Xu Zhongzheng, Xie Yuxin, Wang Xiaolong, Sun Ning, Yang Ziteng, Li Xin, Chen Jia, Dong Yunbo, Fan Herui, Zhao Mingwei
State Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, China.
Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum (East China), Ministry of Education, Qingdao 266580, China.
Gels. 2024 Nov 7;10(11):721. doi: 10.3390/gels10110721.
High-temperature steam injection is a primary method for viscosity reduction and recovery in heavy oil reservoirs. However, due to the high mobility of steam, channeling often occurs within the reservoir, leading to reduced thermal efficiency and challenges in enhancing oil production. Foam fluids, with their dual advantages of selective plugging and efficient oil displacement, are widely used in steam-injection heavy oil recovery. Nonetheless, conventional foams tend to destabilize under high-temperature conditions, resulting in poor stability and suboptimal plugging performance, which hampers the efficient development of heavy oil resources. To address these technical challenges, this study introduces a foam system reinforced with Janus nano-graphite, a high-temperature stabilizer characterized by its small particle size and thermal resistance. The foaming agents used in the system are sodium α-olefin sulfonate (AOS), an anionic surfactant, and octadecyl hydroxylpropyl sulfobetaine (OHSB), a zwitterionic surfactant. Under conditions of 250 °C and 5 MPa, the foam system achieved a half-life of 47.8 min, 3.4 times longer than conventional foams. Janus nano-graphite forms a multidimensional network structure in the liquid phase, increasing internal friction and enhancing shear viscosity by 1.2 to 1.8 times that of conventional foams. Furthermore, the foam gel system demonstrated effective steam-channeling control in heterogeneous heavy oil reservoirs, particularly in reservoirs with permeability differentials ranging from 3 to 9. These findings suggest that the Janus nano-graphite reinforced foam system holds significant potential for steam-channeling mitigation in heavy oil reservoirs.
注高温蒸汽是稠油油藏降黏开采的主要方法。然而，由于蒸汽的高流度，油藏内常发生汽窜现象，导致热效率降低，提高原油产量面临挑战。泡沫流体因其具有选择性封堵和高效驱油的双重优势，被广泛应用于注蒸汽稠油开采中。尽管如此，传统泡沫在高温条件下容易失稳，稳定性差，封堵性能欠佳，阻碍了稠油资源的高效开发。为应对这些技术挑战，本研究引入了一种由具有小粒径和耐热性的高温稳定剂——Janus纳米石墨增强的泡沫体系。该体系使用的发泡剂为阴离子表面活性剂α-烯烃磺酸钠（AOS）和两性离子表面活性剂十八烷基羟丙基磺基甜菜碱（OHSB）。在250℃和5MPa条件下，该泡沫体系的半衰期达到47.8min，比传统泡沫长3.4倍。Janus纳米石墨在液相中形成多维网络结构，增加内摩擦力，使剪切黏度比传统泡沫提高1.2至1.8倍。此外，该泡沫凝胶体系在非均质稠油油藏中显示出有效的汽窜控制能力，尤其是在渗透率级差为3至9的油藏中。这些研究结果表明，Janus纳米石墨增强泡沫体系在稠油油藏汽窜治理方面具有巨大潜力。
