Kevin Dome Large Scale Storage Project

The seismic crew is currently surveying approximately 60 square miles of Kevin Dome. Seismic surveys use sound waves to develop three dimensional (3-D) images of the rock layers underground. They help researchers understand the subsurface environment, select the best locations for wells, and conduct the project in a safe manner. Thanks to advancements in sensor technologies, the seismic surveys for the Kevin Dome project will generate detailed 3-D images and models, with minimal disturbance to the land or the community.

Sensors (about the size of soda cans) called geophones are temporarily installed at the surface to record the reflected sound waves from rock layers. To create the sound waves, seismic vibration trucks equipped with large pads will send vibrations through the earth. Once the geophones are placed, the trucks will move together in a grid pattern lowering the vibration pad onto the surface at regular intervals.

The sound waves travel deep underground and are reflected back as waves from the different rock layers. These reflections will be picked up by the sensors and transmitted to a recording truck, which captures the data for computer processing and analysis. From the timing of the reflection data, the depths of the layers can be determined, and an image of the subsurface can be formed. Collection and processing of the data is a critical first step for conducting a carbon storage project. For the community, these advanced techniques provide an opportunity to collect considerably more detailed geologic data for the northern Montana region than has previously been available. In the long-term, the data from the seismic survey may lead to additional commercial, career and research opportunities. Read our "Seismic Survey Factsheet" here.

Kevin Dome Characterization Study

Kevin Dome is a geologic dome spanning 700 square miles in north central Montana that contains naturally occurring carbon dioxide (CO₂). On the surface the dome looks flat, but the rock layers underground are shaped like an upside down bowl. The BSCSP conducted a study at this dome to learn more about the dome’s properties and to assess whether Kevin Dome could potentially be a good site to do a larger carbon sequestration project. The scientists working on the project wanted to discover more information about the geology of the dome and the CO₂ reservoir it contained. Their research was aimed at answering the questions listed below:

• What is the structural geology of the dome?
• What is the source of the CO₂?
• At what depths was the CO₂ stored?
• How much CO₂ is contained in the dome?
• How is the CO₂ trapped in the dome?
• Is there additional room in the dome to potentially store additional CO₂?
• Are other gas or liquids present in the dome?
• What kind of water quality does the dome have?

What was learned about Kevin Dome

The study used data from oil and gas wells on the dome, rock samples, water quality data, and seismic data. After collecting and analyzing all the data, the scientists learned that the CO₂ is trapped in the pore space of the upper Devonian Duperow formation. The CO₂ does not take up all of the space in the dome and therefore the dome has potential to store additional CO₂. The dome has poor water quality which is a requirement for all carbon sequestration sites. This is important because we want to make sure we don’t store CO₂ in areas where there could be underground sources of drinking water.

Research indicates that the CO₂ trapped in the dome was formed approximately 50 million years ago when the existing sedimentary rock layers were intercepted by magma deep underground. The high pressure of the magma forced the overlying strata upwards giving the rock layers a dome shape. The dome-shaped intrusive structure created from the solidified magma is called a laccolith. The heat and pressure from the laccolith chemically transformed carbonates in the sedimentary rocks to create CO₂.

The CO₂ at Kevin Dome has remained in place for millions of years trapped by cap rocks and due to the buoyancy of the CO₂. Cap rocks are non permeable formations that prevent gas or other liquids in the subsurface from migrating to the surface. Within Kevin Dome, there are impermeable carbonates, shales and anhydrite rocks that overly the Duperow formation and prevent the CO₂ from escaping. The buoyancy of the CO₂ also helps trap the CO₂ in place. Because the CO₂ is more buoyant than other liquids in the formation, it naturally rises to the upper part of the dome and is prevented from moving laterally. The fact that the CO₂ in Kevin Dome has already been trapped for millions of years is an indication that it could potentially store additional CO₂ safely and securely.

Project Findings and Next Steps

The information learned in this study indicates that Kevin Dome has great potential to be large scale carbon storage site. The BSCSP is taking steps to assess the viability of conducting a large scale project at Kevin Dome. There has been a substantial amount of oil and gas exploration on or near the dome, and it is located near several large emission sources of CO₂. Much of the regional infrastructure (roads, pipelines, rail ways) needed for a carbon storage site has already been built. Previous research has found that the Duperow formation could hold up to half of the regions' CO₂ emissions for the next 100 years. Assessing Kevin Dome will be beneficial for other carbon storage projects because Kevin Dome is similar to several other domes in the Big Sky region.