准噶尔盆地二叠系咸化湖相页岩油气富集条件与勘探方向

准噶尔盆地中—下二叠统发育咸化湖相混积型页岩油藏，以吉木萨尔凹陷芦草沟组和玛湖凹陷风城组为典型代表，目前已进入全面勘探开发阶段，是中国陆相页岩油的重要类型和增储上产的重要领域。通过综述准噶尔盆地二叠系页岩油勘探开发实践的进展，系统梳理了准噶尔盆地二叠系页岩油的形成条件与富集模式，结合在玛湖凹陷风城组勘探中取得的常规油—致密油—页岩油有序成藏的全油气系统理论认识，探讨了准噶尔盆地中—下二叠统页岩油的资源前景与勘探方向。研究结果表明：准噶尔盆地二叠纪的咸化水体环境一方面促进了中—高成熟度规模优质烃源岩的发育，另一方面也控制了陆源碎屑、内源碳酸盐以及火山凝灰质颗粒的混积，形成一套广覆式分布于凹陷区的白云质粉砂—细砂岩、白云质泥页岩、泥质白云岩等细粒混积岩，同时，受高频水体动荡影响形成了3类高效的“源-储”组合；页岩油具有“生烃增压、微缝输导、源生邻储”的形成机制，表现为“二油共存、岩相控甜、甜点控富”的富集模式。玛湖凹陷、沙湾凹陷、盆1井西凹陷和阜康凹陷中—下二叠统烃源岩层系是下一步寻找页岩油气的有利勘探领域，具有常规—非常规油气协同探索的巨大勘探前景。

Enrichment conditions and exploration direction of Permian saline lacustrine shale oil and gas in Junggar Basin

The saline lacustrine mixed shale reservoirs are developed in the Middle-Lower Permian formations of Junggar Basin, which are typically represented by Lucaogou Formation in Jimusar sag and Fengcheng Formation in Mahu sag. At present, they have entered the stage of comprehensive exploration and development, and become an important type of continental shale oil and field for increasing reserves and production in China. By reviewing the progress of exploration and development of Permian shale oil in Junggar Basin, this paper systematically summarizes the formation conditions and enrichment model of Permian shale oil. Further, based on the theoretical understanding of the whole petroleum system for the orderly accumulation from conventional oil to tight oil to shale oil in Fengcheng Formation of Mahu sag, the resource potential and exploration direction of the Middle-Lower Permian shale oil in Junggar Basin are explored herein. The results show that the Permian saline water environment in Junggar Basin not only promotes the development of large-scale high-quality source rocks with medium-high maturity, but also controls the mixed sedimentation of terrigenous clasts, endogenous carbonates and volcanic tuffaceous particles, forming a set of fine-grained mixed rocks such as dolomitic siltstone or fine sandstone, dolomitic mud shale, and argillaceous dolomite widely distributed in the sag. Meanwhile, three types of efficient source-reservoir assemblage have formed under the influence of high-frequency water turbulence. The shale oil has the mechanism of pressurization during hydrocarbon generation, transport by micro fractures, hydrocarbon generation in source rock and accumulation in adjacent reservoir, showing the enrichment model of oil coexistence in two occurrence states, sweet spots controlled by lithofacies, and oil enrichment controlled by sweet spots. The Middle-Lower Permian source rock strata in Mahu sag, Shawan sag, Well Pen-1 West sag and Fukang sag are favorable exploration areas for the further exploration of shale oil and gas, and have great exploration potential for the collaborative exploration of conventional-unconventional oil and gas.