About trends in the oil-gas ratio change in the process of exploitation of LUKOIL-West Siberia LLC fields

UDK: УДК 622.276.031

Key words: oil- gas ratio, associated gas recovery, oil degassing by water, thermobaric conditions of separation

Authors: K.E. Kordik, V.V. Shkandratov, A.E. Bortnikov (KogalymNIPIneft Branch of LUKOIL-Engineering LLC in Tyumen, RF, Tyumen), S.A. Leontyev (Ukhta State Technical University, RF, Ukhta)

The results of the analysis of the oil-gas ratio dynamics on the fields of LUKOIL - West Siberia LLC from 2004 to 2014 are presented. The trend of oil-gas ratio increasing is marked in many fields, including the facilities being at late stage of operation. The dynamics of the oil-gas ratio depends on a factors complex, related both to intrastratal changes of fluid properties, and to the conditions of the separation of wells production in the routine preprocessing facilities. Among the reasons, that lead to reservoir changes of the oil-gas ratio, special attention is paid to oil degassing by the injected water. The impact of this factor is especially noticeable in the later stage of the development of the deposit, when water cutting of wells production exceeds 90%. During this period, it is advisable to conduct further studies to determine the gas-oil ratio of produced water. An important aspect, determining the dynamics of the oil-gas ratio, is also a mode of operation of the routine preprocessing facilities, in particular the change of thermobaric regime of oil separation from the gas. The significant oil separation temperature rise in the facilities of LUKOIL - West Siberia LLC is marked during the observation period (from 2004 to 2014), that contributes to a further transfer of low-boiling hydrocarbons in the gas phase and, consequently, leads to the oil-gas ratio increase. Therefore, for the fact-based analysis of the oil-gas ratio change reasons it is required the constant monitoring not only the parameters, characterizing the operating mode of deposit, but also parameters of field separation (temperature and pressure), that is currently neglected.
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