Fracture propagation through disordered porous media: A safety issue for CO2 storage and petroleum production

In this INDNOR pre-project we develop networks (between India & Norway) & necessary competence to work on a big research project in near future - which will be complementary to the ongoing SINTEF-NTNU activities in BIGCCS project. Safe storage of CO2 is a big issue now and natural underground reservoirs are considered as good candidates for such purpose. However during fluid injection in the porous reservoirs (for CO2 storage or petroleum production) cracks open up and existing fractures grow in time due to fluid pressure and stress imbalance and sometimes growth of fractures results in leakage or well-collapse, which are major safety issues. It is important therefore to be able to predict how and where fractures will grow in disordered porous media. Mode lling of fracture initiation and growth is often based on linear elastic fracture mechanics, with resulting predictions that fail to reproduce reality. One of the reasons for the mismatch may be that the microscopic aspect of the fracture initiation proce ss is neglected, that the true elasto-plastic behaviour of the rock is not accounted for. We propose to combine discrete particle modelling (using PFC - Particle Flow Code) on the pore level with stochastic modelling on a mesoscopic level in order to obt ain acoustic data which can be used to monitor micro-crack opening & fracture propagation. The findings from these simulations will be calibrated against controlled laboratory experiments with Acoustic Emission (AE) monitoring. The final goal is to achie ve improved control of the fracturing process (crack opening & fracture propagation) during fluid injection in disordered porous media - which can in turn enhance the safety level for CO2 storage and petroleum production. The main activities of this pre -project will be scientific visits, scholar exchange, guiding master students, supporting workshops etc. as a part of developing networks and competence. Some preliminary results will be produced from model studies.