薄层底水油藏控水用冻胶泡沫的室内研究

Laboratory Research of Water Plugging with Gel Foam in Thin-Layered Bottom-Water Reservoir

薄层底水油藏确定油水界面位置困难,射孔完成法建立底水隔板存在技术限制,而冻胶泡沫兼具冻胶和泡沫的双重作用,选择性好、封堵能力强,控制该类油藏底水锥进问题具有优势。室内实验通过黏度法和改进的Ross-Miles方法对冻胶泡沫体系进行了优选,得到了体系的优化配方为:0.2%聚合物LA100+0.4%有机铬交联剂FH-7+0.25%表面活性剂SDS+N2。体系性能评价结果表明,随反应时间延长(0率24 h),体系黏度由11.6逐渐增至200.0 m Pa·s,泡沫综合值由2838.0增至11899.0 m L·min。随着冻胶逐渐成冻,冻胶泡沫稳定性逐渐增强。体系的注入压力高,阻力系数超过6.0。封堵能力强,封堵率超过93.8%;选择性优于冻胶,可智能识别高渗通道。玻璃填砂可视化物理模拟表明,在生产井的近井地带,冻胶泡沫优先进入水锥入侵通道和底水层,形成稳定的底水隔板,扩大底水波及体积,采收率增值为32.6%。

It was difficult to confirm the oil-water interface in thin-layered bottom-water reservoir. So a novel bottom water separator was built by gel foam to overcome the technical limitations of perforation completion method and solve serious water coning. Gel foam had dual function of gel and foam,whose selectivity and sealing capacity were good. Viscometric method and Ross-Miles method were used to optimize the composition of gel foam. The best formula of gel foam was obtained as follows:0.2%polymer LA100,0.4% organic chromium crosslinking agent FH-7,0.25% surfactant SDS and N2. The performance evaluation results showed that system viscosity increased from 11.6 to 200.0 m Pa·s within 24 hrs,which caused foam comprehensive value increased from 2838.0 to 11899.0 m L·min. Along with the gelling,the stability of gel foam gradually reinforced. The resistance coefficient was larger than 6.0,which resulted in a high injection pressure to supply the stratum energy. The plugging rate exceeded93.8% for different permeability sand-filled pipes. Its selectivity was better than simple gel. Glass visual model result showed that gel foam priority accessed to water cone and bottom water in immediate vicinity of wellbore and formed a barrier to enhance the swept volume of bottom water,which caused oil recovery raising 32.6%.