烷基二苯并噻吩类化合物的运移示踪：基于驱替实验和分子模拟的研究

原油中烷基二苯并噻吩类化合物沿运移路径的分布，除了受地质色层分馏效应的影响，还受到有机质来源、成熟度、沉积环境等多种因素的影响。为了研究地质色层分馏效应单一因素下烷基二苯并噻吩类的运移示踪规律，在驱替模拟实验的基础上，用气相色谱-质谱方法剖析了驱替路径上该类化合物的分布特征和运移分馏规律，并从分子模拟角度进行了佐证。结果表明：随着运移距离的增加，吸附油中二苯并噻吩（DBT）、甲基二苯并噻吩（MDBT）和二甲基二苯并噻吩（DMDBT）的绝对浓度均呈现递减趋势；参数4-/1-MDBT、4,6-/（1,4+1,6）-DMDBT和4,6-/2,4-DMDBT显著减小，而参数2,4-/（1,4+1,6）-DMDBT和（2,6+3,6）/（1,4+1,6）-DMDBT则呈现出显著的上升趋势。根据分子模拟结果，发现烷基二苯并噻吩类与水介质之间吸附作用的强弱同时与化合物的Connolly分子表面积及偶极矩紧密相关，表面积和偶极矩越大，分子越容易与地层介质中的水分子发生吸附作用，且分子偶极矩的差异影响更显著。

Tracer analysis of alkyl dibenzothiophenes migration based on displacement experiment and molecular simulation

The distribution of alkyl dibenzothiophenes in crude oil along the migration pathway are under the effect of various factors such as geochromatographic effect， source， maturity， and depositional setting of the organic matter. To investigate the migration traces of alkyl dibenzothiophenes merely under the geochromatographic effect， we discuss the distribution characteristics and migration fractionation patterns of these compounds along the displacement pathway by gas chromatography-mass spectrometry （GC-MS）， following the simulation experiments on displacement. Furthermore， the migration fractionation mechanism is verified by molecular simulation. The results indicate that with migration， the absolute concentration of dibenzothiophene （DBT）， methyl dibenzothiophene （MDBT） and dimethyl dibenzothiophene （DMDBT） in the adsorbed oil shows a decreasing trend， parameters 4-/1-MDBT， 4，6-/（1，4+1，6）-DMDBT and 4，6-/2，4-DMDBT tend to significantly decline， parameters 2，4-/（1，4+1，6）-DMDBT and （2，6+3，6）/（1，4+1，6）-DMDBT present a significantly rise trend on the other hand. The molecular simulation results show that the adsorption capacity of alkyl dibenzothiophenes in crude oil and aqueous medium is closely related to the surface area of Connolly molecule， a compound， and dipole moment. In general， the larger the surface area and dipole moment， the stronger its adsorption capacity， and the molecular dipole moment is dominant among these two influential factors.