松辽盆地白云岩沉积环境及成因机理  

Sedimentary Environment and Genetic Mechanism of Dolomites in the Qingshankou Formation,Songliao Basin

作　　者：付秀丽 蒙启安[2] 文政[2] 白月[2] 高波[2] 苏杨鑫[2] FU XiuLi;MENG QiAn;WEN Zheng;BAI Yue;GAO Bo;SU YangXin(College of Geoscience,Northeast Petroleum University,Daqing,Heilongjiang 163318,China;Exploration and Development Research Institute of Daqing Oilfield Co.Ltd.,Daqing,Heilongjiang 163712,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]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《沉积学报》2024年第1期113-129,共17页Acta Sedimentologica Sinica

基　　金：中国石油重大科技专项(2021ZZ10)。

摘　　要：【目的】湖相白云岩是松辽盆地发现的一种特殊油气储层类型,为了探讨其沉积环境及成因机理,开展了白云岩宏微观特征及环境参数研究。【方法】通过野外剖面及岩心观察、微观组构观测和元素、同位素组成等多指标综合研究,分析了松辽盆地白云岩的沉积环境及其成因机理。【结果】松辽盆地湖相区白云岩主要为泥晶白云岩,矿物成分主要为铁白云石、黏土和方解石,厚1~25cm,呈层状或透镜状分布于厚层湖相泥页岩中,具有δ13C值偏正、氧同位素δ18O值偏负、稀土元素δEu明显负异常、热液营养物质Ca、Si、Fe、Mg、Al、Na丰富等显著特征,推测其先期为产甲烷细菌成因的原生白云岩,后期受到热液作用改造,形成于相对干燥气候条件下的咸水湖泊环境。【结论】湖相区白云岩沉积环境及成因机理分析对于研究松辽盆地沉积演化和储层评估具有重要意义。[Objective]Lacustrine dolomites create a special oil and gas reservoir found in the Qingshankou Forma-tion of Songliao Basin.To explore its sedimentary environment and genetic mechanism,the macro and micro charac-teristics and environmental parameters of dolomites are conducted.[Methods]A comprehensively study with multi-ple sedimentary and geochemical proxies is presented here.The sedimentary environment and genetic mechanism of the dolomites in the lacustrine area of the Qingshankou Formation are analyzed.[Results]The results shows that the dolomites are primarily argillaceous dolomites,and the mineral components arey iron dolomite,clay,and calcite,with a thickness of 1-25 cm.It is distributed in thick lacustrine mudstones and shales in a layered or lenticular shape.Theδ13C value is positive,the oxygen isotopeδ18O value is negative,the rare earth element ofδEu is an obvious nega-tive anomaly,and hydrothermal nutrients,such as Ca,Si,Fe,Mg,Al,and Na,are enriched.The formation is thought to be a primary dolomite caused by methanogenic bacteria in the early stage and transformed by hydrothermal action in the later stage,forming in a saline lake environment under relatively dry climate conditions.[Conclusions]The analysis of the sedimentary environment and genetic mechanism of dolomites in the lacustrine area is of great sig-nificance to the study of the sedimentary evolution and reservoir evaluation in Songliao Basin.

关 键 词：松辽盆地 白垩纪 青山口组 沉积组构 元素和同位素组成 

分 类 号：P618.13[天文地球—矿床学]