南海原油胶质、沥青质结构表征及原油降黏研究

南海原油储量丰富，其开发利用具有重要的经济价值和战略意义。从南海原油中分离出胶质和正庚烷沥青质并对其进行表征，合成了含氮长链聚合物型降黏剂，同时考察了合成降黏剂对南海原油的降黏效果。结果表明：南海原油属高胶质、高沥青质原油，胶质和沥青质容易形成缔合结构是其黏度较高的主要原因；胶质和沥青质分子具有由烷基链连接起来的含有侧链的芳香片结构，且含有形成氢键的极性基团，胶质和沥青质的平均相对分子质量分别为760和1 129；构建的南海原油胶质和沥青质平均分子结构式参数与表征结果吻合；添加1 000 μg/g降黏剂的南海原油在15 ℃和40 ℃下的降黏率分别为44.2%和40.2%，屈服应力值从1 070 Pa降至563 Pa，降黏效果显著。

STRUCTURE CHARACTERIZATION OF RESIN AND ASPHALTENE AND VISCOSITY REDUCTION OF SOUTH CHINA SEA CRUDE OIL

The South China Sea crude oil has rich reserves; its exploitation has important economic value and strategic significance. Resin and n-heptane asphaltene were separated from the crude oil and their structures were determined. In addition, a nitrogen-containing long-chain polymeric viscosity reducer was synthesized and its effect on viscosity of South China Sea crude oil was studied. The results indicate that South China Sea crude oil has high contents of resin and asphaltene. The high viscosity of South China Sea crude oil is mainly attributed to its associative structure of resin and asphaltene. Moreover, resin and asphaltene molecules contain aromatic sheet with side chain, connecting with alkyl chain and the polar groups which can form hydrogen bonds. Furthermore, the average molecular weights of resin and asphaltene are 760 and 1 129, respectively. The comparison results show that the parameters of average molecular structures of resin and asphaltene are consistent with the characterization values. With an addition of 1 000 of viscosity reducer, the viscosity of South China Sea crude oil at 15 ℃ and 40 ℃ decrease 44.2% and 40.2%, respectively. And the yield stress is reduced from 1 070 Pa to 563 Pa, indicating the remarkable viscosity reduction effect.