海底管道泄漏油气扩散规律数值仿真与对比分析

为研究海底原油与天然气单相泄漏扩散规律的差异性,合理制定应急响应策略,减小事故损失,针对海底管道失效所致的原油与天然气泄漏问题,基于计算流体动力学CFD方法,建立海底油气管道泄漏事故后果预测与评估模型,对特定事故场景下的海底原油与天然气泄漏扩散过程进行模拟与分析,从泄漏扩散过程、工况因素影响、泄漏后果及应对策略4个方面对比原油与天然气的泄漏扩散特性。结果表明:相同工况下,海底原油与天然气在泄漏速率、扩散时间、扩散形态及水平最大扩散距离方面存在显著差别;与天然气相比,原油泄漏扩散行为对工况因素具有更高的敏感性;原油泄漏会引发严重的环境灾害,天然气泄漏则会影响海上结构物的稳定性及引发火灾爆炸事故,据此需合理制定具有针对性的应对策略。

CFD-based comparative analysis for the oil & gas dispersion behavior resulting from the submarine pipeline leakage

To study the difference of submarine oil & gas release and dispersion behavior due to the sea-floor pipeline failure,the present paper has developed a CFD-based model for predicting and evaluating the consequence of the oil & gas release.For the said purpose,we have simulated and analyzed the dispersion process of oil & gas release under a certain accident scenario,including different apertures,pressures,and current velocities based on the above said model.And,then,we have made a comparison to analyze the characteristics of oil & gas dispersion in terms of four aspects,that is,the dispersion process,the release scenario,the release consequence and the tactics to be adopted.The results of our study show that the marine-floor natural gas tends to have a higher leaking and dispersion velocity than the crude oil,at about 21 s as against the 77 s of the gas before they reach the marine surface.On the other hand,oil has a longer horizontal dispersion distance than the natural gas,which makes the dispersion distance of oil at about 120 m,whereas that of natural gas is about 80 m.Due to the high dispersion velocity,natural gas tends to result in a water-jet column on the sea surface,causing a loss buoyancy on the floating platform,whereas oil gives quite different effects.On the other hand,oil spill has a higher sensitivity to the accidental scenarios as compared with the natural gas.For example,the leakage aperture tends to keep on increasing until the oil and gas reach the sea surface,for the change of the leak aperture may imply a much greater effect on the gas form in the entire dispersion process,while it influences the oil release merely at the initial phase.However,no discernible effects can either be found on the velocity of the pressure and the current in the oil & gas dispersion forms,though a great effect has been found on the horizontal distance of the oil dispersion due to the change of the current velocities,whereas such effects can only be found slight in the case of natural gas dispersion.Therefore,comparing the results and consequences of the leakage accidents can help us to conclude that oil spill would cause much more serious environmental risks than the natural gas leaking and loss buoyancy on the floating installations,though both of them can lead to disastrous fire and deflagration.