After three months of scouring the area surrounding Craig, a team of nine geologists have finished preliminary data gathering to determine if the area would be suitable for carbon sequestration.
Carbon sequestration is the process by which carbon dioxide emissions from power plants and other sources are captured and injected into the ground.
The team of geologists from the Colorado Geological Survey began research April 15 and wrapped up around July 15, said David Noe, a field geologist who worked on the project.
During the three months the team was in town, Noe said team members took 1,500 geological readings throughout an area of about 550 square miles surrounding Craig.
“It actually turned out to be a larger area than what we had originally planned just because of some of the things that we found,” he said.
The three-year research project is being done to see if sandstone reservoir rock formations thousands of feet underground would be able to hold captured carbon dioxide.
Despite the research being done on the surface, much of what the team found will help the geologists understand what rocks look like underneath the surface, Noe said.
Among the things geologists measured during their stay in the area included the angles of rocks, the orientation of rock beds and sedimentary rocks, and the location and the direction of faults and fractures underneath the surface.
“Just by taking those simple readings, we can get a lot of information about the way (the rock) presents itself under the ground surface,” Noe said.
The three months of work represents only a small portion of the work that will be completed over the three-year life of the project, Noe said.
The geologists are currently checking the quality of data collected, which should take a few months, Noe said.
“We want to make sure our points plot in the right place on the map,” he said. “… It’s not a very exciting part of the process, but it is one that is absolutely essential for it.”
Once geologists verify and compile the information, Noe said they would be able to determine what potential reservoir rocks they would like to test below the surface.
“At this point we know what the surface geology is like, but ultimately we would like to test the formations that are down at depth,” he said.
Noe said he didn’t know when the project would re-visit the area, but the geologists may identify several areas to drill into to take core samples.
“That is what we need with the different formations that we are interested in,” he said. “We don’t have a lot of information about them besides what have come out of oil and gas electric logs.”
The core samples would be tested for porosity and permeability, among others, Noe said.
“That is the same kinds of things that are important with oil and gas,” he said. “Only in this particular instance, it is in reverse.
“In oil and gas, they are interested in the porosity so they can see what kind of fluid they can bring out of the ground. Here we … (want) to figure out what will happen when we put (carbon dioxide) into the ground.”
Noe said the group was hopeful about one particular block of bedrock south of Craig as being a possible candidate for sequestration.
The area covered about 200 square miles of the 550 square miles the team investigated.
“That is the block that we thought of initially when we put in for this grant that we wanted to take a closer look at it,” he said.