OTC Technology Review: GustoMSC

Named after a crab’s claw, the Chela crane has recently been installed for the first time on the Maersk Invincible rig. This multifunctional arm can reach below the cantilever as well as elevate towards the main deck, providing access to an area traditionally blocked by the drilling cantilever. Designed by GustoMSC, the crane offers efficiency and safety benefits.

The crane can be fitted with a series of sheaves to guide a wireline to any position within the reach of the crane tip. In addition, it provides up to 25 t of hoisting capacity underneath the cantilever at any position, and has the possibility to reach to the main deck of the rig for a handshake with the rig’s main cranes. It can transfer containers and pieces of equipment from the main deck of the rig to underneath the cantilever and vice versa in a single lift operation. This feature improves safety and efficiency, as main crane access to the wellhead deck from the drilling rig is normally blocked by the cantilever.

Figure 1. The Chela on the Maersk Invincible.

The moveable arm creates a sturdy hoisting point underneath the cantilever, enabling wireline operations separated from the drill floor. It thus provides a significant advantage in development drilling, infill drilling and plug and abandonment operations. The wireline operations can take place offline, on any other well, while the derrick moves on to the next well. This feature results in savings in rig days for plug and abandonment operations that can amount to approximately 15%, when compared to the conventional procedure, by providing offline activities such as logging and cementing that normally need to be performed in sequence on the drill floor.

As the crane separates wireline operations from the drill floor operation, it reduces human interface on the drill floor and less interaction is required between different crews as rigging up for the operation is done offline. Enabling a single lift from the main deck to the wellhead platform below the cantilever reduces handshakes. The high level of control, as a result of the short distance from crane tip to hoist, has a substantial impact on the overall safety of the rig.

Chela is a full electrical crane that requires little maintenance. It can be installed on a new build rig or retrofitted to an existing rig. Due to the efficient foundation interface with the cantilever, it requires only limited modification to existing cantilever structures. It is designed to be easily dismountable, and if the same integration points and type of jumper stations are used, the crane can be shared among different rigs within the fleet, increasing flexibility for the operator and contractor.

The technology was introduced in 2016. In the presence of and with input from Maersk, Aker BP, JB Systems and Breman Factory, a factory acceptance test (FAT) was performed that showed the tool’s capabilities and facilitated a fast-track start-up for Maersk. In the summer of 2019, GustoMSC delivered the crane to Maersk and at present the tool is in operation on Maersk Invincible. This XL enhanced ultra-harsh environment jack-up rig is operating offshore in the Valhall field, a giant oilfield in the southern Norwegian North Sea operated by Aker BP.

Read the article online at: https://www.oilfieldtechnology.com/offshore-and-subsea/13052020/otc-technology-review-gustomsc/