Development, Testing, and Field Application of a Heavy-Oil Pipeline-Cleaning Chemical: A Cradle-to-Grave Case History

Abstract

This paper details the complete evolution of a new cleaning chemical for heavy oil and gas pipelines. Information is offered regarding the reason for development, the research involved in formulation of the new product, as well as the laboratory testing. This paper concludes by giving several case histories of application in cleaning operations in Western United States and Texas. Oil naturally contains paraffins, asphaltenes and naphthenates. During transport these hydrocarbon components can precipitate and adhere to the pipeline walls and can become associated with iron sulfide scale. Corrosion can often occur on pipeline walls under these organic deposits. Pigging operations are normally performed to remove organic and inorganic debris from the walls of a pipeline. However, these scales can become very compacted and adhere to the walls of the pipeline. It is often necessary to add surfactant based chemicals to assist in the break-up, softening, and transportation of these deposits. A detailed literature review of the current theory in the chemistry of pipeline cleaning chemicals is presented together with a critical account of the key properties required of these chemistries: wettability alternation, solubilization efficacy of organic materials, emulsification of phases, dispersion, detergency, and defoaming. An explanation of the laboratory development and evaluation has been given as a preamble for the case histories. One case history details how a pipeline operator unsuccessfully tried to clean a 12” 9-mile section of pipeline with a pig. The pig was launched and became stuck along the length of the pipeline. Application of the newly developed product was able to free the stuck pig and removed significant debris. By way of conclusion the paper offers suggestions on how chemicals can be most efficiently used in conjunction with these programs.