What is a J-lay system?
J-lay is used to install rigid pipelines in deep water. With a J-lay system, pipe stalks, consisting of up to six pipes with a total length of 72m, are upended and welded to the seagoing pipe in a near vertical ramp. The ramp angle is adjusted so that it is in line with the pipe catenary to the seabed.
What is S-lay pipeline installation?
In the S-lay method, single lengths of steel pipe (joints) are welded, inspected and coated in a horizontal working plane (firing line) on board a pipelay vessel. As the vessel moves forward, the pipe gradually exits the firing line, curving downward through the water until it reaches the touchdown point on the seabed.
What is a vertical lay system?
Fixed with two struts, a vertical lay system can house tensioners, gantry hoists, A&R systems, power units, tower cranes, centralisers… It is used to set up power cables, flexible flowlines efficiently, thanks to an improved technology.
How do pipe laying ships work?
With surface tow-in, the pipe is moved into place and then any buoyancy modules are removed and the pipe is sunk. Mid-depth tow uses speed to keep the pipe off the seafloor, and after the vessel slows, the pipe settles and sinks. Off-bottom tow is the same concept, with the pipe sitting closer to the sea bed.
What are the methods of laying pipeline in offshore?
There are 4 common methods to install pipeline in offshore area: S-Lay, J-Lay, Reel-Lay, and Towed system.
What is bead stall?
The pipe-laying barge based on their design has several welding stations. The first station in each barge is called as “Bead Stall” or “Line Up”. Where after Line up the pipes stage, welding passes Root & Hot is performed and in the rest of stations the welding passes are struck as Fill & Cap Pass.
What is Flex lay?
The Flex-lay method combines capabilities for the installation of flexible pipelines, risers and in-line structures. The most notable features of a Flex-lay system are its vertical ramp, equipped with one or more tensioners, and a chute or wheel aligner on top.
What is pipelay barge?
9.6. A lay barge is a floating factory where the pipe joints are welded on to the pipeline as it is installed. From the lay barge the pipeline describes an S-curve on the seabed, as shown in Fig. 9.14.
What is the stinger on a pipe lay barge?
A new form of pipe support structure, or stinger, has been designed for laying pipelines offshore from a pipe-laying barge. The new stinger consists of 4 to 12 segments, each about 50 feet in length, each stinger segment is adjustably buoyant and contains rollers for supporting the pipe.
What are the two classification of piping?
Pipes are normally classified based on the material which is used to produce the pipe during manufacturing. In general, there are two types of pipes: Metallic Pipes and. Non-metallic Pipes.
What are the four stages of pipelining?
Four-Stage Pipeline-
- Instruction fetch (IF)
- Instruction decode (ID)
- Instruction Execute (IE)
- Write back (WB)
What method is used to protect under sea water pipeline?
The structure is often shielded against external corrosion by coatings such as bitumastic or epoxy, supplemented by cathodic protection with sacrificial anodes. Concrete or fiberglass wrapping provides further protection against abrasion.
What is a pipe lay barge?
What is a reel lay vessel?
Reel-lay method of rigid pipeline installation refers to a method of pipeline installation where a rigid pipe is un-spooled from a drum, straightened, tension applied, and then laid over a ramp to the seabed.
What is a J-lay pipe?
J-lay is used to install rigid pipelines in deep water. With a J-lay system, pipe stalks, consisting of up to six pipes with a total length of 72m, are upended and welded to the seagoing pipe in a near vertical ramp.
J-lay is used to install rigid pipelines in deep water. With a J-lay system, pipe stalks, consisting of up to six pipes with a total length of 72m, are upended and welded to the seagoing pipe in a near vertical ramp. The ramp angle is adjusted so that it is in line with the pipe catenary to the seabed.
How is the J-lay method suitable for deepwater?
The ramp angle is adjusted so that it is in line with the pipe catenary to the seabed. This way bending of the pipe is kept to a minimum. The J-lay method is very suitable for deepwater because the pipe leaves the lay system in an almost vertical position and the pipeline is only bent (once) during installation (at the seabed).
What are the disadvantages of J-lay pipe laying?
Compared to other lay methods, J-lay has a relatively low production rate due to the single position welding of the pipe. The J-lay method is less suitable for shallow waters as this requires a departure angle close to horizontal.