Liu Fanghui, Zhang Mingmin, Huang Huiyu, Cheng Rui, Su Xin
Sinopec Key Laboratory of Drilling Completion and Fracturing of Shale Oil and Gas, Beijing 102206, China.
Zhejiang Research Institute of Tianjin University, Shaoxing 312369, China.
Polymers (Basel). 2025 Mar 7;17(6):706. doi: 10.3390/polym17060706.
Gas channeling during CO flooding poses a significant challenge to enhanced oil recovery (EOR) in heterogeneous reservoirs, limiting both oil recovery and CO sequestration efficiency. To address this issue, a CO-responsive plugging gel was developed using polyethyleneimine (PEI), sodium dodecyl sulfate (SDS), and nano-silica. The gel formulation, containing 0.8% SDS, 0.8% PEI, and 0.1% nano-silica, demonstrated excellent CO-responsive thickening behavior, achieving a viscosity of over 12,000 mPa·s under selected conditions. The gel exhibited reversible viscosity changes upon CO and N injection, shear-thinning and self-healing properties, and stability under high-temperature (90 °C) and high-salinity (up to 20,000 mg/L) conditions. Plugging experiments using artificial cores with gas permeabilities of 100 mD and 500 mD achieved a plugging efficiency exceeding 95%, reducing permeability to below 0.2 mD. These results emphasize the potential of the CO-responsive plugging gel as an efficient approach to reducing gas channeling, boosting oil recovery, and enhancing CO storage capacity in crude oil reservoirs.
在注CO2驱油过程中，气窜对非均质油藏提高采收率（EOR）构成了重大挑战，限制了原油采收率和CO2封存效率。为了解决这个问题，利用聚乙烯亚胺（PEI）、十二烷基硫酸钠（SDS）和纳米二氧化硅开发了一种CO2响应型封堵凝胶。该凝胶配方含有0.8%的SDS、0.8%的PEI和0.1%的纳米二氧化硅，表现出优异的CO2响应增稠行为，在选定条件下粘度超过12000 mPa·s。该凝胶在注入CO2和N2时表现出可逆的粘度变化、剪切变稀和自愈特性，以及在高温（90℃）和高盐度（高达20000 mg/L）条件下的稳定性。使用气体渗透率为100 mD和500 mD的人造岩心进行的封堵实验，封堵效率超过95%，渗透率降低到0.2 mD以下。这些结果强调了CO2响应型封堵凝胶作为一种有效方法，在减少气窜、提高原油采收率和增强原油储层CO2储存能力方面的潜力。
