鄂尔多斯盆地长7致密油藏特征

Characteristics of Chang-7 tight oil reservoir,Ordos basin

以鄂尔多斯盆地长7致密油藏为例,运用地质统计和对比分析方法,定量表征了长7致密油藏特征。研究表明,长7油藏填隙物含量高,成熟度中等,以微孔隙为主,喉道半径极细,表现为亲油和高残余油饱和度特征,存在较强的应力敏感性和较高的启动压力梯度。可以考虑采用注入改性水改变油藏岩石表面润湿性、注气和超前注水保持油藏压力相对稳定的方式有效开发致密油藏,利用长水平井体积压裂技术增加油藏接触面积。

Taking the Chang-7 tight oil reservoir in the Ordos basin as an example,the reservoir has been quantitatively characterized by means of geological statistics and correlative analysis. It is indicated from the study that,the Chang-7 oil reservoir has high content of filling substance and a medium maturity; micro-pores are predominant and throat radius is extremely tiny,presenting the features of oil wetting and high saturation of residual oil; its stress sensitivity is high and the starting pressure gradient is high. As effective measures,the tight oil reservoir can be efficiently developed by means of injection of modified water for change of the surface wetting property of reservoir rock as well as gas injection and advanced waterflooding to maintain a relatively stable reservoir pressure,and the contact area exposed to oil reservoir can be increased by SRV fracturing technology in the long horizontal well.