A well is plugged when it is no longer used for production or injection. By state law a well is considered abandoned when no injection or production is reported for a year. A permit to plug must then be applied for if a future use exemption is not sought. Unfortunately thousands of the state's abandoned wells have not been plugged. For those wells which have been plugged, proper plugging techniques were not being used until the 1950s.
A well is plugged in order to prevent environmental contamination from fluids or gases from underground, including contamination of drinking water supplies, and also in order to preserve integrity of used and potential production formations. When wells were plugged in the first half of the 20th century it was for the latter reason alone.
A paper which describes the history of plugging and plugging techniques is a useful introduction as is a presentation by the Office of Oil and Gas for industry about current requirements.
Early well plugging materials included nothing, gravel, clay, wood, and occasionally a little cement.
The location of early wells in the state is poorly recorded and when there are records they are inadequate, such as for this 1911 well in Clay county which was "abandoned" in 1926 after the casing was pulled. Better records are available for the 1912 well in Roane county which was plugged in 1929. A data sheet summarizes the completion report and there is a plugging affidavit which explains the plugging process. The last page in the file is a diagram prepared by the Office of Oil and Gas showing locations of plugs, types of material, and depths. Both of these wells were constructed without cement. The plugs for the 1912 well include a wood plug set within the casing not backed by cement and another in the wellbore above the removed portion of casing.
Uncemented steel casing deteriorates quickly in a well's corrosive environment.
Both the 1911 and 1912 wells are within secondary recovery fields where fluid is injected under pressure into the formation these wells were drilled to in order to encourage oil production within the field. Unplugged or improperly plugged wells placed under pressure in a secondary recovery field pose a danger to drinking water aquifers.
High pressures during hydraulic fracturing of new wells can affect nearby plugged and unplugged wells which penetrate or are to the formation being fractured.
Today wells must have 100 foot cement plugs across zones specified by regulation, in addition to a cement plug at the surface topped with a permanent monument. A drilling mud gel spacer is placed between cement plugs.
Permits for class 2 UIC wells by state law must have a valid plugging plan attached to the permit. The UIC section of this website has a number of well permits and permit applications showing these plugging plans. One injection well with documents on this website has been plugged and the plugging permit and plugging affidavit are available to show the plugging plan and work performed. Note the inspector's instruction on the operator's plugging schematic on page 4 of the plugging permit.
Sometimes while drilling or later when production is planned higher in the well, a well is plugged back. In this case the well is still being used for production after plugging of lower formations has been performed. This occurred at a well we looked at, 47-079-01314, where the completion report shows the well was originally drilled to 5958 feet below the surface. A cast iron bridge plug (CIBP) was installed at 5758 feet and then cement placed above the bridge plug to 5600 feet. Production zones for this well are more than 600 feet above the plug.
Gas Well Site Visits
Gas Well Study is the examination of natural gas wells in West Virginia.
Underground Injection Control Class 2 Wells
These wells are used either for the disposal of oil and gas liquid waste or for the enhanced recovery of oil or natural gas.
Gas Well Study Site Visits
Annual reports, environmental assessments, and individual well information.
Select videos from the Gas Well Study YouTube channel.
What Happened at Fernow
An investigation into what caused the vegetation death in the land application area after landspraying hydraulic fracture flowback waste.
The Spill at Buckeye Creek
An investigation into a spill from a Marcellus well site into Buckeye Creek in Doddridge county.