Motor equipments for the recovery of petroleum

The work of drilling, pumping and cleaning oil wells is very successfully handled by slip-ring induction motors. With the cable-tool method of drilling a special arrangement of controllers and resistance is used to obtain the required fine speed control. Similar motors are used for both this and the hydraulic rotary method. Pumping and cleaning, which includes ‘pulling’ the rods and tubing, are in most cases all performed by the same motor which may be a ‘Y-Delta’ or a two-speed machine, depending upon operating conditions. Both of these motors are double-rated, the low rating being used for pumping and the other for pulling and cleaning. High efficiency is essential on the pumping duty and high torque for the heavy work of pulling and cleaning the well. For both types of motors special control features are used to properly protect the equipment as well as to make it most convenient for the operator. For wells pumped by jack-rigs, a portable hoist is employed to pull rods and tubing. This paper presents data covering the horse power requirements and kilowatt-hour consumption for the various operations in drilling and maintaining producing oil wells.