含煤岩系中煤层的差异沉积响应与油气勘探——以玛湖斜坡区侏罗系八道湾组为例  

Differential Sedimentary Response of Coal Seams in Coal-bearing Rock Series and Oil and Gas Exploration:A case study of the J1b Formation in the Mahu slope area

作　　者：孟祥超 周伯玉 陈扬 马海龙[2] 李亮[2] 王科朋 林道峰 赵文苹[2] MENG XiangChao;ZHOU BoYu;CHEN Yang;MA HaiLong;LI Liang;WANG KePeng;LIN DaoFeng;ZHAO WenPing(Petrochina Hangzhou Institute of Geology,Hangzhou 310023,China;Research Institute of Exploration and Development,Xinjiang Oilfield,PetroChina,Karamay,Xinjiang 834000,China;PetroChina Oriental Geophysical Exploration Co.,Ltd.,Zhuozhou,Hebei 072751,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油杭州地质研究院,杭州310023 [2]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 [3]中国石油集团东方地球物理勘探有限责任公司,河北涿州072751 [4]中国石油大学(北京)地球科学学院,北京102249

出　　处：《沉积学报》2023年第4期1212-1226,共15页Acta Sedimentologica Sinica

基　　金：国家科技重大专项(2017ZX05001-002);中国石油科技部重大专项(2021DJ0402,2021DJ0202)。

摘　　要：含煤岩系中不同类型煤层的差异沉积响应,及对邻近砂砾岩成岩成储效应的影响目前研究比较薄弱。基于野外露头、孢粉组合、井—震剖面、岩心相序、测井响应、扫描电镜、电子探针能谱等资料,对研究区稳定厚煤层、局限薄煤层进行了差异沉积响应分析。结果表明,以逆冲断裂I、II为代表的盆缘边界断裂复活及盆地基底的振荡性沉降,为研究区提供了厚层泥炭聚积、宽缓古斜坡背景—广覆式湖侵、阻碍沼泽排水—防止有机质氧化、降低河流梯度—弱化陆源碎屑干扰等四方面有利条件,在近湖盆区首次湖泛面附近形成大面积分布的稳定厚煤层,显微组分指示其成煤沼泽一直保持较佳的滞水还原条件。局限薄煤层分布较零散,具较明显的相控特征,多分布于水动力较弱的扇间/河道间等低能相带,显微组分指示其成煤沼泽存在局部滞水还原条件稍差的半氧化阶段。准同生期—早成岩期,煤系腐殖酸形成早成岩期长石粒内溶孔,溶蚀颗粒成分以富钙斜长石为主。溶蚀产物高岭石胶结物产状以紧贴颗粒的最内部环边为主,纯度高。长石颗粒溶蚀—高岭石充填—压塌缩聚作用形成高岭石完全拟颗粒、高岭石部分拟颗粒,前者纯度高,后者纯度较低。中成岩期,烃源有机酸形成中成岩期长石粒内溶孔,溶蚀组分以钾长石为主,溶蚀残留组分以钠长石为主。溶蚀产物高岭石胶结物产状以颗粒的外层环边或充填粒间孔隙为主,纯度较低。煤系腐殖酸对邻近的砂砾岩储层质量影响以抑制性为主,限定沉积相带、粒度条件下,稳定厚煤层垂向辐射厚度10~30 m,辐射带砂砾岩孔隙度减少2.3%~5.2%,渗透率减小(1.3~2.1)×10^(-3)μm^(2);局限薄煤层垂向辐射厚度3~8 m,辐射带砂砾岩孔隙度减少1.2%~3.5%,渗透率减小(0.8~1.9)×10^(-3)μm^(2)。高刚性颗粒含量是煤系砂砾岩储层原生粒间孔,尤其是准同生期Research on coal-bearing rocks in the different sedimentary responses of multiple coal seams and the effect of adjacent glutenite diagenetic is not currently well developed.Through field observations,sporopollen combination,well-seismic profiles,core phase sequence,and logging responses,such as scanning electron microscope and electron probe energy spectrum data,a stable thick coal seam,and limited thin coal seam were analyzed in the study area for different sedimentary responses.The results showed that through the movement along thrust faults I and II of the basin edge,the oscillation behavior of the boundary faults and basin basement subsidence provides the study area with thick layers of peat accumulation,leading to wide slow-ancient slope cover lake invasion.This hinders the swamp drainage,preventing the oxidation of organic matter and reducing the river gradient.Weakening terrigenous clastic particles interfere with the favorable conditions.A large stable thick coal seam was formed near the first lake flood surface in the lacustrine basin,and the maceral indicates that the coal forming swamp has maintained a good hysteretic water reduction condition.The limited thin coal seams are scattered,have obvious phase-controlled characteristics,and are primarily distributed in the low energy facies zones,such as an interfan/interchannel with weak hydrodynamics.The maceral indicates that the coal forming swamp has a semi-oxidation stage with poor local hysteretic reduction conditions.In the penecongenic-early diagenetic stage,humic acid in coal measures formed dissolution pores in feldspar grains,and the dissolution particles were dominated by calcium-rich plagioclase.The occurrence of kaolinite cement products is found near the inner ring edge of the particles with high purity.Complete and partial kaolinite particles are formed by the dissolution of feldspar particles,kaolinite filling,and collapse polycondensation.The former is of high purity,and the latter is of low purity.In the middle diagenetic stage,organic car

关 键 词：含煤岩系 侏罗系八道湾组(J1b) 稳定厚煤层 局限薄煤层 煤系腐殖酸 

分 类 号：P618.13[天文地球—矿床学]