鄂尔多斯盆地延长组长7致密油储层微观特征

Microscopic characteristics of Chang 7 tight sandstone reservoir in Ordos Basin

针对鄂尔多斯盆地致密油储层特征,利用纳米级CT扫描、场发射扫描电镜、恒速压汞以及核磁共振等技术,对该储层孔隙、喉道以及孔喉配置关系等微观特征进行了系统研究.结果表明：孔隙大小决定了致密油储层的储集能力,鄂尔多斯盆地延长组长7致密油储层的平均孔隙半径为15～20 μm,平均单位孔隙体积为0.05;喉道大小是储层开发下限的主要制约因素,长7致密油储层的喉道半径主要为0.3～0.5 μm,储层中60％的可动流体由半径为0.1～0.5 μm的喉道所控制;在物性较好的储层中,连通性较好的大喉道占30％～40％,而且喉道半径≥0.5μm,而在物性较差的储层中,喉道细小,连通性差的喉道约占60％,而且喉道半径＜0.1μm.

According to the characteristics of tight reservoir in Ordos Basin, based on FESEM, nanometer CT, rate- controlled mercury penetration and NMR, this paper systematically studied the characteristics of reservoir pore, throat and the relationship between pore and throat. The result shows that the size of pores determines the reservoir capacity of tight oil reservoir, the average pore radius ranges from 15 μm to 20 μm, and the average pore volume is 0.05. The throat size is the main restricted factor for development cutoffs. The throat size ranges from 0.3μm to 0.5 μm, and the throats ranging between 0.1 μm and 0.5 μm control 60% of movable fluid of reservoir. The reservoir with better physical properties exists in 30% to 40% big throat with better connectivity and the radius of throat is over 5 p,m. The throat with radius of below 0.1 p,m account for about 60% and connectivity is poor.