Abstract:

Previous studies indicate that the homogenization temperature of many fluid inclusions from the Lower Jurassic J1s and J1b sandstone samples in the hinterland of Junggar Basin are much higher than the maximum temperature that the formation experienced.  In this paper，it is confirmed that three-phases inclusions trapped from oil-water heterogeneous environment are predominant in the abnormal inclusions.  Gas，liquid oil and liquid water can be observed in these inclusions by microscope.  Oil releases yellow fluorescence while gas and water do not under the UV-light.  These inclusions，rich in J₁s and J₁b of many wells，are mainly discovered in the healed cracks，corroded hollows and secondary outgrowth cementation of rock particles. And they usually associated with gaseous hydrocarbon inclusions，salt water inclusions with gaseous hydrocarbon，salt water inclusions and liquid inclusions.  Their homogeneous temperatures range from 130 to 200℃without obvious law.  The abnormal fluid inclusions were trapped in the moved oil-water transitional zone during the secondary migration and adjustment of oil and gas in Eocene-Miocene.  The trapped time of these inclusions were revealed to be about 38-17 Ma based on the homogenization temperatures of salt water inclusions and the burial and thermal histories of the samples.  In addition，the trapped time become older with increase of depth and represent the time the paleo-oil-water contact reached same depth.

Key words: the hinterland of Junggar basin, inhomogeneous fluid inclusion, fluid inclusion fluorescence, homogenization temperature, oil-water transitional zone