海上平台超临界CO_(2)管道泄漏扩散规律实验研究

Experimental study on supercritical CO_(2)leakage and diffusion law on offshore platform

CO_(2)封存是实现中国“双碳”目标的有效技术途径之一,海上CO_(2)封存通常依托海上油气平台管道回注,CO_(2)回注过程中可能发生泄漏而严重影响作业人员安全。以恩平15-1海上平台为研究对象,开展超临界CO_(2)泄漏扩散规律实验研究。通过缩比设计,搭建与恩平15-1相应的物理模型实验平台,利用相似理论和量纲分析方法,设计了超临界CO_(2)泄漏扩散参数,开展了海上平台管道CO_(2)在不同泄漏压力(1.5~3.0 MPa)、泄漏孔径(0.5~6.2 mm)、泄漏方向(水平、竖直、斜45°)及环境风速(0~0.5 m/s)下的相似模型实验,研究泄漏CO_(2)在平台上的扩散情况及浓度分布规律。结果表明:压力和环境风速的变化,会影响CO_(2)泄漏后的近场射流,但对其远场扩散的影响较小;CO_(2)浓度会在泄漏约20 s后达到峰值并保持稳定,不会随泄漏时间的增加而增大;泄漏口径会显著影响泄漏口轴向CO_(2)浓度的分布规律。研究结果为海上平台CO_(2)泄漏监测与安全防护设计提供了参考。

CO_(2)geological storage is one of the most effective approaches to achieve the goal of“carbon peak and carbon neutrality”.Offshore CO_(2)storage usually relies on pipeline reinjection from offshore oil and gas platforms,while leakage may occur during the CO_(2)reinjection process,seriously threatening the safety of operators.Taking the EP15-1 offshore platform as the research object,the experimental study on supercritical CO_(2)leakage and diffusion law was conducted.A physical model experimental platform corresponding to EP15-1 was built through scaled design,the supercritical CO_(2)leakage and diffusion parameters were designed based on the similarity theory and dimension analysis method and similar model experiments on CO_(2)in offshore platform pipelines under different leakage pressure(1.5-3.0 MPa),leakage aperture(0.5-6.2 mm),leakage direction(horizontal,vertical and oblique 45°)and ambient wind speed(0-0.5 m/s)were carried out to study the diffusion and concentration distribution of leaked CO_(2)on the platform.The results show that the changes in pressure and ambient wind speed will affect the near-field jet after CO_(2)leakage,but have little effect on its far-field diffusion.The CO_(2)concentration will reach a peak after about 20 s of leakage and remain stable,and it will not increase with the increase of leakage time.Leakage diameter will dramatically affect the distribution pattern of axial CO_(2)concentration at the leakage port.The research results provide a reference for CO_(2)leakage monitoring and safety protection design on offshore platforms.