Multiphase flows are of paramount importance in the oil and gas industry, considering that most petroleum industries produce and transport oil and gas simultaneously. However, systematic research on pipeline leakage conveying more than one phase at a time is lacking attention. In this work, a numerical method is proposed to investigate the effect of two-phase gas-liquid leak flow behaviour in a subsea natural gas pipeline. The results of the simulations have been validated against the latest experimental and numerical data reported in the literature, and a good agreement has been obtained. The effect of leak sizes, longitudinal leak locations, multiple leakages and axial leak positions on the pressure gradient, flow rate and volume fractions in the pipeline were systematically investigated. The results show that the flow field parameters provide pertinent indicators in pipeline leakage detection. In particular, the upstream pipeline pressure could serve as a critical indicator for detecting leakage even if the leak size is small. Whereas, the downstream flow rate is a dominant leakage indicator if the flow rate monitoring is chosen for leak detection. The results also reveal that when two leaks with different sizes co-occur in a single pipe, detecting the small leak becomes difficult if its size is below 25% of the large leak size. However, in the event of a double leak with equal sizes, the leak closer to the pipe upstream is easier to detect.

考虑到大多数石油工业同时生产和运输石油和天然气，多相流在石油和天然气工业中至关重要。然而，对一次输送不止一相的管道泄漏的系统研究缺乏关注。在这项工作中，提出了一种数值方法来研究海底天然气管道中气液两相泄漏流动行为的影响。模拟的结果已经根据文献中报道的最新实验和数值数据进行了验证，并且已经获得了很好的一致性。系统地研究了泄漏尺寸、纵向泄漏位置、多重泄漏和轴向泄漏位置对管道压力梯度、流速和体积分数的影响。结果表明，流场参数为管道泄漏检测提供了相关指标。特别是上游管道压力可以作为检测泄漏的关键指标，即使泄漏尺寸很小。然而，如果选择流量监测进行泄漏检测，下游流量是主要的泄漏指标。结果还表明，当同一管道中同时发生两种不同尺寸的泄漏时，如果其尺寸小于大泄漏尺寸的 25%，则检测小泄漏变得困难。但是，如果发生大小相同的双重泄漏，则更靠近管道上游的泄漏更容易被检测到。然而，如果选择流量监测进行泄漏检测，下游流量是主要的泄漏指标。结果还表明，当同一管道中同时发生两种不同尺寸的泄漏时，如果其尺寸小于大泄漏尺寸的 25%，则检测小泄漏变得困难。但是，如果发生大小相同的双重泄漏，则更靠近管道上游的泄漏更容易被检测到。然而，如果选择流量监测进行泄漏检测，下游流量是主要的泄漏指标。结果还表明，当同一管道中同时发生两种不同尺寸的泄漏时，如果其尺寸小于大泄漏尺寸的 25%，则检测小泄漏变得困难。但是，如果发生大小相同的双重泄漏，则更靠近管道上游的泄漏更容易被检测到。