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Journal of Nanotechnology
Volume 2018, Article ID 7602982, 9 pages
https://doi.org/10.1155/2018/7602982
Research Article

Experimental Study on Expansion Characteristics of Core-Shell and Polymeric Microspheres

1Enhanced Oil Recovery Institute, China University of Petroleum, Beijing 102249, China
2China Huadian Institute of Science and Technology, Beijing 102249, China
3Australian School of Petroleum, The University of Adelaide, Adelaide, SA 5005, Australia
4China Oilfield Services Limited, Tianjin 300452, China
5CNOOC China Limited, Tianjin Branch, Tianjin 300452, China

Correspondence should be addressed to Tongjing Liu; nc.ude.puc@pucjtl

Received 16 February 2018; Revised 30 March 2018; Accepted 4 April 2018; Published 21 May 2018

Academic Editor: Mingzhou Yu

Copyright © 2018 Pengxiang Diwu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Traditional polymeric microsphere has several technical advantages in enhancing oil recovery. Nevertheless, its performance in some field application is unsatisfactory due to limited blockage strength. Since the last decade, novel core-shell microsphere has been developed as the next-generation profile control agent. To understand the expansion characteristic differences between these two types of microspheres, we conduct size measurement experiments on the polymeric and core-shell microspheres, respectively. The experimental results show two main differences between them. First, the core-shell microsphere exhibits a unimodal distribution, compared to multimodal distribution of the polymeric microsphere. Second, the average diameter of the core-shell microsphere increases faster than that of the polymeric microsphere in the early stage of swelling, that is, 0–3 days. These two main differences both result from the electrostatic attraction between core-shell microspheres with different hydration degrees. Based on the experimental results, the core-shell microsphere is suitable for injection in the early stage to block the near-wellbore zone, and the polymeric microsphere is suitable for subsequent injection to block the formation away from the well. A simple mathematical model is proposed for size evolution of the polymeric and core-shell microspheres.