西南石油大学学报(自然科学版) ›› 2020, Vol. 42 ›› Issue (2): 103-109.DOI: 10.11885/j.issn.1674-5086.2019.05.08.01

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Optimization of Injection Technique of Corrosion Inhibitor in CO2-flooding Oil Recovery

ZHANG Deping1,2,3, MA Feng2,3, WU Yule4, DONG Zehua4   

  1. 1. School of Petroleum Engineering, Northeast Petroleum University, Daqing, Heilongjiang 163318, China;
    2. National Energy and CO2 Flooding and Sequestration Technology Research(Experiment) Center, Songyuan, Jilin 138000, China;
    3. Jilin Oilfield Company, CNPC, Songyuan, Jilin 138000, China;
    4. School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
  • Received:2019-05-08 Online:2020-04-10 Published:2020-04-10

Abstract: Severe downhole corrosion occurred during Jilin CO2 flooding in an oilfield in Jilin due to the high pressure of CO2, high concentration of saline water and sulfate reducing bacteria (SRB) in the produced fluid. Currently, addition of corrosion inhibitors is one of the common methods to protect the oil well and tubes. Through studies of corrosion mechanism and main factor analysis, the effects of inhibitor type, concentration, and injection technique on their filed inhibition efficiency and long-term durability were investigated, aiming at lowering the cost of corrosion management. Then a suitable injection regulation of inhibitor is proposed based on the filed situation in order to improve the long-term efficacy of inhibitor. Injection optimization tests indicate that the corrosion rate has been decreased to <0.076 mm/a. This optimized injection technique of inhibitor not only increases the service life of downhole device and tubes but also decrease the cost of corrosion management.

Key words: CO2 flooding, enhanced oil recovery, CO2 corrosion, corrosion inhibitor, injection technique

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