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Mathematical Problems in Engineering
Volume 2018, Article ID 3015015, 15 pages
https://doi.org/10.1155/2018/3015015
Research Article

Coupled THM and Matrix Stability Modeling of Hydroshearing Stimulation in a Coupled Fracture-Matrix Hot Volcanic System

1China Zhenhua Oil Co., Ltd, Beijing, China
2State Key Laboratory on Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, China
3Chengdu Northern Petroleum Exploration and Development Technology Co., Ltd., Chengdu, Sichuan, China
4Energy & Geoscience Institute, University of Utah, UT, USA
5Borehole Operation Branch Office of Sinopec Southwest Petroleum Engineering Co., Ltd., Sichuan, China

Correspondence should be addressed to Jianchun Guo; moc.361.piv@nuhcnaijoug

Received 20 March 2018; Accepted 30 May 2018; Published 3 July 2018

Academic Editor: Mohammed Nouari

Copyright © 2018 Yong Xiao 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

A coupled thermal-hydraulic-mechanical (THM) model is developed to simulate the combined effect of fracture fluid flow, heat transfer from the matrix to injected fluid, and shearing dilation behaviors in a coupled fracture-matrix hot volcanic reservoir system. Fluid flows in the fracture are calculated based on the cubic law. Heat transfer within the fracture involved is thermal conduction, thermal advection, and thermal dispersion; within the reservoir matrix, thermal conduction is the only mode of heat transfer. In view of the expansion of the fracture network, deformation and thermal-induced stress model are added to the matrix node’s in situ stress environment in each time step to analyze the stability of the matrix. A series of results from the coupled THM model, induced stress, and matrix stability indicate that thermal-induced aperture plays a dominant role near the injection well to enhance the conductivity of the fracture. Away from the injection well, the conductivity of the fracture is contributed by shear dilation. The induced stress has the maximum value at the injection point; the deformation-induced stress has large value with smaller affected range; on the contrary, thermal-induced stress has small value with larger affected range. Matrix stability simulation results indicate that the stability of the matrix nodes may be destroyed; this mechanism is helpful to create complex fracture networks.