Pipeline transport is the long-distance transport of a liquid or gas through a piping system, typically to a market place for consumption.
Liquids, gases, and chemically stable substances can be transported through pipelines. Fuels such as crude and refined petroleum, natural gas and biofuels, ammonia, alcohol fuels, ethanol, hydrogen, and other liquids such as sewage, coal and ore, slurry, beer, brine, milk, water, central heating, hot water or steam, are transported over long or short distances by pipeline.
It is desirable to distribute ethanol through pipelines. However, ethanol’s interest in water and solvent properties requires the use of a dedicated pipeline or significant cleaning of existing pipelines. The main problems with pipeline transport of ethanol are its corrosive nature and its tendency to absorb water and foreign matter in pipelines, which are not a problem with oil and gas. Insufficient volumes and financial efficiency limit the use of ethanol pipelines. In the USA, a minimum amount of ethanol is transported by pipeline. Most ethanol is transported by rail, with the main alternatives being truck and marine tankers.
Slurry pipelines are sometimes used to transport coal or ore from mines. The material to be transported is thoroughly mixed with water before it is introduced into the pipeline; material should be dried at the far end.
Oil pipelines are made from steel or plastic pipes that are usually buried. Oil is transported along pipelines by pumping stations along the pipeline. Natural gas pipelines are made of carbon steel.
Pipelines are one of the safest ways to transport materials compared to road or rail, and therefore pipelines are often the target of military attacks in war.
The latest data for 2014 show slightly less than 2,175,000 miles (3,500,000 km) of pipelines in 120 countries around the world. 75% of all pipelines were located in the three countries, and 65% of the 75% were in the United States, 8% in Russia and 3% in Canada.
Worldwide surveys show that 118,623 miles (190,905 km) of pipeline is planned and under construction. Of these, 88,976 miles (143,193 km) represent projects in the planning and design phase; 29,647 miles (47,712 km) reflect pipelines at various stages of construction.
Petroleum and Natural Gas
In 2014, transporting crude oil by pipeline cost about $ 5 a barrel, while rail transport cost about $ 10 to $ 15 per barrel. Trucking costs are even higher because of the additional labor required; Employment in completed pipelines represents “only 1% of the trucking industry”. Pipelines are a cheaper means of transport by volume.
70% of crude oil and petroleum products are transported by pipeline in the United States. (23% by ship, 4% by truck and 3% by rail) In Canada, 97% of natural gas and petroleum products are shipped by pipeline.
Although pipelines are built under the sea, this process is economically and technically demanding. For this reason, most of the oil carried in the seas is transported by tanker ships. Similarly, it is economically more convenient to transport natural gas in the form of LNG, but the breakeven point between LNG and pipelines will depend on the volume and distance traveled by the natural gas.
Market size for oil and gas pipeline construction experienced tremendous growth before the economic recession in 2008. Following the standstill in 2009, demand for pipeline expansion and upgrades increased the following year as energy production increased. By 2012, almost 32,000 miles of North American pipeline was planned or under construction. However, when additional pipeline options were restricted, transportation by road / sea tanker or rail was put on the agenda.
In some places, a pipeline may have to cross large areas of water such as seas, straits and rivers. In most cases, these pipelines are called “marine” pipelines (also “submarine” or “offshore” pipelines), which are laid entirely on the seabed. They are primarily used to transport oil or gas. It is also preferred in the transportation of water.
In offshore projects, a distinction is made between a “flowline” and a pipeline. The first is an intrafield pipeline in the sense that it is used to interconnect subsea wellheads, manifolds and platforms in a given development area.
The latter, sometimes referred to as the “export pipeline”, is used to bring the source to shore. The construction and maintenance of offshore pipelines, along with other geological hazards, implies logistical challenges that differ from those on land, mainly due to wave and current dynamics.
Construction and Operation
Oil pipelines are made of steel or plastic pipes with an inside diameter of typically 4 to 48 inches (100 to 1,220 mm). Most pipelines are typically buried to a depth of about 3 to 6 feet (0.91 to 1.83 m). Various methods are used to protect pipes from impact, wear and corrosion. These can include wood lining (wood slats), concrete lining, stone shields, high density polyethylene, sand fillers and infill elements.
Crude oil contains varying amounts of paraffin wax, and wax buildup may occur within a pipeline in colder climates. Pipelines are inspected and cleaned using pigging, the practice of using devices known as “pigs” to perform various maintenance tasks. These devices are also known as “scraper”, “Go-devils”, or “smart” pigs. It is used to detect abnormalities in pipes such as dents, metal loss, corrosion, cracking or other mechanical damage. These devices are launched from pig launch stations and travel along the pipeline to be picked up at any other station downstream, cleaning any wax deposits and unwanted material that may have accumulated in the line or by examining and recording the line’s condition.
For natural gas, pipelines are made of carbon steel and range in size from 2 to 60 inches (51 to 1,524 mm) depending on the pipeline type. The gas is pressurized by the compressor stations and is subject to inspection where deemed necessary by a regulatory authority.
Functionally, pipelines can be classified into three categories depending on the purpose:
A group of smaller interconnected pipelines that form complex networks to bring crude oil or natural gas from several nearby wells to a treatment plant or processing facility. In this group, pipelines are usually short – several hundred meters and small diameters. For collecting product from deep water production platforms, subsea pipelines are also considered as collection systems.
Mainly long pipes with large diameters, moving products (oil, gas, refined products) between cities, countries and even continents. These transportation networks include several compressor stations in gas lines or pump stations for crude and multi-products pipelines.
It consists of several small diameter, interconnected pipelines used to deliver products to the end consumer. Supply lines for delivering gas to downstream homes and businesses. Pipelines at terminals for distribution of products to tanks and storage facilities are included in this group.
Development and planning
When a pipeline is built, the construction project should cover not only civil engineering work to lay the pipeline and construct pump / compressor stations, but also all work related to the installation of field devices to support remote operation.
The pipeline is guided along what is known as the “right of way”. Pipelines are generally developed and built using the following stages:
Route (right of way) Selection
Pipeline design: The pipeline project can take a variety of forms, including the construction of a new pipeline, the conversion of an existing pipeline from one fuel type to another, or improvements to facilities along an existing pipeline route.
Approval: After the design is complete and the first pipeline customers have purchased their capacity shares, the project must be approved by the relevant regulatory authorities.
The route is explored, cleaned, channels are opened for main routes and passages (roads, railway, other pipes, etc.), the pipe is adapted, valves and junctions are installed, the pipe and ditches are covered. When construction is complete, the new pipeline is tested to ensure structural integrity. These may include hydrostatic testing and line packing.
In Russia, there are “Pipeline troops” under Rear Services trained to build and repair Pipelines. Russia is the only country with Pipeline Unions.
Operational field devices are instrumentation, data acquisition units and communication systems. Field instrumentation includes flow, pressure and temperature gauges / transmitters and other devices to measure relevant data. These tools are installed at specific locations along the pipeline, such as injection or distribution stations, pumping stations (liquid pipelines) or compressor stations (gas pipelines) and block valve stations.
The information measured by these field devices is then collected in local remote terminal units, which transmit the field data to a central location in real time using communication systems such as satellite channels, microwave connections, cell phone connections.
Pipelines are controlled and operated remotely from what is commonly known as the “Main Control Room”. In this center, all data related to field measurement are consolidated in a single central database. Data are taken from multiple terminal units throughout the pipeline. It is common to have terminal units installed at each station along the pipeline.
Pipeline networks consist of several pieces of equipment that work together to move products from one place to another. The main elements of a pipeline system are:
Initial injection station
Also known as the “supply” or “inlet” station, it is the beginning of the system where the product is injected into the line. Storage facilities, pumps or compressors are often found in these places.
Compressor / pump stations
Pumps for liquid pipelines and compressors for gas pipelines are located along the line to move the product along the pipeline. The location of these stations is defined by the topography of the land, the type of product transported or the operating conditions of the network.
Partial delivery station
Ara istasyonlar” olarak da bilinen bu tesisler, boru hattı operatörünün taşınan ürünün bir kısmını teslim etmesine izin verir.
Block valve station
These are the first line of protection for pipelines. With these valves, the operator can isolate any part of the line or isolate a rupture or leak for maintenance work. Block valve stations are typically located every 20 to 30 miles (48 km) depending on the type of pipeline. While it’s not a design rule, it’s a very common practice in liquid pipelines. The location of these stations depends on the nature of the transported product, the trajectory of the pipeline and / or the operating conditions of the line.
This is a special valve station where the operator can relieve some of the pressure in the line. Regulators are usually located on the downhill side of a hill.
Final delivery station
Also known as “output” stations or terminals, it is where the product will be delivered to the consumer. It can be a tank terminal for liquid pipelines or a connection to a distribution network for gas pipelines.
Leak Detection Systems
Since oil and gas pipelines are an important asset in the economic development of almost every country, leak detection systems for these pipelines are required by either government regulations or domestic policies to ensure the safety of the population and environment in which they operate.
Pipeline companies face government regulations, environmental constraints and social situations. Social factors also affect the functioning of pipelines. Product theft is a major problem for pipeline companies.
Pipelines are monitored physically or by applying various technologies and strategies such as satellite tracking methods. The most common technology for protecting pipelines from leaks is Computational Pipeline Monitoring, or CPM. CPM obtains field information regarding pressures, flows and temperatures to estimate the hydraulic behavior of the product transported. Once the forecast is complete, the results are compared with other field references to detect the presence of an anomaly or contingency that might be related to a leak.
A pipeline that passes under a road or railroad is usually enclosed by a protective casing.
As the temperature is less variable, pipelines are often laid underground. Since pipelines are often metal, it helps to reduce expansion and contraction that can occur with weather changes. However, in some cases it is necessary to cross a valley or river on a pipeline bridge.
Pipelines for central heating systems can be laid on the ground or overhead. Oil pipelines that pass through areas of frozen soil such as the Trans-Alaska-Pipeline are laid and operated from overhead to prevent the frozen ground from melting due to hot oil causing the pipeline to sink to the ground.
When anything abrasive is carried in the pipeline, cathodic protection levels should be checked at appropriate intervals.
Buried fuel pipelines must be protected from corrosion. The most economical method of corrosion control is the use of the required pipeline coating in combination with cathodic protection and technological monitoring of the pipeline.
Cathodic protection above ground is not an option. The coating is the only external protection.
Pipelines are not just an element of trade for major energy resources (oil and gas). They are also linked to geopolitical and international security issues. The construction, placement and control of oil and gas pipelines are often prominently involved in government interests and actions.
A notable example of pipeline policy occurred at the beginning of 2009, and a seemingly pricing dispute between Russia and Ukraine led to a major political crisis. The Russian state gas company cut natural gas supply to Ukraine after negotiations with Ukraine were delayed. In addition to cutting the supply to Ukraine, Russian gas flowing from Ukraine – including almost all supply to Southeast Europe and part of supply to Central and Western Europe – was cut and in some countries heavily dependent on Russian gas for fuel. created a crisis. Russia has been accused of leveraging the conflict to keep other powers, and particularly the European Union, from intervening.
Oil and gas pipelines also have an important place in Central Asian and Caucasian politics.
The mixing of benzene and other volatile organic compounds (collectively BTEX) into the underground environment is a major threat that a pipeline leak can pose. Especially after rain, a pipeline accident will cause BTEX to dissolve and stabilize benzene in water, and then infiltrate the mixture into the aquifer (conductive geological unit that can store water, with high permeability and transport fast enough). Benzene can cause many health problems and is carcinogenic when mixed with drinking water. Additionally, exposure to benzene in livestock, mainly cattle, causes many health problems such as neurotoxicity, fetal damage, and fatal poisoning.
The entire surface of an aboveground pipeline can be directly inspected for material breach. Pooled oil is clear, easily detected and indicates where necessary repairs are required. Because the effectiveness of remote monitoring is limited by the cost of the monitoring equipment, the distance between the sensors, and the data that needs to be interpreted, small leaks in the buried pipe can sometimes go unnoticed.
Pipeline developers may not prioritize effective surveillance against leaks. Buried pipes create fewer complaints. They are less susceptible to extremes at ambient temperature, are protected from ultraviolet rays, and are less exposed to photodegradation. Buried pipes are isolated from airborne threats, electrical storms, hurricanes, hail and acid rain. They are protected from nesting birds, monotonous mammals and stray large plants. The buried pipe is less vulnerable to accident damage, less accessible to vandals, saboteurs and terrorists.
Detection, capping, and curing procedures will limit the dissolution and transport of benzene, for example. Therefore, exposure to benzene will be limited to leaks that are below the detection limit and are not noticed for a long time. A pinhole leak can turn into a significant spill. Detection of pinhole leaks occurs through visual or odor inspection, aerial inspection, or mass balance discrepancies. It is assumed that pinhole leaks were discovered within the 14-day inspection interval, but snow cover and location (eg, far, deep) may delay detection. Benzene typically accounts for 0.1 – 1.0% of petroleum and has varying degrees of volatility and solubility depending on environmental factors.
Sometimes pipeline leaks pose the risk of being misunderstood and interpreted by pipeline operators as pump failures or other problems.
Benzene is considered to be a light aromatic hydrocarbon with high solubility and high volatility. It is unclear how temperature and depth will affect the volatility of benzene.
Difficulties healing dilbit shedding
One of the major concerns about dilbit (diluted bitumen) is that it is difficult to clean. Dilbit spills spilled from a broken pipeline can be transported for kilometers by heavy rain. Oil may continue to be found in the affected earth and groundwater for a long time, despite cleaning.
Hazards and Environmental effects
Fossil fuels can be transported by pipeline, rail, truck or marine vessels. But natural gas requires compression or liquefaction to make vehicle transport affordable. Various reports on the transportation of crude oil through these four methods show pipelines as a proportionally less physical loss, loss of life, property damage and environmental pollution than rail and truck. Due to the impact on habitat, marine transport is significantly affecting the marine habitat.
Pipelines can be targets of vandalism, sabotage, and even terrorist attacks. For example, between early 2011 and July 2012, a natural gas pipeline connecting Egypt with Israel and Jordan was attacked 15 times. In 2019, a fuel pipeline in northern Mexico City exploded after fuel thieves involved. At least sixty-six people were reported as death. In the case of war, pipelines are often the target of military attacks, as the destruction of pipelines can seriously disrupt enemy logistics.