Evaluation and classification of proved and undeveloped OOIP by reservoir complexity index (in case of Salym brown oil fields)

Abstract

The proposed approach allows to evaluate and classify residual non-recoverable OOIP basing on the criterion of development com-plexity. The concept of uninvolved reserves is introduced. To evaluate possible recoverable reserves, a scenario calculation of the oil recovery factor was performed, according to the El-Khatib model based on the statistical method - displacement characteristics. Au-thors developed an express method for evaluation and classification of non-recoverable reserves based on a comprehensive RCI de-velopment complexity index. For a quick evaluation of reserves, authors propose to use the RCI model with three parameters: per-meability of the formation, initial water cut, which is determined by the initial oil saturation, Corey coefficient for oil, water, maximum relative oil and water permeabilities and waterflooding efficiency, determined through the vertical non-uniformity coefficients (Dyk-stra-Parsons) and lateral heterogeneity. Also, a new method is proposed to evaluate of the waterflooding effectiveness - find the ac-cumulated fluid flow through a unit of pore volume using a hydrodynamic simulator (keywords FLOWO and FLOWW). Further, based on the obtained parameters, it is possible to estimate the residual recoverable reserves: with an increase in the criterion, the com-plexity of development increases. In conclusion, a universal approach has been developed for the evaluation and classification of geo-logical reserves for the further selection of the optimal development system.