Abstract: The present invention provides a drilling rig which includes an electrically-controllable tubing injection system. The injection system contains a fixed injector head with two movable injection blocks which are remotely operable to provide a desired opening therebetween. Each injection block contains a plurality of gripping members for holding a range of tubing sizes. The injection blocks automatically adjust to provide the required gripping force and tubing speed according to programmed instructions. A resilient tubing guidance system is positioned above the injector head directs the tubing into the injector head. The rig system contains sensors for determining the radial force on the tubing exerted by the injector head, tubing speed, injector head speed, weight-on-bit during the drilling operations, bulk weight of the drill string, compression of the tubing guidance memeber during operations and the back tension on the tubing reel.