{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T10:29:16Z","timestamp":1792146556441,"version":"4.4.0"},"reference-count":25,"publisher":"MDPI AG","issue":"17","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\/"}],"funder":[{"DOI":"10.13039\/501100002886","name":"scientific research and technology development projects of CNPC","doi-asserted-by":"publisher","award":["2022ZG06"],"award-info":[{"award-number":["2022ZG06"]}],"id":[{"id":"10.13039\/501100002886","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>To address the issues of traditional gels in high-temperature reservoir leakage plugging, such as injection\u2013retention imbalance, poor high-temperature stability, and insufficient thixotropy, this study developed a thixotropic polymer gel system via molecular design and component optimization, aiming to achieve excellent thixotropy, high strength, and wide temperature adaptability (80\u2013140 \u00b0C) while clarifying its gelation mechanism. First, the optimal polymer was selected by comparing the high-temperature stability and crosslinking activity of AM\/AMPS copolymer (J-2), low-molecular-weight acrylamide polymers (J-3, J-4), and AM\/AMPS\/NVP terpolymer (J-1). Then, the phenolic crosslinking system was optimized: hexamethylenetetramine (HMTA) was chosen for controlled aldehyde release (avoiding poor stability\/dehydration) and catechol for high crosslinking efficiency (enhancing strength via dense crosslinking sites). Urea\u2013formaldehyde resin (UF) was introduced to form a \u201cpolymer-resin double network,\u201d improving high-temperature compression resistance and long-term stability. Cyclic shear rheological tests showed the gel system had a larger hysteresis area than the polymer solution, indicating excellent thixotropy before gelation. It gelled completely at 80\u2013140 \u00b0C (gelation time shortened with temperature). At 120 \u00b0C, its viscosity was 7500 mPa\u00b7s, storage modulus (G\u2032) 51 Pa, and loss modulus (G\u2033) 6 Pa, demonstrating good shear thixotropy. The final system (1% J-1, 0.3% catechol, 0.6% HMTA, 15% UF) is suitable for high-temperature reservoir leakage plugging.<\/jats:p>","DOI":"10.3390\/polym17172397","type":"journal-article","created":{"date-parts":[[2025,9,3]],"date-time":"2025-09-03T08:04:15Z","timestamp":1756886655000},"page":"2397","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Fabrication of Thixotropic Polymeric Gel System and Its Gelation Mechanism"],"prefix":"10.3390","volume":"17","author":[{"given":"Zhilei","family":"Zhang","sequence":"first","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuan","family":"Geng","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ren","family":"Wang","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhiyuan","family":"Yan","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Minghao","family":"Sun","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sicong","family":"Meng","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yan","family":"Zhang","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hong","family":"Yang","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yaoxuan","family":"Li","sequence":"additional","affiliation":[{"name":"CNPC Engineering Technology R&D Co., Ltd., Beijing 102206, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuecheng","family":"Zhu","sequence":"additional","affiliation":[{"name":"School of Petroleum Engineering, China University of Petroleum, Qingdao 266580, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zhao, G., Dai, C., Zhao, M., You, Q., Chen, A., and Johnson, S.J. 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