Subsea pipelines cleaning technologies in the absence of the possibility of using pigging devices

UDK: 622.692.4

Key words: oil treatment and transportation, pour point depressant, high-paraffin crude oil, offshore field, pipeline pigging

Authors: A.G. Akhmadeev, Tong Canh Son, Ph.D., Pham Thanh Vinh (Research and Engineering Institute, Vietsovpetro JV, the Socialist Republic of Vietnam, Vung Tau)

The article describes the use in the Vietsovpetro JV a variety of ways subsea pipelines cleaning and capacity recovering in the absence of the possibility of the use of pigging devices. These methods include blowing gas lift pipeline gas; flushing by water from injection system; combined water and gas supply method to create a larger shear stress at the interface with the deposits; dissolving the deposits with condensate formed during the preparation and gas compression; comprehensive method that combines an increase depressant and demulsifier dosage, heating products using mobile steam unit and periodic flushing of the pipeline. Selection of method depends on the characteristics and function of the pipeline, the type and hardness of the deposits, technological capabilities of this type of treatment in each specific pipe. The above methods have their limitations and do not allow for a thorough cleaning, however, provide an acceptable level of transport safety of the high paraffin crude oils.
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