准噶尔盆地南缘芦草沟组页岩的沉积过程及有机质富集机理

准噶尔盆地南缘二叠系芦草沟组页岩是重要的烃源岩和非常规油气资源储层，具有重大页岩油气勘探潜力.然而对准南芦草沟组页岩的沉积过程、古气候控制湖泊水文条件以及页岩中有机质的富集机理的研究相对较少.通过系统的野外地质调查和样品分析测试，主要利用沉积学定性分析和地球化学定量表征相结合的方法对芦草沟组页岩进行了综合研究.结果表明，研究区芦草沟组页岩主要沉积于盐度分层的半深湖-深湖环境；古气候在研究区湖盆流域具有独特的分带性，博格达东北部的古气候较温暖和潮湿，而博格达以西的古气候则相对干旱；博格达东北部较湿润的古气候引起该地区较充足的降雨，促进了湖水的盐度分层，同时降雨促进河流携带大量富营养元素的淡水注入湖泊引起了表层水体生产力升高，导致博格达东北部芦草沟组页岩相对于博格达西部地区具有更高的TOC含量；表层水体的古生产力与较稳定的贫氧-厌氧环境是研究区芦草沟组页岩有机质富集的主控因素. 

Depositional Process and Mechanism of Organic Matter Accumulation of Lucaogou Shale in Southern Junggar Basin,Northwest China

The lacustrine shale succession of the Permian Lucaogou Formation in southern Junggar basin, Northwest China, is the most important hydrocarbon source rock and an unconventional reservoir. However, there are relatively few studies on the deposition process of Lucaogou shale, the hydrologic conditions controlled by the paleoclimate, and the enrichment mechanism of organic matter in the shale. In this study, the Lucaogou shale was studied comprehensively, based on the results of its sedimentological and geochemical test data. Results show that the Lucaogou shale was deposited in a semi-deep to deep stratified lake, which has anoxic, highly saline bottom and oxic, less saline surface water. The lake catchment of the study area has climatic zonality, which presents as that the paleoclimate in the lake catchment of northeastern Bogda was warm and humid and the paleoclimate in the lake catchment of western Bogda was arid. Elevated precipitation in humid climate provides fresh water rich in nutrients to lake caused relatively high paleoproductivity and promotes lake stratification, which led to relatively high TOC in the Lucaogou shale of northeastern Bogda. Organic matter accumulation in the Lucaogou shale was influenced by surface water primary productivity and preservation in stable anoxic bottom water.