普通稠油降黏剂辅助氮气吞吐开采机理

针对普通稠油降黏剂辅助氮气吞吐过程中开采特征不明确、降黏剂和氮气协同作用机理不明晰的问题,通过微观可视实验和物理模拟,揭示吞吐过程中流体微观分布特征和降黏剂作用机理,对比研究普通稠油氮气吞吐、降黏剂辅助氮气吞吐的开采特征。结果表明:在普通稠油降黏剂辅助氮气吞吐过程中,降黏剂能有效分散原油和氮气,形成水包油型乳状液和少量泡沫,乳状液和泡沫的贾敏效应能有效抑制气窜,扩大波及面积,延长气体弹性能量作用时间,提高氮气有效吞吐周期,室内实验普通稠油降黏剂辅助氮气吞吐开采可提高采收率6.5个百分点。研究结果有助于进一步明确降黏剂筛选原则,为降黏剂辅助氮气吞吐现场应用提供借鉴。

Mechanism of Nitrogen Stimulation Assisted by Common Heavy Oil Viscosity Reducer

To address the issues on indefinite production characteristics and unclear synergistic mechanism of reaction between viscosity reducer and nitrogen during nitrogen stimulation assisted by common heavy oil viscosity reducer, the microscopic distribution characteristics of fluid and the mechanism of viscosity reducer in the stimulation process were discovered by microscopic visual experiments and physical simulation to compare and study the production characteristics of nitrogen stimulation assisted by common heavy oil viscosity reducer. The results showed that in the nitrogen stimulation assisted by common heavy oil viscosity reducer, the viscosity reducer effectively dispersed crude oil and nitrogen to form oil-in-water emulsion and a small amount of foam, and the Jamin effect of the emulsion and foam effectively inhibited gas channeling to enlarge the affected area, extend the action time of elastic energy of gas and prolong the effective nitrogen stimulation cycle, and the oil recovery was improved by 6.5 percentage points with nitrogen stimulation assisted by common heavy oil viscosity reducer in the indoor experiments. The study results are conducive to further clarifying the principles of viscosity reducer selection and provide a reference for the field application of nitrogen stimulation assisted by viscosity reducer.