Study on response differences of major polymer flooding in various reservoirs

Daqing Oilfield is the most important and representative reservoir mainly for polymer flooding at present. Almost all reserve potentials of polymer flooding are centralized in Daqing placanticline. From north to south, sedimentary characteristics of placanticline reservoir have strong directivity and regularity. In this paper, types of reservoir for polymer flooding were divided into north multi-stage and multi-rhythm layer, central positive rhythm thick layer and south compound rhythm thick layer, according to the distribution features of major reservoir sedimentary microfacies, vertical heterogeneity and rock and fluid properties. Then, aiming at three kinds of reservoir characteristics, response differences of polymer flooding in these layers were studied comprehensively and systematically in terms of water flooding degree and EOR efficiency. Meanwhile, the root causes of the differences were analyzed. The research results can provide scientific references and technical support for efficient and rational development of polymer flooding in the thick reservoir and also potential tapping on residual oil after polymer flooding.