鄂尔多斯盆地镇北地区延长组长8_1储层微观孔隙结构研究

通过铸体薄片、扫描电镜、高压压汞等分析化验手段,对鄂尔多斯盆地镇北地区长81储层孔隙结构特征进行综合研究,结果表明,镇北地区长81储层砂岩主要以中-细粒岩屑长石砂岩为主,其次为长石岩屑砂岩;研究区孔隙类型主要以剩余粒间孔和次生孔隙为主,长石、岩屑和碳酸盐胶结物的溶蚀是产生次生孔隙的重要原因;小孔和中孔是油气主要的储集空间,细喉道、中喉道和微细喉道是镇北地区长81储层主要的渗流通道。依据毛细管压力曲线的形态以及孔隙结构特征参数把研究区的毛管压力曲线分为三类。

Micro-pore structure study on Chang 8_1 reservoir of Yanchang formation in Zhenbei area of Ordos basin

By means of casting thin sections and scanning electron microscopy(SEM),high-pressure mercury injection,and etc,a comprehensive micro-pore structure study on Chang81 reservoir of Yanchang formation in Zhenbei area of Ordos basin has been carried out.The results show that the reservoir sandstone from Chang 81of Zhenbei area is primarily of medium-fine feldspathic sandstone,and secondly of feldspar lithic sandstone.Pore types in the study area are mainly composed of residual intergranular pore and secondary pore.The dissolution of feldspar,cuttings and carbonate cement is an important cause of the secondary porosity.Small and medium pores can provide main reservoir space for hydrocar-bon,while fine throat,throat and micro-throat can provide main seepage channel for reservoir.Based on morphology of capillary pressure curve and pore structure characteristics parameters,the pipe pressure curve of the study area can be divided into three categories.