短期风化对渤海原油正构烷烃组分的影响

Effects of short-term weathering on the N-alkanes fraction of crude oils in Bohai Sea

溢油风化信息是认识海洋溢油事故发生中溢油行为归宿的必要条件,而油品组分含量等数据是衡量油品风化状况的重要指标。本研究以渤海产轻质、中质和重质3种类型原油为对象,开展实验室原油风化模拟实验,以GC/MS为主要测试手段,探讨短期风化作用对不同类型渤海原油组成的影响。研究得到不同风化程度下各类型原油中正构烷烃组分含量,并以中质油为例对正构烷烃组分变化与蒸发损失间的关系进行了探讨。研究表明,风化作用对不同原油及油品组分含量影响程度存在差异。在24 h风化时间内,渤中28-1轻质原油风化最为严重,最大蒸发损失约为22%;常青号中质原油次之;绥中36-1重质原油受风化作用影响最小,蒸发损失不足1%。3种油品正构烷烃组分含量分别为70.28×10^-3、38.19×10^-3和0.42×10^-3,并随风化时间增加呈降低趋势,且不同C数正构烷烃组分含量降低程度不同。常青号原油中C13~C26正构烷烃组分含量变化与蒸发率呈显著相关关系,可以作为溢油风化程度的评价指标。

The information on the weathering of spilled oil is necessary to the study of the behavior and fate of the spilled oil,in which the information of the oil fraction content is important especially. In this study,a lab scale experiment was conducted and the effects of short- term weathering on the several crude oils（ light,medium and heavy oil）were investigated using GC-MS. The concentrations of n- alkanes at various degrees of weathering were obtained,and the correlation between evaporation percentage and the concentration of n- alkanes was indicated. The effects of weathering on the crude oils and faction contents varied from oil to oil. The BZ28-1 crude oil was seriously weathered with the evaporation percentage of approximately 22% in 24 hours. The next is the CQH crude oil,and the SZ36-1crude oil is weathered least with the evaporation percentage less than1%. The concentrations of n- alkanes fraction in the crude oils were approximately 70. 28 × 10^- 3,38. 19 × 10-3and 0. 42 × 10^- 3,respectively. The abundance of n-alkanes gradually decreased with the weathering time extended,and the degrees of concentration reduction were different among different carbon numbers. The concentration changes of the C13~ C26 in CQH crude oil and the evaporation percentages were confirmed as the linear correlation,which could be considered as the indicated index of weathering degrees.