The cleaning campaign

摘要

John Mundy, Project & Lead Design Engineer, Pipeline Engineering, UK, discusses specialist pigging equipment to support progressive pipeline cleaning. Progressive cleaning of oil pipelines is often required due to a combination of factors. The leading cause is a prolonged period without pigging, which itself may be due to a number of reasons. The most common of these is unplanned maintenance, causing a cessation of pigging operations, but there can also be a general deficiency of pigging in either frequency or effectiveness. The debris handling capabilities of the receipt facilities is the other main factor, as many are not designed to handle the large quantities of debris that can be delivered after restarting pigging following prolonged periods without pigging. The requirement to return the pipeline to a clean state is usually driven by a deterioration of the pipeline hydraulics due to the build-up of debris, or the legal requirement to perform an inline inspection (ILI) to confirm the integrity of the pipeline. A lengthy period without pigging can often be followed by launching a standard pigging tool into the pipeline. This can result in a stuck pig, or have a major impact at the receipt facility, if the quantity of debris in the line is not fully understood. This is where the progressive cleaning approach should be employed.