Pipeline Trenching Technology For Arctic Regions

1761 words - 7 pages

3 Post-trenching Technologies
3.1 Jetting
This is the most common method of pipeline trenching though little work has been done to improve this technology. Basically it uses the compressed air or water to cut or liquefy the seabed soils around and in front of the pipeline by the surface pumping equipment and passes through the nozzle at the end of horse to create high pressure intensity. Excavated soils are removed by air lifts, water eductors or submersible pumps.
But there are some limitations of this method in deep water due to the adverse effects of quasi-static and dynamic responses of the umbilical horses. Because of this long and bulky horse in deep water, it is extremely hard to control the trenching location which might cause damage to the pipe, sled or horses. Typical jet trenching operation and jet barge are illustrated in figure 8 and figure 9 respectively.
Conventional jetting has used compressed air but it was ineffective in removing soil in deep water due to the high hydrostatic pressure. High hydrostatic pressure reduces the air volume and thus provides small lifting force on bottom. So, in modern jetting machines, water jet employs for cutting.

In order to stabilize the jetting machine, skids that slide on the sea bed or buoyancy tanks on a machine that rolls along the pipeline can be used. These methods are further referred as a jet sled and a jet machine respectively and discussed later in this chapter.
Encountered soils along the pipeline play a crucial role when determining the trenching speed and jetting pressure. In cohesive soils, trenching speed is a function of ratio of jetting pressure to undrained soil strength. High speed trenching is used for larger ratios and vice versa. Normally, this trenching speed is within few meters per minute.
In the cohesionless soils are generally easy to cut and requires quite low jetting pressures. But it has some serious limitation because of the cohesionless nature. In order to achieve trench slope stability and prevent the infill behind the trenching machine, a shallow trench slope should be made. Further, excavated soils should be deposited far enough away so that they do not infill the trench before the pipeline installation and use the air lifts at 8-40 m depths and the water eductors at depth lesser than 8m.In very shallow depth(<4m),a small pontoon barge can be used to remove this excavated soils. In deep water, high trenching speed and low number of passes should be required.
3.1.1 Jet Sleds
This is an early version of jetting machine and slides along the seabed on skids. This skid width should be enough to make the required trench width and generally wider skids use for cohesionless soils to make a shallow wider slopes. This machine is relatively high weight and required a large pull force. In order to transport and handle a large barge with a large crane is required so that has enough deck space where the large pumps can operate to give more power for cutting. Therefore, jet...

Find Another Essay On Pipeline Trenching Technology for Arctic Regions

What is the federal government’s strategy to support its claims to sovereignty in the high Arctic?

1641 words - 7 pages operate in The Arctic regions of Canada. The first area is a sub branch of the Canadian Army reserves called the Canadian Rangers. The ranger’s oversee safety and patrol the isolated areas of the Arctic. The rangers are extremely important because they are according to the government “Our eyes and ears in the North”. They conduct many essential sovereignty operations including routine patrols for suspicious activity, participation in local events and

Design gas pipeline Essay

2220 words - 9 pages . (M.O.Lawal) In 1865,a 6inch diameter gravity oil line was made in Pennsylvania and USA transporting 7000 barrels/day. Other regions in the world were developing pipelines system and realizing huge transportation savings. In 1878, in Baku, Azerbaijan, the nobel brothers built a 3 inch diameter, 10 kilometer oil pipeline that reduced costs of transportation by 95%. (Hopkins, 2007) Long pipelines started to be made around the 20th century for

The Consequences of the Economic Development of Polar and Sub-Polar Regions

1406 words - 6 pages become sources of great economic development and prosperity. Due to their proximity to many highly populated countries, Arctic regions have perhaps experienced greater economic development than Antarctic regions. The route of this economic development began during the 17th century, when indigenous people began to increase their contact with the outside world. For example, by 1700, trading had already begun with the

Evaluate The Impact Of Global Warming on Resources Access and Security in The Arctic Circle.

2194 words - 9 pages Russia's case, Turkmenistan has been the major source of supply. But, in 2009 a new gas pipeline has been constructed for China. Therefore, this resulted in a dramatic shift for Russian trade. Even if trade between Turkmenistan and Russia still exist, in the future it is predicted that China will demand more gas and consequently Russian trade would be completely cut off. For this particular reason, countries are now increasing their arctic operations to

The Arctic melting proof of global warming

921 words - 4 pages increases the volume of water in the oceans, the ocean level rises leading to a higher possibility of mass deaths mostly caused by Tsunamis if earthquakes strike the coastal regions. This is because this region is responsible for regulating earth’s climate system. The ice that covers the Arctic region functions as a reflector where it reflects much of the sun’s heat back into space. This helps in cooling the planet and making it habitable and

Climate Change

1097 words - 4 pages classified as recreational, household and commercial. (Fergal & Prowse, 2007). If climate continues to change there would be an increased affect on the availability of fish in certain regions, as well as an increase in recreational fishing (Fergal & Prowse, 2007). For arctic species, northern communities are likely to see a decline in fish population as the earth begins to change (Fergal & Prowse, 2007). This could potentially damage the

The Berger Report;referenced: Thomas Berger, the inquiry, 1970's vs.present

1283 words - 5 pages THE BERGER REPORT Before the Berger InquiryOil and gas has been part of the economy and Canadian arctic for a long time. Aboriginals long used oil for things such as land construction and especially in their productions of the canoe. For trade, oil was used amongst themselves. From this, early Western explorers saw oil potentially available. This led

Horizon offshore Inc

1803 words - 7 pages as other areas in Southeast Asia, such as Thailand and Vietnam. The Company's pipe lay vessels employ conventional S-lay technology, which is appropriate for operating on the United States continental shelf and in many international areas. For larger pipe burying projects, or where deeper trenching is required, the Company uses the Canyon Horizon, the dedicated pipe bury barge.For the nine months ended 9/30/02, revenues fell 2% to $195.4 million

Most Don't Like It Hot

1446 words - 6 pages but, in the Arctic the temperature rise is higher than any where else. In the past two decades the amount of ice that has melted in the Arctic is astronomical. According to the Christian Science monitor center “temperatures are 25 degrees higher than normal.”(Kister, 2005) The reason for that is because the “ice acts like a mirror to the sun’s energy, reflecting much of it back out into space. As Arctic ice disappears, dark ocean water and land

Oil Drilling in the Alaskan Wildlife Refuges

2433 words - 10 pages natural beauty and ecological importance. The Arctic Refuge was established to conserve fish and wildlife populations and habitats in their natural diversity, as well as provide the opportunity for local residents to continue their subsistence way of life. The U.S. Fish and Wildlife Service, which manages the Refuge, calls it “the only conservation system unit that protects, in an undisturbed condition, a complete spectrum of the arctic ecosystems in

A Heated Debate On ThePolar Vortex

633 words - 3 pages results in warmer global water and air currents. Scientists are also arguing that the “Polar Vortex” is a theory made up by media and global warming theorists, who are trying to gain fame or cause panic. Although there is almost no argument that greenhouse gas emissions have impacted the arctic regions ice cover, climate scientists and meteorologists claim that the earth has heated and cooled in fluctuations for millennia, and that changing

Similar Essays

Essay About Arctic Wolves; Habbitat, Diet, Lifestyle, History And Future Science Research Paper

500 words - 2 pages Arctic wolf The arctic wolf is a Lupus arctos and is located in the artic regions of North America along with Greenland. They primarily prey on Musk oxen, Peary caribou, Arctic foxes, ptarmigan, lemmings, seals, nesting birds, and Arctic hares. Due to the harsh living conditions Arctic wolves’ don’t have that many predators only the Polar bear. When it comes to reproduction wolves are able to start at two years of age. However research shows

Shell In The Arctic Essay

2413 words - 10 pages and WWF, are actively trying to ban arctic drilling. According to the WWF, clean-up of an oil spill is nearly impossible since the technology, which currently exists, does not cater to ice conditions. In addition, due to the short summer season combined with low temperatures and limited sunlight, it would take decades for the Arctic to recover from habitat disruption or oil spills. There Arctic is an area of world interest, and can easily become

The Alaskan Highway Pipeline Project Essay

2204 words - 9 pages gas and push it through the pipeline) as well as meter stations (where the gas gets tested and measured).Estimated project highlights in Alaska only:Length: 745 miles (1200 km)Pipe diameter: 48 inches (122 cm)Compressor Stations: 6Construction time: 3 yearsProduction Costs: $6.8 billion (estimated) for the whole project*Predeger, D. (2005) ANWR [internet]. Arctic Power. Available from:http://www.anwr.org/[Accessed November, 2005].What is the

Canada's North Essay

1805 words - 8 pages pipeline has yet to be constructed, increased knowledge and assessment from all parties involved is preparing the territory and country for possible changes that may be just around the corner. Canada played a crucial role in the creation of the Arctic Council in 1996. Early on it was supported by both the Liberal and Conservative governments and mandated that Aboriginal representation was necessary to provide a holistic approach at Northern