鄂尔多斯盆地元托子地区长7储层特征及其控制因素

Characteristics and Controlling Factors of Chang 7 Reservoir in Ordos Basin

阐明致密储层特征及其主要控制因素对分析油气聚集规律具有重要意义。元托子地区长7层段属于典型的致密储层,为阐明其特征及主控因素,研究中综合利用了粒度分析、铸体薄片、扫描电子显微镜、压汞法、黏土矿物x射线衍射和常规物性分析等,并结合岩心和测井资料宏观印证。结果表明:元托子地区长7段发育三角洲前缘亚相,包括水下分流河道,河口坝及分流间湾微相。岩石类型以长石石英砂岩和石英砂岩为主,填隙物以铁方解石和水云母为主,储集空间主要以残余粒间孔和长石溶孔构成的粒间孔—溶孔组合。长7储集层孔隙类型主要为粒间孔—溶孔组合以及少量的微裂隙等。孔隙度主要集中在2%~18%,渗透率一般为0.05×10^(-3)μm^(2)~18.49×10^(-3)μm^(2)。

It is of great significance to clarify the characteristics of tight reservoir and its main controlling factors for analyzing the law of oil and gas accumulation.Chang 7 in Yuantuozi area is a typical tight reservoir,and Chang 7 in Yuantuozi area is a typical tight reservoir.In order to clarify its characteristics and main control factors,particle size analysis,casting thin section,scanning electron microscope,mercury intrusion method,X-ray diffraction of clay ore and conventional physical property analysis were comprehensively used in the study,and macroscopic verification was made by combining core and logging data.The results show that delta front subfacies are developed in Chang 7 member of Yuantuozi area,including underwater distributary channel,mouth bar,and distributary bay.The rock types are mainly feldspar quartz sandstone and quartz sandstone.The interstitial materials are mainly iron calcite and hydromica,and the storage space is mainly composed of intergranular pores-dissolved pores composed of residual intergranular pores and feldspar dissolved pores.The pore types of Chang 7 reservoir are mainly intergranular pore-dissolved pore combination and a small amount of micro-cracks.The porosity is mainly concentrated in 2%~18%and the permeability is generally 0.05×10^(-3)μm^(2)~18.49×10^(-3)μm^(2).