Types of pipelines
The two major categories of pipelines used in Oil and gas industry are:
After crude oil is drilled out from a land or a sea based drilling station, it is transported by pipelines to onshore tank batteries. A tank battery separates oil, gas and water. Once the oil is separated, it is either sent for storage or refining through large diameter, long-distance trunk lines which are pressurized to overcome friction and changes in terrain elevation. Once refined, the product pipelines carry gasoline, jet fuel, diesel, ammonia and other liquids to storage or distribution centers. Liquid pipelines can also carry liquefied petroleum gas (LPG), liquefied natural gas (LNG) and highly volatile liquids (HVL) such as ethane, propane and butane.
Natural Gas Pipelines
Similar to liquid oil pipelines, natural gas pipelines are also used to carry natural gas liquids (NGL) for refining and distribution. Unlike oil pipelines, natural gas transmission systems use compressors to force the gas through the pipeline. Pipelines can also be categories based on their utility, for example, in a distribution network, “Gathering” pipelines move oil and gas from source to processing facilities, “Feeder” pipelines move the product to transmission lines, “Transmission” pipelines move product across vast areas to distribution centers and “Distribution” pipelines carry natural gas to the customer.
Although the industry has maintained a good safety record for pipelines, The potential and subsequent impact of a catastrophic pipeline failure cannot be ignored. Even when not ignited, the spilt material can cause significant damage to the surrounding environment and wildlife, contaminate underground water supply, damage land and block transport (Figure-2). If ignited, the damage can be catastrophic and can lead to explosions, loss of life and equipment, wildfires, air pollution and damage to property. Although natural gas is lighter than air, it usually rises and dissipates into air but when ignited, the initial blast and radiated heat could be just as deadly (Figure 3).