Oil & Gas Geology ›› 2023, Vol. 44 ›› Issue (2): 510-520.doi: 10.11743/ogg20230220

• Methods and Technologies • Previous Articles    

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

Gang YAN1,2(), Yaohui XU2(), Baolei LIU3, Yanze SUN4, Shanshan LI2, Shouyu ZHAO2, Ming ZHONG5   

  1. 1.Hubei Cooperative Innovation Center of Unconventional Oil and Gas,Yangtze University,Wuhan,Hubei 430100,China
    2.Hubei Key Laboratory of Petroleum Geochemistry and Environment,Yangtze University,Wuhan,Hubei 430100,China
    3.Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering,Yangtze University,Wuhan,Hubei 430100,China
    4.Exploration and Development Research Institute of PetroChina Changing Oilfield Company,Xi’an,Shaanxi 710018,China
    5.School of Energy and Resources,China University of Geosciences (Beijing),Beijing 100089,China
  • Received:2022-11-06 Revised:2023-01-05 Online:2023-04-01 Published:2023-03-17
  • Contact: Yaohui XU E-mail:202073036@yangtzeu.edu.cn;yaohuixu@126.com

Abstract:

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.

Key words: alkyl dibenzothiophene, Connolly molecule, geochromatographic effect, displacement experiment, molecular simulation, hydrocarbon migration

CLC Number: