Modular MDDM top drive designed to cut time for change outs, slash ...

D RILLING RIG EQUIPMENT
Modular MDDM top drive designed to cut
time for change outs, slash failures
IN 2005, TRANSOCEAN went in search of a “nextgeneration
top drive” that could significantly improve operational
performance to meet customer demands. Specifications
required for this new-generation design were tough, including
a 99.9% uptime on an annual basis. Out of several ideas proposed
by different equipment manufacturers, Aker Solutions’
MDDM (modular direct drilling machine) was selected.
According to Aker, the MDDM’s increased performance would
enable Transocean to drill wells up to 50,000 ft, with an overall
design philosophy of reducing the total cost of ownership of a
derrick drilling machine.
A contract was signed by October 2005, initiating a development
phase with the two companies collaborating on the
design and field-testing of the new top drive. Transocean
provided background data based on analysis of the downtime
history of 72 top drives from various vendors over a five-year
period. Design and the prototype were completed in 2007 and
implemented on the Transocean Enterprise-class newbuilds .
MDDM DESIGN
Perhaps the most notable feature of the MDDM is its modular
design. When an important component of the top drive breaks
down, only that part is changed out, thus reducing the time
required for change-out and repair and therefore overall downtime
.
“We put a lot of effort into making the MDDM easy to take
apart and put together again,” said Bjørn Rudshaug, vice
president R&D for Aker Solutions. A lot of time was spent on
clearly defining the different functions and splitting them up
into different modules, then achieving optimal interaction at
the interface between the modules, according to the company.
So what kind of time reduction can the user expect to see?
According to results of a workshop test simulating the drilling
rig environment, it takes less than 70 minutes to change out an
AC motor. Some top drive designs require more than five hours
for a motor change, he said . The time required to change out
the main shaft on the MDDM is around eight hours, compared
with approximately 72 hours with other top drives, he added .
The MDDM design also tackles downtime from the other end
– the root cause of failure. A analysis of the bearing and main
shaft was completed during the design phase, with Transocean
creating a load chart for deepwater vessels based on actual
measurements on their high-end deepwater rigs, according to
Aker. This data set formed the basis for calculation of the main
bearing in the MDDM, significantly reducing the risk for failure
in this key component.
The analysis also showed that the lubrication and cooling system
for the bearings were just as critical as the bearings – if
the lubrication system fails without proper monitoring, a subsequent
bearing failure was likely. This resulted in a redundant
lubrication system, with two systems working independent of
each other with full lubrication flow and pressure monitoring.
An identical analysis for motors also was done, finding that the
motor cooling system was one of the main root causes for failure.
A failure of the motor cooling system has the same effect
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The MDDM was designed to provide an annual uptime of 99.9%
by cutting down on failures and repair time.
of a failure of the motor itself. Once again, a redundant system
was implemented, with a water-cooled AC motor that has a
redundant cooling system.
Aker believes that redundant systems are key to planning outof-service
time. The company said that if the motor fails on the
MDDM, it can still deliver 80% of full drilling performance with
one motor. “It’s really designed to minimize downtime in every
possible sense of the word,” Mr Rudshaug emphasized.
The top drive system also features a 1,200-ton or 1,250-ton
lifting capacity, making it a powerful machine suitable for the
deep and ultra-deep wells that Transocean and other drilling
contractors are drilling offshore. It also incorporates dual
motors delivering 2,400 hp and more than 100,000 ft-lb of
continuous drilling torque, another significant advance, the
company says.
Safety also will be increased with the MDDM, with a remotecontrolled
multifunctional pipe handler that enables 360° continuous
rotation capability. Additionally, the need for stabbing
hands when handling casing has been removed, eliminating
manual intervention.
Manriding operations also are eliminated by providing maintenance
personnel a stable work platform to gain access to the
top drive system.

D RILLING RIG EQUIPMENT
The TorqueMaster has a makeup and breakout capacity of 50,000
ft-lbs between its main tong and drill floor and between the top
drive and its backup tong.
Other features of the MDDM include:
• Continuous main shaft from power swivel through gearbox
and pipe handler.
• Remote-controlled multifunctional pipe handler, enabling
360° continuous rotation capability.
• Auto-positioning to ensure safe, easy and accurate orientation.
The MDDM has already been installed in the derrick of
Transocean’s sixth-generation ultra-deepwater drillship
Discoverer Clear Leader . All Enterprise-class newbuilds are
also equipped with the MDDM, Aker said .
Mr Rudshaug added that Aker is discussing the MDDM with
other clients as well, though he said it was too early to provide
details.
“All components are made from the highest quality, which
means it’s not the cheapest top drive. But it is, from our opinion,
the best,” he said. “It is the Lexus among top drives.”
Aker also has created the MDDM 1000, which uses the same
modular design philosophy and many of the same key components,
but adjusted for lower loads and smaller physical
dimensions. The prototype of this machine is scheduled to be
completed in Q3 2008, with delivery beginning in Q1 2009.
DRILLING SIMULATOR
Through its recent acquisition of First Interactive, Aker has
launched a new-generation drilling simulator that will enable
realistic 3D visualization and real-time scenario-building.
While the simulator will be primarily used for training of rig
50 September/October 2008 D R I L L I N G CONTRACTOR
operators, it also holds great opportunities for the upgrade
market, Mr Rudshaug said. First, a 3D model of an existing
installation is made, then verified with offshore laser scanning.
Then a control system is added to the rig so the simulator is
fully integrated and reflects the rig. When changes are made –
only on the simulator – the upgrade can be verified on the rig
without costing the operator dayrate. The upgrade can even be
verified before it’s actually built, he said.
“This gives great opportunity for optimizing and reflecting the
fact that the most expensive part of a drilling rig upgrade is
the lost income of time spent on installation and commissioning.
This time will be significantly reduced by this method.”
Mr Rudshaug explained that drawings on paper can be hard to
imagine. But when it’s run like a video game as you’re sitting
in a simulator chair, a much more direct picture can be formed
of how the upgrade might work.
“It’s also good for optimizing procedures and movements and
how things have done on the drill floor. We have great expectations,”
he said. The simulator is based on the advanced drilling
simulators that Aker has already sold in conjunction with drilling
packages.
TORQUEMASTER
One of the newest rig innovations coming into the drilling
industry to improve safety and efficiency is the high-efficiency
jackup from Maersk Contractors, two recently delivered from
Keppel FELS in Singapore and two still under construction.
The four units will be identical, all featuring drilling packages
from Aker.
Included in the drilling package is Aker’s TorqueMaster, which
can make up and break out pipe, collars and casing from 2
3/ 8 in. to 20 in. It is based on two tongs that can be separated,
with the main tong a gateless one that can rotate 360° continuously
with a torque capacity of 150,000 ft-lbs. The machine also
offers a makeup and breakout capacity of 50,000 ft-lbs between
the main tong and drill floor and between the top drive and the
backup tong.
To continue the trend especially seen in the North Sea of
using remote operations facilities onshore to manage offshore
work, a computer monitoring and executing system in the
A new drilling simulator can be useful in both the training of rig
operators and for helping to verify and optimize rig upgrades,
according to Aker Solutions.

The TorqueMaster recently began operations on Maersk’s new
high-efficiency jackup. According to Bjørn Rudshaug, Aker vice
president R&D, there have been only a few minor and readily fixable
“teething problems” on the Maersk Resilient.
TorqueMaster allows for off-site monitoring. It also stores
makeup and breakout information on the machine .
The Maersk Resilient, the first of the four high-efficiency
jackups, went into operation in March 2008 and has been “a
milestone for us because it was the first TorqueMaster that
commenced operation,” Mr Rudshaug said.
As Aker and Maersk gained operational experience, he said,
there have been some “teething problems” – with the HMI
(human-machine interface) and with some extremely smalldiameter
production tubing. The fixes have been quick, however,
he pointed out.
A TorqueMaster also is already working on StatoilHydro’s
Heidrun platform with good results, he said. A total of 20
TorqueMasters have been sold to date.
FUTURE, CHALLENGES
Aside from the industrywide challenge of finding qualified personnel,
Aker is facing a unique challenge on the supply side
coming from – of all places – the wind mill industry.
“The slew ring bearing we use in a lot of our equipment is the
same type that many of the wind mills use, and the wind mill
industry is draining the market of slew ring bearing,” he said.
“We quote for 30 and the wind mill producers quote for 3,000.
Who will get attention? It’s a big problem for us.”
On the technology side, Aker is looking towards integrated
operations as the way forward. “We are striving to align the
whole Aker Solutions into integrated operations thinking. How
can we get the operation itself, not only the drilling operation
but others too, to be more integrated?” Tools such as the drilling
simulator is such an integration tool , but “there are more
aspects to come. That’s a challenge we’re facing right now.”
D R I L L I N G CONTRACTOR
September/October 2008
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