Abstract: Based on the research of sandstone slice samples and its petrological characteristics in Chang 4+5，Chang 6 sandstone reservoir of YD oilfield, diagenesis and the influence degree of diagenesis on porosity and permeability of reservoir were studied. Diagenetic evolution sequence in Chang 4+5，Chang 6 sandstone reservoir was established and diagenetica stage, pore evolution of the study area were devided. The results indicated that sandstone diagenesis this area was strong and abundant. Mechanical compaction, pressure solution, cementation and metasomatism were the key factors which led to loss of the primary pores in Yanchang Group sandstone reservoir. Also, the above factorsresulted in flow ability lost of acidic ground fluids, which made dissolution become poor and reservoir become particularly tight. According to the classification discipline of clastics diagenesis phase, the sandstone of Yanchang Group experienced sorts of diagenesis, where its intensity was significant and was now in the early period of late diagenetic (A). Sandstone pore had experienced many evolution processes, which were the initial pore slashed. A small amount of residual intergranular pores was retained and all kinds of pores gradually developed into corrosion pores. Diagenesis in upper Chang 4+5 was more favorable for hydrocarbon transfusion and reservoir.

Key words: YD Oilfield,     ,  Yanchaug group,     ,  Diagenesis,     ,  Diagenetic evolution sequence,    ,  Diagenetic stage,    ,  Pore evolution

摘要： 通过对 YD油田延长组长4+5、 长6砂岩储层薄片样品的系统研究, 并结合样品的岩石学特征, 详细 分析了研究区所经历的成岩作用类型, 建立了研究区延长组长4+5、 长6砂岩的成岩演化序列, 并划分了研究区的 成岩阶段及孔隙演化。结果表明, 研究区砂岩的成岩作用异常强烈且类型较多, 其中对延长组砂岩储层原生孔隙大 量消失起到关键作用的是压实、 压溶和胶结作用, 这些作用可使地下酸性流体失去流动能力, 导致溶蚀作用发育较 差, 储层致密; 根据碎屑岩成岩阶段划分规范, 延长组砂岩目前已处于晚成岩初( A) 期; 砂岩孔隙的演化过程从原始 孔隙的缩减演化到粒间孔的少量保留, 最后演化为各类溶蚀孔发育, 其中长4+5上储层更有利于油气的渗流与储 集。

关键词:  YD油田, 延长组,  , 成岩作用,  , 成岩演化序列, 成岩阶段, 孔隙演化