Title: The effects and control of viscosity loss of polymer solution compounded by produced water in oilfield development

Authors: Zhihua Wang; Yang Liu; Xinpeng Le; Hanying Yu

Addresses: Key Laboratory of Enhanced Oil & Gas Recovery, Ministry of Education, Northeast Petroleum University, No. 199 Fazhan Road, Daqing 163318, China ' Key Laboratory of Enhanced Oil & Gas Recovery, Ministry of Education, Northeast Petroleum University, No. 199 Fazhan Road, Daqing 163318, China ' Key Laboratory of Enhanced Oil & Gas Recovery, Ministry of Education, Northeast Petroleum University, No. 199 Fazhan Road, Daqing 163318, China ' Key Laboratory of Enhanced Oil & Gas Recovery, Ministry of Education, Northeast Petroleum University, No. 199 Fazhan Road, Daqing 163318, China

Abstract: To avoid the environment pollution and remit the pressure of produced water stored up in water stations at high-water-cut stage, a special technology of enhanced oil recovery (EOR), in which produced water is used for compounding polymer solution, has been formed in Daqing Oilfield. However, the viscosity loss is difficult to be avoided only by modifying the polymer production. Then the effects of salinity, bacteria and reducing substances of produced water on viscosity loss are analysed respectively in this paper. The results proved that biodegradation and chemical degradation are as important as mechanical degradation in polymer solution. As more complicated processes and higher cost are needed for the desalination of produced water, a sterilisation-aeration treatment technique with simple process and low cost is proposed. The application of proposed procedures indicated that, viscosity loss of polymer solution with different molecular weights and different concentrations can be reduced by 10 mPa.s, and more than 100 mg/L polymer working concentration can be saved in compounding with the same viscosity. [Received: May 29, 2012; Accepted: December 8, 2012]

Keywords: polymer flooding; produced water; viscosity loss; aeration; sterilisation; Daqing Oilfield; China; oilfield development; environmental pollution; enhanced oil recovery; EOR; salinity; bacteria; biodegradation; chemical degradation; mechanical degradation; desalination.

DOI: 10.1504/IJOGCT.2014.060068

International Journal of Oil, Gas and Coal Technology, 2014 Vol.7 No.3, pp.298 - 307

Received: 21 Jun 2012
Accepted: 08 Dec 2012
Published online: 24 May 2014 *

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