FORMATION OF THE SUBTLE RESERVOIRS AND THEIR EXPLORATION IN THE CENTRAL JUNGGAR BASIN

The deep sag was located in the depression of the Junggar foreland basin.The early hydrocarbon accumulation in reservoirs,the development of fluvial-delta sand body and the distribution of unconformity and sequence overlaps were controlled by the Chepaizi-Mosuowan paleo-uplift formed in the Jurassic.The subtle reservoirs consisted of stratigraphic,lithologic,faults or their combination were developed in the area.Due to late strong tilting,trap types and their validity around the paleo-uplift were changed.The reservoirs underwent late modification and late hydrocarbon recharge and various kinds of reservoirs were formed.Hydrocarbon formation and distribution in the deep sag was controlled by the paleo-uplift.