Abstract: A formation injection tool disposable in a casing of a production well includes an intake flow control assembly, a seal mechanism located below the intake flow control assembly, and a discharge flow control device located below the seal mechanism. The intake flow control assembly is attached to a lower end of a pump extending downward within the well casing past and below an upper productive formation. In response to an upstroke of the pump, the intake flow control assembly permits one-way flow of undesired heavier fluid, such as water, from the upper productive formation downwardly and into the intake flow control assembly concurrently as desired lighter fluid, such as oil and/or gas, flows from the upper productive formation upwardly within the well casing to the ground surface. The seal mechanism establishs a closure seal within the well casing between the upper productive formation and lower disposal formation.