Study On Water Displacement Efficiency In Extra - High Water Cut Stage

When the field development in the advanced stage, most of the oilfields have entered into the extra-high water cut period, faced with the problem of high moisture content, low recovery efficiency, seriously affect the field overall economic benefits. Oil displacement efficiency is an important parameter to predict the effect of oilfield development and oil recovery ratio, how to accurately predict and calculate the oil displacement efficiency, becomes the key to improve the oil recovery ratio. Therefore, this article mainly studied the measurement standards, influencing factors, influence factors and calculation methods of the water displacing oil efficiency.First of all, the existing factors affecting the oil displacement efficiency are analyzed in the article. Combined with the experimental data of Salto oilfield, by means of the mathematical statistics software and the grey correlation analysis, we do the multivariate analysis for the oil-water displacement efficiency from the perspective of macro and micro respectively.Secondly, the existing calculation methods of oil displacement efficiency analyze the adaptability in this paper. On this basis, from the angle of microscopic, the stress distribution of remaining oil drops is analyzed, and the quantitative expressions of displacement efficiency in the parallel capillary bundle model is deduced; From a statistical point of view, combined with the oil droplets moving condition, we get the quantitative characterization of oil displacement efficiency in the three-dimensional pore network model.Finally, because the calculation methods of oil displacement efficiency are more, it has certain limitation in the calculations; this paper proposes a new forecasting method. Using the improved method of BP neural network and the grey system theory to predict the oil displacement efficiency, compared with actual value, the result shows that the method of grey system theory have advantages of simple use, high prediction accuracy, etc.Through the above studies, on the one hand, make up and improve the related theory about the oil-water displacement efficiency, on the other hand, effectively and reasonable guide the water injection development oilfield.