{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T21:08:35Z","timestamp":1790111315488,"version":"4.0.1"},"reference-count":31,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2025,9,3]],"date-time":"2025-09-03T00:00:00Z","timestamp":1756857600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>A CO2-responsive TMPDA\u2013SDS\u2013SiO2 gel system was developed and evaluated through formulation optimization, structural characterization, rheological testing, and core flooding experiments. The optimal formulation was identified as 7.39 wt% SDS, 1.69 wt% TMPDA, and 0.1 wt% SiO2, achieving post-CO2 viscosities above 103\u2013104 mPa\u00b7s. Spectroscopic and microscopic analyses confirmed that CO2 protonates TMPDA amine groups to form carbamate\/bicarbonate species, which drive the micellar transformation into a wormlike network, thereby enhancing gelation and viscosity. Rheological tests showed severe shear-thinning behavior, excellent shear recovery, and reversible viscosity changes under alternating CO2\/N2 injection. The gel demonstrated rapid responsiveness, reaching stable viscosities within 8 min, and maintained good performance after 60 days of thermal aging at 90 \u00b0C and in high-salinity brines. Plugging tests in sand-packed tubes revealed that a permeability reduction of 98.9% could be achieved at 0.15 PV injection. In heterogeneous parallel core flooding experiments, the gel preferentially reduced high-permeability channel conductivity, improved sweep efficiency in low-permeability zones, and increased incremental oil recovery by 14.28\u201334.38% depending on the permeability contrast. These findings indicate that the CO2-responsive TMPDA\u2013SDS\u2013SiO2 gel system offers promising potential as a novel smart blocking gel system for improving the effectiveness of CO2 flooding in heterogeneous reservoirs.<\/jats:p>","DOI":"10.3390\/gels11090709","type":"journal-article","created":{"date-parts":[[2025,9,3]],"date-time":"2025-09-03T15:15:57Z","timestamp":1756912557000},"page":"709","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Research and Development of a CO2-Responsive TMPDA\u2013SDS\u2013SiO2 Gel System for Profile Control and Enhanced Oil Recovery"],"prefix":"10.3390","volume":"11","author":[{"given":"Guojun","family":"Li","sequence":"first","affiliation":[{"name":"College of Petroleum Engineering, Yangtze University, Wuhan 430100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meilong","family":"Fu","sequence":"additional","affiliation":[{"name":"College of Petroleum Engineering, Yangtze University, Wuhan 430100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun","family":"Chen","sequence":"additional","affiliation":[{"name":"Oil and Gas Technology Research Institute, PetroChina Qinghai Oilfield Company, Jiuquan 736202, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuhao","family":"Zhu","sequence":"additional","affiliation":[{"name":"College of Petroleum Engineering, Yangtze University, Wuhan 430100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Bui, D., Nguyen, S., Ampomah, W., Acheampong, S.A., Hama, A., Amosu, A., Koray, A.-M., and Appiah Kubi, E. 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