Top drive of the future

© 2010Aker Solutions

Aker Solutions Drilling technologies features

Top drive of the future
Aker Solutions invested its significant experience and competence together with Transocean to design a drilling machine that redefines drilling machines. The result: An award-winning product designed for 99.9 percent uptime and radically reduced time to repair and replace key components. The MH MDDM 1000 AC™ from Aker Solutions emerges at a crucial time, as many rigs are built or upgraded to requirements of deeper water and higher utilisation.

A handful of untrained technicians approached the newly developed MH MDDM 1000 AC™ with a list of repair and replacement jobs. The list had resulted from study of millions of hours of top drive operations; these were the most common jobs.

The results were stunning.

The client, Transocean, had stipulated rapid times. A main shaft often takes up to eight hours to change. Transocean wanted to see it done in four. Motors often take 10+ hours to change. Replacing the AC motor on the MH MDDM 1000 AC™ should take less than four. The team of untrained engineers managed to replace the pipe handler completely in less than 90 minutes. They switched out the AC motor, including its coupling and the air flex brake, in 70 minutes.
[See Bellow “Time to repair” table]

“This was a workshop environment, so the engineers had access to cranes that may not be available in situ, and there is obviously no heaving of the floor. Nonetheless, these results were thrilling. On an 18-point laundry list of repairs, we were able to cut repair times 41 percent,” said Arnt Aske, the project director at Aker Solutions who coordinated the MH MDDM 1000 AC™’s development.

It is this kind of performance, the close working relationship with Transocean and the tool’s potential for a worldwide fleet of drilling rigs needing upgrades, that led to the MH MDDM 1000 AC™’s selection for the OTC Spotlight on New Technology Award.

“We are delighted to receive this recognition from OTC. In order to offer our clients the best products, we need to always be at the forefront of technological developments. The MH MDDM 1000 AC™ is further evidence that we are leading the way in our industry,” says Thor Arne Håverstad, President of Aker Solutions’ drilling equipment unit.

Designed performance
It is the story behind the MH MDDM 1000 AC™ that established a foundation for this kind of success. Note that it is not the first of its kind; it is in fact the little brother to the MH MDDM 1250 AC™, which was first installed on Transocean’s Discoverer Clear Leader.

That initial technology was developed starting in 2005, with an equally demanding set of specifications from Transocean. Facing a drilling programme of steadily deeper wells and higher utilisation costs, Transocean wanted 99.9 percent uptime on an annual basis and a design philosophy of radically reduced lifetime cost of ownership.

Transocean chose to work with Aker Solutions for this initial machine. To the project, Transocean provided background data based on analysis of the downtime history of 72 top drives over a five-year period. Furthermore, Transocean inserted a handful of operators and engineers, who meshed with Aker Solutions’ own development team.

The MH MDDM 1250 AC™’s development followed a pattern unfamiliar to the oil and gas industry.

“The kind of platform thinking we used on the MH MDDM 1250 AC™, and which we employed to great effect on this machine, is more common to the automobile industry. With one robust platform and a very integrated design team, you can rapidly develop many other models. It stems from the need to cut time and costs associated with launching new products in the market,” said Bjørn Rudshaug, head of technology and innovation in Aker Solutions’ drilling business unit.

As a result of this revolutionary approach to design, the MH MDDM 1000 AC™ could be developed on a fast track. From start-up of the new top drive’s development work until its commissioning on Discoverer Luanda at DSME, only 20 months passed.

Many of the decisions taken during development of the MH MDDM 1250 AC™, such as extensive use of mechanical, hydraulic and electrical quick connectors and beefed-up dimensions of the main swivel and gearbox (based on root cause analysis of countless top drive failures), could simply be adjusted to the MH MDDM 1000 AC™’s needs.

Meeting a market need
The MH MDDM 1000 AC™ was designed to accommodate pretty much any of Transocean’s 50+ drilling rigs, which means it is appropriate for the upgrading of hundreds of rigs worldwide. Aske stated: “The majority of rigs will need to upgrade top drives in the coming five to ten years.” It is that broad market Aker Solutions believes it can reach with this product.

“The evolution in drilling rigs and drilling technology, the increasing level of deepwater operation and the high utilisation levels made necessary by high day-rates have transformed the industry in a decade,” said Aske. “We designed the MH MDDM 1000 AC™ to meet the toughest criteria in terms of performance and flexibility, and the dimensions of the derricks on most later generation drilling rigs.”

Deeper drilling programmes are taking many top drives to the edge of their operational limits and beyond, with a deleterious effect on failure rates. With day rates climbing up to and over USD 500 000, those failures were increasingly costly. The MH MDDM 1000 AC™ was designed around this new operational logic, stepping up the power available on the drill string while enabling rapid replacement of wearing parts without downtime.

The machine’s size makes it available to the vast majority of drilling rigs today. A number of other features increase its attractiveness to operators as well. Operational efficiency is improved by a pipe handler that swivels freely 360 degrees. Flexibility is improved by a mud intake that can come in directly behind the top drive, or from either side.

The first MH MDDM 1000 AC™ units, installed on Discoverer Luanda, were commissioned in South Korea late last year and the ship is headed for West Africa to drill its first well. The top drives, however, have already been through extensive tests at what Bjørn Rudshaug described as the world’s most extensive top drive testing facility.

“The MH MDDM 1000 AC™ was pull-tested, run continuously for 96 hours and the IBOP mechanism was tested in an operating environment. The full-scale pull test put the top drive into a mechanical frame and tested it. It didn’t make one sound. As an engineer, you love that. It was perfectly designed and assembled,” said Aske.

The 96-hour continuous operation test involved connecting the main shaft to a dynamic braking table, including a torque measuring device, to study the full operational power and torque it will experience in the field. It was precisely this test that uncovered some issues with the MH MDDM 1250 AC™ during its development; the results for the MH MDDM 1000 AC™ were perfect.

Spotlight on new technology
In mid-March 2010, Aker Solutions’ MH MDDM 1000 AC™ was selected by organisers of the Offshore Technology Conference as a recipient of the Spotlight on New Technology Awards. Among the criteria for this award are its broad interest and significant impact. Aker Solutions hopes that both Transocean and the wider drilling community will appreciate the strengths of the machine.

“This technology is a clear move by Aker Solutions to position itself at the forefront of developments in drilling components. The background for the MH MDDM 1000 AC™’s development, the resources spent on it and its ability to accommodate almost any rig are all designed to hit the market’s needs,” said Aske.

While Aker Solutions remains coy regarding any concrete sales goals, Aske indicates that the company has production capacity stretching up to 10+ units per year. The MH MDDM 1000 AC™ is priced at a premium compared to many other top drives, but Aker Solutions believes lower operating costs and higher utilisation will quickly make up this difference.

“The operating environment of many drillers is different than it was only a decade ago; legacy top drives are struggling to maintain satisfactory levels of performance. The MH MDDM 1000 AC™ was designed specifically to change that, and launch a new paradigm for top drives in this market,” concluded Aske.

Gearbox and main swivel alloys
Development of the MH MDDM 1000 AC™ and its antecedent – the MH MDDM 1250 AC™ – began by combing a treasure trove: Several years of performance data from numerous top drive models. Scrutiny of this data singled out areas of the top drive most often responsible for downtime. The gearbox and main swivel were among the worst culprits. As a result, Aker Solutions' subsidiary Aker Wirth was brought in to beef up these elements.

“We focused on deflection of both the main shaft and the swivel housing/load frame while loaded. It is crucial for the lifetime of the main bearing that these have the same deflection so the load is transferred correctly. The lifting capacity was raised to 1000 tons by selecting another type of alloy for the main shaft,” said Dag Håverstad in Aker Solutions’ MDDM technical development team.

The strong collaboration between Transocean and Aker Solutions is good example of how a close relationship between customer and technology provider drives the industry forward. The award from the OTC, combined with the positive early operational feedback, has given the MH MDDM 1000 AC™ a great start and puts it on course to become the industry's top drive of the future.

Source: Aker Solutions