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Geofluids
Volume 2017 (2017), Article ID 9080325, 8 pages
https://doi.org/10.1155/2017/9080325
Research Article

Impact of the Microstructure of Polymer Drag Reducer on Slick-Water Fracturing

1The Unconventional Natural Gas Institute, China University of Petroleum, Beijing 102249, China
2State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China

Correspondence should be addressed to Fu-jian Zhou; nc.ude.puc@jfuohz

Received 1 June 2017; Revised 7 August 2017; Accepted 21 August 2017; Published 27 September 2017

Academic Editor: Zhien Zhang

Copyright © 2017 Zhi-yu Liu 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

Many studies have focused on the drag reduction performance of slick-water, but the microdrag reduction mechanism remains unclear since the microstructure of the drag reducer and its effect on this mechanism have not been well studied. In this study, the microstructure of the drag reducer in slick-water was effectively characterized by transmission electron microscopy. The viscoelasticity and drag reduction performance of the drag reducer with different microstructures were then investigated. Further, the effects of the microstructure of the drag reducer on the viscoelasticity and drag reduction performance of slick-water were analyzed. The results demonstrated that the viscoelasticity of slick-water is governed by the microstructure of the drag reducer, which exhibits a network structure. In addition, the drag reduction performance is related to the viscoelasticity. At low flow rates, the drag reduction performance is dominantly influenced by viscosity, whereas, at high flow rates, it is governed mainly by elasticity. Furthermore, the drag reducer with a uniformly distributed network structure exhibits the most stable drag reduction performance. This drag reducer was used in a field test and the obtained results were consistent with those of a laboratory experiment.