Jennifer Pallanich Hull
Gulf of Mexico Editor
Deep Marine Technology's DeepWorker 2000 made its petroleum debut in the Gulf of Mexico in July. The one-person sub was called on to remove a damaged fitting on an injector line at Ewing Bank block 878 in 1,545 ft water depth. On its inaugural mission, the sub removed the fitting, but previous damage, as well as its inaccessible location, prevented the replacement of the injector line. The final option required replacing the flange and connecting a new injector line. The DeepWorker 2000 removed the original flange and o-ring, installed the new flange and o-ring using its onboard hydraulic tools, and connected the new injector line.
DMT's approach of placing a person in the water, down to 2,000 ft of water, runs contrary to the custom of using an ROV to accomplish the job. DMT's B.J. Thomas, CFO, said the submarine's pilot working to make underwater repairs has better depth perception by virtue of being at the job site.
"It's difficult to operate in a 3D world from a 2D screen," Thomas said.
DMT President and CEO Paul McKim said the submarine, or directly operated vehicle (DOV), "opens a world of possibilities for subsea work since we are untethered."
Man as a new tool
McKim said DOVs supplement existing tools, like ROVs, available to operators. The 3,800-lb DOV does not require the use of a fully dynamically positioned vessel, which drastically reduces rates for the unit. The DeepWorker 2000 can be launched off of a boat as small as 130 ft-long. With no umbilical to restrict movement, the unit can be deployed and retrieved from different locations, for instance, launched from one side of a platform and retrieved from the opposite side, which comes in handy when the sub performs surveys.
The two DeepWorker 2000s, which comprise what the company calls a spread, completed their second task by performing a site survey for pre-installation of a jacket. The three-day bathymetry and metrology survey at South Timbalier block 316 in 450 ft of water encountered one surprise: a mass of drill mud.
The DeepWorker 2000 is lowered into the Gulf of Mexico from the Atlas DP-1 Ryan T during sea trials.
"We had to do more surveying of the area on how much there was and how high it was," McKim said.
To complete the bathymetry and metrology surveys, DMT worked with Fugro Chance. DMT and Fugro computer software systems were integrated in preparation for this and future teamwork efforts, adding one day to the schedule.
A growing fleet
The company says its approach will save time and money while safely completing each assignment.
"We're faster, so jobs may not last as long, but because of the efficiency of the job and the savings to the customer, it creates more demand," McKim said.
As of July, Houston-based DMT had two DeepWorker 2000s. The pair of DOVs goes on all jobs together to ensure continuous bottom time and safety. Another spread is due in later this year, with DMT expecting to order up to two more spreads next year.
"It's a function of how fast we can grow," Thomas said. He said operators in the Gulf may be waiting to see how the DOV performs before contracting to use the units for repair work or surveys.
DMT plans to begin manufacturing the units in 4Q 2002 in partnership with sister company DeepWork Inc. Each unit takes at least 3-4 months to build. When a company decides it wants to operate the units, DMT will manufacture the units and license the company to operate the units in a specific part of the world. The subs were originally developed by Phil Nuytten, and his company, DeepWork Inc., has licensed DMT for exclusive use in the GoM. DMT bought the subs for $600,000 each.
"When we bought the subs, they had no home, and no support, and no way to launch and retrieve them," said DMT COO J.J. Riddle. "Now we have a fully integrated system for launch, recovery, and maintenance of the subs while they're offshore."
Five months and an outlay of money later, the company has the equipment necessary to support each of the subs offshore, including lights, a camera, manipulators, and sonar. When it licenses a territory, DMT/DWI plans to provide the support to perform offshore tasks when the subs are delivered. Purchase of a DeepWorker 2000 will include training, certifications, manuals, and tools, and support systems.
"We can take the package to Brazil and offer them the opportunity to do what Deep Marine Technology has done in the Gulf of Mexico and be protected by their having exclusive rights to this technology," McKim said.
There are 14 DeepWorker 2000s in the world. As of July, the units have a combined working time exceeding 1,500 hours without incident, McKim said.
Safety measures include a fully redundant electronic system. The pilot's pod can separate from the unit, and all work is monitored topside. The pilots all go through lengthy training to be able to maneuver the machines, and DMT is in talks with universities and training academies to set up a certification program for sub pilots. DMT employs nine pilots who come from different oil and gas backgrounds.
"That made a big difference on those jobs," Riddle said, adding that each pilot on hand was able to help with expertise from a different background. "Every time we got to a stumbling point on a job, someone stepped up. Somebody had been there before."
When one of the DOVs surfaces and is brought back onto the vessel, it needs 20-30 minutes before it is ready to dive again, McKim said.
"I'm excited how it's been accepted in the industry," McKim said.
DeepWorker 2000 specifications:
- Length: 8.25 ft
- Beam: 5.3 ft
- Height: 5.6 ft
- Operating depth: to 2,000 ft
- Life support: 72 hr
- Max speed: 2.5 knots
- Crew: one pilot
- Certification: Lloyd's Register of Shipping
- Manipulator: two each, seven-function HD-7 Hydrolek manipulators