咸化碱湖富有机质页岩层系黏土矿物发育特征及转化机制——以准噶尔盆地玛湖凹陷风城组为例  

Development characteristics and transformation mechanism of clay minerals in the organic-rich shale layers of saline-alkali lake:A case study of Fengcheng Formation in Mahu Sag,Junggar Basin

作　　者：姚雪玉 梁新平 金之钧[1,2,3] 王小军 高嘉洪 雷海艳 朱涛 YAO Xueyu;LIANG Xinping;JIN Zhijun;WANG Xiaojun;GAO Jiahong;LEI Haiyan;ZHU Tao(National Key Laboratory of Petroleum Resources and Engineering of China University of Petroleum(Beijing),Beijing 102249,China;School of Earth and Science,China University of Petroleum(Beijing),Beijing 102249,China;Institute of Energy/School of Earth and Space Sciences,Peking University,Beijing 100871,China;Daging Oilfield Limited Company,Daqing 163002,China;Mahu Exploration and Development Project Department,Xinjiang Oilfield Company,PetroChina,Karamay 834000,China)

机构地区：[1]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [2]中国石油大学(北京)地球与科学学院,北京102249 [3]北京大学能源研究院/地球与空间科学学院,北京100871 [4]中国石油大庆油田有限责任公司,黑龙江大庆163002 [5]中国石油新疆油田分公司玛湖勘探开发项目部,新疆克拉玛依834000

出　　处：《天然气地球科学》2025年第1期72-85,共14页Natural Gas Geoscience

基　　金：国家自然科学基金(编号:42090025)资助.

摘　　要：为系统研究碱湖页岩中黏土矿物的发育特征及转化模式,并探究在碱湖沉积环境中黏土矿物发育情况,利用扫描电镜观察、X射线衍射分析等实验,对准噶尔盆地玛湖凹陷风城组页岩在不同沉积环境下黏土矿物的组合特征及动态转化规律进行研究。结果表明:在碱湖沉积中心,发育少量以蒙脱石及伊/蒙混层组合特征为主的黏土矿物(<5%),同时,大量碎屑黏土矿物(蒙脱石等)在强碱性的成岩环境下发生溶蚀,转化为钾长石等自生硅酸盐矿物,且由于CO_(3)^(2-)/HCO_(3)^(-)存在导致沉积中心出现黏土矿物转化迟滞现象。边缘斜坡区的黏土矿物含量比沉积中心高(平均为11.57%),以伊利石、绿泥石、伊/蒙混层发育为主,其成岩环境经历了强碱性向弱碱—弱酸性的转变,原始碎屑黏土矿物在该种成岩环境下未发生溶蚀转化,随着地层温压的升高发生伊利石化和绿泥石化。黏土矿物在转化过程中会生成大量的自生石英等脆性矿物,同时会产生次生孔缝,对后续页岩油气的压裂开发具有积极影响。To systematically study the development characteristics and transformation modes of clay minerals in alkaline lake shale,and explore the development of clay minerals in alkaline lake sedimentary environments,Based on scanning electron microscopy(SEM)observation and X-ray diffraction,this paper investigates the characteristics and dynamic transformation of clay minerals in different sedimentary environments of the Fengcheng Formation shale in Mahu Sag.In the sedimentary center of the alkaline lake,only a small amount of clay minerals(<5%)are developed,mainly characterized by smectite(S)and illite-smectite mixed layers(I/S).The detrital clay minerals were dissolved in a strongly alkaline diagenetic environment,transforming into au⁃thigenic silicate minerals such as K-feldspar.Moreover,the presence of CO_(3)^(2-)/HCO_(3)^(-)can delay the transforma⁃tion of clay minerals in the sedimentary center.In the edge slope zone,the content of clay minerals(average 11.57%),which is mainly the illite(I),chlorite(C),and I/S is higher than that in the sedimentary center.The diagenetic environment is transformed from strongly alkaline to weakly alkaline-weakly acidic,and the primitive detrital clay minerals have not been dissolved and can be preserved in the early diagenetic stage,and il⁃litization and chloritization occurr with the increase of stratigraphic temperature and pressure.The transforma⁃tion of clay minerals can produce many brittle minerals such as authigenic quartz and K-feldspar,which not only increases the brittleness of shale reservoirs but also generates secondary pores and fractures,and is beneficial for the exploration and development of shale oil and gas.

关 键 词：黏土矿物 成岩演化 碱性湖盆 风城组 玛湖凹陷 

分 类 号：TE122.2[石油与天然气工程—油气勘探]