水驱油孔隙动用规律的核磁共振实验研究

通常采用室内岩心分析来进行水驱油研究,但是常规方法无法给出水驱油过程岩石不同大小孔隙的动用情况.借助于核磁共振T2弛豫谱技术,将含油孔隙区间划分为弛豫时间小于10ms、10~100ms、大于100ms三个孔径区间,对长庆油田地区5块岩心样品进行了水驱油后不同大小孔隙动用规律的实验研究.实验结果表明,5块岩样水驱油剩余油主要存在于弛豫时间小于10ms的小孔隙和10~100ms的中等孔隙中,大于100ms的大孔隙内剩余油含量很小.提高水驱油压力梯度后,增采油量主要来自10~100ms的中等孔隙和大于100ms的大孔隙,小于10ms的小孔隙增采油量很小.

Experimental study of active pore distribution during water driving by using NMR

The conventional core analysis methods cannot give the distribution of active pore size after the process of water drive. With NMR T2 relaxation spectrum, the oil-bearing pore size can be divided to three ranges according to relaxation time T2, that is, T2 is less than 10 ms, T2 is from 10 ms to 100 ms, and T2 is greater than 100 ms. The active pore size distribution of five cores from Changqing Oilfield after water drive is studied. The experimental results show that the remaining oil of 5 samples mainly exists in the small pore of T2 less than 10 ms and the mediate pore of T2 from 10 ms to 100 ms, and remaining oil in the larger pore of T2 more than 100 ms is little. And after water pressure gradient is increased, the increment of oil production mainly comes from the mediate pore and the larger pore, and that from the smaller pore is little.