Crude oil migration in sea-ice: Laboratory studies of constraints on oil mobilization and seasonal evolution
Crude oil migration in sea-ice: Laboratory studies of constraints on oil mobilization and seasonal evolution
复制标题
海冰中的原油运移：石油流动限制和季节演变的实验室研究
DOI：
10.1016/j.coldregions.2019.102924
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发表时间：
2020
影响因子：
4.1
通讯作者：
M. O'Sadnick
中科院分区：
文献类型：
--
作者：
M. Oggier;H. Eicken;J. Wilkinson;C. Petrich;M. O'Sadnick
北极海洋活动和碳氢化合物开发的增加了北极海冰内和冰下石油泄漏的风险。在不断增长的海冰下溢出的石油将被包裹在冰盖之内。在春季和初夏，这些被困的石油将向上迁移，遍布冰体积，并最终汇集在表面。目前我们对这些过程的理解存在差距，这对溢油清理工作和生境损害评估有重大影响。在三组冰槽实验结果的指导下，我们开发了一个半经验的多阶段石油迁移和浮出水面模型，以帮助预测冰中石油的行为相关的溢出响应。根据以前的研究，在冰下释放时，石油浸透了冰骨架层，在生长季节基本上保持不动。当冰的固有渗透率随着表面融化的开始而增加到10− 11 m2以上时，石油会迅速通过冰盖的整个深度迁移，主要是通过次生孔隙空间。然后，孔隙之间不断增加的连通性允许油侵入原始孔隙空间。最后，随着冰的变质，石油占据了大部分孔隙空间。我们的地层分析表明，由于孔隙空间更曲折，颗粒冰阻碍了冷冰中石油的浮出水面。它还表明，在生长季节石油运动的潜力受到从油/冰界面到表面的迁移途径的可用性的限制。与以前的研究结果相反，我们的研究结果表明，如果存在这样的石油迁移途径，在生长季节，在冷冰中可能会发生显着的石油动员。因此，我们追踪了石油通过冷冰（Tice< −5 °C）中的大型盐水通道向上迁移，垂直距离达30厘米，导致石油在释放后24小时内浮出水面。在冰融化和变质过程中，油的运动与散装盐水体积分数的大小和油透镜储层的大小有关。根据这些发现开发预测性石油迁移模型将有助于溢油应急规划、石油探测和损害评估。
Rising Arctic maritime activities and hydrocarbon development increase the risk of an oil spill in and under Arctic sea-ice. Oil spilled under growing sea ice would be encapsulated within the ice cover. During spring and early summer, such trapped oil would migrate upwards, pervading the ice volume and ultimately pooling at the surface. Current gaps in our understanding of these processes have major implications for spill clean-up efforts and habitat damage assessments. Guided by results from three sets of ice-tank experiments, we have developed a semi-empirical multi-stage oil migration and surfacing model to help predict oil in ice behavior relevant to spill response. According to previous studies, upon under-ice release, oil saturates the ice skeletal layer, remaining largely immobile during the growth season. As intrinsic ice permeability increases above 10−11m2with the onset of surface melt, oil migrates rapidly through the full depth of the ice cover, primarily through the secondary pore space. Then, the ever-increasing connectivity between the pores allows the oil to invade the primary pore space. Finally, as the ice deteriorates, oil occupies most of the pore space. Our stratigraphic analysis revealed that granular ice impedes surfacing of oil in cold ice due to the more tortuous pore space. It also showed that the potential for oil movement during the growth season is constrained by the availability of migration pathways from the oil/ice interface to the surface. In contrast to previous findings, our results indicate that if such oil migration pathways are present, significant oil mobilization can occur in cold ice during the growth season. Thus, we tracked upward oil migration through large brine channels in cold ice (Tice< −5 °C) over vertical distances of up to 30 cm, leading to surfacing of oil, within 24 h after release. During ice melt and deterioration, oil movement is tied to the magnitude of the bulk brine volume fraction and the magnitude of the oil lens reservoir. Development of a predictive oil migration model based on these findings will aid spill response planning, oil detection and damage assessments.