Three-dimensional distinct element modeling of fault reactivation and induced seismicity due to hydraulic fracturing injection and backflow  

作　　者：Zirui Yin Hongwei Huang Fengshou Zhang Lianyang Zhang Shawn Maxwell 

机构地区：[1]Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai,200092,China [2]Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai,200092,China [3]Department of Civil and Architectural Engineering and Mechanics,University of Arizona,Tucson,AZ,85721,USA [4]MaxSeis LLC.,Calgary,Alberta,T2P 3N9,Canada

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2020年第4期752-767,共16页岩石力学与岩土工程学报（英文版）

基　　金：supported by the Key Innovation Team Program of Innovation Talents Promotion Plan by Ministry of Science and Technology of China(Grant No.2016RA4059);National Natural Science Foundation of China(Grant Nos.41672268 and 41772286)。

摘　　要：This paper presents a three-dimensional fully hydro-mechanical coupled distinct element study on fault reactivation and induced seismicity due to hydraulic fracturing injection and subsequent backflow process,based on the geological data in Horn River Basin,Northeast British Columbia,Canada.The modeling results indicate that the maximum magnitude of seismic events appears at the fracturing stage.The increment of fluid volume in the fault determines the cumulative moment and maximum fault slippage,both of which are essentially proportional to the fluid volume.After backflow starts,the fluid near the joint intersection keeps flowing into the critically stressed fault,rather than backflows to the wellbore.Although fault slippage is affected by the changes of both pore pressure and ambient rock stress,their contributions are different at fracturing and backflow stages.At fracturing stage,pore pressure change shows a dominant effect on induced fault slippage.While at backflow stage,because the fault plane is under a critical stress state,any minor disturbance would trigger a fault slippage.The energy analysis indicates that aseismic deformation takes up a majority of the total deformation energy during hydraulic fracturing.A common regularity is found in both fracturing-and backflow-induced seismicity that the cumulative moment and maximum fault slippage are nearly proportional to the injected fluid volume.This study shows some novel insights into interpreting fracturing-and backflowinduced seismicity,and provides useful information for controlling and mitigating seismic hazards due to hydraulic fracturing.

关 键 词：Induced seismicity Fault reactivation Hydraulic fracturing BACKFLOW Geomechanical modeling Distinct element method 

分 类 号：P315[天文地球—地震学]