Factors of Hydrocarbon Accumulation of Jurassic-Cretaceous in Block-3 of Central Junggar Basin

The hydrocarbon accumulation of Jurassic and Cretaceous in Block-3 of central Junggar basin is mainly controlled by source rock, sedimentary facies, palaeo-uplift, abnormal pressure, fault and unconformity. The multi-phase hydrocarbon generations of multi-source rocks offer rich material base. The development of premium reservoir rocks within the favorable sedimentary facies belt provides spaces for hydrocarbon accumulation. The abnormal high pressure and lithology could serve as sealing process, preventing from hydrocarbon diffusion. Paleo-uplift controls the formation and development of traps. Early formed faults link with source rocks and reservoir sands, and late formed fault-unconformity assemblage can serve as dimensional and reticulate pathway of fluid migration. All these factors allow the hydrocarbon accumulation to be formed here. Base on these characteristics, the accumulation stage is determined, and the accumulation model is established. The accumulation characteristics can be summarized as multi-stage hydrocarbon generation, mixed source charge, fault-unconformity conduction, and ultimate reservoir formation by rebuilding at late period.