| 摘要: |
| 目的 针对延长油田低渗高盐油藏现有表面活性剂驱不能提高波及体积、只能提高洗油效率、低渗区原油动用程度低、提高采收率有限的实际生产问题，开展了低渗高盐油藏调驱技术研究。方法 基于毛管束理论，研发了OBU-3低黏超低界面张力表面活性剂体系作为驱油用大段塞，与反离子自主装形成ACS-2高黏超低界面张力表面活性剂体系作为调驱用小段塞，组合成多段塞实现深部调驱。结果 大小段塞注入质量分数分别为0.5%和2.7%，吸附10次后界面张力仍达到超低值，表现出了较好的耐吸附损失性。OBU-3低黏超低界面张力表面活性剂体系乳化性和润湿性好，有利于提高洗油效率，而ACS-2高黏超低界面张力表面活性剂体系的流变性、黏弹性和黏温性良好，有利于扩大波及体积，调整吸液剖面。两体系组成的多段塞表面活性剂（0.1 PV小段塞驱+0.2 PV大段塞驱+后续水驱）组合调驱效果好，平均提高采收率为14.8个百分点，比只采用大段塞驱提高了1倍，具有聚/表二驱的驱油效果。结论 多段塞表面活性剂组合调驱能有效降低无效水循环，提高波及效率，且不含有强碱或弱碱，避免腐蚀结垢，能显著提高经济效益，对低渗高盐油藏提高采收率具有指导意义。 |
| 关键词: 低渗高盐油藏 多段塞 表面活性剂驱 组合调驱 超低界面张力 黏弹性 |
| DOI：10.3969/j.issn.1007-3426.2025.02.015 |
| 分类号: |
| 基金项目:国家重点研发计划项目“CO2驱油技术及地质封存安全监测”（2020-610624-07-03-042345）；国家自然科学基金“特高温高盐油藏驱油用TTSS系列表面活性剂的开发”（51074133）；国家自然科学基金项目“超深层页岩气藏两亲性碳基纳米粒子强化超临界CO2微泡沫压裂液及其携砂机理研究”（52474045）；四川省自然基金重点项目“超深层页岩气藏两亲性石墨烯强化超临界CO2微泡沫压裂液及其稳泡机理”（2023NSFSC0027） |
|
| Research on the combination of slug surfactants for profile control and flooding in low-permeability and high-salt reservoirs |
|
Yongzhao YANG1, Xueying ZHANG2, Yujun ZHOU3, Ming ZHOU4,5, Xiao GUO5, Jiangbo MA1
|
|
1.Xingzichuan Oil Production Plant of Yanchang Oilfield Co., Ltd., Yan'an, Shaanxi, China;2.Chongqing Gas District, PetroChina Southwest Oil & Gasfield Company, Chongqing, China;3.College of Chemistry and Chemical Engineering, China West Normal University, Nanchong, Sichuan, China;4.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Engineering, Chengdu, Sichuan, China;5.School of New Energy and Materials, Southwest Petroleum University, Chengdu, Sichuan, China
|
| Abstract: |
| Objective The use of present surfactants for flooding in low-permeability and high-salt reservoirs in Yanchang Oilfield cannot increase the swept volume, but only improve the oil washing efficiency, resulting in low utilization of crude oil in low permeability areas and limited improvement in oil recovery. Therefore, it is necessary to carry out research on the technology of profile control and flooding in low-permeability and high-salt reservoirs. Method Based on the capillary bundle theory, a low viscosity and ultra-low interfacial tension surfactant (OBU-3) system was developed as a large plug for oil displacement, and combined with a high viscosity and ultra-low interfacial tension surfactant (ACS-2) system formed by self-assembling counterions as a small plug for oil displacement control to form a multi-stage plug, achieving deep profile control and flooding. Result The injection mass fractions of the large and small plugs were 0.5 wt% and 2.7 wt%, respectively. After 10 adsorption cycles, the interfacial tension reached an ultra-low value, demonstrating good resistance to adsorption loss. The emulsifying and wetting properties of OBU-3 were good, which was conducive to improving the efficiency of oil washing, while ACS-2 had good rheological property, viscoelasticity, and viscosity-temperature property, which were conducive to expanding the swept volume and adjusting the liquid absorption profile. The combination of multi-segment plug surfactants (0.1 PV small segment plug flooding + 0.2 PV large segment plug flooding+subsequent water flooding) had a good oil recovery effect, with an average increase of 14.8 percentage points, which was twice as much as using only large segment plug flooding, and had the oil flooding effect of polymer/surface secondary flooding. Conclusion The combination of multi-stage plug surfactants profile control and flooding can effectively reduce ineffective water circulation, improve sweep efficiency, and not contain strong or weak alkalies, avoiding corrosion and scaling. It can significantly improve economic benefits and provide guidance for improving oil recovery in low-permeability and high-salt reservoirs. |
| Key words: low-permeability and high-salt reservoirs multi-stage slug surfactant flooding combined profile control and flooding ultra-low interfacial tension viscoelasticity |
