Case study · Offshore geotechnical
Keeping crews away from the drill floor
Bespoke remotely-operated iron roughnecks for two offshore geotechnical drilling vessels – engineered to DNV, and to the derricks already in place.
Making up and breaking out drill pipe is among the most hazardous routine tasks on a geotechnical drilling rig. Doing it by hand means chains or tongs, and people standing at well centre while the string is under load.
GeoQuip Marine needed that work automated on two offshore vessels – without replacing the derricks it already had.
The constraint
Off-the-shelf iron roughnecks are built for oil and gas. They are heavy, expensive and sized for derricks far larger than a geotechnical rig. Neither vessel could take one, and the cost was disproportionate to the scope.
The two derricks were also different from each other: different structural arrangements, different height constraints. Anything supplied had to fit what was already there, on both.
What we did
We designed and supplied bespoke remotely-operated iron roughnecks for both vessels, engineered in accordance with DNV and built to each derrick’s specific envelope.
The design keeps the operator at a pedestal or in the driller’s cabin rather than at well centre. Torque is set and repeatable, safety interlocking is complete and the unit is compact enough for single and twin-mast geotechnical rigs.
Design features
- Torques against the power swivel, acting as a bit breaker
- Full safety interlocking, achieved without a PLC
- Compact enough for single and twin-mast geotechnical rigs
- Pedestal-mounted controls plus custom driller’s-cabin control
- Calibrated, adjustable torque setting
- Adjustable cylinders to clamp drill sections and control vertical position
The interlocking is worth drawing out. Achieving it without a PLC means there is no software layer between the operator and a safe state – fewer failure modes, simpler fault-finding offshore and nothing to reflash when something needs changing at sea.
The result
Both vessels operate with personnel clear of the drill floor during pipe handling. The units met each derrick’s constraints rather than requiring modification to the vessel, and cost a fraction of the oil-and-gas equivalent.
The iron roughneck is now a MintMech product line.