油气藏评价与开发 ›› 2022, Vol. 12 ›› Issue (5): 794-802.doi: 10.13809/j.cnki.cn32-1825/te.2022.05.011

• 方法理论 • 上一篇    下一篇

低渗稠油油藏降黏剂-CO2复合驱提高采收率机理研究

郭德明1(),潘毅1(),孙扬1,巢忠堂2,李晓楠2,程诗胜2   

  1. 1.西南石油大学,四川 成都610500
    2.中国石化江苏油田分公司,江苏 扬州225009
  • 收稿日期:2021-08-13 发布日期:2022-09-27 出版日期:2022-10-26
  • 通讯作者: 潘毅 E-mail:873224527@qq.com;panyiswpu@126.
  • 作者简介:郭德明(1995—),男,硕士,从事注气提高采收率及油气藏流体相态研究。地址:四川省成都市新都区新都大道8号西南石油大学,邮政编码:610500。E-mail: 873224527@qq.com
  • 基金资助:
    CNPC—PCL重大科技专项“稀油高凝油大幅度提高采收率关键技术研究与应用”(2017E-1603)

EOR mechanism of viscosity reducer-CO2 combined flooding in heavy oil reservoir with low permeability

GUO Deming1(),PAN Yi1(),SUN Yang1,CHAO Zhongtang2,LI Xiaonan2,CHENG Shisheng2   

  1. 1. Southwest Petroleum University, Chengdu, Sichuan 610500, China
    2. China Sinopec Jiangsu Oilfield Company, Yangzhou, Jiangsu 225009, China
  • Received:2021-08-13 Online:2022-09-27 Published:2022-10-26
  • Contact: PAN Yi E-mail:873224527@qq.com;panyiswpu@126.

摘要:

低渗稠油油藏实施CO2驱是目前发展的主要提高采收率综合利用的技术,但受CO2低黏度、高流度的影响,稠油油藏CO2驱易过早气窜,为此探索了低渗稠油油藏CO2-降黏剂降黏改善流度比调驱可行性,明确了低渗稠油油藏CO2-水溶性降黏剂复合驱提高采收率机理。结果表明:KD-45A水溶性降黏剂在缺少外力搅拌的情况下,只能乳化原油表层以起到降黏效果,降黏效果较差,但降黏剂段塞能够改善因黏度差引起的油气过大的流度比,有效地控制CO2沿气流通道突进;水溶性降黏剂乳化形成的O/W形乳状液过渡带黏度接近水相,能够防止水溶性降黏剂的指进,使降黏剂段塞对CO2的调驱作用更加明显、CO2的波及面积更大;CO2在降黏剂中的溶解会降低CO2-降黏体系剂的界面张力,充分发挥二者的协同驱油作用;CO2溶于降黏剂后形成碳化水可以大幅降低重力和黏度差异对波及面积的影响,形成较为稳定连续的驱替界面,复合驱油体系的驱油机理相互协同、叠加,可大幅提高稠油采收率。

关键词: 低渗油藏, 稠油, 提高采收率, 水溶性降黏剂, CO2复合驱

Abstract:

The implementation of CO2 flooding in heavy oil reservoirs with low-permeability is currently the main comprehensive utilization technology for enhanced oil recovery. However, due to the low viscosity and high mobility of CO2, CO2 flooding in heavy oil reservoirs is prone to premature gas channeling. For this reason, the feasibility of low permeability heavy oil reservoirs with CO2-viscosity reducer to reduce viscosity and improve mobility ratio has been explored, and the mechanism of the combined flooding of CO2 and water-soluble viscosity reducer for low-permeability heavy oil reservoirs to EOR is obtained. The results show that the KD-45A water-soluble viscosity reducer can only emulsify the surface of crude oil to reduce the viscosity without external stirring. The viscosity reduction effect is poor, but the viscosity reducer slug can improve the mobility ratio caused by viscosity differences, which can effectively control the CO2 rushing along the airflow channel. The O/W-shaped emulsion transition zone formed by the emulsification of the water-soluble viscosity reducer has a viscosity close to the water phase, which can prevent the fingering of the water-soluble viscosity reducer, so that the viscosity reducer slug has a more obvious control and displacement effect on CO2, and the swept area of CO2 is larger. The dissolution of CO2 in the viscosity reducer will reduce the interfacial tension of the CO2-viscosity reducer system, which can give full play to the synergy between the two displacement effect. The formation of carbonized water after CO2 dissolves in the viscosity reducer can greatly reduce the influence of gravity and viscosity differences on the swept area, forming a relatively stable and continuous displacement interface. The displacement mechanisms of the combined flooding system are synergistic and superimposed, which can significantly improve the recovery rate of heavy oil.

Key words: low permeability reservoir, heavy oil, EOR, water-soluble viscosity reducer, CO2 compound flooding

中图分类号: 

  • TE357