Lin Baicen, Wei Yunsheng, Gao Shusheng, Ye Liyou, Liu Huaxun, Zhu Wenqing
Research Institute of Petroleum Exploration & Development, Beijing 100083, China.
University of Chinese Academy of Sciences, Beijing 101408, China.
ACS Omega. 2025 Jun 5;10(23):24916-24931. doi: 10.1021/acsomega.5c02218. eCollection 2025 Jun 17.
CCUS-EGR is becoming the most cost-effective method for energy saving and emission reduction globally. However, the acidic nature of CO can alter the reservoir permeability over time, affecting the stability and sustainability of gas injection. To explore this, long-term CO injection simulations were conducted on tight sandstone, carbonate rock, and volcanic rock. By applying gas and water permeability calculation methods, the reservoir permeability was monitored in real time throughout the long-term displacement process. Combined with NMR measurements, cross-lithology comparison analysis was conducted to investigate the evolution characteristics of pore structure and flow capacity, as well as the key influencing factors in various lithological reservoir samples. The results show that the influence of long-term CO replacement and shut-in well reinjection replacement on the seepage capacity of the rock samples mainly comes from the combined effects of clay expansion, mineral particle settling and plugging, and reaction dredging to increase infiltration, and the process of water-rock reaction involves mineral particles reacting, dissolving, dislodging, transporting, and plugging. The long-term replacement and shut-in well reinjection experimental process of dense sandstone seepage capacity slightly reduced or basically unchanged, due to the greater clay effect; with carbonate rock calcite and dolomite as the main components, CO-water-rock reaction is dominated by mineral dissolution and clearing channels to increase seepage, with a significant increase in seepage capacity; feldspar is abundant in volcanic rocks, leading to mineral precipitation and pore-blocking during CO-water-rock reaction. This results in mesopore enlargement and blockage of both micro- and macropores. The channel clearing and permeability enhancement are weaker compared with carbonate reservoirs, with only a slight increase in overall seepage capacity. These findings provide valuable guidance for the efficient implementation of the CCUS-EGR.
碳捕集、利用与封存结合废气再循环（CCUS-EGR）正成为全球最具成本效益的节能减排方法。然而，CO的酸性性质会随时间改变储层渗透率，影响注气的稳定性和可持续性。为探究此问题，对致密砂岩、碳酸盐岩和火山岩进行了长期CO注入模拟。通过应用气体和水渗透率计算方法，在长期驱替过程中实时监测储层渗透率。结合核磁共振测量，进行跨岩性对比分析，以研究孔隙结构和渗流能力的演化特征，以及各类岩性储层样品中的关键影响因素。结果表明，长期CO置换和关井再注入置换对岩石样品渗流能力的影响主要来自黏土膨胀、矿物颗粒沉降与堵塞以及反应疏通以增加渗透率的综合作用，水岩反应过程涉及矿物颗粒的反应、溶解、脱落、运移和堵塞。致密砂岩渗流能力的长期置换和关井再注入实验过程略有降低或基本不变，这是由于黏土效应较大；以碳酸盐岩中方解石和白云石为主要成分，CO-水岩反应以矿物溶解和疏通通道增加渗流为主，渗流能力显著增加；火山岩中长石含量丰富，导致CO-水岩反应过程中矿物沉淀和孔隙堵塞。这导致中孔隙扩大，微孔隙和大孔隙均被堵塞。与碳酸盐储层相比，通道疏通和渗透率增强较弱，总体渗流能力仅略有增加。这些研究结果为CCUS-EGR的高效实施提供了有价值的指导。
