Abstract: The Wuerhe area in Junggar basin has abundant resources of oil sand, mainly originated from source rocks of Permian in Manas lake sag. The oil and gas from it migrate/accumulate upward along the developed fractures and the uncomfortable surfaces, and form the reservoirs. Because of the water-washing, oxidation and biodegradation near the surface, the light components of the crude oil consumed continually, finally forming the oil sand deposits. The distribution of oil sand in this area is closely related with fractures/faults and unconformities, hence the oil sand body's distribution occurs along the fractures and the unconformities.

Key words: Wuerhe, oil sand, fracture, fault, unconformity, crude densification