【作者】 SYLLA Lamine；

【导师】 熊德琪；

【作者基本信息】 大连海事大学 ， 环境科学， 2012， 博士

【摘要】 非洲西部的几内亚湾是非洲最大的海湾,其沿岸有10多个国家及临近地区。几内亚湾拥有丰富的海上石油资源,目前已探明的石油储量超过800亿桶,约占世界总储量的10%,已经逐渐成为世界最重要的产油区之一,主要出口到欧洲,北美洲等西方国家,以及中国、日本、印度等亚洲国家。几内亚首都Conakry港水域是非洲石油运往北美和欧洲的必经之路,因此存在较大的船舶溢油事故风险。虽然近年来非洲的原油生产和石油工业迅速发展,但在溢油污染应急和风险防范方面还非常落后,为此本论文从几内亚近岸海域的水文气象条件与地理环境出发,开展海上溢油行为模拟模型以及溢油污染风险评估研究,对于提高几内亚国家的海上溢油应急指挥决策能力,完善溢油应急预案与应急力量规划,尽可能地降低溢油事故污染可能造成的生态损害和经济损失,具有重要的理论意义和应用价值。论文的主要研究内容及成果概述如下：1、较系统全面地总结综述国际上有关溢油模型和溢油模拟系统的研究现状和发展趋势；对近年来在全球、特别是非洲水域发生的主要溢油污染事故进行了统计,并分析了随着非洲特别是几内亚湾石油产量和运输量的增长,几内亚湾近海海域存在发生重大平台和船舶溢油事故的风险；而目前西非各国尚未建立溢油应急反应体系,应急能力十分薄弱；2、针对几内亚近岸海域的地理环境特征,开展该水域海上溢油行为模拟模型研究,包括：根据几内亚近岸海区的河口湿地特征,建立了潮流计算模型；根据非洲原油的理化性质特点,建立了能够模拟海上溢油的蒸发、乳化、溶解、分散等行为归宿,以及密度和粘度等性质变化规律的海上溢油风化模型；基于“油粒子”理论和随机走动算法,建立能够模拟溢油在海洋环境中的漂移轨迹和扩散动态的海上三维溢油漂移扩散模型；采用“粒子一浓度”转换技术,提出能够模拟溶解分散的石油烃在水下的扩散动态和浓度分布的计算方法。并应用开发的系统对发生在几内亚水域中的不同溢油案件进行模拟和验证。3、根据溢油事故的发生时间具有不确定性的特点,提出随机模拟统计法进行溢油污染风险影响评价。对几内亚首都科纳克里港附近海域的每个溢油事故进行近3年共300个不同情景的漂移扩散轨迹模拟计算,每次事故情景发生时间是不确定的,随机选取过去3年中的任一时刻。而相应的风场数据取自近3年的逐时风向、风速历史监测数据,流场数据取自上述海洋动力模拟结果。每一次事故模拟均计算并记录各个计算网格的油膜漂移经过时间、油膜厚度等数据,最后进行统计,得到溢油对环境敏感目标的污染概率、溢油污染岸线的概率、最快影响时间和油膜厚度分布等信息。与采用假定气象数据的典型情景模拟法相比,评价结果更加合理可靠,同时可以更全面地评价溢油事故可能对周围环境敏感资源产生的危害风险；4、应用随机模拟统计法分别分析了几内亚首都Conakry港水域船舶在锚地和航道发生溢油事故后对周围岛屿和重要敏感生态资源保护区的污染危害风险。得到由于主导风向为西北风和西南风,在航道发生船舶溢油事故后,溢油对位于航道南侧的Loos岛和东南方向的Conakry西岸的污染风险相对最大,污染概率分别为20%和16%、溢油最快到达时间分别为6h和8h,有必要加强应急防范；5、分析了几内亚现有的溢油应急体系和应急能力现状,以及存在的问题；在此基础上,结合上述Conakry港水域溢油污染风险评价结果,有针对性地提出了能够有效降低几内亚水域溢油事故风险的应急防范对策和管理措施建议。更多还原

【Abstract】 As the largest bay in Africa, the Gulf of Guinea is in West Africa, where oil resource is rich in the coastal, with more than ten countries and neighboring regions. It has become the one of the most important oil-producing areas in the world, the ascertained oil reserves are more than80billion barrels, accounting for about10%of the world’s reserves. They mainly exported to Europe, North America and other western countries, as well as China, Japan, India, and other Asian countries. The water near Conakry, the capital of Guinea is the only way that the oil in Africa to North America and Europe is been shipped and there is a major risk of ships oil spill.This research uses numerical model that allows for qualitative and quantitative assessment of damage on marine environmental resources caused by spilled oil and appropriate responses. The research method is based on an important exploitation of library resources about oil spill and Guinean marine environment, also an analysis state-of-art of research and application of marine environment risks damage assessment techniques and methods; dissertation framework assessment environment resources damages resulting from marine oil spill by using numerical modeling, that focus on development and application of numerical assessment model from system and software. It has important theoretical significance and application value for developing the decision power of emergency command in Guinea and reducing ecological damage and economic loss as far as possible.The main research content and results in this paper are summarized as follows:1. The international research status and development trend of oil spill model and simulation system are comprehensive summarized. The recent statistics of mainly oil spill accidents in the world and African waters are analyzed that with the growth of oil production and traffic volume in African especially the Gulf of Guinea, the risk of significant platform and ship oil spill accident in the offshore area of Gulf of Guinea is existing while the Western African countries have not yet established oil spill emergency response system and the emergency power is very weak.2. The maritime simulation system of oil spill behavior is researched aiming at the hydrological and environmental characteristics of the waters in Conakry, Guinea, including Hydrodynamic Model on the basis of the characteristic of estuary wetland in coastal sea areas of Guinea; oil weathering model used for simulating the fate of oil spill such as evaporation, emulsion, dissolution, scatter and the qualitative change of density and viscosity according to the physical and chemical characteristics of crude oil in Africa. Oil drifting trajectory model is used for simulating the trajectory and diffusion dynamic of oil spillage in the marine environment based on the theory of oil particles and Random Walk Procedures. The dynamic of diffusion and distribution of concentration of soluble dispersive petroleum hydrocarbons underwater is calculated through the switching technique of "particle-concentration". The development systems are applying to simulate and verify the different oil spill cases occurred in Conakry, Guinea waters.3. Stochastic simulation statistic method is proposed to make the impact assessment for pollution risk of oil spill based on the feature of uncertainty of the occurrence time of oil spillage. The300different accident scenarios of oil spill accidents in the waters of Conakry, Guinea in recent3years is calculated by drifting trajectory simulation, each time is uncertain, randomly selected in any time from the past3years. The corresponding wind data is taking from nearly3years of hourly wind direction, historical monitoring data of wind speed, field data is obtained from the results of ocean dynamic simulation. Every accident simulation is calculated and recorded the data of drift last time and thickness of oil film in every gridding, the information of pollution probability that oil spill working on environment sensitive target and shoreline as well as the fastest effect time and oil film thickness distribution will got in the final statistics. Comparing with typical scenarios simulation method using assumed meteorological data, evaluation results are more reasonable and reliable that hazards risk that oil spill might cause on the sensitive resources around the environment can be evaluated more comprehensive.4. The stochastic simulation statistic method is used to analyse the hazards risk that oil spill in anchorage ground and channel might cause on the sensitive resources around the environment. We get that due to the direction of dominant wind is northwest and southwest, after the occurrence of ship oil spill accident in the channel, the pollution risk seems maximum relatively for the Island of Loos on the southeast of the channel and Conakry west bank on the southeast, the probability of pollution is20%and16%and fastest reach time is6h and8h respectively. It is necessary to strengthen the emergency prevention.5. On the basis of the analysis of existing emergency system of oil spill and current situation of emergency ability and existing problems, combining the above-mentioned evaluation result of the pollution risk of oil spill in Conakry waters, emergency precaution strategies and management measures to reduce the risk of the oil spill accident in Guinea are put forward pertinently.Oil spill models have been used and simulated to assess a possible environmental impact then developed an information system for a possible effective response on Conakry, Guinea waters in case the country is confronted by an oil spill situation. This research can be in good agreement with the investigating results that have been achieved and can help Guinean government, international organizations and shipping industry authorities to set up urgent, rigorous and coherent policies to protect marine environment and to manage oil exploitation and transport against an oil spill situation.更多还原