低盐水驱对中低渗砂岩采收率及润湿性影响
Influences of Low Salinity Waterflooding on Oil Recovery and Wettability of the Medium and Low Permeability Sandstone
胥亚玲 1马其豪 1陈诺 1刘家聿 1丁宏娜1
作者信息
- 1. 东北石油大学石油工程学院,黑龙江大庆 163318;提高油气采收率教育部重点实验室(东北石油大学),黑龙江 大庆 163318
- 折叠
摘要
低盐水驱是一项前沿的改善水驱技术,具有成本低、环境友好等优点.大庆油田中、低渗储层物性较差,化学驱效果不理想,而低盐水驱在中、低渗储层应用前景良好.分别选大庆油田中、低渗透率岩心各5块,采用矿化度为1000～10000 mg·L-1盐水开展岩心驱替实验和接触角测试.结果表明:当注入水矿化度由10000 mg·L-1降为5000 mg·L-1时,采收率增加,等渗点右移,含油饱和度下降,储层变为水湿;当注入水矿化度从5000 mg·L-1降为1000 mg·L-1时,采收率下降,等渗点左移,驱替压力上升,引发黏土膨胀,含油饱和度上升,储层为中性润湿.因此,利用低盐水驱开发大庆油田中、低渗油藏可行,能够提高原油采收率,并改善注入能力,并且矿化度阈值为5000 mg·L-1.
Abstract
Low salinity waterflooding is a cutting-edge improved water flooding technology with the advantages of low cost and environmental friendliness. The physical properties of medium and low permeability reservoirs in Daqing Oilfield are poor, and the effect of chemical flooding is not ideal. However, low salinity waterflooding has a good application prospect in medium and low permeability reservoirs. In this paper, five medium and low permeability cores from Daqing Oilfield were selected, and salt water with salinity of 1000 mg·L-1 to 10000 mg·L-1 was used to conduct core displacement experiments and contact angle tests. The results showed that when the salinity of injected water decreased from 10000 mg·L-1 to 5000 mg·L-1, oil recovery increased, the isopermeability point shifted to the right, oil saturation decreased, and the reservoir became water wet; when the salinity of injected water decreased from 5000 mg·L-1 to 1000 mg·L-1, the recovery factor decreased, the isopermeability point shifted to the left, and the displacement pressure increased, causing clay swelling, increasing oil saturation, and the reservoir became neutral wetting. Therefore, using low salinity waterflooding to develop medium and low permeability reservoirs in Daqing Oilfield is feasible, which can improve crude oil recovery and injection capacity, and the mineralization threshold is 5000 mg·L-1.
关键词
低盐水驱/中、低渗储层/驱油效果/相对渗透率/润湿性Key words
Low salinity waterflooding/Medium and low permeability reservoirs/Oil displacement efficiency/Relative permeability/Wettability引用本文复制引用
基金项目
黑龙江省自然科学基金项目(YQ2022E009)
出版年
2024
NETL
NSTL
万方数据