Oil and gas accumulations in the sandy conglomerate diagenetic traps that developed in the fan delta of the Triassic Baikouquan Formation of the Mahu sag, Junggar Basin, differ from stratigraphic accumulations controlled by sedimentary facies. This study uses conventional gas chromatography–mass spectrometry measurements, mineralogical and petrological data, fluid inclusion analyses, and geophysical inversion to confirm the trap type and accumulation processes. The results indicate that accumulations in the sandy conglomerate formed in distributary channels of the fan-delta front, with the boundary controlled by reservoir quality. In turn, reservoir quality was controlled by differential diagenesis caused by detrital-feldspar content, paleotemperature, and formation fluids, suggesting that the trap is a diagenetic trap. The diagenetic trap formed from secondary pores developed in the fan-delta front facies with seals forming through a combination of altered sandy beds and mudstone. The critical physical property of the reservoir, based on the ratio of its average capillary radius to the ratio of its seal, is a crucial parameter for describing diagenetic trap boundaries. Here, it effectively distinguishes between reservoirs at different burial depths. A good correlation exists between the formation of the diagenetic traps and hydrocarbon filling. Three hydrocarbon charging and two accumulation stages are identified. The diagenetic traps primarily formed in the Jurassic, and the last charging stage of highly mature oil charge occurred in the Early Cretaceous. Few studies have investigated the conglomerate diagenetic trap studied herein, so this study should improve the understanding of oil and gas traps.

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准gar尔盆地成岩圈闭的成因及带电历史

准gar尔盆地麻湖凹陷三叠系百口泉组扇三角洲发育的砂砾岩成岩圈闭中的油气成藏与沉积相控制的地层成藏不同。这项研究使用常规的气相色谱-质谱法测量，矿物学和岩石学数据，流体包裹体分析以及地球物理反演来确定圈闭的类型和聚集过程。结果表明，在扇三角洲前缘分布河道中形成的砂砾岩中堆积物，其边界受储层质量控制。反过来，储层质量受碎屑长石含量，古温度和地层流体引起的差异成岩作用的控制，表明该圈闭是成岩圈闭。成岩圈闭是由扇三角洲前相中发育的次生孔隙形成的，并通过改变的砂岩层和泥岩的组合形成了封闭。基于储层平均毛细半径与密封比例的比率，储层的关键物理性质是描述成岩圈闭边界的关键参数。在这里，它可以有效地区分不同埋藏深度的储层。成岩圈闭的形成与油气充填之间存在良好的相关性。确定了三个碳氢化合物充注和两个聚集阶段。成岩圈闭主要形成于侏罗纪，高度成熟的装油的最后装料阶段发生在白垩纪早期。很少有研究调查本文研究的砾岩成岩圈闭，