Fact vs. Fiction

What are injections, and why are they done?

In some industries, fluids (like water, gas, or other materials) are injected underground for purposes like disposing of waste, recovering oil and gas, or storing substances. This process involves drilling wells and injecting fluid into rock layers deep below the Earth’s surface.

What do we mean by “low pressure” and “highly regulated” injections?

• Low Pressure: Fluids are injected underground at a controlled, gentle pressure to avoid stress on underground rock layers.
• Highly Regulated: Injection activities are closely monitored and must follow strict rules and safety standards set by government agencies. These regulations control how much, how fast, and where fluids can be injected.

How do regulations reduce earthquake risk?

• Site Selection: Before injections begin, scientists study the geology of the area to avoid known fault zones or areas at higher risk for earthquakes.
• Pressure Limits: Class VI wells have the highest regulatory threshold to ensure fluids are injected at safe, low pressures to prevent fractures or disturbing underground faults.
• Monitoring: Operators continuously monitor pressure, fluid amounts, and seismic activity. If any unusual activity occurs, injections can be adjusted or stopped immediately.

Why is this process safe and important?

Low-pressure, highly regulated injections are designed with safety as the top priority. Here’s why they’re safe:

1. Careful Science-Based Planning: Scientists spend months, sometimes years, studying an area’s geology before approving an injection site. They avoid fault zones and ensure rock layers are stable.
2. Continuous Monitoring: Operators use advanced technology to monitor every step of the process in real-time. If anything unexpected happens—even small shifts—operations are adjusted or stopped immediately to ensure safety.
3. Pressure Management: By limiting pressure and fluid amounts, the injections are gentle and do not disrupt the natural state of underground rock layers. It’s like pouring water into a sponge slowly rather than forcefully flooding it.

What does the science say?

Studies show that the risk of earthquakes from low-pressure, regulated injections is extremely low. Most induced earthquakes happen when injections are poorly managed or when fluids are injected at high pressures near faults. Following regulations greatly reduces this risk.

What is Injected?

In most projects, the main substance injected into underground storage sites is highly concentrated CO₂. Before being injected, the CO₂ is separated from other gases during the capture process and then compressed into a type of material that is made up of both liquid and gas.

What is injected?

• Capture from industrial processes: Our rigorous purification systems ensure that the CO₂ meets strict quality standards before injection.
• CO₂ Itself: Carbon dioxide is not toxic at low concentrations; it is a natural component of the air we breathe.
• Interaction with Subsurface Materials: When CO₂ is injected underground, it can react with the surrounding rock and water. This might release substances like heavy metals or other minerals naturally present in the rock. Most evidence shows that these reactions are slow and small, with little to no risk of widespread contamination. These reactions are measured and incorporated into the material selection and monitoring system.

Safety Measures already in Place

To make sure no harmful materials are introduced into the environment, CCS projects are subject to strict regulations and monitoring by our local Louisiana based experts. Some of these measures include:

• Site Selection: Storage sites are carefully chosen based on their geology to ensure that the CO₂ remains trapped and doesn’t leak to the surface or into groundwater.
• Purity Standards: The CO₂ is purified to meet specific standards before injection, minimizing the presence of impurities.
• Monitoring Systems: Advanced monitoring systems are used to track the movement of CO₂ underground and detect any potential leaks or reactions that could pose risks.
• Regulatory Oversight: CCS projects are subject to strict regulations that dictate the quality of the CO₂ and the conditions for injection. These rules are in place to ensure that no toxic or hazardous materials are injected alongside the CO₂.

Depth of storage

When looking for potential carbon storage sites, operators and regulatory bodies recommend injection depths at least 3,000 feet deep, far below the level of drinking water reserves at a depth of around 150 feet, according to USGS. Storing carbon dioxide at these depths guarantees a temperature and pressure that is optimal for storing carbon dioxide. The CENLA Hub’s storage area has multiple sites with formations at depths ranging from 4,500 feet to greater than 10,000 feet—more than two miles underground.

Composition of Storage Zones

The formations used for injection in the CENLA area consist of sandstones saturated with salt water. These saline aquifers are known for having the largest capacity for storing CO₂ while not impacting the USDW. The saline aquifer at the CENLA Hub is also ‘capped’ with natural rock layers, which act as a very solid barrier to keep the storage separated from drinking water layers closer to the surface.

Regional advantages

The USGS says that the region in the U.S. with the most storage potential for carbon dioxide is the Coastal Plains region, which includes Louisiana and the coastal basins from Texas to Georgia. The Coastal Plains region has the potential to store 2 trillion metric tons of CO₂, according to USGS. That amount of CO₂ storage would fill nearly half of the entire Grand Canyon! The CENLA site itself has the potential to be one of the largest deep underground storage centers in the U.S.

Carbon capture and storage (CCS) involves injecting captured carbon dioxide (CO₂) deep underground to prevent it from contributing to climate change. A common concern is whether this CO₂ might leak back to the surface. Our experts work hard to ensure that injected CO₂ remains safely stored and keep CCS the reliable and secure solution that it is. 

Why Doesn’t CO₂ Leak?

1. Careful Site Selection:
   1. Storage sites are chosen based on their geological features. These include deep rock formations, such as saline aquifers or depleted oil and gas reservoirs, that naturally trap CO₂.
   2. Layers of impermeable rock (known as caprock) act as a seal, preventing CO₂ from escaping.
2. Depth of Injection:
   1. CO₂ is injected thousands of feet below the surface, well below drinking water sources and far from areas that could be impacted. At these depths, the CO₂ becomes ‘supercritical’, meaning it’s denser and less likely to move.
3. Trapping Mechanisms:
   1. Structural Trapping: CO₂ is physically trapped under layers of impermeable rock.
   2. Residual Trapping: Tiny amounts of CO₂ get stuck in the pores of the surrounding rock.
   3. Dissolution Trapping: Over time, CO₂ dissolves into underground water, becoming even less mobile.
   4. Mineral Trapping: Over decades or centuries, CO₂ reacts with minerals in the rock to form stable, solid compounds.
4. Well Penetration Evaluation
   1. All existing well penetrations within the area are reviewed and their current status is evaluated.
   2. If the wells have not been properly plugged, a corrective action plan is put in place to re-enter and properly plug the wells prior to any CO₂ injection.

How Do We Monitor for Safety?

1. Baseline Studies:
   1. Before injection begins, detailed studies are conducted to understand the site’s geology and ensure it is suitable for long-term CO₂ storage.
2. Advanced Monitoring Technology:
   1. Sensors and seismic imaging are used to track the CO₂ plume underground and ensure it stays within the designated storage area.
   2. Above confining zone monitoring wells are installed to detect any leaks before they reach the USDW.
   3. Groundwater monitoring wells are installed to detect any potential leaks early.
3. Regulatory Oversight:
   1. CCS projects follow strict regulations to ensure safety. Regular inspections and reporting are mandatory to verify that storage sites are performing as expected.

What If a Leak Occurs?

Although the risk of leakage is very low, contingency plans are in place for all CCS projects. These include:

• Rapid response systems to seal leaks.
• Continuous monitoring to detect any issues early, ensuring immediate action can be taken.

The CENLA Hub storage site has ideal geology for CO₂ storage, and the project is designed to prevent movement of CO₂ outside the acreage leased with our community partners. Routine monitoring plans used to track CO₂ movement are approved and reviewed by regulators and are required for storage projects.

Calculation

The distance CO₂ travels is a function of the amount of CO₂ injected and the properties of the geologic formation used to store the CO₂. This is a key calculation in the Class VI permitting process, and the main priority of the monitoring program.

1. Trapped by Natural Rock Barriers: CO₂ is injected into deep underground rock formations called reservoirs. These formations are capped by layers of dense, impermeable rock that trap the CO₂ in place. Think of it like putting a lid on a container—the CO₂ stays where it’s injected and does not move upward to overlying formations.
2. Targeted Injection Zones: Before injection begins, scientists carefully select specific rock layers that are naturally stable and able to hold CO₂ safely. These zones have been tested and proven to store CO₂ effectively.
3. CO₂ Behavior Underground: The movement of CO₂ in the subsurface is based on the geologic properties of the formation used to store the CO₂. Predicting and monitoring CO₂ movement in the subsurface has been done for decades and is an important aspect to the Class VI process.
4. Strict Monitoring: Injection sites are constantly monitored using advanced sensors and computer models to ensure the CO₂ remains inside the geologic formation targeted for CO₂ storage. The movement of the CO₂ is reported on annually and computer models are updated regularly to ensure the CO₂ remains on the landowners inside the unit that are being compensated for the project. The monitoring will continue until stabilization of the CO₂ plume is verified expected time frame is ten years post injection. For reference, regulators currently require 50 years of monitoring post injection. 

The Science Supports This

CO₂ injection has taken place in the United States for over 50 years to increase the recovery of oil and gas fields. It is a tested process that is ongoing with 1000’s of wells today.  Carbon capture and storage (CCS) projects around the world have successfully stored CO₂ underground for decades without any significant spread. Experience has shown that with proper site selection, design, and construction, the CO₂ stays exactly where it’s meant to be—deep underground and out of the atmosphere.

Key Takeaway

The reality is that CO₂ has been injected for decades. CO₂ storage site development located in suitable underground rock formations, surrounded by natural barriers, and closely monitored is a sound and effective process This technique is a proven, safe, and effective way to reduce emissions and protect our planet for future generations.