Hydraulic fracturing is usually linked to tight formations with low permeability. In CO₂ storage projects, where injection often targets high-permeability saline aquifers, fracturing may seem unnecessary. But real field conditions don’t always match expectations. Even in seemingly permeable reservoirs, operators can face restricted injectivity caused by tight zones, formation damage, or well design factors. When CO₂ injection rates drop below target, fracturing becomes a practical solution to restore or enhance flow.
When Fracturing Helps in CO₂ Injection Wells
In large-scale carbon capture and storage (CCUS) projects, the goal is to inject and store millions of tonnes of CO₂ each year—often around 10,000 tonnes per day for decades.
Maintaining that rate requires stable injectivity. Several issues can limit performance over time:
- Formation damage from drilling or completion fluids
- Unexpected low-permeability streaks within the aquifer
- Well architecture that restricts flow, especially in vertical wells
In these cases, hydraulic fracturing increases the effective injection area, lowers wellbore pressure, and helps maintain continuous CO₂ flow under stable conditions.
Understanding the Role of Well Design
Fracturing decisions depend on how the well is constructed.
- In horizontal wells, multiple fractures along the lateral can enhance contact with the formation and support long-term performance.
- In vertical wells, a single fracture can improve injectivity near the wellbore.
Managing Leakoff: The Importance of CO₂ Foam Systems
One of the main challenges during stimulation is fluid leakoff—when treatment fluid quickly enters the formation instead of creating or extending a fracture. High-permeability formations are especially prone to this issue.
To control leakoff and improve proppant transport, engineers often use CO₂ foam-based fluids, particularly supercritical CO₂ foam.
These fluids:
- Reduce fluid loss to the formation
- Improve proppant placement
- Remain compatible with the injected CO₂
This approach has been described in field studies, including SPE Paper 217816, which highlights CO₂ foam as an effective option for stimulation in disposal wells.
Designing and Modeling the Fracture
Accurate modeling is essential for designing safe and effective stimulation treatments.
Simulation tools allow engineers to:
- Model foam systems (CO₂ or nitrogen-based)
- Predict pressure and rate changes
- Visualize fracture geometry and growth
- Assess long-term injectivity under storage conditions
By using simulation, teams can design a fit-for-purpose treatment that balances injectivity, containment, and reservoir performance. For more on the practical aspects of when and why fracturing helps in CO₂ disposal wells—including formation challenges, well design, and fluid selection—see our Q&A discussion:
Designing and Simulating the Treatment
Even in high-permeability saline aquifers, hydraulic fracturing can play an important role when injectivity falls short of design targets. Simulation tools such as FracPro help engineers analyze foam-based systems, pressure responses, and fracture geometry under realistic CO₂ injection conditions.
With careful design, appropriate fluid systems, and reliable modeling tools, fracturing supports sustained CO₂ injection rates and helps ensure the long-term success of storage projects. Connect with our team to learn more about FracPro or our other digital solutions.