凝灰质成分对砂岩储集性能的影响

与正常砂岩相比，凝灰质砂岩的碎屑颗粒来源多样，矿物成分复杂、易于转化，成岩作用及孔隙演化过程更为复杂。对贝尔凹陷苏德尔特地区兴安岭油层岩心、薄片、压汞、扫描电镜等实验资料及前人研究成果综合分析表明，砂岩中凝灰质成分的性质、组分、含量、成因不同，对砂岩孔隙结构及储集性能的影响也不同；不同埋藏阶段与成岩环境凝灰质的蚀变存在较大差异，对砂岩孔隙发育的影响也不尽相同。脱玻化作用能在一定程度上改善砂岩的储集性能，粗粒易溶部分的溶蚀对次生孔隙起到显著的建设性作用；由凝灰质蚀变的黏土矿物、特殊矿物以及这些矿物在中、晚埋藏阶段形成的一系列矿物转换有利于次生孔隙的发育，但对渗透性的改善并不十分显著。

Effect of tuffaceous components on physical property of sandstone reservoir

Compared with the normal sandstones, the tuffaceous sandstones have the properties of diversity origination, complex mineral components, easily transformed mineral, complex digenesis and porosity evolution. The comprehensive analyses of cores, thin slices, SEM, mercury-injection data and former research outcome of Xing’anling oil layer in the Suderte area of Beier Depression indicate that the diversities of the property, components, content and origin of tuffaceous sandstone have different effects on the porous structure and reservoir physical property of sandstones. The tuffaceous alteration is different under different burial phase and diagenetic environment and has different effects on the porosity of sandstone. The devitrification can improve the accumulation conditions of sandstones reservoir in some degree, and the corrosion of coarse grain have a constructive affection to the secondary porosity. The clay, abnormal mineral originated from tuff and the translation of mineral generated during the late burial phases are beneficial to the development of the secondary porosity, but not very efficient to the improvement of permeability.