Dynamic Detection of the Multiple Hydrate Blockages in Natural Gas Pipeline Using Mass Pulse at the Inlet

Abstract

Due to the influence of low temperature, high speed and agitation in the pipeline, gas hydrate can be easily formed and blocks the pipeline. If the non-complete blockage pipeline segments are accurately detected with the number, location, length and magnitude of the blocked segments identified, the proper pigging operation scheme can be made to reduce the risk of complete blockage in the pipeline. The authors put forward that by using mass pulse launched at the pipeline inlet, the characteristic data of pipeline blockages can be identified through its propagation characteristics in multiple non-completely blocked natural gas pipeline segments. In this paper, the mathematical model of gas transient flow in a pipeline with multiple blockages is established, and pulse propagation in the blocked pipeline is simulated by using time splitting algorithms and TVD / Godunov mixed format. Under the conditions of maintaining the valve open at the end of the pipeline, the history curve of pressure fluctuation at the pipeline inlet is analyzed to dynamically identify the number of segments blocked in natural gas pipeline, blockage positions, blockage length, and blocking magnitude of multiple blockages.