长岭气田登娄库组致密砂岩储层特征及孔隙演化

松辽盆地南部长岭气田尚处于开发前期,储层特征及孔隙演化规律认识不清。结合岩心观察、薄片鉴定及多种测试资料进行了储层岩石学特征、孔隙结构特征、成岩作用特征及孔隙演化规律的系统研究。结果表明:登娄库组储集砂岩整体岩屑及长石含量较高,成分成熟度低;储层溶孔发育、孔喉配位数低,孔喉组合为细孔-小微喉型;成岩作用包括压实压溶作用、胶结作用、交代作用、溶解作用等4种。砂岩初始孔隙度为34.1%,压实作用孔隙损失27.7%,胶结交代作用孔隙损失6.0%,溶解作用增加孔隙4.2%,目前储层孔隙度大约在4.6%。岩石成分成熟度低、胶结类型致密、填隙物含量高以及强烈的后生成岩改造作用是导致储层致密的主要原因。

Tight sandstone reservoir characteristics and pore evolution of Denglouku formation in Changling gas field

Changlling gas field in southern Songliao basin is still in early development stage,and there is no clear understandings on reservoir characteristics and pore evolution regularities.In combination with core observation,thin section analysis and a variety of test data,the systematic studies on reservoir rock characteristics,pore structure characteristics,diagenesis and pore evolution regularities have been carried out.The results showed that:the sandstone reservoir of Denglouku formation is of high lithic and feldspar content,low compositional maturity,developed dissolved pores,and low coordination number.The pore throat combination is small and micro throat type.The diagenesis includes compaction pressure solution,cementation,metasomatism,dissolution and other four kinds.The initial porosity of sandstone is 34.1%,after compaction the porosity lost of 27.7%,after the cementation and metasomatism the porosity lost of 6%,while after the dissolution the porosity increased4.2%.At present,the porosity is about 4.6%.Low rock compositional maturity,dense cement type,high interstitial content and a strong role in the transformation of post-rock generation are found to be the main causes of dense reservoir.