Field Applications of an Evaluation Model for Enhancing Recovery Efficiency to Polymer-flooding

Abstract Polymer flooding development tests stared from 1990’s were carried out on Daqing and Shengli oilfields in China, with water-flooding as its most important development measures formerly, which enlarged size scale of tests continuously. Stable production and enhancing recovery efficiency in these oilfields were implemented by polymer flooding technology. Successful field applications showed the yearly production rate reached to nearly 90 million bbl in Daqing oilfield. Feasible and effective report has not been provided yet on the problem that the range of recoverable reserves and recovery efficiency can be reached after polymer flooding. Considering most oilfields accomplished polymer flooding in quick succession and some oilfields were just developed by polymer flooding, practical resolution should be recommended such as the corresponding evaluation model for enhancing recovery efficiency range of polymer flooding. The resolution can also provide an evaluation basis of enhancing recovery efficiency for alkaline-surfactant-polymer flooding in future. This paper proposed an evaluation model for enhancing recovery reserves and recovery efficiency of polymer-flooding based on production decline model of reservoir engineering. Applications of these concepts are illustrated with field examples. Results indicated that recovery efficiency by polymer-flooding after the water-flooding development may be increased between 7% and 12% in Chinese oilfields. The evaluation model has been used effectively to predict EOR effect in Chinese oilfields.