Abstract: Located in the southern part of Pre-Caspian Basin, Bikzhal Northwest Block oilfield is a recently-found Jurassic oil field in Adaiski region. The property of crude oil is good and the density 0.83g/cm3. The oilfield sees a high production and a stable reservoir pressure. The daily production has bee kept stable at 100 tons for three years. The reservoir rock is quartz sandstone of delta facies with desirable physical properties. The average porosity is 35.25% while the average permeability is 913.83mD. Mudstone with a thickness of 60 meters developed above Jurassic system and was matched with screen of inverted fault, forming an excellent top-sealing and laterally-blocked fault trap. The main factors controlling Jurassic accumulations in Bikzhal Northwest Block include suitable buried depth, reasonable reservoir-cap assemblage good lithological boundary rock on the upper disc of inverted fault, excellent hydrocarbon sources and salt window conditions.