A 
petroleum well having a well casing, a 
production tubing, a source of time-varying current, a downhole chemical 
injection device, and a downhole induction 
choke. The casing extends within a 
wellbore of the well. The tubing extends within the casing. The 
current source is located at the surface. The 
current source is electrically connected to, and adapted to output a time-varying current into, the tubing and / or the casing, which act as electrical conductors for providing downhole power and / or communications. The 
injection device having a communications and control module, a chemical container, and an electrically controllable chemical 
injector. The communications and control module is electrically connected to the tubing and / or the casing. The chemical 
injector is electrically connected to the communications and control module, and is in fluid communication with the chemical container. The downhole induction 
choke is located about a portion of the tubing and / or the casing. The chemical 
injector is electrically connected to the communications and control module, and is in fluid communication with the chemical container. The downhole induction 
choke is located about a portion of the tubing and / or the casing. The induction choke is adapted to 
route part of the 
electrical current through the communications and control module by creating a 
voltage potential between one side of the induction choke and another side of the induction choke. The communications and control module is electrically connected across the 
voltage potential. Also, a method is provided for controllably injecting a chemical into the well downhole, which may be used to: improve lift efficiency with a 
foaming agent, prevent deposition of solids with a paraffin 
solvent, improve a flow characteristic of the flow 
stream with a surfactant, prevent 
corrosion with a 
corrosion inhibitor, and / or prevent scaling with scale preventers.