N.V. Grigoriev, A.A. Faizullina, A.E. Fedorova
DOI: https://doi.org/10.25689/NP.2025.3.112-122
Abstract
Analysis of geological conditions presented in this paper suggests that increased concentrations of non-hydrocarbon compounds in oil and gas are associated with carbonate rock distribution zones, mainly in basins whose sedimentary cover comprises thick, fully developed salt-bearing formations; such formations cause anomalous distribution of geobaric, geothermal and hydrochemical fields, which, in turn, leads to anomalies in the composition of hydrocarbon fluids filling the traps in salt-bearing basins.
The authors analyze the physical trends in evolution of nitrogen solubility accounting for the partial pressure in the atmosphere and gas caps. Depending on specific conditions, nitrogen absorption by water and its release (liquid gas liberation) can take place.
As evidenced from well drilling data, nitrogen gas shows are confined to salt-bearing rocks in hydrochemical sediments, while the transition of dissolved gases into free phase often results from inversion movements during formation of the Peri-Caspian Depression and from decompressions of formation water due to geological reasons in the course of field development. Moreover, ingress of formation brines in subsalt rocks increases the salinity of formation water and reduces gas solubility facilitating release of the latter into free phase.
Key words:
nitrogen show, subsalt horizon, near edge zones, groundwater, gas accumulations, Pre-Caspian Depression, hypsometry
References
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Authors
N.V. Grigoriev, Head of Sector, Formation Evaluation and Well Test Department, TatNIPIneft Institute – PJSC TATNEFT
186А, Sovetskaya Str., 423462, Almetyevsk, Russian Federation
E-mail: grin@tatnipi.ru
A.A. Faizullina, 2nd Category Engineer, Formation Evaluation and Well Test Department, TatNIPIneft Institute – PJSC TATNEFT
216, Sovetskaya Str., 423462, Almetyevsk, Russian Federation
E-mail: FayzullinaAnzhelaA@tatnipi.ru
A.E. Fedorova, Research Associate, Formation Evaluation and Well Test Department, TatNIPIneft Institute – PJSC TATNEFT
186А, Sovetskaya Str., 423462 Almetyevsk, Russian Federation
E-mail: oilgas@tatnipi.ru
For citation:
N.V. Grigoriev, A.A. Faizullina, A.E. Fedorova Poisk prichin gazoproyavleniy na Severo-Yeltyshevskom mesterozhdenii [Search for causes of gas shows in Severo-Yeltyshevskoye field]. Neftyanaya Provintsiya, No. 3(43), 2025. pp. 112-122. DOI https://doi.org/10.25689/NP.2025.3.112-122. EDN GDEPLG (in Russian)