The Colossal Gas Pipe Laid At The Bottom Of The Ocean | Megastructures | Spark

The Ormen Lange gas field, located 120 km off Norway's coast, is a massive underwater reserve with over 300 billion cubic meters of natural gas. The project's goal is to supply enough gas to meet 20% of Britain's needs for 40 years, replacing unsustainable coal. The challenge involves drilling through 2,000 meters of seabed, constructing the world's longest sub-sea pipeline spanning 1,200 km, and overcoming treacherous terrain with the help of advanced ROVs. The project, led by Norsk Hydro, is set to cost $10 billion and take a decade to complete, pushing the boundaries of engineering and technology.

To extract gas from the Ormen Lange field, engineers devised an innovative approach using a template, an underwater structure that guides drills to the gas field. This eliminates the need for traditional surface platforms and allows for remote operation from a control center 120 km away. The template is a game-changer, enabling drilling in extreme conditions. The process involves assembling the template on land, transporting it to the field, and precisely placing it on the seabed, a task complicated by weather and the need for accuracy.

The deployment of the underwater template is a high-stakes operation involving a massive crane ship and ROVs. The template, weighing 1,000 tons, must be transported by barge and precisely placed on the seabed using computer-controlled thrusters and ROVs as eyes. The operation is practiced extensively in a 3D virtual environment before execution. The successful placement of the template is critical, as it cannot be retrieved once submerged, marking a permanent commitment to the project's success.

Drilling at the Ormen Lange field requires a specialized ship, the West Navigator, to drill the deepest wells in the world, reaching two thousand meters into the seabed. The drilling data is monitored in real-time and recorded in a virtual database to guide future operations. The template is powered by a control cable called an umbilical, which carries electricity and hydraulic fluid. The construction of the pipeline involves dealing with a challenging seabed landscape, including a 300-meter cliff face and a rugged terrain from a historical landslide.

The construction of the Ormen Lange pipeline faces geological challenges, such as the Storega landslide's impact on the seabed and the need to protect marine life and fishing grounds. Engineers use a 3D model to plot the pipeline's route and employ various techniques to prepare the seabed, including the use of an innovative underwater excavator called the Spider. The pipeline's construction also involves the transformation of the small island of Gossa and the community of Nihomna into a major industrial center for gas processing.

The construction of the Ormen Lange pipeline is a monumental task involving thousands of workers, both onshore and offshore. On land, a gas processing plant is built with meticulous planning and virtual reality simulations. Offshore, workers use ROVs for tasks like pipe laying and heavy lifting. The pipeline's end termination unit (PLET) is a critical component made and tested onshore before being lowered to the sea floor, where it connects the underwater template to the main pipeline.

The pipeline project utilizes advanced robotics with the Spider, an underwater excavator inspired by Swiss forestry machines. The Spider operates at depths of up to 1,000 meters, excavating trenches for the pipeline. It navigates through challenging terrain with the help of an umbilical connected to a support vessel. The operation is a significant mobilization of complex and agile robots, showcasing the capabilities of modern underwater engineering.

Laying the Ormen Lange pipeline is a complex operation due to the irregular and rugged North Atlantic seabed. The pipeline's weight and the need to avoid unsupported spans require careful leveling of the seafloor using gravel. Specialized ships and ROVs work together to ensure the pipeline is laid on a flat and smooth path. The operation must be continuous to avoid strain on the pipe, with precise coordination and constant monitoring.

The final stages of the pipeline construction involve meticulous assembly and testing. The pipeline is welded in sections, with each joint checked for flaws using ultrasound technology. The pipeline is then covered in a protective coating before being lowered to the sea floor. The operation requires a constant supply of pipe sections and precise control to ensure the pipeline's integrity. Once laid, the pipeline is inspected using internal gauges, known as 'pigs,' to detect any weak spots or breaks.

The pipeline's route to the processing plant at Nihomna is fraught with unexpected challenges, including a shipwreck discovered near the landfall point in England. The team must halt work to investigate and recover artifacts from the wreck, using ROVs as a new tool for archaeology. In Norway, the team deals with raw gas containing liquid slugs, which are managed by building a massive slug catcher to prevent potential explosions at the treatment plant.

The completion of the Ormen Lange pipeline represents a significant leap in undersea engineering technology. The project's innovations may pave the way for future exploration in the Arctic. As the pipeline becomes operational, the team moves on, leaving behind a testament to their engineering prowess hidden beneath the North Sea. The pipeline's construction has been a monumental challenge, showcasing the capabilities and limits of human engineering in extreme marine environments.