Pipeline hydrotest method of cold water in frigid zone

Compared with the air pressure test method, it is more secure to use hydrotest method for oil and gas pipelines in frigid zone. However, the problem in water freezing must be solved. The main anti-freezing measure include: the automatical water heating with electric tracer heating system in pipe pressure test process, the temporary tents used to keep warm at both ends of pressure test segment, and heating installation equipments etc. In the process of hydrotest, the pressure boost of pipeline is done by using high pressure pumps, a complete set of built-in electric heating system is used to ensure the pipeline temperature, two water-injection pumps with the flow rate in 100 m³/h and discharge head in 101 m are used to inject water into pipe, and foam pigs are sent repeatedly to remove residual water to clean the accumulated water in pipeline. The simulation experiments under different environmental temperatures show that the hydrotest technology of cold water with electric tracer heating system is in accordance with the specified acceptance criteria in SY 0401-98 Standard for Construction and Acceptance of Oil and Natural Gas Pipeline Project. It is suitable for pipeline segment hydrotest in frigid zone, which can improve the pipeline construction technology in frigid zone.