Oil and Gas Transportation by Pipelines
The transportation of crude oil, petroleum products, natural gas, LNG, and natural gas liquid (NGL) by pipeline is perhaps the most economic mode of onshore transportation (ASTM MNL58). In addition, there are offshore pipelines for the transportation of these commodities (Figure 3.23). In 2018, China completed the country’s longest petroleum pipeline under the sea in the South China Sea (CCTV, 2018). SK Engineering & Construction Company (South Korea) completed an undersea pipeline in the Persian Gulf as shown in Figure 3.24 (VM, 2017).
FIGURE 3.23 The offshore pipeline is the next big thing in the pipeline development (www. pipeline-journal.net).
FIGURE 3.24 Offshore pipeline construction in the Persian Gulf (VM, 2017).
The total length of oil and gas pipeline in the world is more than 2 million km according to a report by Global Data (2019). The total length of crude oil pipeline is 379,000 km, that of petroleum products pipeline is about 267,000 km, that of natural gas pipeline is about 1.3 million km, and NGL pipelines constitute more than 92,000 km. As shown in Figure 3.25, North America has the highest oil and gas pipeline length with 41% of total pipeline length in the world. With the increase in oil and gas production and the increase in consumption in the
FIGURE 3.25 Share of global oil and gas pipeline length by region, Sept 2019 (source: Midstream Analytics, GlobalData Oil and Gas © GlobalData [2019]).
US, there was a great American oil and natural gas pipeline boom in 2018, as discussed by Forbes (2019).
Another use of pipelines in undersea transportation is for offshore production facilities as was shown in Figure 3.16. Risers are the connection between subsea and production facilities at the surface. Materials including hydrocarbons and injection fluids are brought to the water surface from the seafloor by pipes known as risers. Risers are either rigid or flexible but insulated to withstand seafloor temperatures. Water temperature may vary from 30°C at the surface to -ГС at the seafloor (Leffler et al., 2011).
The choice between pipeline and ship is mainly a matter of distance. For short distances, transportation by pipeline is the most economical method as pipelines are easy to manufacture, have a longer life, lower maintenance costs, and better assurance of continuous delivery. For natural gas transportation, the use of pipeline is mainly a factor of capacity of gas delivery and distance. For radius of greater than 2000 km, marine transport should be used instead of pipeline. For the case of long distances, the best option would be to convert natural gas into liquid form known as LNG, or to convert to liquid through processes such as Firscher and Tropsch known as gas to liquid (GTL). Compressed natural gas (CNG), used for short distances, requires pressurizing the gas through pump stations. In the LNG process the volume of gas can be reduced significantly by a factor of 1:600, and the LNG option dominates the market for the marine transportation of natural gas (ASTM MNL58).
One of the biggest sources of pipeline failure and causes of leaks is due to internal corrosion of the pipe. For example, on January 8, 1999, a leak in a 12-inch pipe at an industry tank farm in Benavides County, Texas, spilled more than 10,000 barrels of crude oil, and the cause was internal corrosion. Later the EPA announced that the responsible company paid the largest civil fine for 300 oil spills for its pipelines and oil facilities in six states, and it was requested that the company improve its leak- prevention program and help environmental projects (EPA, 2000). In 1994 the Kolva River oil spill was the largest oil spill caused by corroded pipeline in the Russian Arctic. About 2 million barrels of oil were released, mainly into the landscape but some into the river as well.
In January 1969, nearly 3 million gallons of oil spewed from a drilling rig near the coast of Santa Barbara, California. The pipe blowout cracked the seafloor and the oil plume killed thousands of seabirds. About 35 miles of coastline were coated with oil up to 6 inches thick, and about 800 square miles of ocean were affected (CNN, 2015). On January 18, 2000, a pipeline owned by Petrobras ruptured and spewed about 8,200 barrels of heavy oil into Guanabara Bay outside Rio de Janeiro in Brazil (US EPA, 2001). Another example in which pipeline damage caused an oil spill accident is Statfjord Oil Spill on December 12, 2007, during the loading of a tanker off the coast of Norway. More than 21,000 barrels of oil were spilled into the North Sea. This was the second largest oil spill in Norway after the Ekofisk oil spill in 1977. The cause of the accident as shown in Figure 3.26 was a break in the hose between the seabed and the tanker connection. The spill covered an area of 23 km2 on the same day, but after one day the spill was 10 km long and 5 km wide with a thickness of 100 microns or 0.1 mm (EMSA, 2013).
FIGURE 3.26 Damaged hose that caused second largest oil spill in Norway (source: EMSA, 2013).
As this book is being written and on June 12, 2020, the Globe and Mail reported that there was an oil spill released from the Canadian government-owned Trans Mountain pipeline near Vancouver in British Columbia. The company delivers 300,000 barrels of crude oil every day through a 1150-km pipeline from Alberta and British Columbia with 111 km in the state of Washington in the US. The company said the spill was contained and the crew immediately began the cleanup operation; however, the amount of oil spilled is not yet reported.
FIGURE 3.27 An oil refinery is seen near an oil slick along the coast of Refugio State Beach in Goleta, California on May 19, 2015 (The Atlantic, 2015).
