松辽盆地深层储层砂岩中火山碎屑物质在成岩阶段的变化与孔隙发育  

Relationship Between Pore-Space Evolution and Deeply Buried Alteration During Diagenetic Stage of the Volcanic Fragments in Reservoir Greywacke from the Songliao Basin,NE China

作　　者：刘万洙[1] 庞彦明[2] 吴河勇[2] 高有峰[1] 门广田[2] 任延广[2] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]大庆油田勘探开发研究院,黑龙江大庆163712

出　　处：《吉林大学学报（地球科学版）》2007年第4期698-702,共5页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(40372066);高等学校博士学科点专项科研基金(20030183042)

摘　　要：松辽盆地深层储层砂岩中岩屑成分主要为火山岩岩屑,体积分数最高可达60%。填隙物主要为凝灰质杂基和成岩期后的钙质及硅质胶结物,体积分数在11%～19%。其形成环境主要为陆相断陷盆地的河流、三角洲和扇三角洲。岩石的成分成熟度和结构成熟度普遍低,而储层物性通常却很好。孔隙铸体、岩石薄片和电镜分析结果表明,富火山岩岩屑储层岩石的物性受碎屑成分、填隙物和成岩流体3个因素影响,其中火山岩碎屑在埋藏成岩作用中易于形成的次生孔隙是改善储层物性的主要原因。岩屑砂岩与储层物性相关的主要成岩后生变化有:(1)埋藏压实作用使碎屑岩原生孔隙大量减少;(2)溶蚀、脱玻化、次生矿物的生成和重结晶等成岩作用的总效应导致孔隙增加;(3)成岩流体改造和蚀变作用使火山碎屑物质形成大量次生孔隙,从而改善了砂岩储层的物性。Volcanic detritus are dominant in those composing the reservoir greywacke in the Songliao Basin,and their content can be up to 60%. Matrix of the lithic sandstones, with volume percent Ca. 11% to 19% of matrix, is dominantly tuffaceous, with minor siliceous and calcite cement. They formed in continental faulting basins and their sedimentary facies mainly include river, delta and fan delta. Both compositional and textural maturities of the sandstone are low, whereas such reservoir features as porosity and permeability are generally high. Data from thin-section, skeletal cast and electron microscope indicate that clastic components, matrix and diagenetic fluid are three main factors governing reservoir features of the sandstone rich in volcanic fragments. Alteration of volcanic grains during deeply buried stage can cause secondary inter-and/or intra-grain spores resulting in improvement of the reservoir features. Post-diagenetic variations related to the reservoir features include.（1） Primary porosity of greywacke is sharply reduced during burial-diagenesis; （2） Solution, devitrification as well as forming and recrystallization of secondary mineral can increase primary porosity as a whole;（3） Reaction between diagenetic fluid and volcanic materials can result in abundant secondary pore, which improved physical characteristics of the reservoir sandstone.

关 键 词：松辽盆地深层 岩屑砂岩储层 火山岩碎屑 成岩作用 孔隙度渗透率 储集空间演化 

分 类 号：P618.13[天文地球—矿床学]