The paper analyses multiphase flow induced vibration on gathering pipeline on Novoportovskoe field. At high gas and liquid flow rates, a slug flow regime is formed in the pipeline, in which areas with a high liquid content (slug) and low liquid content (bubbles) alternate in the flow. The slug with high liquid content is pushed by the gas flow and its velocity can reach significant values exceeding the gas and liquid velocities as a mixture. Due to the high velocity (up to 25 m / sec on the object under consideration), this flow regime can have a significant mechanical impact on the pipeline during the passage of the
U-shaped expansion units. When the plug passes through the expansion units, the forces acting on the turns of the pipeline (knee) are unbalanced; this can cause the appearance of a short but significant force trying to move the pipeline. Under certain conditions, these forces can significantly exceed the frictional forces holding the pipeline and cause pipeline displacements, and increase the risk of mechanical damage to the pipeline (for example, when it falls from the supports). An important factor affecting slug dynamics is the terrain relief under pipeline - in the upward flow parts, it is possible to form severe slugs that can travel long distances and has a high influence.
The paper consider a model of multiphase flow taking into account the hydrodynamic and terrain slugging, propose a model of flow influence on a pipeline, describe graphical tools for estimating the degree of influence of the flow on the pipeline. Model proposed compared with field measurements. Recommendations are given to reduce the negative effect of the slug flow on the pipeline.
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