AGL has commenced the permanent decommissioning of eight gas wells and two seismic monitoring bores in the NSW Hunter Valley, following its recent decision to exit the Hunter Gas Project.
Decommissioning involves the use of a rig to fill the well with cement, which is specified for this purpose, to the depth of the coal seam.
The cement-filled well casing, which already has several layers of steel and cement, is cut off at least 1.5 metres below ground level and sealed with a metal plate which records data including the well name, its depth and exact location. These details also are provided to NSW government regulatory authorities for any future reference.
The site is then rehabilitated, meeting licence conditions and giving utmost regard to environmental protection, subsoil and topsoil management, erosion control and revegetation.
This process will take around two to four weeks per well and the project will take approximately three months to complete.