Catwalk Machines (CWM) Information
Catwalk machines (CWM) are pipe handling systems that are used to transport tubular objects and ancillary equipment to and from the drill floor. CWMs automate pipe handling operations in order to minimize manual handling when adding sections of pipe to the drill string. They are one of several equipment types used to carry out pipe handling operations such as gantry cranes, tailing arms, bridge rackers, fingerboards, stabbing systems, horizontal to vertical arms, and racking arms.
Video credit: North Rig Catwalk Technologies / CC BY-SA 4.0
Catwalk machines transfer drillpipe and other equipment – including risers, telescopic joists, slip joints, casings, subs, and collars – from storage areas to the drill floor. Objects to be transported are loaded onto conveyors or carts which transport them along the machine. CWMs are typically operated by remote control from a driller’s cabin. Although CWMs increase upstream capital costs, they can improve drilling efficiency and reduce occupational hazards, both of which result in cost savings and increased safety.
Catwalk machines may be specified by the range of pipe sizes accommodated and load-handling capacity.
- Maximum safe working load will dictate the weight of pipe that the machine can handle.
- Tubular length is the maximum length of pipe that can be transported.
- Tubular handling diameter specifies the smallest and largest diameter of pipe that the machine is capable of moving.
Many CWMs are hydraulically powered, whereas others are electrically driven, such as with a variable frequency drive. CWMs are often custom-built to the specifications of the oil rig for which they are intended.
Image credit: Cameron
Catwalk machines often have optional features that provide additional or improved functionality. Some examples are:
- A heavy tool frame allows transport of particularly heavy pipe.
- Tubular feed systems neighboring the CWM can continuously provide pipe to eliminate wasted time waiting for restock by other handling equipment or deck cranes.
- Tailing arms can provide additional stabilization and guidance to piping to ensure accurate and safe transport.
- Lift and separator arms, pipe dividers, tubular raises, auxiliary hoists, and side pushers facilitate pipe handling and transport.
- Safety features of CWMs include ramping speed down at the end of travel, overload protection, emergency load lowering, and fail to safe braking.
Image credit: NOV