Quantitative Characterization Of Polymer Flooding Production Performance

The quantitative characterization of dynamic change rules in polymer flooding units in Shengli oilfield and the disclosure of the influential factors and dynamic change characteristics of polymer flooding in different types of reservoirs can provide important guideline for scheme programming, performance evaluation and prediction and field tracking and adjustment in polymer flooding.Polymer flooding units in Shengli oilfield are classified into 5 categories in the paper. Different types of polymer flooding units display different rules in injection production performance. Polymer flooding performance quantitative characterization models are established. In these models, four characteristic parameters with specific physical meanings are included. The characteristic parameters are original times, peak value times, finishing times and peak values. The corresponding automatic solution method based on real-coded genetic algorithm is presented. Taking 14 polymer flooding units of Shengli oilfield as an example, the matching between the quantitative characterization models and the field data and studies about production performance quantitative rules in different kinds of polymer flooding units are conducted. It is indicated that the mathematic models are concise and can be extrapolated, in which the parameters are easy to determine. These models have universal significance and can also be used in the matching and prediction of similar growth curves in the engineering problems.Based on the quantitative characterization of polymer flooding performance, the quantitative rules of oil increment, change of water cut are obtained. And the quantitative relationship between the oil increment and the water cut change is also obtained.Taken polymer flooding units in Shengli oilfield as prototype model is built and 15 dynamic influential factors and influential rules in polymer flooding are discussed. It is indicated that the main influential factors of performance characteristics in polymer flooding include: variation coefficient of permeability, underground oil viscosity, underground water salinity, underground temperature, polymer flooding injection moment, injection amount, injection rate, injection-production ratio, relative permeability reduction factor and adsorption.Genetic algorithm is employed to match the tendency for polymer flooding units presenting certain dynamic change tendency to obtain performance quantitative characteristic model for early performance prediction in polymer flooding.