湖相热液白云岩成因机理——以准噶尔盆地玛湖凹陷二叠系风城组为例  

Genetic Mechanism of the Huxiang Hydrothermal Dolomite:A case study of the Permian Fengcheng Formation in the Mahu Sag,Junggar Basin

作　　者：王剑 周路[1,3] 刘金 马聪 卞保力[4] 李啸[4] 张宝真[5] WANG Jian;ZHOU Lu;LIU Jin;MA Cong;BIAN BaoLi;LI Xiao;ZHANG BaoZhen(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Research Institute of Experiment and Detection,Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China;School of Geosciences and Technology,Southwest Petroleum University,Chengdu 610500,China;Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China;Fengcheng Oilfield Operation Area,Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China)

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500 [2]中国石油新疆油田分公司实验检测研究院,新疆克拉玛依834000 [3]西南石油大学地球科学与技术学院,成都610500 [4]中国石油新疆油田分公司勘探开发研究院,新疆克拉玛依834000 [5]中国石油新疆油田分公司风城作业区,新疆克拉玛依834000

出　　处：《沉积学报》2024年第1期130-141,共12页Acta Sedimentologica Sinica

基　　金：国家科技重大专项(2017ZX05008-004-008);新疆维吾尔自治区重点实验室开放课题(2017D04023)。

摘　　要：[目的]湖相白云岩是一种重要的油气储层岩石类型,但成因机制研究较晚且相对薄弱。[方法]为研究湖相热液白云岩成因机理,以准噶尔盆地玛湖凹陷二叠系风城组白云岩为例,采用岩心观察描述,岩石薄片鉴定、扫描电镜、稀土元素、稳定同位素、流体包裹体等实验分析,系统研究了风城组白云岩的岩矿特征、地球化学特征。[结果]风城组白云岩主要发育在风城组二段和三段,以分散型、纹层型、条带—团块集合体型产出。白云岩形成于高盐度、强还原和受热液控制的典型碱湖环境。深部热液侵入为湖盆提供了丰富的Mg^(2+)、Fe^(2+)、HCO_(3)^(-)、CO_(3)^(2-)离子,为白云岩的形成提供了物质基础。湖相热液白云岩存在两种成因:一是热液—蒸发沉积成因,在热液侵入及干旱强蒸发作用下,高Mg/Ca、高pH值、高盐度湖盆水体提供了云化作用的介质,形成纹层状白云岩。二是埋藏—热液交代成因,深部热流沿断裂上升侵入地层,促进埋藏白云岩化,形成条带—团块状白云岩。[结论]研究结果对我国其他盆地湖相热液白云岩的研究具有重要借鉴意义。[Objective]Lacustrine dolomite is an important reservoir rock type,but its genetic mechanism is rela-tively weak and late.[Methods]To study the genetic mechanism of lacustrine hydrothermal dolomite,taking the Permian Fengcheng Formation dolomite in the Mahu Sag,Junggar Basin as an example,the petrographic and geo-chemical characteristics of the Fengcheng Formation dolomite were systematically studied by means of core observa-tion and description,thin section identification,and scanning electron microscopy(SEM)analysis of rare earth ele-ment(REE)stable isotope fluid inclusions.[Results]The study shows that the dolomite of the Fengcheng Formation is mainly developed in the Second and Third members of the Fengcheng Formation,and the dolomite is formed in the typical alkali lake environment with high salinity and strong reduction and controlled by hydrothermal.It is produced in the form of dispersing type,laminated type,banded and massive size type.The deep hydrothermal intrusion pro-vided abundant ionsof Mg^(2+),Fe^(2+),HCO_(3)^(-)andCO_(3)^(2-)for the lacustrine basin,which provided material basis for the formation of dolomite.Lacustrine hydrothermal dolomite has two types of genesis:one is hydrothermal-evaporative de-position.Based on the hydrothermal intrusion and intense evaporation,the high Mg/Ca ratio,PH,and salinity lake basin water provided the medium for cloud formation and formed lamellar dolomite.The other is burial-hydrothermal metasomatism.Deep heat flow rises along the fault and intruded into the formation,promoting burial dolomitization,and forming massive and banded dolomite.[Conclusion]The results are of great significance for the study of hydro-thermal dolomite in other basins in China.

关 键 词：白云岩 热液 成因机理 风城组 玛湖凹陷 准噶尔盆地 

分 类 号：P581[天文地球—岩石学]