Fugro dives deep into underwater 3D
Real-time visualization helps with installation of wye sled subsea structure
by Sam Pfeifle
August 01, 2012
HOUSTON – Fugro Chance has clients in the
offshore drilling industry who make all kinds of difficult requests for
surveying services underwater in the Gulf of Mexico. Fugro really pushed the
envelope with a case in early May, though.
Essentially, the client needed help with
the installation of something called a wye sled, which is a sort of steel
mudmat that supports a collection of underwater valves and pipe connections. To
install it, however, they needed to first dredge out underneath pipeline and
remove a bunch of concrete coating. This stirs up the bottom of the ocean and
makes it virtually impossible to see anything.
To complicate matters, the sled needed to
be installed adjacent to an existing live pipeline. What happens if this big
piece of steel bumps into the live pipeline because the crane operator doesn’t
know exactly where to put it? Can you say Deepwater Horizon?
The equipment in need of underwater installation.
Or, as Tony Gray, manager of data
management, Marine Construction Survey, for Fugro Chance, put it in a recent
conversation with SPAR: “Whenever you’re installing a very heavy piece of
equipment adjacent to an existing pipeline that is live, there is, I would say,
a tremendous amount of risk.” However, because of tremendous cost of operating
offshore, the client didn’t want to have to wait around until the dust settled.
What to do?
Gray and system engineer Jesus Zertuche
decided to take a pass at using CodaOctopus’ Echoscope 3D
Sonar, which uses a phased array of more than 16,000 sonar beams to create
a live 3D underwater image. “We basically showed them what the possibilities
were through a visualization using the device,” Gray said. But, “as far as
doing any trials? This was such a fast-tracked schedule, we all had to do
something of a leap of faith. Certainly, we knew enough about it that it made
sense and we were able to do some pre-project planning on a very fast track,
but the alternative was nothing, so it was that kind of situation.”
“This allowed [the client] to actually in
real time make decisions,” Zertuche said. “They could say, ‘take the crane up a
little, move it over.’ In terms of using other technologies, you’ve got the
post-processing where the sea state can change.” The live look ability was
extremely important, as Zertuche could sit with the clients in the survey room,
watching the operations live on a big screen TV, and provide rotated views,
views they requested, almost as though they were working with a bank of
Of course, it wasn’t actually as good as
video. Here’s an example of the image produced:
After everything was installed, Zertuche
took some measurements from the data and compared them to known distances and
Fugro Chance was satisfied with the solution’s performance. “Jesus could
consistently get within a half a meter of what we were certain the relationship
was,” Gray said.
Half a meter? “In this particular
situation, we weren’t building a watch,” Gray laughed, “and once you get down
to doing the metrology of doing point to point tie in of spool pieces, this isn’t
the tool that would do that for you. You’d need a much tighter solution. But
for this, yes, half a meter was plenty good … I’m not sure what they would have
done if we didn’t have it. It certainly would have been a much, much, much
slower process. If this didn’t work, we’re back to as high a risk as an oil
company could take in a situation like this.”
In the future, Gray and Zertuche envision
quite a few other applications for the technology, and both agreed it’s
something they could integrate with other 3D data capture technologies (also of
Coast Guard is in the middle of testing the device). “I could definitely
see getting the legs of a platform, subsea, from an Echoscope, and then from
the water surface on up, using lidar, or some other kind of laser scanner, to
get a full and complete picture of a platform,” said Gray.