The objective of this research work is to conduct a comprehensive study of fault activation mechanisms and delve into the mechanisms involved in fault reactivation processes in CO2 storage. Faults constitute a major component of geological formations and change the rock mass system's mechanical behavior significantly, in particular at large scales. The focus of this research is to conduct an analysis of key caprock geomechanical design parameters and compare the significance of each parameter. In this study, the well-documented studies on caprock integrity analysis and fault activation were reviewed and evaluated. The key geomechanical design parameters associated with CO2 storage were identified and discussed. Accordingly, a procedure for weighting these parameters was developed based on the Fuzzy Analytic Hierarchy Process (FAHP) and used in the comparison of the selected parameters. Based on the developed weighting scheme, the fault friction angle has the highest significance in caprock behavior followed by rock mass permeability and regional in-situ stress ratio. The obtained results are in harmony with practical observations and published research works. With further verification, the proposed approach can be used in the selection of key geomechanical design data required for CO2 storage site analysis and design.
KEYWORDS
CO2 Storage, Fault activation mechanisms, Numerical modelling, weighting procedures
