STUDY OT THE INFLUENCE OT RESIDUAL OIL ON CONDENSATE LOSSES AT SREDNEBOTUOBINSKIY OIL AND GAS CONDENSATE FIELD

Introduction. As a result of the operation of the Srednebotuobinskoye feld, with an advanced decrease in pressure in the gas condensate area of the formation as compared to the underlying oil rim, an uncontrolled fow of oil into the gas condensate reservoir occurs. At the same time, one of the important indicators of feld development is the condensate recovery factor (CIR), which represents the ratio of losses of hydrocarbons in the reservoir to their geological reserves. This phenomenon has a negative impact on the condensate recovery of deposits, including the process of precipitation of heavy hydrocarbon fractions. Materials and methods of research. The infuence of residual oil on reservoir losses of hydrocarbons in the development of gas condensate deposits in the northern dome of the Srednebotuobinskoye feld was determined based on the results of experimental studies. The determination of the effect of oil vapors on condensate recovery was carried out experimentally on a PVT unit by the method of differential condensation or on the basis of analytical methods under the condition of oil content in the gas condensate system. Experimental study of oil-gas systems was carried out on combined reservoir samples in the presence of residual oil. Based on the results of thermodynamic studies, predictive curves of reservoir condensate losses were constructed for the current period of reservoir development. Results and Discussion. The presence of residual oil has a certain impact on reservoir losses of hydrocarbons and thermodynamic properties at all stages of feld development. As a result, the steam-gas system contains a certain amount of oil fractions. Their concentration (oil content) in the reservoir gas depends on the reservoir pressure, as well as the composition of the reservoir oil. Therefore, it has a negative impact on the value of the condensate recovery factor and component recovery of hydrocarbons. This issue is of particular relevance for the reservoir systems of the Srednebotuobinskoye oil and gas condensate feld. In order to determine the oil content of reservoir systems, empirical formulas are actively used. Methods for predicting the presence of residual oil in a multicomponent mixture are based on the use of equations of state. Conclusion. During the operation of the oil and gas condensate reservoir of the Srednebotuobinskoye feld, the component composition (mixture of gas condensate vapors and oil) of the produced gas condensate system changes, which affects the change in the composition of the formation fuid during the development of the feld. Prediction of the effect of residual oil and its crossfows of the underlying oil rim on the amount of condensate recovery was carried out under various thermodynamic conditions. The graphical dependence shows that in the presence of heavy oil fractions in the gascondensate system, the condensation process intensifes. At the same time, formation condensate losses in the reservoir increase.

condensation onset pressure, condensate recovery factor, reservoir development, saturated condensate, condensate losses, separation gas, reservoir oil, contact condensation, experimental PVT studies

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