Pressure equilibration induced by reactivation of deep carbonate faults
© 5th International Conference on Fault and Top Seals 2019. All Rights Reserved. Fluid production is known to induce stress changes in the reservoir that can be large enough to reactivate nearby dormant faults. Interestingly, following the reactivation of a fault, fluid pressure equilibration between the two sides of the fault can sometimes be observed. A sealing fault then becomes a flow channel, provoking leakage of the reservoir into the adjacent layer or fluid invasion leading to problematic early water breakthrough. In order to characterise this highly coupled, non-linear Thermo-Hydro-Mechano-Chemical (THMC) behaviour of the fault and quantify fluid invasion, we introduce a multi-scale numerical framework using the REDBACK finite element simulator. This approach links the reservoir (km) scale - implementing a poro-elastic model - to the fault-scale (m) - implementing a THMC reactivation model. The complex behaviour of the fault is upscaled into an interface law that links the stress state of the fault to its response in terms of slippage and permeability. Using this framework, we investigate the fault reactivation scenario in the case of a production from a well located next to a sealing fault in a high P,T carbonate reservoir.
