【摘要】 歧口凹陷沙河街组一段下亚段湖相碳酸盐岩储层储集空间多样、物性变化快、非均质性极强,其储层质量的差异性严重影响了该区油藏分布规律的认识和有利储层的预测。针对这一问题,综合利用钻井资料、测井资料、岩心观察、薄片鉴定及分析化验等资料对研究区储层特征及储层质量差异机理进行了研究。研究发现,沙一下亚段碳酸盐岩储层储集空间包括原生孔隙、次生溶孔和裂缝,为中孔中渗储层。储层质量差异具体表现为储层的孔渗性在空间上差异明显;优势储集空间具有明显的分区性;不同类型的碳酸盐岩物性差异很大,颗粒石灰岩的孔渗性最好,泥粉晶白云岩次之,灰泥石灰岩最差。储层质量差异受沉积相、不均匀溶蚀和构造作用的控制。生物滩、鲕粒滩是优质储层发育的有利沉积相带;断层附近的泥粉晶白云岩有利于裂缝发育。由岩石矿物成分、原生孔隙及裂缝发育程度的不同引起的不均匀溶蚀是导致研究区碳酸盐岩储层质量差异的根本原因。更多还原

【Abstract】 The lacustrine carbonate reservoirs with multi-type reservoir spaces are strongly nonhomogeneous in the Lower Member 1of Shahejie Formation in Qikou Sag.It is difficult to understand the oil pool distribution and predict favorable reservoirs in the study area.In order to solve this problem,this paper comprehensively applied drilling data,logging data,core observation,thin section identification and analysis assay data to study characteristics and formation mechanism of lacustrine carbonate reservoirs.Primary pore,secondary dissolution pore and fracture are developed in the medium porosity and medium permeability carbonate reservoirs.The reservoir quality difference includes three aspects.Firstly,porosity and permeability are obviously different in the space.Secondly,the dominant reservoir space partition is evident.Thirdly,porosity and permeability are various in different lithologies.The particle limestone is of the highest porosity and permeability,micritic dolomite is the second,and micritic limestone is the lowest.Reservoir quality difference is evidently controlled by sedimentary facies,heterogeneous dissolution and tectonics.Organic bank and oolitic bank are favorable sedimentary facies for high quality reservoirs in this area.Micritic dolomite near the faults is inclined to fracture.Heterogeneous dissolution caused by different components and the development degrees of primary pore and fracture is the basic factor that caused the reservoir quality difference.更多还原