Norway’s 44in gas pipeline costs US$3.8M per mile, Guyana’s 12in gas pipeline to cost US$4.7M per mile

Aug 01, 2021 News

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Kaieteur News – The world’s longest underwater natural gas pipeline is some, 725 miles long and was constructed at a cost of some US$2.8B or just about US$3.8M per mile for a pipeline that is about a meter in diameter.The Langeled Pipeline delivers 26 billion cubic meters (900 billion cubic feet) of natural gas to the UK National Transmission System each year; the price tag came in at 1.7 billion pounds (US $2.8 billion).
At the time of completion it was longest sub-sea pipeline ever built with a diameter of 44 inches. Guyanese were given an estimated cost for the pipeline during a media briefing held at the Arthur Chung Conference Centre, where the local head of the gas to energy taskforce, Winston Brassington disclosed that the offshore pipeline and riser are projected to cost some US$630M while the onshore pipeline will run from Crane West bank Demerara, to the Wales termination point would amount to some US$100M. Guyana is paying just about US$4.7M per mile for its 153 miles of pipelines, according to official figures touted by the gas to shore taskforce.
As such it would mean that Guyana is earmarked to pay about 25 percent more per mile than the amount it cost Norway to build Langeled, and for a pipeline that is, at 12 inches in diameter, significantly smaller.
The Langeled Pipeline project included the construction of a new gas terminal at Nyhamna to process the gas coming from Ormen Lange. A consortium now exports natural gas from Nyhamna to Easington on the east coast of England through this state of the art marine pipeline.
Building the pipeline was said to come with immense technological challenges since the North Sea bed is not a flat bottom but is a treacherous series of channels, trenches, and ridges and it has cyclical plate tectonic events, not to mention a number of existing pipelines.It plunges to depths of 5 km (3.2 miles) making water pressure a significant factor in design and construction.
As such, an autonomous underwater vehicle, Hugin, a product of Kongsberg Maritime, was employed to survey the sea bed, using advanced radar to determine the most cost effective route.
With an understanding of the features and hazards, design engineers went to work on plans to allow a 44 inch pipe, with 25mm (1 inch) thick walls, to negotiate the terrain while minimizing impact on fisheries and ecosystems.
In order to lay the pipeline a remote-controlled underwater excavating vehicle called the Nexan Spider, capable of moving underwater mountains, prepared the seabed floor.
Three million tonnes of rock was brought to areas of the sea floor to level the terrain where needed.
The pipeline was built using 100,000 pipe sections, each coated in asphalt to reduce corrosion and a stability coating of concrete.
Two pipe laying ships, including Soltaire, the largest pipe laying ship in the world, laid 8 km (2.5 miles) of pipe a day. Once the pipe was laid, deep water hyperbaric welding teams welded the pipes together from inside a watertight enclosure called Pipeline Repair Habitat.
The project was completed in 2006 after three years of work and both Norway and the UK have benefited enormously from the project; the UK receives about 20% of its natural gas directly from the pipeline.
Meanwhile despite public consternation over the feasibility and environmental impacts related to the Guyana Project the Stabroek Block Operator has begun geotechnical and geophysical pipeline route surveys within Guyana’s Exclusive Economic Zone, along the Demerara River and off the Demerara Coast.
The survey area is approximately 12 nautical miles (22.2 kilometres) from the Coast of Guyana and covers an area of 457.4 square nautical miles (1568.9 square kilometres).
This exercise is scheduled to conclude on October 15, 2021, and will incorporate the use of the OSV Cape Davis which will display the international signal for vessels engaged in such activities. MARAD had said this operation will incorporate the use of the vessels MV Wise Fox, MV Risen Star and MV Sealand Chirp, which will all be displaying the international signal for vessels engaged in such activities. The purpose of the surveys, is to inform the most ideal route for the proposed natural gas pipeline.
The massive project includes the construction and operation of a pipeline that will transport up to 50 million standard cubic feet per day (MSCFD) of dry gas from the Liza Phase One and Liza Phase Two Floating Production, Storage, and Offloading (FPSO) vessels to an onshore natural gas processing plant which will drop the pressure of the gas, dehydrate it, separate out propane, butane and pentanes +, and treat the gas to the specification to be received by a planned 200 Megawatt power plant.
The project site lies approximately 23 km upriver on the west bank of the Demerara River on abandoned sugarcane fields. The project is expected to pave the way for a massive industrial park to be established at Wales which is expected to stretch across over 10,000 acres of land while the pipeline will terminate at Crane.
Exxon is currently conducting a number of public scoping meetings across Guyana ahead of the Environmental Impact Assessment study for the proposed gas-to-energy project.
The EPA had previously anticipated that the project is expected to affect a vast portion of the surrounding environment in one but or another, and consequently requires an Environmental Impact Assessment to be done.

 

 

 

 

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