About CCUS Projects

Class VI Process

The application process for a Class VI (Class Six) permit adds another layer of rigor to the research because this step aims to make sure CO₂ can be stored in a safe, secure and environmentally responsible manner before storage operations begin. As part of its review of this information, LDCE hosts a public hearing to discuss the project. The process is designed to:

Recognize and safeguard against four characteristics of the project: CO₂’s buoyancy, its ability to move through the pore space, its ability to promote corrosion in the presence of water, and the fact it will be injected in large volumes.
Protect underground sources of drinking water (USDW): Ensuring no leaks into aquifers, even ones not drinkable today but potentially usable in the future.
Prove the capability for safe, secure storage: Confirming the geology (pore space, cap rock, faults) can securely contain CO₂ for the long term.
Require strong safeguards: Reviewing well design, construction, monitoring and emergency response plans.
Ensure accountability: Requiring operators to prove financial responsibility, long-term monitoring and compliance with strict regulations.

Determining the Area of Storage

Applicants must first map the Area of Review (AOR), the area around the storage site where pressure or fluid movement could affect underground drinking water (USDWs). Using data from the research phase and computer models, they predict how CO₂ and pressure will move underground over time. As part of this step, all wells inside the AOR must be identified and checked to see if they need to be repaired or plugged. The AOR can be adjusted as more information is gathered.

Proving Operations Can Be Safe

Once the extent of the storage area is determined, applicants must demonstrate:

Geology is suitable: Although it is important to prove the storage layer is porous enough to allow CO₂ to easily move through it, the primary objective is to demonstrate that the cap rock is:
- hundreds of feet thick,
- stretches well beyond the intended storage area, and
- is impermeable so that CO₂ cannot move through it.
The presence of multiple layers of this type of cap rock above the storage layer provides an additional safety factor.
USDW is safe: All underground sources of drinking water (USDWs), even those not drinkable today, will be protected by both the mechanical design of the well and multiple layers of cap rock.
Well design mitigates risks: Wells are engineered with corrosive protection and multiple layers of steel and cement to prevent leaks of CO₂ or other fluids.
Operational planning is complete: Plans to operate the site well during and after CO₂ injection include:
- Description of the source of CO₂
- Analysis of the chemical and physical characteristics of the CO₂ stream
- Proposed average and maximum daily rate and overall volume
- Proposed average and maximum injection pressure
Monitoring and testing plans are in place: A detailing of how the movement of the CO₂, reservoir pressure, and condition of the wells will be tracked, which could include:
- Mechanical integrity testing
- Operational monitoring, such as in-well pressure and temperature gauges
- Groundwater sampling and testing of fluids from the storage reservoir
- Plume and pressure-front tracking, such as 4D seismic, which is like a time-lapse ultrasound of the subsurface that shows how the CO₂ is moving
- Surface air, atmospheric and soil gas monitoring
- Induced seismicity monitoring
- Vegetation monitoring
Emergency response is prepared: Plans are developed detailing how to detect and respond to the unlikely event of an emergency, quickly and effectively.
Financial responsibility is assured: Operators must prove they can cover the costs of long-term monitoring, closure and any corrective action if needed.

Construction of CO₂ Injection Well

Although all wells in Louisiana are built safely to protect the environment from research operations, Class VI well specifications have extra safety features built in to protect the environment during long-term CO₂ storage. Class VI wells have tougher installation processes, more rigorous testing and built-in monitoring requirements.

The wells are built to robust standards using multiple corrosion-resistant steel pipes, surrounded by layers of cement that are formulated to withstand long-term contact with CO₂ and brine. Together they form multiple barriers that protect underground drinking water (USDW) from the unlikely occurrence of a leak.

The first and widest layer of protection, the surface casing, is installed to a depth below the deepest layer of underground drinking water (USDW) and cemented in place.
The second layer of protection, a production casing or liner, is installed inside the surface casing and extends all the way down to the storage layer and cemented in place.
Third, in most cases, the tubing, the pipe which delivers products to storage, is installed inside the production casing or liner.

In the end, underground drinking water (USDW) is protected by multiple layers of steel and cement.

Finally, generally a specially designed plug, the packer, is installed inside the production casing or liner, above the end of the tubing, to prevent any fluids from traveling back up the casing.

LDCE periodically inspects the construction of the well to ensure it is built according to regulations.

Construction of Monitoring Wells

Operators are required to install monitoring wells to different depths to monitor the health of the storage layer, confirm the underground sources of drinking water (USDW) remain unaffected and provide early warnings in the unlikely occurrence that CO₂ or other fluids were to move into unexpected areas above the storage layer.

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