Because it is the law.
The Regulation states that abandonment must include the following steps:
- Return of the well tag to the Ministry of Environment
- Make all reasonable efforts to remove the well casing or well screen and all other equipment and debris in the well (unless the well is removed by overdrilling)
- Plug the annular space with a continuous column of an abandonment barrier that prevents any movement of water, natural gas, contaminants or other material
- Seal the well at ground surface with 50 to 150 cm of bentonite chips, pellets, granules or powder
- Fill the remaining well opening to ground surface with soil cover or other material that is in keeping with the surface material immediately adjacent to the well opening