They have tested fifteen wells there, laid 210 miles of pipes to bring the gas to central processing platform and install control cable throughout the pipeline network. A major step remains; building the giant pipeline to get the gas to shore. It will take almost 20,000 pipes and months of work to construct 135 miles project trail. And there is only one pipelay ship in the world strong enough to build it, the ultimate pipelay ship Allseas Solitaire.
She has got to lay this vast pipeline earlier than the central processing platform begins pumping gas. Few vessels will dare to attempt this mission, but this pipelay ship is not any common pipelaying ship. She is the largest pipelaying vessel in the world. At 12000ft the Eiffel tower could easily lay on her deck, a pipe welding assembly line runs entire length of the ship and a huge stringer system from her stern to steer the pipeline to the sea floor.
Like the Lorelay the other pipelay ship on the project this super ship builds pipline in one continous motion, welding the pipes together inside her hall and depositing finished pipeline through the stringer to the sea floor. But unlike the other pipelay vessels she does it on much much bigger scale. The ship’s six holds carriers over 21000 tons of pipes that’s more than the weight of 120 jumbo jets. Even this many pipes doesn’t last long.
This mega pipelay vessel can lay four miles of pipes in a day. Huge material barges continuously supplies pipes to keep this mega pipelayer busy. And that’s where the pipelay ship’s crane swings into action. These cranes are built for speed. Most cranes have a single long boom, but these giant cranes has two arms giving them amazing accuracy and speed. To complete this project on schedule this pipelay vessel has to build and lay the pipeline fast. And that’s happen on the firing line where the crew turns the individual pipes into a single seaway pipeline 135 miles long.
Here the 40ft, six and half ton pipes are welded together. This is the Allseas Solitaire’s secret weapon in efficiency. Other pipelay vessels can weld 40ft pipes into a pipeline, one at a time, but this pipelay ship’s firing line can handle these 80ft monsters. The pipe is welded together at eight welding stations; each weld adds more strength to the joint. A special system even welds the joints inside the huge pipe, seen on the screen. Completing this pipeline will take over 21,000 welds. At the end of the welding work the pipeline move out of the stern of the ship into the sea guided by the huge stringer.
But that’s not wouldn’t really happens. Miles of pipeline on the seafloor is directly connected to ship like a massive anchor. Huge tensioners like tractor treads squeeze the pipe to hold it to let it out. When pipe moves from the firing line and then into the sea its really the ship that create folds to the new pipeline growing into the belly. The Solitaire will work round the clock to complete the pipeline on schedule. This is the deepest pipeline she ever laid. But her biggest challenge is still ahead.
Installing a massive T-assembly, a connector that will allow future pipelines to link to the independence trail. Welding a large T-shaped structure into the pipeline shouldn’t be hard; but the problem comes when trying to push the bocky shape structure out of the assembly line designed for pipes. The crew has a plan but that is unsafe.
135 miles away in Texas coast the construction of independence project hub is in final stage of completion. This gigantic floating platform will process all the gas from the project’s fifteen deep sea wells and send it 135 miles to shore along the independence trail. Soon this mega structure will be towed out to the offshore gas field but first they should finally complete building it. The processing hub is made up of two parts; the upper unit or processing platform and the lower unit or hull to keep the hub afloat. The enormous processing platform will process billion of cubic ft natural gas everyday enough for the cooking and heating needs of five million US households.
When the platform is complete it will be the heart of the largest gas processing project in the Gulf of Mexico and the deepest anchored platform in the world, but first the team needs to join the upper and lower units together. Just outside of the harbour another mega mover arrived the Mighty Servant-3 a float on/float off vessel. On her large deck the massive floatation hull, the four tower structure on which the huge central platform will be fitted. The Flo/Flo ship has brought the hull all the way from Singapore where it was built, an incredible ten thousand miles journey.
Now this rig mover ship has to offload her cargo and she does this in very unusual way. Her huge blast tanks inside will slowly flood letting the ship settle two stories lower in sea water. Then the three tugs will pull the hull free; it’s a simple but dangerous process. Both the cargo and the ship will quickly become unstable. And the huge tower hull will catch the wind like sails, in a strong gust the hull could sway, crushing anything in its path. Conditions have to be perfect.
Out in the Gulf of Mexico the Solitaire is about to tackle the critical part of the gas project. The pipelay ships already laid miles of pipeline of the independence trail to bring processed gas to shore. Now they have to install massive ‘T’ structure so that the future pipelines can hookup to the project trail. But, first the crew must weld the T into the pipeline. After welding T, it moves down the firing line, now when the operation gets dangerous as the pipeline access to the ship’s hull three powerful clamps called tensioners bears its weight. They hold the massive strain of nearly two miles of pipeline hanging between the ship’s stern and ocean floor.
But to let the huge T structure each tensioner or clamp has to be opened one at a time and all the way to pipeline 655 tons slip only on to two tensioners out of three tensioners. If one fails now, hundred of feets of pipe will splash through the ship on its way to the seafloor. First of the three tensioners opens, all eyes watches as the T moves forward. The other two tensioners strains onto the load they hold. Twice more one tensioner opens the entire strain is held by the other two. Finally the T is other side of the three tensioners on its way to the seafloor. Its a major success for the pipelay vessel bringing the ship one step closer to complete the pipeline on schedule.
On the Texas coast the massive central gas processing platform and the hull that will float it must be joined together. But first the team has to get the hull off the flo/flo ship Mighty Servant-3. This mega heavy lift ship offload by sinking letting the cargo float. Now the tricky operation of offloading cargo by sinking ship begins. The hull, four gigantic towers jolt up like huge sails, every time the winds kicks up the enormous structure strains against the mooring lines with tons of force.
On the bridge of flo/flo ship the captain carefully controls the flooding of ballast tanks. Over the next ten hours this ship slowly sinks into the harbor. Finally, after a globe crossing voyage from Singapore the hull is afloat. The gigantic gas processing platform is as big as city block and weighing 9000 tons. The crews have to lift it 200ft up into the air and strategically lower on to the hull’s four pillars. Its like hoisting 400ft warship. And there is one mega machine for this job, the heavy lift device or HLD. Its one of the biggest crane of its kind in world.
But, the first step is to slide the topside (platform) on the skid way and onto the large cargo barge. It will take two heavy winches and little lubrication. The winches turn and the seven stories platform starts to move forward. At the water edge of the harbour the sliding process gets trickier. Water in ballast tanks of the cargo barge is carefully adjusted to accept the massive weight of the huge platform. It takes eight hours but finally the platform is on the barge. Tug boats adjusts the barge with the platform into the position underneath the HLD.
