A number of oil and gas reservoirs have been discovered in the periphery of the Shawan sag and the well Pen- 1 West sag in the Junggar basin. Among these, the Jurassic Sangonghe Formation reservoir in the well Pen- 5 block, located west of the Mosowan uplift, is a typical oil and gas accumulation characterized by the coexistence of normal black oil, light oil, condensate oil, and natural gas, with a complex spatial distribution. However, the genetic relationships between crude oil, condensate, and natural gas, as well as the origin of the condensate and the process of hydrocarbon charging and accumulation, are not clear. In this paper, based on the analysis of the geochemical characteristics of crude oil, condensate oil, and natural gas in the reservoir, combined with the results of reservoir geology and oil tests, the origin of condensate oil and gas, the process of reservoir filling and accumulation, and the geological and geochemical control factors are discussed. The results show that the normal black oil and condensate oil in the Jurassic Sangonghe Formation of the well Pen- 5 block exhibit highly similar carbon isotopic and biomarker compositions, suggesting they are mature crude oil generated from organic matter in the oil window and are derived from lacustrine source rocks in the Permian Fengcheng Formation and Lower Wuerhe Formation in the West sag of well Pen- 1. The condensate oil is mainly composed of low- carbon- number alkanes, enriched in cyclohexane and methylcyclohexane, but contains relatively low concentrations of low- carbon- number aromatic hydrocarbons such as benzene, toluene, and xylene. The n- alkane distribution in the condensate oil is a mirror image of the distribution of n- alkanes in high- density waxy crude oil, and the ratio of toluene/n- heptane to n- heptane/methylcyclohexane cannot effectively identify its origin. However, the n- alkanes distribution, along with the parameters of nC7/nC19, methylcyclohexane/nC19, and toluene/nC19 can effectively identify gas- washed fractionation condensate and gas- washed fractionation residual oil. The Jurassic Sangonghe Formation reservoirs in the well Pen- 5 block have experienced three stages of hydrocarbon charging and accumulation. In the early stage, crude oil generated from the source rocks of the Permian Fengcheng and Lower Wuerhe Formations in the West sag of well Pen- 1 was charged and formed successively. In the later stage, highly mature Permian oil and gas were charged again, which gradually displaced and gas- washed the crude oil in the early reservoir. The gas- cap condensate is not a product of organic matter in the high- maturity stage but is mainly caused by gas invasion/gas washing in the reservoir, with only a small amount of high- maturity condensate mixed in.