Mineralization factors of Baijiantan oil sand in northwest Junggar Basin

This paper analyzes the mineralization factors of Baijiantan oil sand area such as oil sand distribution,oil sources,reservoir sand,and migration pathway.The oil sands in this area mainly distribute in Cretaceous Tugulu formation and Jurassic Qigu formation.The distribution is extensive and the oil-bearing rate is medium.The oil-bearing series mainly exist in mid-Permian Fengcheng formation in Mahu depression.Qigu and Tugulu formations are mainly fluvial-delta deposition where favorable sand bodies had formed and served as reservoir space for hydrocarbon accumulation.Fractures and surface of unconformity were migration pathways and dominated oil and gas migration.On the above basis,three mineralization models are established for this area,including drape type,bitumen seal type and updip pinch-out type,which may guide future oil sand exploration in this area.