Unstable Polymer Flooding and Its Application in Offshore Heavy-Oil Field of China

Abstract

As the injection conformance reversion induced by single-slug continuous polymer flooding usually compromises EOR results, a novel and unstable discontinuous polymer injection pattern and the corresponding black-oil-based multi-component polymer model is proposed, which allows to conduct research on mechanisms and key injection parameter optimization in offshore heavy-oil reservoirs. In addition, its pilot test and results in J oilfield of Bohai Bay of China will be discussed. It shows that unstable polymer flooding pattern can improve compatibility between the injected liquid and reservoir heterogeneity, which makes the alternation law of flow resistance force of layers tend to be the same and contain conformance reversion, which make the injection conformance of heavy-oil reservoir turn to ‘U’ type from ‘V’ type, finally enhances liquid suction amount of the low-permeability zone and its remaining oil mobilization. Proper alternating injection cycle can best suppress conformance reversion and creates best EOR results. An alternating injection cycle optimization model is developed based on uniform design method. Good EOR results are shown in the pilot test, the central production well witness more than 7.3 percentage decrement in water cut and more than 70% increment in oil production rate. These can provide technical guidance for sustainable and efficient development of heavy-oil reservoir.

Copyright 2019, IPPTC Organizing Committee.

This paper was prepared for presentation at the 2019 International Petroleum and Petrochemical Technology Conference in Bei**g, China, 27–29, March, 2019.

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