低渗透油藏氮气泡沫交替驱不同注入参数优化

Optimization of injection parameters of foam-alternating-nitrogen flooding in Low permeability reservoirs

单纯进行氯气驱时，氮气易沿高渗通道发生气窜，严重降低了氮气驱的提高采收率效果。气液交替注入可有效降低气相的相对渗透率，抑制气窜，是一种很好的提高氯气驱驱油效果的EOR方法。为了得到最佳开发效果，有必要对注入参数进行优化。通过对氮气泡沫交替驱不同注入参数的优化研究得出，最佳注入方案为气液比为1：1、段塞大小为0．17PV，即交替段塞大小越小、交替周期越多时的驱油效果越好。

When single nitrogen flooding, gas channeling of nitrogen easily occurs along high permeability channels. It severely reduced the EOR effect of the nitrogen flooding. The water ahernating gas （WAG） can effectively reduce the relative permeability of gas, and inhibit gas channeling. So it＇ s a good EOR method to increase nitrogen-drive-oil effect. In order to get the best development effect, it is necessary to optimize the injection parameters. Based on the optimization of different injection parameters of nitrogen-alternating-foam （NAF） drive, we can obtain that the optimum injection project is： gas-to-liquid ratio 1：1 and the size of slug 0.17 PV, that is, the smaller the alternating slug size and the more the alternating cycle, the better the oil displacement effect is.