There are more than 6,500 offshore oil and gas installations in some 53 countries worldwide. More than 50% of these installations are in the US Gulf of Mexico. The next five largest areas in descending order are Asia, the Middle East, the North Sea, the West African coast and South America.1 These six regions account for the majority of the existing offshore oil and gas installations. The installations are built for exploration (drilling) and production including preparing water or gas for injection, processing oil or gas, cleaning produced water for disposal and various accommodations).
From these production platforms, the oil and gas is transported to various units: to storage tanks, for the removal of moisture and hydrogen sulphide, to refineries and direct as gas supply to power plants, petrochemical plants, fertilizer plants, etc. This is mainly accomplished via pipelines dug underground, usually termed crosscountry pipelines. The terrain through which these pipelines pass varies among undersea, sandy soil, rocky soil, soft mud, brackish water, river beds, terrain rich in minerals and moisture, etc. The fact that these pipelines carry the most flammable material means that the safety of the pipelines, people and environment need to be doubly assured. This is achieved by the following approaches.
- Laying the pipelines underground, so that in case of any leakage or explosion, the surrounding earth will dampen it to a certain extent.
- Proper selection of protection methods:
- selection of steel pipe composition to minimise or avoid internal corrosion and assure high strength and toughness of the pipe; and
- selection of a suitable internal corrosion protection method and external corrosion protection method.
- Corrosion monitoring of the pipeline to know its periodic health.
- Use of non-destructive testing (NDT) methods to periodically clean the pipeline and assess the corrosion damage from inside.
- A corrosion management and pipeline integrity management approach.
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