsk, Russia; 2 Tyumen State University, Tyumen, Russia; 3 M. K. Ammosov North-Eastern Federal University, Yakutsk, Russia

The article examines results of the analyses of the chemical composition of natural gases obtained during exploration and appraisal drilling in the northeastern Berezovskaya Depression at the Kederginskoye gas condensate field. Potential sources of anomalously high contents of CO2 in natural gas in the sedimentary cover are discussed based on previously published data. It is shown that CO2 contents may become raised by virtue of thermal hydrolysis of carbonate rocks enriched in organic matter. It was concluded that the local increase in the temperature in the section was assisted by emplacement of intrusive bodies in the Kederginskoye gas condensate field section during the neotectonic activation of the faults. The presented herein geological and specific site conditions affecting product recovery from the Kelorsky productive horizon (reservoir) are indicative of the presence of highly fractured zones formed under tectonic compression. It is recommended to include analysis of the carbon isotopic composition which is crucial for understanding formation mechanisms of CO2.

Keywords: carbon dioxide, Ichere Formation, Lower Cambrian, magmatic intrusions, increase in temperature, hydrolysis of carbonate rocks.

DOI 10.20403/2078-0575-2025-3-28-35

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