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研究了鄂尔多斯盆地大牛地气田下石盒子组辫状河相砂岩储层成岩作用,分析了成岩作用对储层物性的影响。结果表明,下石盒子组砂岩储层成岩作用处于早成岩B期至晚成岩A期。压实作用、胶结作用和溶解作用是控制储层物性演化的主要成岩作用,其中压实作用和胶结作用造成了储层原生孔隙的大量丧失。自生粘土矿物、碳酸盐矿物以及石英次生加大是造成本区储层物性降低的主要胶结物。溶解作用对于储集性能的改善起到了重要作用,而晚成岩阶段的酸性流体以及高岭石伊利石化所产生的H+是下石盒子组储层溶解作用发生的主要动力和介质。
The diagenesis of Braided River sandstone reservoirs in Lower Shihezi Formation of Daniudi Gas Field in Ordos Basin was studied and the effect of diagenesis on reservoir physical properties was analyzed. The results show that the Lower Shihezi sandstones reservoir diagenesis is in the early diagenesis B to late diagenesis A period. Compaction, cementation and dissolution are the major diagenetic processes that control the evolution of reservoir properties. Compaction and cementation result in a large loss of primary pores in the reservoir. The growth of authigenic clay minerals, carbonate minerals and quartz secondarily is the main cement that leads to the decrease of reservoir physical properties in this area. Dissolution plays an important role in the improvement of reservoir properties. However, acid fluid in late diagenetic stage and H + produced by kaolinite illite are the main driving force and medium for reservoir dissolution in Lower Shihezi Formation.