Page 311 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

OIL AND GAS EXPLORATION AND PRODUCTION 289

acid solutions, acidic inorganic liquids, phosphoric acid, caustic alkali liquids, acidic
organic liquids, potassium hydroxide solutions, sulfuric acid, cleaning liquids,
hypochlorite solutions, basic organic liquids, liquid amines, and ammonia solutions.
Internal corrosion of tankers usually requires mitigation when an oxidizer or a
corrosive material is transported. Internal corrosion from settled contamination is lim-
ited because of high throughput and movement of the contents during transportation.
Internal corrosion of tankers is more of a problem during storage over a long time if
the tankers are not properly cleaned in the beginning.
Shipping containers such as drums and pails are subject to corrosion damage and
failure when corrosive materials are shipped. Usually, internal corrosion is not a prob-
lem when the goods are shipped by the manufacturer as proper container material is
used when the containers are transported in a short time. Corrosion can be a prob-
lem and result in failure when the contents are stored beyond the material’s shelf life.
The corrosion failure of containers with hazardous waste is a serious problem. This
problem occurs when wastes are mixed or when they are contaminated and stored in
noncompatible materials.
External corrosion of tanker trucks and railcar-mounted tanks is a problem. Both
general and pitting corrosion from the atmosphere and splash water from the road-
way or rail bed can affect the tank’s structural integrity. This can be a serious prob-
lem in locations where chloride sources are present such as road salt or airborne
marine atmosphere and airborne industrial pollution. The common mitigation method
involves painting of the tanks.
In the case of tanker trucks and railcar-mounted tanks, linings and corrosion
allowances for internal corrosion are used. In the case of transportation of corrosive
materials corrosion-resistant alloys are used. In extreme cases, rubber bladder tanks
have been used on flat-bed trailers or railcars. External corrosion is controlled with
coatings and designs that minimize crevices. One possible solution to minimize
crevice corrosion is by placing a horizontal tank with a circular cross-section on
legs, thus avoiding direct contact with other surfaces.

4.25 OIL AND GAS EXPLORATION AND PRODUCTION

Corrosion in oil field production environments can be in the range of zero corrosion
to severely high corrosion. Crude oil at normal production temperature (less than
∘
120 C) without dissolved gases is not corrosive. The economics of controlling cor-
rosion in many oilfields are dependent on efficient separation of crude oil from other
contaminants. While the rates of corrosion may vary, the species causing corrosion
are nearly universal. Carbon dioxide and hydrogen sulfide gases dissolved in water
define most of the corrosion problems in oil and gas production. Other problems
include microbiological activity and the accumulation of solids.
The mechanisms of CO corrosion are well defined, but the reality inside a pipeline
2
occurs when CO acts in combination with H S, deposited solids, and other environ-
2
2
ments. Hydrogen sulfide is highly corrosive but in some cases forms a protective
sulfide scale that prevents corrosion. Microorganisms can attach to pipe walls and