合水地区长8超低渗储层渗透率控制因素及表征

Permeability Controlling Factors and Characterization of Ch8 Ultra-low Permeability Reservoir in Heshui Area,Ordos Basin

压实作用、胶结作用和溶蚀作用是影响鄂尔多斯盆地合水地区长8砂岩物性的主要成岩作用类型。碳酸盐胶结物在研究区含量超过90%,且溶蚀程度较弱,往往形成低孔隙度、低渗透率的致密储集层;在碳酸盐强烈胶结地区,储层物性很差,碳酸盐胶结是特低渗透储层形成的一个主要原因。建立渗透率测井解释模型时考虑碳酸盐含量,通过建立渗透率与碳酸盐含量的关系,以及碳酸盐含量与相关测井数据的关系,得到计算渗透率的参数,从而实现了渗透率控制因素的表征。通过岩心刻度测井发现,考虑碳酸盐含量的测井解释模型可信度较高,对油田开发有一定的指导意义。

The main diagenesis types are compaction, cementation and corrosion, which influence sandbody physical property of Ch8 reservoir in Heshui area, Ordos basin. The content of carbonate cement is approximate 90% and dissolution degree is very weak in this zone, and reservoir stratum is often low porous and permeable compact rock. In the carbonate strong cementation zone, reservoir property is poor, and carbonate cement is one reason of the ultra-low permeability reservoir formation. Therefore, carbonate cement should be considered when permeability log interpretation model is established. We can get permeability calculating parameters by building relationships between permeability and the content of carbonate cement and relationships between the content of carbonate cement and correlative log data. The characterization of controlling permeability factors are expressed by this method. Core calibration logging presents that permeability interpretation model with carbonate cement is credible. It has guiding significance for oilfield development.