Leigh Paterson/Inside Energy
The search is continuing for the source of a gas leak that shut down a school in Midwest, Wyoming at the end of May.
Fleur de Lis, the company that operates the neighboring Salt Creek oil field, says it has plugged one leaking well near the school, worked on another six and is continuing to monitor as many as 30 other wells in the area.
The Salt Creek field is the oldest in Wyoming, and, according to the Wyoming Oil and Gas Conservation Commission, there are approximately 140 wells within a half mile radius of the school and approximately 550 wells within a one mile radius around the Midwest school.
Many of those wells were drilled decades ago, and those that have been abandoned may or may not be properly plugged. In the past, it was common for companies to abandon wells by filling them with mud or even fence posts.
It’s also possible that not all well locations are known. A 2006 study by the National Energy Technology Laboratory identified several dozen wells in a single square mile of the Salt Creek Field that were not in company databases.
Staff at Midwest School first reported a strange odor on May 25 and initial air quality testing detected high levels of carbon dioxide as well as volatile organic compounds inside the school. Students finished out the school year at the old North Casper Elementary School.
Additional air quality testing is ongoing, to help backtrace the leak.
“And also to identify potential human health risks from those gases,” said Kelly Weidenbach, Director of the Casper- Natrona County Health Department.
In the meantime, the company has offered to relocate any families living nearby who would like to leave.
A previous Inside Energy investigation also found that state records for the locations of abandoned wells in Wyoming and surrounding states are not always accurate, and that abandoned wells are frequently unmarked on the surface. In the map below, we have noted known well locations by the latitude and longitude listed in the state well database, but the well locations on the ground may not correspond to state records.
This map shows wells in and around Midwest, Wyoming, based on information in the state oil and gas commission’s database. Zoom out to see the nearly 750 active and former wells within a 1 mile radius of the town. Wells that are being inspected in relationship to the leak near Midwest School are yellow (as of June 10, 2016), wells that are active are red, and wells that are plugged/abandoned are pink. Click on a well to see which company operates it.
The Wyoming Oil and Gas Conservation Commission provided Inside Energy with a list of 10 wells (below) that Fleur de Lis has worked on or is monitoring. Information about the individual wells can be located on the Wyoming Oil and Gas Conservation Commission website.
The table below shows information provided by the Wyoming Oil and Gas Conservation Commission on the recent work that has been done on nearby wells to investigate the source of the potential leak.
Editor’s Note: An earlier version of the story used an Inside Energy analysis of Wyoming Oil and Gas Conservation Commission data which found approximately 744 wells within a mile of the school. We’ve updated the post with new numbers from the WOGCC to say there are approximately 140 wells within a half mile radius of the school and approximately 550 wells within a one mile radius around the school.