Seawater capacitance – a promising proxy for mapping and characterizing drifting hydrocarbon plumes in the deep ocean

[摘要] Hydrocarbons released into the deep ocean are aninevitable consequence of natural seep, seafloor drilling, and leakingwellhead-to-collection-point pipelines. The Macondo 252 (Deepwater Horizon)well blowout of 2010 was even larger than the Ixtoc event in the Gulf ofCampeche in 1979. History suggests it will not be the last accidentalrelease, as deepwater drilling expands to meet an ever-growing demand. Forthose who must respond to this kind of disaster, the first line of actionshould be to know what is going on. This includes knowing where an oil plumeis at any given time, where and how fast it is moving, and how it isevolving or degrading. We have experimented in the laboratory with inducedpolarization as a method to track hydrocarbons in the seawater column andfind that finely dispersed oil in seawater gives rise to a large distributedcapacitance. From previous sea trials, we infer this could potentially beused to both map and characterize oil plumes, down to a ratio of less than0.001 oil-to-seawater, drifting and evolving in the deep ocean. A sidebenefit demonstrated in some earlier sea trials is that this same approachin modified form can also map certain heavy placer minerals, as well ascommunication cables, pipelines, and wrecks buried beneath the seafloor.

[学科分类] 海洋学与技术