In the late 1940s, sufficient reserves of oil and natural gas were developed in Alberta to justify their transportation to markets in the East and the US. Since pipelines are the most economical method of transporting liquids and gases, the Canadian pipeline system grew rapidly.
In the late 1940s, sufficient reserves of oil and natural gas were developed in Alberta to justify their transportation to markets in the East and the US. Since pipelines are the most economical method of transporting liquids and gases, the Canadian pipeline system grew rapidly. This system is currently the second longest in the world (242 000 km), ranking after the US (2 080 000 km) and tied with the USSR (242 000 km). Alberta has the most developed system with 105 850 km, followed by Ontario with 52 690 km, Saskatchewan with 43,120 km, BC with 24 570 km, Manitoba with 8380 km and Québec with 6060 km. In total, 200 100 km carry gas and 42 300 km carry oil and liquid products.
Structure of the System
A simple pipeline is a long length of pipe with pumps, valves and control devices for conveying liquids or gases. A pipeline network consists of gathering systems, main trunk lines and distribution systems. These parts are analogous to the roots, trunk and branches of a tree. The gathering system transports a mixture of oil, gas and sometimes water from the production wells to collection points such as a gas processing plant or a treating facility where the water is removed and the oil and gas are separated. Most of the gathering lines are located in the West.
The trunk or main pipelines move oil or gas at high pressures over long distances through large diameter pipes from the collection points to the market centres. Energy to overcome friction is supplied by pump or compressor stations spaced at approximately 100 km intervals. As markets expand, the capacity of the trunk lines is increased by installing parallel lines (loops) or adding more pumps or compressors. The location and construction starting dates of the major trunk lines are shown on the map. Although the initial construction is complete in 2 to 3 years, additional construction may continue for decades as the capacity of the line is increased to meet market demands.
In the case of oil, trunk lines supply the refineries which, in turn, distribute the products to the retailer by truck or product pipelines. Product pipelines move more than one product at a time. This is done by pumping batches of each commodity, say gasoline and diesel fuel, one after the other. Most product lines are located near population centres in the East, although the Cochin line crosses much of the country (Edmonton to Sarnia via the US).
Natural gas is withdrawn from the trunk line and delivered to the consumer via the distribution system. This part of the network is the longest of the 3 systems. The total length of the distribution systems is about equally divided between eastern and western Canada. Typically, the pipes in this system are of small diameter and are operated at low pressure.
Regulations and Politics
The first Pipe Line Act was passed in 1949. In 1959 the federal government established the National Energy Board which has the authority to regulate pipelines crossing provincial or international borders. The primary function of this body is to issue export permits and set pipeline tariffs. In addition the NEB considers allied issues such as petroleum reserve estimates, costs, environmental factors and engineering and safety practices. Occasionally a commission is appointed to examine a particular issue, as was the case for the MACKENZIE VALLEY PIPELINE where environmental and land claims posed difficult problems.
Pipeline construction has been politically controversial with debate raging about many major lines. Intense controversy surrounded the TRANSCANADA PIPELINE (see PIPELINE DEBATE) and the Mackenzie Valley pipeline, which was never built. However, the construction of the NORMAN WELLS pipeline, which follows the MacKenzie River for 520 km, was completed with little objection. Once the political issues are resolved, the design, construction and operation of all portions of the pipeline system are subject to governmental regulations. All pipelines must conform to accepted engineering, environmental and safety standards of federal as well as provincial jurisdictions.
Most pipelines are constructed of steel, although plastic and aluminum are sometimes used in natural-gas distribution networks. Steel pipelines are formed by welding short (20 m) sections of pipe together. After the welds are X-rayed, the pipe is wrapped with a protective coating and then buried. All pipelines, regardless of type, are inspected and pressure tested before being used. Small diameter plastic lines are commonly "plowed in" instead of being laid in a trench. The plastic pipe is unreeled from a large spool through a special plow which is pulled by a large tractor. This method is quick and causes very little surface disturbance. The usual depth of burial is about 1.5 m for large pipes and slightly less for small pipes, although the Interprovincial crosses the Strait of Mackinac at water depths exceeding 70 m. Canada is the world leader in winter pipeline construction, having developed unique trenching machines for permafrost and muskeg. Canadian pipeline companies are designing and constructing pipelines in the USSR, China and Southeast Asia.
Pipelines are operated every day of the year. Increasingly, the operation of the pipelines is directed by a computer from a remote control room. This technology allows the pressure, flow and energy consumption throughout the line to be monitored continuously. The computer can do leak detection calculations quickly and initiate remedial action such as closing emergency valves, shutting off pumps and alerting repair crews. As a further precaution, periodic tests are made to assure the safe operation of lines. Occasionally wax and foreign material are removed from oil lines by "pigging." A pig is a bristle-covered cylinder which is pushed through the pipeline by the fluid pressure moving the wax in front of it. The term pig is derived from the squeal made as the bristles rub against the pipe wall. "Smart pigs" are equipped with sensors and recorders so that the inside of the line can be inspected for corrosion and weak spots.
No major breakthroughs are expected in land-based pipelines; however, technology is evolving to accommodate the increasing amount of heavy oil being produced. These technologies include heated lines, piping of heavy oils diluted with a light oil and pumping an emulsion of heavy oil and chemically treated water. The Canadian climate imposes 2 serious problems for off-shore underwater piping systems: pack ice and icebergs. In the high arctic islands, pipelines must be trenched completely through the pack ice before being laid on the ocean floor. Large-scale tests are now under way to develop this technology. Off the East Coast, icebergs gouge the ocean floor to a depth of 50 m when they approach the shoreline. Since these gouges are deeper than pipelines can currently be buried, new technologies are being developed to overcome this problem.