摘要
以显微薄片观察为基础,结合扫描电镜、电子探针、薄片能谱、元素kσ面分布以及阴极发光等分析手段对四川盆地北部雷四上亚段古风化壳储层主要埋藏成岩作用的类型、特征、成因及对储层的影响进行了研究和探讨。本区雷四上亚段风化壳储层经历的埋藏成岩作用类型主要有压实压溶作用、破裂作用、胶结作用、埋藏溶蚀作用、自生矿物的形成等。通过对裂缝内充填胶结矿物的分析研究,认为矿物胶结期次有两期:第一期为碱性热液形成碳酸盐岩矿物(铁白云石、铁方解石);第二期为富含F-、Si4+、Sr-等离子的酸性热液形成石英、萤石、天青石等热液矿物。溶蚀作用有四期,依次为:第一期酸性热液-第二期碱性热液-第三期酸性热液-第四期碱性热液溶蚀。溶蚀作用形成的脉内晶间孔、脉内晶间溶孔以及溶蚀缝占埋藏次生孔隙的主导地位。
Based on thin-section observation,the type,features,genesis of the main burial diagenesis of Upper Leikoupo 4(T2l4) Member in northern Sichuan Basin(a paleoweathering crust reservoir) and their impact on reservoir are studied by means of SEM,electron probe,thin-section energy spectrum,element kσ surface distribution and cathodoluminescence.Results show that this reservoir experienced many diagenesis of solution pressure and dissolution,fracturing,cementation,burial dissolution and authigenic mineral formation.In addition,cement filling mineral within fractures is also analyzed and it is considered that there are two stages for mineral cementation: one is that alkaline hot solution forms carbonate rock minerals(including both ankerite and ferrocalcite);another is that acidic hot solution with rich F,Si 4 + and Sr form some hot solution minerals(including quartz,fluorite and celestite).And there are four stages for dissolution,including the first for acidic hot solution,the second alkaline hot solution,the third acidic hot solution and the fourth alkaline hot solution,individually.Intercrystalline pore within pulse,intercrystalline solution pores within pulse and dissolution fractures formed in dissolution play a dominate role in burial secondary pores.
出处
《天然气勘探与开发》
2012年第1期7-12,79,共6页
Natural Gas Exploration and Development
