Does the pump torque twist the riser?
At pump start-up there is a partial rotation of the riser in the area of the pump which ceases immediately the pump speed increases and the riser fills to become a rigid system. This is not detrimental to the performance of the system, merely a consequence of the elastic nature of the riser and has major benefits in the resistance of shock loadings. It is imperative that the wellhead is designed and installed so that the pump hangs centrally in the borehole in order to avoid any chance of cable damage when the pump moves.