top of page

Stress Path Prediction

Currently, a significant challenge in carbon capture and storage implementation lies in understanding the complex geomechanical behaviour of depleted reservoirs prior to and during CO2 injection. The initial stress state of these reservoirs, shaped by their production history, remains poorly constrained, and the hysteresis effects on stress paths during the transition from hydrocarbon production to CO2 injection are not well understood. This knowledge gap creates substantial uncertainty in predicting critical operational parameters, including fault reactivation potential, fracture pressures, and overall reservoir integrity. The INCAST project addresses these challenges through state-of-the-art integrated geomechanical-geophysical-fluid flow modeling, systematically investigating scenarios of varying complexity. By combining advanced numerical simulations with field observations, the project aims to develop robust predictive capabilities for stress evolution during CO2 injection, enabling more accurate risk assessment and optimization of injection strategies. This comprehensive approach will enhance our ability to evaluate storage site suitability, design monitoring programs, and ultimately ensure safe and efficient long-term CO2 sequestration in depleted reservoirs.

stress_path.png

A) Commonly assumed stress path evolution, B) commonly observed stress path evolution for depletion; C) assumed stress path during CO2 injection without hysteresis; D) possible stress path evolution during depletion and injection with hysteresis.

Induced Seismicity

induced_seismicity.png

Results of stress-based probabilistic modelling to predict microseismicity (from Smith, 2012)

Induced seismicity represents a critical challenge for carbon capture and storage projects, not only as a significant technical and safety concern but also as a potential barrier to public acceptance and regulatory compliance. The occurrence of seismic events, even at micro scales, can lead to operational restrictions or complete withdrawal of operating licenses, undermining project viability and broader CCS implementation efforts. Through the INCAST initiative, a comprehensive approach to seismic risk assessment and management is being developed, integrating advanced stress-based probabilistic modelling with real-time microseismic monitoring enhanced by machine learning algorithms.

 

This innovative methodology enables both the identification of high-risk storage sites during the initial assessment phase and the implementation of sophisticated early warning systems during operations. By combining geomechanical understanding with cutting-edge data analytics, the project aims to predict, detect, and characterize seismic events with unprecedented accuracy and speed. This enhanced predictive and monitoring capability will enable operators to implement proactive mitigation strategies, maintain safe injection parameters, and provide transparent, evidence-based assurance to regulators and local communities, ultimately supporting the sustainable deployment of carbon storage projects.

Fault Reactivation and Self Healing

The integrity of carbon storage systems critically depends on understanding and predicting the complex interplay between fault behavior and natural healing mechanisms within geological formations. While fault reactivation poses a significant risk by potentially creating leakage pathways to the biosphere, INCAST adopts a sophisticated approach that transcends conventional fault stability analyses based solely on friction coefficients and stress estimates. The project integrates multiple factors including mechanical stratigraphy, across-fault fluid flow dynamics, and the intricate coupling between pore pressure and stress states to develop more reliable prediction models. Complementing this comprehensive fault analysis, INCAST also investigates the self-sealing mechanisms in geological formations, which could provide natural safeguards against potential leakage through reactivated faults or induced fractures in the overburden. Through a combination of laboratory experiments and advanced thermo-hydro-mechanical modelling, the project aims to quantify closure pressures and healing rates of faults and fractures under various conditions. This integrated understanding of both fault reactivation risks and self-healing potential enables more accurate identification of suitable storage sites, helping operators assess whether natural healing processes could effectively counteract potential leakage pathways, ultimately contributing to more reliable risk assessment and storage site selection strategies.

fault_reactivation.png

A) Permeability vs stress of fractures shale; b), c), d) CT imges of fractured shale under confining pressures of 7, 14 and 21 Mpa respectively

seismic_monitoring2.png

INCAST will use the results from THM modelling to assess the best methods for monitoring subsurface CO2 storage sites.

The successful implementation of large-scale carbon capture and storage projects hinges critically on establishing cost-effective and reliable monitoring systems that can provide continuous assurance of CO2 containment and minimal leakage to the biosphere. Through advanced thermo-hydro-mechanical modelling, INCAST aims to optimise monitoring strategies by identifying the most sensitive and economically viable geophysical techniques for different geological settings and injection scenarios. This approach enables operators to strategically deploy monitoring resources where they will be most effective, balancing comprehensive surveillance with operational efficiency.

 

The project further enhances monitoring capabilities by developing sophisticated machine learning algorithms that can process and interpret microseismic data in real-time, enabling rapid detection and characterisation of subsurface changes during CO2 injection. This integration of advanced modelling with artificial intelligence not only improves the accuracy and speed of monitoring responses but also provides operators with powerful tools for early warning system implementation, regulatory compliance demonstration, and public assurance of storage security. By optimising both the selection and interpretation of monitoring methods, INCAST supports the development of more cost-effective and reliable CCS projects while maintaining the highest standards of environmental safety and public confidence.

bottom of page