Depleted Oil and Gas Fields - CCUS Terms

Description:
Depleted Oil and Gas Fields are underground reservoirs that have produced most of their economically recoverable oil or gas. These fields have existing infrastructure and geological characteristics suitable for storing carbon dioxide (CO₂).

Explanation:
In the context of Carbon Capture, Utilization, and Storage (CCUS), depleted oil and gas fields offer a practical and effective solution for the long-term storage of captured CO₂. Here’s how depleted oil and gas fields work and their importance within the broader CCUS framework:

• Carbon Capture. While depleted fields do not directly involve the capture phase, they are integrally linked as final destinations for the CO2 captured from various industrial and power generation processes. The infrastructure originally used for hydrocarbon extraction can often be repurposed for CO2 injection, minimizing new infrastructure needs.
• Utilization. Although primarily seen as storage sites, depleted oil and gas fields can also be used for Enhanced Oil Recovery (EOR). During EOR, injected CO2 increases the pressure within the reservoir, helping to mobilize and extract residual oil, thus extending the field’s productive life. This process not only stores CO2 but also enhances the extraction of oil, creating a form of utilization.
• Storage. The primary role of depleted oil and gas fields in the CCUS chain is to provide a secure and capacious environment for storing large volumes of CO2. These fields have geologically stable structures and are typically capped by impermeable rock layers that prevent the upward migration of gases. Their extensive geological data help in assessing their suitability and integrity as CO2 storage sites.

Advantages:
Storing CO₂ in depleted oil and gas fields helps reduce GHG emissions by preventing CO₂ from reaching the atmosphere, supporting international climate goals and commitments like the Paris Agreement; it provides a cost-effective method for storing large volumes of CO₂ by utilizing existing infrastructure, reducing costs and promoting profitability for businesses and industries involved in CO₂ storage, while clear and transparent storage processes help build public trust and acceptance of CCUS projects, ensuring community support and participation.

Challenges:
Implementing CO₂ storage in depleted oil and gas fields can be technically complex and require significant expertise, making sound science and engineering principles crucial for success; securing sufficient funding and resources for CO₂ storage projects can be challenging, necessitating adequate investment for the success of storage initiatives; and navigating regulatory requirements and market barriers can be difficult, requiring clear and supportive policies to foster the development and deployment of CO₂ storage technologies.

In summary, Depleted Oil and Gas Fields are essential for promoting the development and deployment of Carbon Capture, Utilization, and Storage technologies. By providing a secure environment for the long-term storage of CO₂, they help reduce greenhouse gas emissions and contribute to global efforts to mitigate climate change.