准噶尔盆地风城组硅硼钠石中包裹体特征及其地质意义  

Characteristics and geological significance of inclusions in searlesite from the Fengcheng Formation in the Junggar Basin,China.

作　　者：刘晋陇 王国芝 李娜[2,3] 赵甫峰[3] 雷庆[3] 刘刚[3] 景阳[3] 王子昂[3] LIU Jinlong;WANG Guozhi;LI Na;ZHAO Fufeng;LEI Qing;LIU Gang;JING Yang;WANG Ziang(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;College of Earth Sciences,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]油气藏地质及开发工程国家重点实验室,成都理工大学,四川成都610059 [3]成都理工大学地球科学学院,四川成都610059

出　　处：《沉积与特提斯地质》2024年第2期326-338,共13页Sedimentary Geology and Tethyan Geology

基　　金：国家重大科技专项子课题(2016ZX05002-002-007)。

摘　　要：准噶尔盆地风城组的含钠白云岩和油页岩是重要的油气藏和主要的烃源岩,正确认识硅硼钠石的成因,对明确含钠白云岩的成因以及预测优质白云岩储层具有重要意义。为探究风城组白云岩、硅质岩的成因,本文选取准噶尔盆地风城组60件岩芯样品磨片制样,通过观察硅硼钠石及其中包裹体岩相学特征,再结合包裹体显微测温,得到包裹体均一温度和盐度(w(NaCleq))等多项参数,探讨了硅硼钠石成因以及其对寄主岩石成因的指示意义。结果表明:(1)风城组泥页岩、白云岩和硅质岩中均出现了团块状硅硼钠石和似斑状硅硼钠石,且硅硼钠石中的包裹包括油包裹体和流体包裹体两大类,具体类型为气液两相的油包裹体(O型)、纯液相油包裹体(PO型)、气液两相流体包裹体(W型)、纯液相流体包裹体(PW型);(2)从深部到浅部,团块状硅硼钠石的均一温度峰值范围由108.8~129.4℃变为72.8~89.8℃,似斑状硅硼钠石的均一温度范围由50.4~86.4℃变为54.2~66.4℃;(3)团块状硅硼钠石中W型包裹体盐度为8.41%~18.22%,无明显集中范围;似斑状为6.88%~15.37%,流体在沉积岩形成过程中属于高盐度流体。此次通过对准噶尔盆地风城组硅硼钠石岩相学和包裹体研究,结合前人对研究区风城组硅质岩地球化学研究,综合表明,硅硼钠石寄主岩石属于碱性盐湖背景下,中低温热液流体与碱性盐湖水混合沉积成因。The sodium-rich dolomite and oil shale in the Fengcheng Formation of the Junggar Basin are important oil and gas reservoirs and major source rocks.Correctly understanding the genesis of siliceous boron sodium rocks is of great significance for identifying the origin of sodium-rich dolomite and predicting high-quality dolomite reservoirs.In order to investigate the genesis of the dolomite and siliceous rocks in the Fengcheng Formation,this study selected 60 core samples from the formation and prepared thin sections.By observing the petrographic characteristics of siliceous boron sodium rocks and their fluid inclusions,as well as measuring the homogenization temperature and salinity of the inclusions,the genesis of siliceous boron sodium rocks and their significance for the host rocks are explored.The results show that:(1)blocky and vein-like siliceous boron sodium rocks were found in the mudstone,dolomite,and siliceous rocks of the Fengcheng Formation,with fluid inclusions including oil inclusions and aqueous inclusions of gas-liquid two-phase(O-type),pure liquid(PO-type),gas-liquid two-phase fluid(W-type),and pure liquid fluid(PW-type);(2)the homogenization temperature peak of blocky siliceous boron sodium rocks exhibits a decrease from 108.8~129.4℃in the deep section to 72.8~89.8℃in the shallow section,while that of vein-like siliceous boron sodium rocks ranges from 50.4~86.4℃in the deep section to 54.2~66.4℃in the shallow section;(3)the salinity of W-type fluid inclusions in blocky siliceous boron sodium rocks varies from 8.41%to 18.22%without a distinct concentration range,while that of vein-like siliceous boron sodium rocks ranges from 6.88%to 15.37%,indicating that the fluids during the sedimentation of the rocks are high salinity fluids.Based on the petrographic and fluid inclusion studies of the siliceous boron sodium rocks in the Fengcheng Formation of the Junggar Basin,along with previous geochemical research on siliceous rocks in the study area,it is concluded that the host rocks of siliceous bo

关 键 词：风城组 盐湖沉积 低温热液 硅硼钠石 流体包裹体 

分 类 号：P618.13[天文地球—矿床学] P578.93[天文地球—地质学]