Identification of corrosion or production issues In offshore wet sour gas production with long pipelines, hydrate and corrosion inhibition is required and essential in order to ensure safe, reliable and cost-effective operations. With the identified operating conditions, corrosion will become a major concern for the operation of Karan facilities. Identifying the nature of the anticipated corrosion processes is a key to determining the major components of any future corrosion management program. In particular, top of the line corrosion was identified as a potential issue in specific locations in the field as large quantities of organic acids are present in the condensed water. TLC occurs when the surrounding environment cools down the produced gas that is saturated with water vapor. As the gas is cooled, the water vapor in the gas will condense. When this happens, corrosion can occur. This type of corrosion has not been experienced by the author’s company. However, other offshore gas producers around the world have experienced this problem. To help identify the corrosion challenges for this field, the author’s company initiated in 2008 a comprehensive study to determine the likelihood and extent of different corrosion mechanisms at such conditions.
LABORATORY STUDY ON SOUR TLC Introduction Top of the line corrosion is a type of corrosion which happens in stratified flow when strong gradients of temperature between the outside environment and the process fluid lead to water condensation on the internal walls of the pipe line. It was first identified in the ’60s1 and is now a growing concern for the oil and gas industry. Many field cases have been published since, both for onshore and offshore production environments2-9. The presence of the condensed water can induce severe problems of general corrosion and pitting typically on the upper part of the pipe (between 9 and 3 o’clock).