松辽盆地长岭凹陷青一段典型细粒沉积有机质差异富集机制  

Study on Differential Enrichment Mechanisms of Organic Matter in a Typical Lithofacies Fine-grained Sag,Songliao Basin

作　　者：马妍 孙永河 冯进来[1] 刘颖 印长海 MA Yan;SUN YongHe;FENG JinLai;LIU Ying;YIN ChangHai(College of Earth Sciences,Northeast Petroleum University,Daqing,Heilongjiang 163318,China;Institute of Unconventional Oil and Gas Development,Chongqing University of Science and Technology,Chongqing 401331,China;The Sixth Oil Production Plant of PetroChina Changqing Oilfield Company,Yinchuan 750000,China;Exploration and Devlopment Research Institute,PetroChina Daqing Oilfield Company Limited,Daqing,Heilongjiang 163318,China)

机构地区：[1]东北石油大学地球科学学院,黑龙江大庆163318 [2]重庆科技学院非常规油气开发研究院,重庆401331 [3]中国石油长庆油田公司第六采油厂,银川750000 [4]中国石油大庆油田有限责任公司勘探开发研究院,黑龙江大庆163318

出　　处：《沉积学报》2025年第2期734-749,共16页Acta Sedimentologica Sinica

基　　金：东北石油大学引导性创新基金项目(2020YDL-09);重庆市自然科学基金创新发展联合基金项目(2022NSCQ-LZX0053);重庆英才创新领军人才项目(17202)。

摘　　要：【目的】明确沉积环境演化与岩相类型、有机质富集特征的响应关系具有重要意义。为了揭示长岭凹陷青一段细粒沉积岩的岩石学特征及古沉积环境的垂向变化规律,明确青一段典型细粒沉积的有机质差异富集过程。【方法】开展显微薄片、主/微量元素测试等分析实验,结合研究区地质资料,分析了典型岩相类型与其古沉积环境,阐述了不同古沉积环境影响下,典型细粒沉积有机质差异富集机制。【结果】长岭凹陷青一段下部、中部、上部主要发育的细粒沉积岩岩相类型分别为中有机质块状混合质细粒沉积岩相、高有机质纹层状/层状长英质细粒沉积岩相、低有机质块状黏土质细粒沉积岩相。目的层位在垂向上的古气候、陆源输入程度、古生产力、古盐度及古氧相的演化具有明显阶段性,共同影响着垂向上不同岩相的有机质富集机制,其中,下部为中古生产力—中保存条件—强絮凝沉积的有机质富集机制,中部为高古生产力—高保存条件—弱絮凝沉积的有机质富集机制,上部为低古生产力—高保存条件—强絮凝沉积的有机质富集机制。【结论】该地区青一段细粒沉积岩有机质的差异富集机制的建立,为其富有机质泥页岩的形成机制提供新思路,并为长岭凹陷青一段非常规油气勘探提供地质依据。[Objective]It is important to clarify the response relationship between the evolution of sedimentary environment and the lithofacies and the enrichment characteristics of organic matter.[Methods]Conducting analyses such as microsection and major/trace element testing,combined with geological data of the study area,typical lithofacies types and their paleosedimentary environments were analyzed,and the differential enrichment mechanism of typical fine-grained sedimentary organic matter under the influence of different paleosedimentary environments was explained.[Results]The study shows that the lithofacies types of fine-grained sedimentary rocks in member 1 of the Qingshankou Formation in Changling Sag can be divided into medium organic matter massive mixed,high organic matter laminar/layered felsic,and low organic matter massive clayey shale facies according to the lower,middle and upper parts.The vertical evolution of paleoclimate,terrigenous input,paleoproductivity,paleosalinity,and redox environment of the target horizon has distinct stages,which jointly affect the vertical distribution of lithofacies types and the enrichment mechanism of organic matter.Among them,the lower organic matter is the enrichment mechanism of middle paleoproductivity,medium preservation conditions,and strong flocculation sedimentation;the middle organic matter is the enrichment mechanism of high paleoproductivity,high preservation conditions,and weak flocculation deposition;and the upper organic matter is the enrichment mechanism of low paleoproductivity,high preservation conditions,and strong flocculation deposition[.Conclusions]The establishment of the differential enrichment mechanism of organic matter in the fine-grained sedimentary rock of the First member of the Qingling Formation provides a new idea for the formation mechanism of organic rich shale,as well as a geological basis for unconventional oil and gas exploration of the Qing 1 member in Changling Sag.

关 键 词：细粒沉积岩 有机质 古沉积环境 纹层状 青一段 长岭凹陷 

分 类 号：P595[天文地球—地球化学]