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本文论述了鄂尔多斯盆地南部的主力油层(侏罗纪延安统延_(10)砂层组)在成岩过程中的孔隙演化史。作者认为:1.成岩作用改造砂层(岩)的过程,也是改造砂层(岩)中孔隙的过程,砂层(岩)中孔隙的演化史是原生孔隙不断消失和次生孔隙不断形成和消失的过程。2.石英砂屑岩(Quartz arenite)的孔隙度降低,主要是成岩期自生矿物在砂岩孔隙中的沉淀作用造成的;含柔性碎屑组分多的砂屑岩,其孔隙度的降低主要是成岩期的压实作用造成的。3.砂岩中碎屑矿物和自生矿物在成岩期的溶解作用,能产生可观的次生溶孔。本区延(?)砂层组中的次生溶孔主要发育在富含长石的砂屑岩中。此外,还有受力破碎产生的裂隙孔和某些砂岩组分脱水产生的收缩孔等次生孔隙。4.延_(10)砂层组中的次生溶孔,形成于沉积物已固结成岩的阶段。紧邻延(?)砂层组之上的煤系地层和其下的三叠纪延长统泥质岩中有机质,在埋藏成岩热演化过程中所产生的二氧化碳,使地层水的 PH 值降低成为酸性水,这些水进入砂岩中,使其中的长石被溶蚀和高岭土化,从而产生了次生溶孔。5.受沉积物源控制的砂岩碎屑组分,对砂岩原生粒间孔隙的保存和次生孔隙的发育有明显的控制作用。可以在查明沉积物源的基础上,预测砂岩原生孔隙和次生孔隙的有利分布区.6.本区延_(10)砂层组的某些孔?
This paper discusses the evolution of porosity in the diagenetic process of the main oil layer in the southern Ordos Basin (Jurassic Yan’an sutra - (10) sandstone group). The author thinks: 1. The process of diagenesis reforming sand (rock) is also the process of rebuilding the pores in the sand (rock). The evolution history of the pores in the sand (rock) is the continuous disappearance of primary pores and the continuous formation of secondary pores The process of disappearing. 2. The porosity of Quartz arenite decreases, mainly due to the sedimentation of authigenic minerals in the sandstone pores during the diagenetic period. The porosity of the sandstone containing more soft detrital components is mainly Compaction caused by diagenesis. 3. The dissolving effect of detrital minerals and authigenic minerals in sandstone during diagenesis can produce considerable secondary dissolved pores. The secondary dissolved pores in the Yan (?) Sand formation in this area mainly develop in feldspar-rich sandy rocks. In addition, there are secondary pores, such as cracked pores generated by force fracture and shrinkage pores generated by dehydration of some sandstone components. 4. Delay _ (10) sand group of secondary dissolved pores, formed in the sediment has been formed into the rock stage. The organic matter in the Paleogene Yanchang mudstone next to the Yanchang sandstone group and the carbon dioxide produced during the burial diagenetic thermal evolution reduce the pH value of formation water to acidic Water, which enters the sandstone, causes the feldspar to be eroded and kaolinized, creating secondary pores. Sediment-controlled sandstone clastic components have significant control over the preservation of primary intergranular pores and secondary porosity in sandstone. The favorable distribution of primary and secondary pores in sandstone can be predicted based on the identification of sedimentary source.6.How does some pores in the extension _