INVESTIGATION OF OIL SECONDARY MIGRATION IN CAINAN OILFIELD USING PYRROLIC NITROGEN COMPOUNDS-A CASE STUDY OF THE JURASSIC XISHANYAO RESERVOIRS IN THE EASTERN DISTRICT OF CAINAN OILFIELD

In recent years,pyrrolic nitrogen compounds were successfully utilized for the research of oil migration ways in the world.Oil samples from reservoir Xishanyao Group in the eastern district of Cainan oilfield are the same oil family,in which pyrrolic compounds are dominated by alkyl-carbazole and C₂-,C₃-carbazoles constitute the main parts of alkyl-carbazole.The analyses of parameters for the migration fractionation effects of pyrrolic compounds indicated that there were two oil recharge directions including the north and the west,and the reservoir-inner faults may facilitate oil migration processes.The Jurassic coal-bearing strata in the North Dongdaohaizi Depression which lies to the west of the Baijiahai Uplift are pro-bably the main hydrocarbon source kitchen.Furthermore,an other source kitchen in the Fukang Depression and its north slope which lie to the south of the Baijiahai Uplift is also undeniable.