Abstract: Following the formation of Eurasian Plate and the closure of Paleo-Asian Ocean, the Kazakhstan Plate (Orocline) was formed in the late Paleozoic. As influenced by the closure of the Junggar-Balkhash Ocean and the hot and arid paleoclimate, a series of residual oceanic and coastal continental margin saline lacustrine basins were formed during the Early to Middle Permian along the oceanic-continental closure zone in Junggar Basin located at the eastern margin of Kazakhstan Plate. The comprehensive analyses of lithology, sedimentary facies, geochemistry, seismic stratigraphy, and seismic lithology show the following. (1) The Lower-Middle Permian Fengcheng Formation, Lucaogou Formation, Hongyanchi Formation and Pingdiquan Formation in Junggar Basin are mainly composed of saline sediments (including residual oceanic and saline lacustrine sediments). Specifically, Fengcheng Formation is mainly distributed in Mahu sag, Penyijingxi sag, Shawan sag and Fukang sag along the closure zone of the western Junggar residual ocean and northern Tianshan residual ocean, Lucaogou Formation and Hongyanchi Formation are mainly distributed in Fukang sag and Bogda Mountain region along the northern Tianshan-Solunke residual ocean, and Pingdiquan Formation is mainly distributed in Wucaiwan sag, Shishugou sag and Shiqiantan sag along the Kalamaili residual ocean. (2) The saline sediments are distributed regularly, and gradually migrated from west to east and from bottom to top from Early to Middle Permian. (3) Fengcheng Formation, Lucaogou Formation and Pingdiquan Formation are the main source rocks of Permian in Junggar Basin, which contain bacteria-rich algal organic matter and are typically characterized by saline lacustrine sediments. (4) The formation and migration of the Early to Middle Permian residual oceans and saline lacustrine basins in Junggar Basin controlled the distribution of sedimentary facies and high-quality source rocks. Petroleum exploration practices reveal that the high-quality saline lacustrine source rocks in Mahu sag in the west and Jimusaer sag in the east of the basin control the formation of hydrocarbon accumulation areas with 1 billion to billions of tons reserves, indicating that there may be great oil-gas resource potential in the distribution centers of saline sedimentary source rocks in Penyijingxi Sag, Shawan sag, the southern margin area of the basin and Fukang sag. Although there is no deep drilling to confirm those at present, their exploration prospects are worth looking forward to.

Key words: Junggar Basin, Permian, saline lacustrine basin, bacteria and algae, Paleo-Asian Ocean

摘要： 晚古生代,伴随着欧亚板块的形成与古亚洲洋的关闭,哈萨克斯坦板块(山弯构造)得以形成。早—中二叠世,因受准噶尔—巴尔喀什洋关闭及炎热干旱古气候影响,位于哈萨克斯坦板块东缘的准噶尔盆地沿洋陆闭合带形成了一系列残余洋与近海陆缘咸化湖盆。岩性、沉积相、地球化学、地震地层和地震岩性综合分析表明:①准噶尔盆地中—下二叠统的风城组、芦草沟组、红雁池组和平地泉组以咸化沉积(包括残余洋和咸化湖沉积)为主,其中,风城组主要沿西准噶尔残余洋和北天山残余洋的闭合带分布于玛湖凹陷—盆1井西凹陷—沙湾凹陷—阜康凹陷一线,芦草沟组和红雁池组主要沿北天山—索伦克残余洋分布于阜康凹陷—博格达山一带,平地泉组主要沿卡拉麦里残余洋分布于五彩湾凹陷—石树沟凹陷—石钱滩凹陷一带;②咸化沉积的分布规律明显,在早二叠世—中二叠世逐渐呈自西向东、自下向上迁移;③风城组、芦草沟组和平地泉组是准噶尔盆地二叠系最主要的烃源岩,含富菌藻类有机质,具有典型的咸化湖沉积特征;④准噶尔盆地早—中二叠世残余洋和咸化湖盆的形成与迁移控制了沉积相与优质烃源岩的分布。勘探实践揭示,盆地西部玛湖凹陷和东部吉木萨尔凹陷优质咸化湖相烃源岩控制了十亿至数十亿吨级规模储量聚集区的形成,这预示着在盆1井西凹陷、沙湾凹陷、南缘—阜康凹陷一带等咸化沉积烃源岩分布中心可能有巨大的油气资源潜力,尽管目前尚无深井钻揭,但其勘探前景值得期待。

关键词: 准噶尔盆地, 二叠纪, 咸化湖盆, 菌藻, 古亚洲洋