DETECTION OF ALKYLATED FLUORENONES AND THEIR ORIGIN IN OIL SANDS OF TRIASSIC, THE ORDOS BASIN

Six oil sand samples were collected from the sandstone reservoirs of Yanchang Formation in the northwestern areas of the Ordos Basin,Northwest China.Oil sand extracts were analyzed by GC-MS.A series of alkylated fluorenones have been detected.They are products of oxidation-reduction reaction of fluorene and benzo-fluorene in reservoir.This process can be considered as the result of that during the time of subaerial exposure in the later diagenetic stage A,the fluorene and benzo-fluorene in oil sand are oxidized to fouow the permeating of meteoric water with bacteria and oxygen under the alkali-diagenetic enviornment and participation of the sialicate in Yanchang Formation.