Abstract: A continuous feed injection unit used for example for injection and removal of continuous well string from wells operates in a dual speed configuration. The unit comprises a first hydraulic motor, a second hydraulic motor, cooperating continuous well string gripping chains connected to be driven by the first and second hydraulic motors, a hydraulic power supply connected to provide pressurized fluid to the first and second hydraulic motors and a control system for the hydraulic power supply. The control system for the hydraulic power supply has a motor speed control valve with at least a first and second operating configuration, the first operating configuration providing power fluid to the first and second hydraulic motors in parallel and the second operating configuration providing power fluid to the first and second hydraulic motors in series. The hydraulic power supply may be a conventional power tong hydraulic supply.

Abstract: A continuous well string injection unit and balancing system, in which the continuous well string injection unit is suspended using a sling connected to a pair of suspension points. The balancing system comprises a length-adjustable member connected to the rod injector at a third suspension point, and a controller for adjusting the length of the length-adjustable member.