Unconventional results and interpretation of displacement experiments for oils with increased viscosity using different displacing agents
Sufficiently labour-intensive lab experiments have been conducted during 2008-2009. Those experiments were devoted to displacement of oils with increased viscosity by different agents. Experiments were carried out under in-situ conditions of one Eastern Siberia field, on reservoir models of 0.3, 1.0, 5.0 and 20.0 m length correspondingly. Oil viscosity in different experiments was equal to 10 or 20 centipoise. Various displacement agents were used, namely, water, polymer solution, water-gas mixture and emulsified solution. While mobility ratio for water displacing oil is much less than unity, viscosity of displacing agents considered was several times bigger than the viscosity of oil displaced. Due to outstanding nature of results, they cannot be interpreted by traditional methods. Consequently, specialized method was developed to handle the observed data. Using it, parameters necessary for 3D reservoir simulations were derived. The experiments fulfilled change our vision regarding the process of oil displacement in porous media. Therefore they make significant influence on methodology of corresponding lab investigations, opening new research directions in core flow experiments; solution algorithms for corresponding flow problems and methodology of 3D flow simulations for oil fields development; comprehension of new possibilities concerning enhanced oil recovery. Eventually the authors formulate original conclusions regarding theory and practice of oil fields development and outline feasible ways of further investigations.