动用孔隙界限实验及致密油开发方式

EXPERIMENT OF THE RECOVERABLE PORE LIMITS AND TIGHT OIL DEVELOPING METHODS

致密油一次采收率低,注水与注气开发是常用的提高采收率方法,但注入性与动用程度尚不明确,因此评价开发方式与动用孔隙界限之间的关系对致密油提高采收率方法的实施尤为重要。采用核磁共振测试与驱替实验相结合的方法,真实展现不同注入介质和注入条件下注入介质与原油的真实驱替过程,明确了不同开发方式与动用孔隙界限的关系。研究表明:水驱和CO_2驱随着驱替压差逐渐增大,动用孔隙界限初期下降比较快,逐渐趋于稳定;水驱和CO_2驱动用孔隙界限与岩心渗透率均呈线性关系;致密油储层CO_2驱动用孔隙界限明显低于水驱动用孔隙界限。

The primary recovery of the tight oil is rather lower,the water and gas injections are the commonly adopted EOR methods,but their injectivities and produced degrees are not obvious,therefore it is very important for the influence of the relationships between the developing method evaluation and recoverable pore limits on the above two stimulations. With the help of the combination of nuclear magnetic resonance( NMR) and core flooding tests,the true flooding processes of the media and crude oil were displayed in the cases of different injecting media and conditions,thus the relationships between the different developing methods and recoverable pore limits were made clear. The studies show that for the water and CO_2 floodings,with the gradual rise of the pressure differences,the developed pore limits drop rather faster in the beginning,and then tend to stabilize; there exit linear correlations between the limits and core permeability; the developed limits of CO_2 flooded tight oil reservoirs are obviously lower than those of the waterflooded ones.