Abstract: A method of operating a wellhead compressor includes selecting a plurality of operating points of the wellhead compressor, measuring the tubing pressure at the plurality of operating points of the wellhead compressor and determining an efficiency achieved by the wellhead compressor when operating at each of the operating points based on at least the measured tubing pressure at each of the operating points. A production curve is generated of well pressure as a function of flow rate from a combination of measured data and predicted data. An operating point of the wellhead compressor is selected from the production curve based on at least the efficiency of the wellhead compressor at the selected operating point and the wellhead compressor is operated at the selected operating point. The steps of the method are repeated after operating the wellhead compressor at the selected operating point for a predetermined period of time.

Abstract: A lifting/skidding device includes an electric motor, a gear coupled to the motor and a lifting/skidding mechanism coupled to the gear, wherein the motor is embodied as a permanent magnet synchronous machine. The lifting/skidding device is adapted for lifting/skidding an offshore construction.