Safety enhanced in NOV’s ST-120 iron roughneck

Drilling Contractor attended a demonstration of National Oilwell Varco’s (NOV) ST-120 iron roughneck at one of its Houston manufacturing facilities in late September. The tool features 120,000 ft-lbs of maximum breakout torque and a full 12 ft of extended reach on a trackless design for enhanced safety.

The ST-120 can be run in manual mode or the optional automatic mode, and the latter can be controlled from the driller’s control console or from a handheld wireless remote control. “If it’s in auto mode, none of the manual functions will work. If it’s in manual mode, none of the auto functions will work,” explained Craig Brooks, drillfloor tools product line manager for NOV. “It forces them to make a decision… The goal is to make sure only one person is operating it and only one person is in control to help reduce injuries.”

The tool also uses sensors to detect if someone accidentally steps into the operating space. “It automatically shuts down, and you cannot restart it unless you go out and hit one of three emergency stop buttons on the machine,” Mr Brooks said. “It forces you to go out to the tool and make sure nobody is in harm’s way before you start the tool up again.”

The first ST-120 unit was sold in 2007 and went into operation in 2008. Approximately 60 units have been sold to date, mostly going to newbuild drilling rigs under construction in shipyards. To facilitate the installation process, NOV tested all software internally before shipping the first unit. “We ran through any bugs here rather than at the shipyard, and we had almost no issues in installation,” Mr Brooks said.

In addition, NOV still keeps a unit in Houston so the company can continue to perform software upgrades and testing and other R&D.

The company also expects to release the next model, the ST-160, by April 2011. “It’s going to look almost identical except it will have more torque and will be able to accept casing tongs,” Mr Brooks said. “It will be able to change out the casing tong without using cable lines or tuggers.”

“Whereas today with most casing tongs, when you change them out, you have to get a winch to lift the casing tong to the head of the roughneck. With the ST-160, you’ll be able to do it virtually hands-free,” he added.

NOV also anticipates installing a system on the ST-160 that will monitor usage and adjust maintenance schedules accordingly. “It will notify users when they need to service their equipment based on actual usage rather than assumed usage,” said Brian Winter, NOV global product engineer.

“Usage depends on what activity you’re engaged in. A day of drilling is a lot different than a day of tripping in terms of this machine. While tripping, you’re using this machine every minute and a half to every three minutes. In drilling, it could be three hours before it’s used. We want people to service it based on actual usage rather than based just on a time frame,” Mr Winter said.

NOV shipped its first iron roughneck in 1975 and has shipped over 2,300 units since.