SIMULATION EXPERIMENT OF THE GEOCHROMATOGRAPHIC EFFECT OF AROMATIC HYDROCARBONS DURING HYDROCARBON EXPULSION

A simulation experiment has been conducted at a low temperature(150℃) and pressurized condition in order to study the geochromatographic effect of the aromatic compounds in the course of the hydrocarbon expulsion from the black mudstone strata and the calcilutyte strata.The samples used in the experiment are source rock samples with or without oil mixed,which were collected respectively from the mudstone strata at 3 160 m in the lower part of the 3rd Member of Shahejie Formation,Well Tuo-73 and the calcilutyte strata at 2 432 m in the upper part of the 4th Member of Shahejie Formation,Well Liangxie-61 in the Dongying Sag,the Bohai Bay Basin.The organic carbon content of the two samples are 3.08% and 4.0%,and the vitrinite reflectance(_Ro) are 0.42% and 0.45% respectively.The results show that the geochromatographic effect is directly related to the molecular weight,since the high-weight molecular hydrocarbon is more difficult to migrate and the geochromatographic effect is thus more insignificant.The hydrocarbon expulsion causes the ion flow content of the light-weight hydrocarbon series,such as naphthalene,increase and the ion flow content of the high-weight hydrocarbon series,such as triaromtic sterane,decrease in the whole.While within the hydrocarbon series,the rearranged 1,3,6-TMN(trimethylnaphthalene) can migrate more easily than the 1,2,5-TMN,whereas the dethylphenanthrene migrates more difficultly than the mother phenenthrene;the relative contents of the compounds in dibenzofurans,dibenzothiophenes,and biphenyl series change greatly compared with the other series,and the related ratios of the compounds within the above hydrocarbon series are regarded as potential indicators of hydrocarbon migration.