油气藏评价与开发 ›› 2025, Vol. 15 ›› Issue (4): 672-678.doi: 10.13809/j.cnki.cn32-1825/te.2025.04.017

• 矿场应用 • 上一篇    下一篇

低渗致密油藏CO2-黏弹性流体协同驱油效果评价及矿场应用

汤瑞佳(), 陈龙龙, 谢旭强, 赵聪, 王蓓蕾, 江绍静   

  1. 陕西延长石油（集团）有限责任公司研究院，陕西 西安 710065
  • 收稿日期:2024-07-05 发布日期:2025-07-19 出版日期:2025-08-26
  • 作者简介:汤瑞佳（1987—），男，硕士，高级工程师，主要从事油田提高采收率技术研究工作。地址：陕西省西安市雁塔区唐延路61号延长石油科研中心，邮政编码：710065。E-mail：trj558@126.com
  • 基金资助:
    陕西省重点研发计划“低渗透油藏气驱分级封窜体系研发与性能评价”(2023-YBGY-311);陕西省秦创原“科学家+工程师”项目“碳中和背景下油藏CO2地质封存关键技术”(2022KXJ-050)

Effectiveness evaluation and field application of CO2-viscoelastic fluid synergistic flooding in low-permeability tight reservoirs

TANG Ruijia(), CHEN Longlong, XIE Xuqiang, ZHAO Cong, WANG Beilei, JIANG Shaojing   

  1. Research Institute of Yanchang Petroleum (Group) Co. , Ltd. , Xi’an, Shaanxi 710065, China
  • Received:2024-07-05 Online:2025-07-19 Published:2025-08-26

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摘要：

CO2波及效率与气窜问题，是制约低渗致密储层CO2驱油效果的关键因素。针对CO2驱波及效率低、易气窜的技术难题，提出利用黏弹性流体体系（CMS）来改善低渗致密储层CO2驱油效果，系统研究了CMS油藏条件下的黏弹性、界面活性、可注入性及封堵和驱油性能，探索了CO2-CMS的协同驱油作用，并开展了矿场试验。实验表明：油藏温度介于30~80 ℃时，质量分数为0.5%的CMS表现出一定的黏弹性，且以弹性为主，随温度升高，流体的黏性和弹性减弱；在油藏温度45 ℃时，CMS黏度为3.27 mPa·s，且弹性较强。此外，CMS能够有效降低油水界面张力至2.68×10-2 mN/m，岩心在CO2-CMS中浸泡后，水相接触角下降至8.75°，表明亲水性得到增强。CO2-CMS在低渗致密岩心的注入性良好，且段塞尺度越小，注入效果越佳。在长岩心驱替实验中，采用0.3 PV段塞式CMS驱后再CO2驱，采收率提高幅度可达27.79%。在双管并联岩心驱替实验中，CMS-CO2交替驱效果最佳，可有效封堵高渗岩心，启动低渗岩心，采收率提高幅度达26.28%。现场试验井组的数据表明：应用CMS后，整体产液、产油量均有所上升，气窜井产出气中CO2体积分数显著下降。这一研究成果为低渗致密油藏提升CO2驱油效果提供了新的技术借鉴和解决方案。

关键词: CO2驱油, 黏弹性流体, 低界面张力, 低渗致密, 协同, 封堵

Abstract:

CO2 sweep efficiency and gas channeling are key factors restricting the effectiveness of CO2 flooding in low-permeability tight reservoirs. To address the technical issues of low sweep efficiency and gas susceptibility to channeling in CO2 flooding, a viscoelastic fluid system (CMS) was proposed to improve CO2 flooding in low-permeability tight reservoirs. A systematic study was conducted on the viscoelasticity, interfacial activity, injectivity, plugging performance, and oil displacement performance of CMS under oil reservoir conditions. The synergistic flooding performance of CO2-CMS was explored, and field trials were carried out. Experimental results demonstrated that at reservoir temperatures ranging from 30-80 ℃, CMS with a mass fraction of 0.5% showed certain viscoelasticity, with elasticity as the dominant characteristic, and both viscosity and elasticity decreased as temperature increased. At an oil reservoir temperature of 45 ℃, the viscosity of CMS was 3.27 mPa·s, and it exhibited strong elasticity. Furthermore, CMS could effectively reduce the oil-water interfacial tension to 2.68×10-2 mN/m. After core samples were immersed in the CO2-CMS system, the water-phase contact angle decreased to 8.75°, indicating enhanced hydrophilicity. The CO2-CMS system demonstrated good injectability in low-permeability tight cores, with smaller slug sizes yielding better injection performance. In long-core displacement experiments, using a 0.3 PV slug of CMS followed by CO2 flooding increased the recovery rate by up to 27.79%. In double-tube parallel core displacement experiments, alternating CMS and CO2 proved most effective, as it successfully sealed the high-permeability cores and mobilized low-permeability cores, resulting in a 26.28% increase in recovery. Field trial data from well groups indicated that after applying CMS, the overall liquid and oil production increased, and the CO2 volume fraction in gas-channeling wells significantly decreased. This research provides new technical insights and practical solutions for improving the efficiency of CO2 flooding in low-permeability tight reservoirs.

Key words: CO2 flooding, viscoelastic fluid, low interfacial tension, low-permeability tight reservoir, synergy, plugging

中图分类号: 

  • TE357