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Geofluids
Volume 2017, Article ID 5235140, 13 pages
https://doi.org/10.1155/2017/5235140
Research Article

Impact of Petrophysical Properties on Hydraulic Fracturing and Development in Tight Volcanic Gas Reservoirs

1Unconventional Natural Gas Institute, China University of Petroleum-Beijing, Beijing, China
2Texas Tech University, Lubbock, TX, USA
3Oil & Gas Technology Research Institute, Changqing Oilfield Company, Xi’an, China
4China University of Petroleum-Beijing at Karamay, Xinjiang, China
5CNODC Brasil Petroleo E Gas Ltda, Rio de Janeiro, RJ, Brazil

Correspondence should be addressed to Yinghao Shen; moc.621@oahgniynehs and Mianmo Meng; moc.361@pucmmm

Received 29 July 2017; Accepted 12 November 2017; Published 13 December 2017

Academic Editor: Ebrahim Fathi

Copyright © 2017 Yinghao Shen 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

The volcanic reservoir is an important kind of unconventional reservoir. The aqueous phase trapping (APT) appears because of fracturing fluids filtration. However, APT can be autoremoved for some wells after certain shut-in time. But there is significant distinction for different reservoirs. Experiments were performed to study the petrophysical properties of a volcanic reservoir and the spontaneous imbibition is monitored by nuclear magnetic resonance (NMR) and pulse-decay permeability. Results showed that natural cracks appear in the samples as well as high irreducible water saturation. There is a quick decrease of rock permeability once the rock contacts water. The pores filled during spontaneous imbibition are mainly the nanopores from NMR spectra. Full understanding of the mineralogical effect and sample heterogeneity benefits the selection of segments to fracturing. The fast flow-back scheme is applicable in this reservoir to minimize the damage. Because lots of water imbibed into the nanopores, the main flow channels become larger, which are beneficial to the permeability recovery after flow-back of hydraulic fracturing. This is helpful in understanding the APT autoremoval after certain shut-in time. Also, Keeping the appropriate production differential pressure is very important in achieving the long term efficient development of volcanic gas reservoirs.