Properly plugging a well ensures the safety of our citizens and the environment both above and below the ground. North Dakota requires that a plugging procedure be submitted and approved by the North Dakota Oil and Gas Division. The Division does a review of each well for details such as: depth of the wellbore, casing string information, production zones, depths of perforations, cement bond logs, depths of potential formations to be plugged or requiring isolation, and any other known wellbore issues specific to the individual well. These procedures not only isolate oil and gas zones, but more importantly, protect our freshwater aquifers and resources.
Once procedures are approved by the Oil and Gas Division, plugging can commence. This involves placing combinations of cement plugs and mechanical plugs at strategic depths in the well. Oil and Gas Division field inspectors witness the placement of plugs and cement in the well. Once the well has been plugged to the satisfaction of the Division, casing is cut off three to four feet below the surface and a steel plate is welded on top, ending the life of the well.
Frequently Asked Questions
Plugging operations on average take 3-5 days of work for a crew of 15-20 people. However, this can vary as the plugging process at the end of a well’s life is just as complicated as initially drilling the well due to crews dealing with older subsurface features and equipment.
Each well is unique in its design and each location has unique geology. This means that the technique used in Bottineau County to plug a well may be very different from the techniques used in Dunn County; or, the complexity of the well may vary the length of time it takes to safely plug the well.
North Dakota has 11,224 plugged wells. These were plugged either due to age, economics, maintenance, environmental and safety risks, or many other factors.
Once a well has been plugged, while technically feasible, the likelihood of it being brought back to production is extremely low –and even more so after site reclamation has been completed.