On 2019-03-04,the largest induced earthquake(ML4.18)occurred in the East Shale Basin,Alberta,and the underlying physical mechanisms have not been fully understood.This paper proposes a synthetical geoengineering metho...On 2019-03-04,the largest induced earthquake(ML4.18)occurred in the East Shale Basin,Alberta,and the underlying physical mechanisms have not been fully understood.This paper proposes a synthetical geoengineering methodology to comprehensively characterize this earthquake caused by hydraulic fracturing.Based on 3D structural,petrophysical,and geomechanical models,an unconventional fracture model is constructed by considering the stress shadow between adjacent hydraulic fractures and the interactions between hydraulic and natural fractures.Coupled poroelastic simulations are conducted to reveal the triggering mechanisms of induced seismicity.It is found that four vertical basement-rooted faults were identified via focal mechanisms analysis.The brittleness index(BI)along two horizontal wells has a high magnitude(BI>0.5),indicating the potential susceptibility of rock brittleness.Due to the presence of overpressure,pre-existing faults in the Duvernay Formation are highly susceptible to fault reactivation.The occurrence of the earthquake clusters has been attributed to the fracturing fluid injection during the west 38^(th)-39^(th) stage and east 38^(th) stage completions.Rock brittleness,formation overpressure,and large fracturing job size account for the nucleation of earthquake clusters,and unconventional natural-hydraulic fracture networks provide fluid flow pathways to cause fault reactivation.This workflow can be used to mitigate potential seismic risks in unconventional reservoirs in other fields.展开更多
基金This research was supported by Science Foundation of China University of Petroleum,Beijing(No.2462023BJRC001)National Natural Science Foundation of China Project(No.52204039).
文摘On 2019-03-04,the largest induced earthquake(ML4.18)occurred in the East Shale Basin,Alberta,and the underlying physical mechanisms have not been fully understood.This paper proposes a synthetical geoengineering methodology to comprehensively characterize this earthquake caused by hydraulic fracturing.Based on 3D structural,petrophysical,and geomechanical models,an unconventional fracture model is constructed by considering the stress shadow between adjacent hydraulic fractures and the interactions between hydraulic and natural fractures.Coupled poroelastic simulations are conducted to reveal the triggering mechanisms of induced seismicity.It is found that four vertical basement-rooted faults were identified via focal mechanisms analysis.The brittleness index(BI)along two horizontal wells has a high magnitude(BI>0.5),indicating the potential susceptibility of rock brittleness.Due to the presence of overpressure,pre-existing faults in the Duvernay Formation are highly susceptible to fault reactivation.The occurrence of the earthquake clusters has been attributed to the fracturing fluid injection during the west 38^(th)-39^(th) stage and east 38^(th) stage completions.Rock brittleness,formation overpressure,and large fracturing job size account for the nucleation of earthquake clusters,and unconventional natural-hydraulic fracture networks provide fluid flow pathways to cause fault reactivation.This workflow can be used to mitigate potential seismic risks in unconventional reservoirs in other fields.
基金funded by the National Natural Science Foundation of China(41801185,32171550)the Natural Science Foundation of Sichuan Province(2023NSFSC0191)+1 种基金the Strategic Priority Research Program(category A)of Chinese Academy of Sciences(XDA20020302)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021371).
