Author(s)

Chunmiao Ma, Lu Yang

Corresponding Author

Lu Yang

Abstract

According to the geochromatographic effect, we can infer the general trend of oil migration based on the change of hydrocarbon composition in oil. In the oil migration carrier bed, oil is the mobile liquid mobile phase medium; the adsorbed water and bound water are stationary liquid fixed phase medium. The compounds in petroleum have a liquid-liquid geochromatographic fractional effect with adsorbed water and bound water. Due to the difference of adsorption function between the isomers of methyldibenzothiophene (MDBT) and methyldibenzofuran (MDBF), its relative content will change regularly with the migration of oil. In this paper, the Conolly molecular surface algorithm and DMol3 are used to calculate the molecular surface area and volume of target molecules. The water molecule with a radius of 1.5Å is used as a probe to make it roll on the surface of target molecules 1-MDBT, 4-MDBT and 1-MDBF, 4-MDBF respectively. The calculation results show that the surface area of 1-MDBT is 200.21Å2 and the volume is 184.28Å3; the surface area of 4-MDBT is 204.32Å2 and the volume is 186.34Å3; the dipole moment of 4-MDBT is larger. The surface area of 1-MDBF is 193.60Å2 and the volume is 175.06Å3; the surface area of 4-MDBF is 196.88Å2 and the volume is 174.77Å3, the dipole moment of 1-MDBF is much larger than that of 4-MDBF. Comparatively speaking, 4-MDBT and 1-MDBF have stronger adsorption. Therefore, when oil moves in the carrier bed, with the increase of migration distance, the parameters 4-/1-MDBT and 1-/4-MDBF decrease gradually

Keywords

Connolly surface, Methyldibenzothiophene, Methyldibenzofuran, Reservoir geochemistry, Geochromatographic effect