Internal coating of carbon steel pipelines is well known and widely used to prevent internal corrosion, CO2 corrosion, stress corrosion cracking (SCC) and microbiological-induced corrosion (MIC). The effectiveness of coatings is dependent on the coating material and the quality of the coating application throughout the pipeline. One of the most critical challenges associated with constructing an effectively internally coated pipeline is ensuring that the internal field joints1 are coated with good quality assurance, which in turn is largely dependent upon the quality of the girth weld2 profile.
Remotely operated visual cameras are generally used to assess the coatability of the weld joints. The camera provides a 2-D top-down view of the weld area which aids the field personnel to identify possible weld anomalies or other features that require attention prior to field joint coating.
Laser Scanning is a technique that provides an accurate real-time 3-D imaging of the field joint area which is evaluated using an algorithm and thus a quantifiable and repeatable coatability analysis of the internal field joint area. This paper discusses the process and advantages of the laser scanning and how it can help improve construction schedule while raising the level of quality assurance for the girth weld coating.
Carbon steel pipelines are widely used in the oil and gas industry as a fast and secured means for transportation of hydrocarbons, water and other fluids from their source to the destination. Pipelines are routed through varying environments such as land, sea, deserts, sabkha, marshy areas, which exposes the external surfaces of the pipelines to corrosive environment. These pipelines are often used for transportation of different fluids, which are generally corrosive due to their chemical composition.
Corrosion is a chemical or electrochemical reaction between a metal and its environment resulting in loss of material and its properties. Corrosion generally occurs when materials made from metal return to their original state through a chemical reaction known as oxidation. Corrosion is accelerated when the pipe surface is exposed to water and contaminants such as O2, H2S, CO2 or chlorides. Corrosion is the primary factor affecting the service life and reliability of pipelines throughout the world. In the Middle East, operators face unique risks and challenges, more due to corrosion, which can lead to premature pipeline failures and ultimately replacement, not to mention, production deferment and downtime due to repair or replacement time. Pipeline failures can be catastrophic causing loss of life and severe effect to the environment.