Debatable interpretation of hydrocarbon saturation of osinsky carbonate reservoirs and solution methods

Koshkarova E.F. efkoshkarova@tnnc.rosneft.ru “Tyumen petroleum research center” LLC Tyumen
Naumov V.A. “Tyumen petroleum research center” LLC Tyumen
Bukharova I.A. “Tyumen petroleum research center” LLC Tyumen
Tikhonova K.V. “Tyumen petroleum research center” LLC Tyumen
Chirgun A.S. “Taas-Yuryakh Neftegazodobycha” LLC Irkutsk
DOI: 10.24412/2076-6785-2023-6-32-36

Abstract
The paper describes the analysis of the Dakhnov-Archie functions FRF = f(Sw) based on core data from Srednebotuobinskoye field before and after extraction. The equations were used to determine the hydrocarbon saturation indices in the carbonate reservoirs of the osinsky horizon. The values of the log-based oil and gas saturation coefficient and the core-based geophysical surveys of wells for the gas- and oil-saturated part of the reservoir were compared. The function based on the core studies before extraction proved to be the most reliable one. This function was applied for the first time to determine the oil and gas saturation coefficient of the osinsky reservoirs for reserves estimation purposes.

Materials and methods
Two petrophysical functions were built to determine the hydrocarbon saturation of carbonate reservoirs of the osinsky horizon based on core data before and after extraction. The post-extraction function is based on core data from 13 wells (1 029 samples), the pre-extraction function is based on the core from a single well (67 samples).

Keywords
osinsky horizon, carbonate reservoir, wettability, oil and gas saturation, core extraction, petrophysical function
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