原位二氧化碳泡沫驱提高采收率实验

Experimental Study on Enhanced Oil Recovery by In-situ CO₂ Foam Flooding

叶秀茹 汪万飞 付 红

YE Xiuru WANG Wanfei FU Hong

原位CO2 泡沫驱是一种很有潜力的提高采收率技术。通过原位CO2 泡沫驱提高采收率实验，优化了生气体系、泡沫体系以及注入参数，得到了最佳的注入量、注入速度和适用的渗透率级差范围。研究结果表明，在温度 为70℃，地层水矿化度为10000mg/L条件下，得到可以作用于地层深部的原位CO2 泡沫体系，其配方为：2.1% 碳酸氢铵+1.6%醋酸+9.5%氯化铵+0.1%α-烯烃磺酸钠AOS+0.1%油酸酰胺丙基甜菜碱DHSB，泡沫体积可达 810 mL，泡沫综合指数为15552mL·min。该体系形成的泡沫在油藏中部具有较高黏度和较大弹性的特性，能够 有效封堵高渗通道，表现出良好的封堵能力。在渗透率级差为6左右时，原位CO2 泡沫体系注入速度控制在1.0 mL/min左右，注入段塞量控制在0.3PV，能够发挥最佳的调驱效果。研究还发现，该泡沫体系在渗透率级差为 3.9～13.7的非均质储层中能有效提高采收率，而在渗透率级差为15.6的条件下，虽然未能显著提高低渗层采收率，但在高渗管中仍然有一定的洗油作用。本研究为原位CO2 泡沫驱技术的应用和优化提供了重要参考。

In-situ CO2 foam flooding is a promising enhanced oil recovery technology. In this paper，the in-situ CO2 foam flooding enhanced oil recovery was studied experimentally. The gas generation system，foam system and injection parameters were studied， and the optimal injection volume，injection rate and applicable permeability ratio range were obtained. The experimental results showed that under the condition of the temperature of 70 ℃ and the salinity of 10000 mg/L，the in-situ CO2 foam system was composed of 2.1% ammonium bicarbonate + 1.6% acetic acid + 9.5% ammonium chloride + 0.1% sodium alpha-olefin sulfonate AOS + 0.1% DHSB. The foam volume could reach up to 810 mL，and the foam comprehensive index was 15552 mL· min. The foam formed by the system had the characteristics of higher viscosity and larger elasticity in the middle of the reservoir， and could effectively block the high permeability channel，showing good plugging ability. When the permeability difference was about 6，the injection rate of in-situ CO2 foam system was controlled at about 1.0 mL/min and the injected slug volume was controlled at 0.3 PV，the best flooding effect could be achieved. It was also found that the foam system could enhance effectively oil recovery in heterogeneous reservoirs with the permeability ratio difference of 3.9—13.7. While the permeability ratio difference was 15.6，the system could not significantly enhance oil recovery of low-permeability layer，but still performed some washing actions in high-permeability cores. This research provides important references for the application and optimization of in-situ CO2 foam flooding technology.

10.19346/j.cnki.1000-4092.2024.01.015