尿素在稠油油藏注蒸汽开发中的实验研究及应用

对稠油注蒸汽添加尿素及泡沫剂开采技术的机理进行了研究,并在河南油田进行现场应用.研究表明:尿素水溶液可降低油-水界面张力,使原油粘度大幅度下降;蒸汽添加尿素驱、尿素及泡沫辅助蒸汽驱技术不仅能改善蒸汽的波及体积,提高采收率,而且还能明显提高采油速度.现场试验效果表明,该技术可使阶段油汽比提高114%,采注比提高116%,并且成功率达100%,累计增油17 003.34 t,获得了较高的经济效益.该技术可在蒸汽吞吐后期不适宜转蒸汽驱的边际油藏及蒸汽驱效果不理想的稠油油藏考虑应用.

Experimental study and application of urea in steam flooding of heavy oil reservoir

The recovery mechanism of heavy oil steam flooding by adding urea and foaming agent is studied and applied in Henan oilfield. The study shows that urea solution can reduce the interfacial tension of oil-water contact and oil viscosity; urea added steam flooding and urea and foam assisted steam flooding can improve the swept volume, recovery factor and oil recovery rate. Site test indicates that this technology can improve stage oil-steam ratio by 114%, injection-production ratio by 116%, with success ratio of 100% and cumulative oil increment of 17003.34 t. This technology can be used in marginal reservoirs which are unsuitable to steam drive in the late stage of cyclic steam stimulation and heavy oil reservoirs which have poor steam drive response.