Chemical-assisted Pipeline Pigging Cleaning Operations

Transcript

Details have been given on the development of a successful cleaning chemical for hydrocarbon transport pipelines. Elaboration on the formulation research of the new product and laboratory testing is summarised with case histories of applications in western USA and the Gulf Coast. Hydrocarbon transportation can result in precipitation of paraffins, asphaltenes, and naphthenates that adsorb to the walls of the pipeline becoming associated with corrosion originated iron sulphides. Pigging operations alone do not always remove all these deposits due to compaction and a strong adherence to the walls of the pipeline. It therefore becomes necessary to add surfactant based chemicals to assist in the break-up and removal of these deposits. A literature review is made regarding the current practice of pipeline cleaning, including the key properties required of cleaning chemicals – namely: wettability, solubilisation, emulsification, dispersion, detergency, and defoaming. One case history details how the pipeline operator had previously tried to clean a 12 inch diameter, 15 km section of pipeline with a pig. The pig was launched and became stuck along the pipeline. Application of the newly developed product was able to free the stuck pig and remove significant debris that the pig has become lodged against. Details of the pigging programme, coupled with chemical solutions for this programme, are given.