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利用岩心、常规测井、铸体薄片、扫描电镜等资料,确定姬塬油田长6段钙质夹层岩电特征和分布规律,依据钙质砂岩和非钙质砂岩之间沉积和成岩的差异性,探讨岩石学特征和成岩演化过程对钙质夹层分布的影响。结果表明:钙质夹层的分布与沉积微相和砂泥岩组合类型密切相关,宏观上受砂泥岩厚度以及砂体的成因类型控制,微观上受碳酸盐胶结物来源和孔隙空间的综合影响。胶结物来源的充足程度与砂岩周围暗色泥岩的厚度以及砂泥岩距离密切相关;孔隙空间的大小受砂体岩石学特征和后期成岩演化的双重控制,刚性颗粒含量高、粒度粗、分选好的砂岩,原生孔隙发育,碳酸盐胶结时期孔隙空间较大,利于钙质夹层的形成;早期压实和绿泥石胶结作用减少孔隙空间,是阻碍碳酸盐沉淀的关键成岩作用。三角洲前缘储层中靠近厚层泥岩、原生粒间孔隙发育且未经历强烈压实和绿泥石胶结作用改造的沉积相带容易发生碳酸盐胶结形成钙质夹层。
According to the difference of sedimentation and diagenesis between calcareous sandstone and non-calcareous sandstone, the lithologic characteristics and distribution of calcareous intercalations in Chang 6 member of Jiyuan oilfield are determined by using core, conventional logging, thin cast film and scanning electron microscope. , To explore the influence of petrology characteristics and diagenesis evolution on the distribution of calcareous interbeds. The results show that the distribution of calcareous interbeds is closely related to the combination of sedimentary microfacies and sandstone and mudstone, and is controlled macroscopically by the thickness of sandstone and mudstone and the genetic type of sand body. Microscopically, it is affected by the source of carbonate cement and pore space. The adequacy of the cementation source is closely related to the thickness of the dark mudstone and the distance between the sandstone and mudstone around the sandstone. The size of the pore space is controlled by the petrological characteristics of the sand body and the evolution of the later diagenesis. The rigid grain content is high, the grain size is coarse, Sandstone, primary porosity and carbonate cementation during the pore space larger conducive to the formation of calcareous interbed; early compaction and chlorite cementation to reduce pore space, is hindered carbonate sedimentation of the key diagenesis. In the delta front reservoir, close to the thick mudstone, the sedimentary facies belt with primary intergranular pores developed without alteration of strong compaction and chlorite cementation is prone to carbonate cementation to form calcareous interlayer.