【摘要】 利用岩石普通薄片、铸体薄片、阴极发光薄片及孔渗数据,分析了鄂尔多斯盆地陇东地区三叠系延长组储层岩石学特征对成岩作用和孔隙发育的影响。结果表明,岩屑类型及含量、云母类矿物含量及碎屑颗粒粒度对成岩作用影响最大。大量泥岩、千枚岩等塑性岩屑的存在降低了岩石的抗压强度,在埋藏过程中易被挤压变形,形成假杂基充填堵塞孔隙;碳酸盐岩、中酸性火山岩等易溶岩屑的存在则可增强岩石的可溶性,利于溶蚀孔隙的形成。云母类矿物在孔隙水的参与下水化析出钾离子造成碱性环境,降低了石英的稳定性,促进了石英的压溶与缝合线的形成;另一方面云母蚀变后析出的硅铝铁成分在石英与长石颗粒周围形成绿泥石膜胶结,在粒间孔隙中形成高岭石与含铁类矿物胶结,降低了孔隙度和渗透率。颗粒粒度主要控制砂岩的抗压性和胶结强度。更多还原

【Abstract】 Various data including common thin sections,cast thin section,cathode luminescent thin sections and poroperm characteristics were used to analyze the influence of petrologic characteristics on diagenesis and pores development of the Yanchang Formation in Longdong area,Ordos Basin.The results show that the types and contents of debris,the contents of minor minerals(such as mica)and the size of the clastic particle are the main factors affecting diagenesis.The existence of large amount of plastic debris from rocks such as mudstone and phyllite reduces the strength of rock.These plastic debris are vulnerable toe compressional deformation during burial and can form pore-filling pseudo matrix.The existence of soluble debris from rocks such as carbonates and intermediate and acidic volcanic debris can enhance solubility of rocks,being favorable for the formation of dissolution pores.With the pore water participation,the hydration of minor minerals can release potassium ion which causes alkaline environment.This can reduce quartz stability,and promote the pressure solution of quartz and the formation of the sutures.On the other hand,the silicon-aluminum-iron composition being released from mica alteration could form chlorite membrane cement around quartz and feldspar particles,and kaolinite and iron bearing mineral cement in intergranular pores.These cements can reduce porosity and permeability.Grain size mainly controls the compaction resistance and bond strength of sandstone.更多还原