Pipe Bending for Reel-Lay Operations

The method of any preceding claim, comprising:

• pausing movement of the pipe through the bending zone;
• detaching tie hold-back element from the internal mandrel;
• withdrawing the hold-back element from the pipe;
• attaching an additional pipe section to a trailing and of the pipe;
• inserting the hold-back element to extend internally along the additional pipe section and the pipe to the internal mandrel;
• reattaching the hold-back element to the internal mandrel;
• and
• resuming movement of the pipe through the bending zone.

An internal mandrel for resisting radially-inward deformation of an inner surface of a pipe during bending of the pipe along a longitudinal axis, the mandrel comprising:

• longitudinally-spaced pipe-engaging elements;
• a tensile flexible or hinging link disposed between the elements to allow relative angular movement between the elements as the pipe bends;
• and
• a hold-back connection on one of the elements to apply hold-back force to that element to be transmitted in use to the other element by tension in the tensile link;
• wherein a pressure compartment is defined between the pipe-engaging elements;
• wherein the pressure compartment contains a fluid mass;
• and
• wherein the Held mass comprises a gel, wax or granular filler material.

Pipe-bending apparatus for bending an elongate pipe section continuously along a longitudinal axis of the pipe section, the apparatus comprising:

• an internal mandrel arranged to fit inside the pipe section to resist radially-inward deformation of an inner surface of the pipe section with respect to the longitudinal axis during bending;
• an elongate tensile hold-back element arranged to extend internally along the pipe section from an external anchor to the internal mandrel to hold the internal mandrel at a bending zone as the pipe section advances longitudinally past the internal mandrel;
• an external mandrel defining the bending zone;
• and
• a drive for advancing the pipe section through the bending zone;
• wherein a reel serves as the external mandrel and as the drive.