Technical Discussion of Dual Completion Well Issues
Statewide Rules 9 and 46 both require that injected fluids remain confined to the authorized injection/disposal interval. The technical review of the well completion evaluates whether confinement of injected fluids can be ensured.
Dual completion wells, particularly those with open productive perforations, pose several technical challenges that must be addressed in order to operate the well efficiently.
The first challenge is confinement of injected fluids to the authorized injection interval. Since a tubing or packer failure in the injection string will immediately result in injection into the open productive perforations, the well must have some method of monitoring and detecting this type of downhole problem.
The second challenge deals with demonstrating mechanical integrity of the entire wellbore. The Mechanical Integrity Test (MIT) must also test the casing between the productive perforations, and the injection perforations. This necessarily makes the MIT process cumbersome and expensive.
One partial solution to these issues is to apply for the production zone, injection zones, and the intervening formations to be part of the "authorized injection interval". The practical result of this strategy is that "leaks" between the production and injection zone will remain confined to the authorized injection zone and therefore not require regulatory oversight. The MIT will only need to test the interval from ground surface to the top of the "authorized injection zone", thus eliminating the need to demonstrate mechanical integrity between the production and injection perforations.