中国南方海相页岩气选区评价体系研究

【作者】 李建青；

【导师】 蒲仁海；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2012， 博士

【摘要】 近年来非常规天然气受到各个国家和石油公司的高度重视,页岩气已成为全球非常规天然气勘探开发的热点领域,目前缺乏针对中国页岩气特点的选区评价方法。作者从页岩气成藏的区域地质背景入手,采用“构造控盆、盆控沉积相、相控页岩分布”的研究思路,以页岩气成藏要素研究为主线、应用盆地分析技术分析页岩气藏特点及研究区页岩气成藏基本条件,对研究区和美国五大页岩气盆地的页岩气成藏条件进行类比分析,探索了中国南方页岩气有利目标评价思路和技术方法。中国南方页岩时代老、热演化程度高、保存条件差、构造条件及地面条件复杂,所以中国南方页岩气选区评价体系和标准应以保存条件为核心、地质评价与经济评价相兼顾。利用氩离子抛光、扫描电镜及GRI方法,系统研究了3套页岩储集空间以纳米级孔隙为主,下寒武统页岩孔径以2～10nm为主,占70%,下志留统龙马溪组页岩孔径一般为2～50nm(74.3%),2～10nm及10～50nm各占大约45%左右,而二叠系大隆组页岩孔径稍大,孔径主要分布在10～50nm,下寒武统泥页岩纳米级孔喉较小,储集性能相对较差,下志留统和上二叠统泥页岩储集物性较好。南方海相沉积盆地演化具多阶段性,不同演化阶段沉积了不同类型的暗色页岩层系,黔南坳陷早寒武世被动大陆边缘盆地沉积的九门冲组(牛蹄塘组)深水陆棚相页岩、川东南地区晚奥陶世-早志留世克拉通内滞留沉积的五峰组-龙马溪组深水陆棚相泥页岩,以及湘中地区晚二叠世半深海盆地沉积的大隆组盆地相硅质页岩是页岩气勘探的“甜点段”。运用选区评价关键参数,对下寒武统、上奥陶-下志留统、上二叠统三套主力页岩层系进行选区评价,指出川东南地区、黔中隆起及周缘、湘中地区3个有利区带。在有利区带内继续深化评价,针对三个重点勘探层系、四种泥页岩类型,优选出黔南坳陷黄平区块、川东南彭水区块等有利勘探目标。评价方法体系及时指导勘探生产,页岩气探矿区得以拓展,钻探井(黄页1井、彭页1井、湘页1井)获得良好的效果。更多还原

【Abstract】 Recent years, unconventional gas attaches great concerns of various countries and oil companies. Shale gas has become a hotspot area in global unconventional natural gas exploration and development currently. But a suitable method to evaluate Chinese shale gas do not exist to select area. The author anlayzed regional geological setting of shale gas reservoir and shale gas characteristics and basic conditions of shale gas accumulation of the study area based on "tectonic controls basin, basin controls sedimentary facies, facies control shale distribution ". Shale gas reservoir elements are mainly researched using basin analysis technology. Meanwhile a analogically analyses of the shale gas accumulation conditions of American five major shale gas basins and the study area are carried out in order to explores the evaluation ideas and technical methods of favorable objective of shale gas in Southern China. Shale in Southern China is old, with high degree of thermal evolution, poor storage conditions, complex structural conditions and ground conditions, so the evaluation system and standards of the selected area’s shale gas in Southern China should take the retention conditions as the core, with geological assessment and economic evaluation taken into account.Using Argon ion buffing, scanning electron microscopy and GRI, system researched3sets of the shale reservoir space, they mainly contain the nanoscale pore, the aperture of lower Cambrian shale is mainly2～10nm, accounting for70%, the Lower Silurian Longmaxi shale aperture is generally2～50nm (74.3%),2～10nm and10～50nm each accounted for about45%, while the pore size of Permian Dalong Formation shale is slightly larger, the pore diameter is mainly distributed between10and50nm, the nano-scale pore throat of lower Cambrian clay shale is smaller, with relatively poor storage performance, storage properties of lower Silurian and upper Permian clay shale is preferable.The evolution of Southern marine sedimentary basin is multi-stage, different evolutionary stages have different types of dark shale sets. There are a few "sweet spots" of shale gas exploration. They include Jiumenchong Formation’s deep-water continental shelf shale formed on the early Cambrian passive margin of Qiannan sag, Wufeng-Longmaxi Formation’s deep-water continental shelf mud shale of the intracratonic lag deposit formed in Southeast Sichuan in Late Ordovician-Early Silurian, and the Dalong Formation’s basin siliceous shale formed in the Bathyal basin in Late Permian of Hunan areaWe select three sets of main shale of Lower Cambrian, Upper Ordovician-Lower Silurian and Upper Permian by the key parameters of interested area. There are three favorable zones which were Southeast Sichuan,around the upheaval in the middle of Yunnan province and central Hunan. We continued to evaluate it and preferably choosed some main exploration aims like huangping zone in Qiannan sag, pengshui zone in Southeast Sichuan for the three important exploration layer systems and four types of shalesEvaluation system guided exploration and production timely, the mining area of shale gas were expanded, the drilled wells (eg. HY1、PY1、XY1) got good effect.更多还原