A method of operating a rotary pump having a stator and a rotor driven to rotate therein by a submersible pump driver connected to the rotary pump in a production assembly suspended in a well casing from a wellhead, the method comprising:
- providing production tubing extending in a longitudinal direction of the well casing so as to be in communication between the wellhead and the rotary pump;
- providing at least one control line extending alongside the production tubing so as to be arranged to communicate a drive input from the wellhead to the submersible pump driver to drive rotation of the rotary pump and such that said at least one control line has greater tensile strength in the longitudinal direction of the well casing than the production tubing;
- and
- suspending the rotary pump and the submersible pump driver in a production position in the well casing from the production tubing and said at least one control line such that said at least one control line provides greater support to the rotary pump and the submersible pump driver than the production tubing.