超低渗裂缝性油藏泡沫辅助空气驱油实验

EXPERIMENT OF THE FOAM-ASSISTED AIR FLOODING IN ULTRALOW-PERMEABILITY FRACTURED OIL RESERVOIRS

鄂尔多斯盆地南部红河油田长8油藏为典型的超低渗裂缝性油藏,水驱开发中注入水沿裂缝窜流,导致油井水淹。泡沫辅助空气驱油技术是利用空气作为驱替介质,同时采用泡沫作为调剖剂来封堵裂缝,从而达到提高采收率的目的,是非均质性强、高含水油藏提高原油采收率最有发展前景的技术之一。为此,对超低渗裂缝性油藏泡沫辅助空气驱油进行了研究。实验表明,红河油田长8油藏原油在油藏条件下能发生低温氧化反应,同时泡沫对高渗透率地层具有较好的封堵性能,能有效地防止注入空气窜流;相比于水驱,泡沫辅助空气驱油技术能大幅度提高原油采收率,同时气体突破时氧气含量在甲烷-空气混合物的爆炸极限以下。

Reservoir Chang 8 of Honghe Oilfield in South Ordos Basin is a typical ultra-low-permeability fractured oil reservoir. In the stage of water flooding development, the injected water channelled through the fractures and lead to cross flow and watered-out oil wells. Foam-assisted air flooding takes the air as one kind of displacing agent and at the same time adopts the foam as profile control agent to plug the fractures so as to realize the aim of enhan- cing the oil recovery. Thus it has become one of the most promising EOR technique for strong heterogeneous and high-water-cut oil reservoirs. Therefore the studies on foam-assisted air flooding for the above oil reservoir are con- ducted. The experiment shows that LTO reaction can occur under the conditions of reservoirs in Honghe Oilfield. Meanwhile, the foam possesses excellent blocking performance for high-permeability formation, thus the cross flow of the injected air can be effectively avoided; comparing with the water flooding, enhance the oil recovery, and meanwhile the O2 concentration can be remained un ane-air mixture when the air is broken through. the above technique can greatly der the explosion limits of meth-ane-air mixture when the air is broken through.