An Overview of Corrosion in Oil and Gas Industry

The oil and gas industry is normally divided into three major components: upstream, midstream, and downstream. The upstream sector explores, locates, and produces crude oil and natural gas from both underground and underwater fields, which are referred to as onshore and offshore fields, respectively. For this, the upstream sector is sometimes referred to as exploration and production (E&P). Types of wells handled in the upstream sector include oil, gas, and water. The midstream sector involves the transportation (by pipeline, rail, barge, oil tanker, or truck), processing, storage, and wholesale marketing of crude or refined petroleum products. Pipelines and other transport systems are used to move crude oil and natural gas from production sites to refineries and petrochemical plants. Natural gas pipeline networks gather gas from natural gas producing wells and from separation and purification plants and deliver it to downstream sector and customers, such as local utilities. Midstream operations often overlap with some elements of the upstream and downstream sectors. For example, the midstream sector may encompass natural gas processing plants that purify the raw natural gas as well as removing and producing elemental sulfur and natural gas liquids (NGLs). The third component is the downstream sector that includes crude oil refineries, petrochemical plants, and petroleum products distribution. One major component of the downstream sector is the refining of crude oil into gasoline, diesel, jet, and other fuels. In addition, the downstream industry provides thousands of products such as jet fuel, heating oil, asphalt, lubricants, synthetic rubber, plastics, fertilizers, antifreeze, pesticides, pharmaceuticals, natural gas, and propane. At the early stages of crude oil production from a newly discovered field, the produced fluids streams are normally dry. Water, however, is required for corrosion to occur at low temperatures. As a result, the majority of equipment used in oil production were conveniently constructed from the relatively low cost carbon steel that has the required strength for pressure containment. It is very common that the life of these installations exceed 50 years without the need to apply any corrosion control measure as long as the streams remain dry or dominated by the