准噶尔盆地玛湖斜坡区侏罗系八道湾组一段（J₁ b ₁）为紧邻侏罗系/三叠系（J/T）不整合面之上的一套砂（砾）岩沉积，在油气来源、不整合面控藏效应等方面存在较大争议，严重制约油田现场勘探决策。为此，基于含烃包裹体、埋藏史—热史—孔隙演化史、源—储剩余压力差等资料，综合分析八道湾组一段（J₁ b ₁）油气充注史，探讨J/T不整合面之上大气淡水压实—离心流氧化降解效应及对油气垂向差异性富集的控制作用。结果表明：①玛湖斜坡区侏罗系八道湾组一段（J₁ b ₁）经历了3期油气充注。侏罗纪（J）末期构造抬升期对应第Ⅰ期油气充注，以下伏二叠系风城组（P₁ f）烃源岩排出的原生油气充注为主，油气充注的有效动力强，主要充注于J₁ b ₁中上部薄层砂岩内。白垩纪（K）末构造抬升期、古近纪+新近纪（E+N）初缓慢埋藏期分别对应第Ⅱ期、第Ⅲ期油气充注。以下伏三叠系百口泉组（T₁ b）油藏油气向J₁ b ₁调整充注为主。油气充注的有效动力减弱，主要就近运聚至J₁ b ₁底部厚层砂砾岩内。②J/T不整合面之上大气淡水压实—离心流氧化降解作用导致靠近J/T不整合面的八道湾组一段（J₁ b ₁）底部厚层砂砾岩内油气性质稠化。八道湾组一段（J₁ b ₁）上部薄层砂岩受高油气充注有效动力、油气运移路径上烃类组分产生的地质色层效应影响，轻烃组分含量及含油饱和度总体较高。结论认为，八道湾组一段（J₁ b ₁）轻质油气富集区优选应遵循原则：①垂向层位优选上部薄层砂岩；②平面范围界定应综合考虑母岩、沉积相带、通源断裂、鼻凸四大因素。基于此，优选油气富集区786 km²/4块。

The first member of the Badaowan Formation （J₁ b ₁） in the Mahu slope area of Junggar Basin is a set of sand （gravel） rock deposits adjacent to the J/T unconformity. There are great controversies in hydrocarbon source， reservoir controlling effect of unconformity surface and reservoir densification mechanism of coal-bearing rock series， which seriously restricts the field exploration decision. Therefore， based on the analysis of the homogenization temperature， salinity and laser Raman spectra of hydrocarbon-bearing saline inclusions， combined with the data of burial history， thermal history， pore evolution history， and source-reservoir residual pressure difference， the hydrocarbon charging history of J₁ b ₁ was comprehensively analyzed. The effects of atmospheric fresh water compacting-centrifugal flow oxidation degradation on J/T unconformity and the inhibition effect of coal measure humic acid on the quality of coal bearing rock conglomerate reservoir on the control of vertical differential accumulation of oil and gas are discussed. The results show that： （1） J₁ b ₁ of Jurassic Badaowan Formation experienced three stages of oil and gas charging in Mahu slope area. The tectonic uplift period at the end of Jurassic （J） corresponds to the oil and gas charging stage I. The primary oil and gas charging in the Lower Permian Fengcheng Formation （P₁ f） is the main one， and the effective power of oil and gas charging is strong， and the oil and gas charging is mainly charged in the middle and upper thin sandstone of J₁ b ₁. The Late Cretaceous （K） tectonic uplift period and the Early Tertiary （E+N） slow burial period correspond to the second stage and the third stage of oil and gas charging respectively. Oil and gas in Baikouquan Formation （T₁ b） of the Lower Triassic is mainly charged to J₁ b. The effective dynamic of oil and gas charging is weakened， and it mainly accumulates in the thick sand conglomerate at the bottom of J₁ b ₁. （2） The compaction of atmospheric freshwater above the J/T unconformity and the oxidative degradation of centrifugal flow result in the thickness of oil and gas properties in the bottom thick sand conglomerate of Badaowan Formation （J₁ b ₁） near the J/T unconformity. The thin sandstone field in the upper part of Badaowan Formation （J₁ b ₁） is affected by the high effective power of oil and gas charging and the geological layer effect of hydrocarbon components along the oil and gas migration path， and the content of light hydrocarbon components and oil saturation are generally high. It is concluded that the selection of oil-gas rich area of Badaowan Formation （J₁ b ₁） coal-bearing rocks should follow the following principles： （1） The vertical upper layer should be dominated by the upper thin sandstone （strong effective oil and gas charging power， light oil weight and high oil saturation）， and the thick sand conglomerate far from the J/T unconformity plane （≥ 60 m）； （2） The range of plane oil-gas rich area is defined by considering four factors： parent rock of medium acid volcanic rock， outer front facies zone of braided river delta， fault development zone and nose convex structure development zone. With the combination of the above factors， the optimal oil and gas rich area is 786 km²/ 4 blocks.