General Best Practices for Underground Injection Wells
- • Consider all geological information prior to applying for a permit for an underground injection well. This includes: the geological and hydrological characteristics of the zone of confinement (this is the area that prevents the material injected into the ground from migrating to other areas); the potential for the movement of the fluid from the injection zone to other areas; the number of other wells penetrating the injection zone and adding more waste material to this area; the existence of fractures and faults and the potential for fracturing to occur in the confining zone; and the corrosive characteristics of the fluid and the potential for penetrating the confining zone.
- • Construct and maintain the integrity of the well casing to prevent migration of fluids into the ground and into the drinking water strata. Cement the casing properly to the ground and sidewalls of the hole which the well goes through. The casing must go into the impermeable area beneath the drinking water strata and the cement must be attached to the casing below the drinking water strata. Determine the casing size, weight, composition, and protective coating.
- • Determine the type of tubing as well as its composition, coating, and ability to withstand bursting from pressure or the waste material disposal.
- • Predetermine the mechanical integrity of the well and evaluate it periodically to make sure that the injection pressure and the fluid volumes have not damaged the system and interfered with the mechanical integrity of the unit.
- • Continuously monitor injection pressure, volume of material being injected, type of material, rate of injection, and the annulus pressure.
- • Where applicable, continuously monitor drinking water wells to determine if they are becoming contaminated.
- • Never use a drinking water well for disposal of any type of waste even if the well has run dry. The drinking water well is in an aquifer which may be renewed from various sources and the waste will contaminate any other drinking water wells which will be utilizing this aquifer.
- • Develop in advance a plugging and closing plan which meets the specifications of the authorizing authority.