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Offshore Pipe Laying

Mar 04, 2024
Therefore, a materials barge is towed

offshore

and lengths of

pipe

are delivered to the jarva barge builder for unloading on deck and ready for use, the

pipe

s reaching 30 feet and with or without weight layer, depending If necessary, the stinger is a floating lattice pontoon that supports the pipe while it is placed from the stern of the

laying

barge. The pipe is fed through the stinger and rides over the roller beds to facilitate its passage depending on the diameter of The pipe and the depth of water it is placed in determines the number of sections that make up the stinger and the deployment angle at which the pipe is placed.
offshore pipe laying
The stinger shown in this movie is a single section stinger before As pipeline operations begin the stinger is lifted from the deck of the barge builder and secured to the stern of the labyrinth by what is known as the hitch which has hydraulic retaining pins on board the barge to hold it in place on the hitch, after that the lifting straps are removed, so the large platform crane is free for use in other lifting operations, a flange is welded to the end of the pipe that will accommodate the traction head, the The pulling head will be bolted to the pipe end flange and a bolt tensioning procedure ensures that the pulling head is secured in place.
offshore pipe laying

More Interesting Facts About,

offshore pipe laying...

The ax ring is the gasket that maintains the seal between the pipe flange and the flange. of the drive head the ax ring is inserted and the flange face is screwed up the pipe and the flange faces of the drive head are screwed all the slack in the bolts is removed with the use of spanners jacks To accommodate the hydraulic jacks, an extended portion of the stud bolt is required to pass through the hex nut and the hydraulic jack is placed over the bolt to be tightened. Reaction nut, the reaction nut is then screwed onto the part of the stud that protrudes through the hydraulic jack when it contacts the hydraulic jack, the reaction nut retains. the hydraulic jack on the bolt the hydraulic whips are connected to the hydraulic jack in a ring main circuit and in turn are connected to a hydraulic pump unit and the oil is pumped at high pressure to the hydraulic jacks the hydraulic jacks of the hydraulic pump They push against the face of the flange and the reaction nut and since the reaction nut is screwed to the bolt, all the resulting load is transferred to the bolt stretching it, actually as the bolt is stretched the hex nut is lifted of the flange manually with zero torque by applying an abdominal bar through the slot. on the bridge of the hydraulic jack into the specially designed opening in the nut, the nut can be slid down to make contact with the face of the flange, the pressure is released from the hydraulic jacks and the load is retained on the bolt by the nut placed against the face of the flange, vernier caliper readings are taken at the cardinal points of the flange faces to check that the spacing of the flange faces is uniform around the dma or man anchor Deadbolt is a means of ensuring that the traction head is positioned in its target box.
offshore pipe laying
In an area five meters long and five meters wide, the dma is a single 7.5 tonne Stef shark anchor attached to the pulling head by three 52 millimeter diameter steel cables for a total length of 980 meters with a test tension load of 50 tons while

laying

the pipe. It is possible, with the grip of the tensioning machine and the pulling of the barge anchors, to pull the pipeline along the seabed after laying two kilometers of pipeline from the point of contact. The DMA prevents this from happening once the DMA is in place and attached to the traction head the traction head is ready to be launched through the stinger and eventually land on the sea floor as you can see in the pictures.
offshore pipe laying
Film footage of this remotely operated vehicle, lengths of pipe are stored on the top deck and transferred to the ready rack as required for welding preparation. Each section of pipe comes in 10 meter sections and on the ready rack each end of the pipe is prepared for welding. The ends of the pipe are cleaned and beveled and when the two ends of the pipe are welded together, this is known. As a filler joint, the red circular brush sweeps for fire hazardous materials. The pipe enters the transfer station and waits to be transferred to station one to align the pipe before welding the field joint.
The pipe enters station one for alignment. first field joint weld known as root welding the alignment machine that has adjustment points every 45 degrees for the end of both pipe sections to adjust them to perfect alignment for welding together root welding is performed by a method of welding known as surface tension transfer and the second pass and subsequent welds are made by flux core welding, the surface tension transfer welding box, unwinding the welding wire, the first pass known as root welding, cleaning the world of the root and preparing for the second pass which will be welded by the flux core welding technique, then the root welding is completed, all the second and subsequent welds around the circumference of the field joint are made in the sections two and four in the pipe welding tunnel.
The field joint welds are inspected by x-ray and a lead cover known as the doghouse is placed. the field joint for protection of the radiography process anodes waiting to be welded to the pipe sacrificial anodes are used to protect the pipe from corrosion known as sacrificial anodes because the material they are made of is less noble than metal which the pipe is made of therefore oxygen from the seawater is attracted to the anode and the anode corrodes instead of the pipe. This is how the pipe is protected from corrosion. mpi magnetic particle inspection from the anode to the pipe to ensure that there are no cracks on the surface of the pipe. weld securing the anode to the pipe, the anode welded in place and welds coated with protective paint to add further protection against direct contact with seawater, the field joint is covered with a cps gray heat shrink sleeve, this wrap Consists of a thick cross-linked backing coated with a very high shear strength hot melt adhesive during installation, the adhesive melts and flows filling surface irregularities and providing an excellent bond to the metal filler joint by cooling the field joint and cps gray shrink sleeve wrap to maintain position for placing pipe.
The barge has an eight-point anchor mooring pattern with the use of eight anchor winches. The lay barge can be moved in a combination of forward, aft, port or starboard after the pipeline has passed through the various stations to complete the field joint composition. The barge advances a field joint a distance of 10 meters, this is known as a drawpipe. The operators of the eight anchor winches work in a control room known as a tower. From there they can control the entry and exit of the winch cables. For your combined and precise positioning of the laying barge during pipe pulling, the front winches pull a load of approximately 20 tons each, the theft mode tension monitor measures the load under which the cable is located. anchor and that information is displayed on the tower that supports the tensioning machine. the pipe with a tension of 48 tons and can grab the pipe with a tension of up to 60 tons what you are about to hear is the sound of tortured metals the diving intervention is mainly routine checks that were carried out on board the builder lb java every 12 hours and may consist of, among others, one the continuity of the pipe from the end of the stinger two the depth profile of the stinger three the integrity of the stinger four passage of the pipe through the stinger preparation for diving clothing the diver throw the diver left surface pipe on the stinger the lift to the surface example of two section stinger just when you thought you were alone the lying head is the opposite version of the pulling head, i.e. at the end of the last section of pipe, a pipe end flange is welded as usual, a joint wrap is applied in place, then the pipe is pulled down the welding tunnel to make room for the arrival of the welding head. placement, at the same time as preparation for the bolt tensioning procedure is carried out.
The support head is lowered through the welding tunnel deck hatch using the Manitowoc crawler crane on deck. This is done with the support head entering through the fillet weld tunnel cover hatch due to restricted access. Once through the welding tunnel cover hatch, the load is transferred to chain hoists and then the laying head is placed in line with the pipe to be flanged by screwing the flanges together by inserting the ax ring all the bolts. Hydraulic jacks are now in place and reaction nuts are in place Hydraulic whips are in place Hydraulic tightening of the bolts completed and the flange guard in place Using a stop and recovery cable, the prop head is now ready to transition to through the stinger under tension at the correct angle until it reaches the sea floor and can be disconnected at some future date, a construction barge will tie the respective ends of the pipe with the use of a spool and riser so that it is become an integral part of a marine platform that you

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