{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:34:02Z","timestamp":1760060042895,"version":"build-2065373602"},"reference-count":33,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,7,26]],"date-time":"2025-07-26T00:00:00Z","timestamp":1753488000000},"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>In petroleum exploration and production, lost circulation not only significantly increases exploration and development costs and operational cycles but may also lead to major incidents such as wellbore instability or even project abandonment. This paper constructs a polymer gel plugging system by optimizing high-molecular-weight polymers, crosslinker systems, and resin hardeners. The optimized system composition was determined as 1% polymer J-1, 0.3% catechol, 0.6% hexamethylenetetramine (HMTA), and 15% urea\u2013formaldehyde resin. Experimental studies demonstrated that during the initial stage (0\u20133 days) at 120 \u00b0C, the optimized gel system maintained a storage modulus (G\u2032) of 17.5 Pa and a loss modulus (G\u2033) of 4.3 Pa. When the aging period was extended to 9 days, G\u2032 and G\u2033 decreased to 16 Pa and 4 Pa, respectively. The insignificant reduction in gel strength indicates excellent thermal stability of the gel system. The gel exhibited superior self-filling capacity during migration, enabling complete filling of fractures of varying sizes. After aging for 1 day at 120 \u00b0C, the plugging capacity of the gel system under water flooding and gas flooding conditions was 166 kPa\/m and 122 kPa\/m, respectively. Furthermore, a complete gel barrier layer formed within a 6 mm wide vertical fracture, demonstrating a pressure-bearing capacity of 105.6 kPa. This system shows good effectiveness for wellbore isolation and fracture plugging. The polymer gel plugging system studied in this paper can simplify lost circulation treatment procedures while enhancing plugging strength, providing theoretical support and technical solutions for addressing lost circulation challenges.<\/jats:p>","DOI":"10.3390\/gels11080578","type":"journal-article","created":{"date-parts":[[2025,7,28]],"date-time":"2025-07-28T09:53:02Z","timestamp":1753696382000},"page":"578","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["High Strength and Strong Thixotropic Gel Suitable for Oil and Gas Drilling in Fractured Formation"],"prefix":"10.3390","volume":"11","author":[{"given":"Yancheng","family":"Yan","sequence":"first","affiliation":[{"name":"Sinopec Southwest Oil & Gas Company Engineering Technology Research Institute, Chengdu 610031, China"}]},{"given":"Tao","family":"Tang","sequence":"additional","affiliation":[{"name":"Sinopec Southwest Oil & Gas Company Engineering Technology Research Institute, Chengdu 610031, China"}]},{"given":"Biao","family":"Ou","sequence":"additional","affiliation":[{"name":"Sinopec Southwest Oil & Gas Company Engineering Technology Research Institute, Chengdu 610031, China"}]},{"given":"Jianzhong","family":"Wu","sequence":"additional","affiliation":[{"name":"Sinopec Southwest Oil & Gas Company Engineering Technology Research Institute, Chengdu 610031, China"}]},{"given":"Yuan","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China"}]},{"given":"Jingbin","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/j.powtec.2020.05.026","article-title":"Fracture plugging zone for lost circulation control in fractured reservoirs: Multiscale structure and structure characterization methods","volume":"370","author":"Yan","year":"2020","journal-title":"Powder Technol."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Fang, J., Zhang, X., Li, L., Zhang, J., Shi, X., and Hu, G. (2023). Research progress of high-temperature resistant functional gel materials and their application in oil and gas drilling. Gels, 9.","DOI":"10.3390\/gels9010034"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"130630","DOI":"10.1016\/j.energy.2024.130630","article-title":"Epoxy resin microencapsulated by complex coacervation as physical-chemical synergetic lost circulation control material","volume":"293","author":"Guo","year":"2024","journal-title":"Energy"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"He, Z., Fan, S., Fang, J., Yu, Y., Zhang, J., Li, S., and Xu, P. (2023). Research and application of fast plugging method for fault zone formation in Tarim Basin, China. Energies, 16.","DOI":"10.3390\/en16114330"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1786","DOI":"10.2118\/218401-PA","article-title":"Plugging mechanism of rigid and flexible composite plugging materials for millimeter-scale fractures","volume":"29","author":"Bai","year":"2024","journal-title":"SPE J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"125046","DOI":"10.1016\/j.molliq.2024.125046","article-title":"Magnetic smart polymer gel with directional plugging for conformance control in oil reservoirs","volume":"405","author":"Wang","year":"2024","journal-title":"J. Mol. Liq."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"213729","DOI":"10.1016\/j.geoen.2025.213729","article-title":"Fracture plugging performance and mechanism of adhesive material in bridging system during well drilling","volume":"247","author":"Bai","year":"2025","journal-title":"Geoenergy Sci. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e52981","DOI":"10.1002\/app.52981","article-title":"Synthesis of a low viscosity amphoteric polyacrylamide and its application in oilfield profile control","volume":"139","author":"Pu","year":"2022","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"225","DOI":"10.2118\/74602-PA","article-title":"Gel propagation through fractures","volume":"16","author":"Seright","year":"2001","journal-title":"SPE Prod. Facil."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1880","DOI":"10.2118\/214315-PA","article-title":"Experimental study on fiber balls for bridging in fractured-vuggy reservoir","volume":"28","author":"Chen","year":"2023","journal-title":"SPE J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"135967","DOI":"10.1016\/j.colsurfa.2024.135967","article-title":"Delayed crosslinking gel fracturing fluid with dually crosslinked polymer network for ultra-deep reservoir: Performance and delayed crosslinking mechanism","volume":"708","author":"Xu","year":"2025","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"14023","DOI":"10.1021\/acs.energyfuels.0c02810","article-title":"Experimental evaluation of the shielded temporary plugging system composed of calcium carbonate and acid-soluble preformed particle gels (ASPPG) for petroleum drilling","volume":"34","author":"Zhai","year":"2020","journal-title":"Energy Fuels"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Wang, Z., Liu, Y., Huang, W., Yang, X., Liu, Z., and Zhang, X. (2023). Preparation and performance evaluation of a plugging agent with an interpenetrating polymer network. Gels, 9.","DOI":"10.3390\/gels9030205"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"134294","DOI":"10.1016\/j.colsurfa.2024.134294","article-title":"Development of a plugging material featuring external flexibility and internal rigidity","volume":"697","author":"Bu","year":"2024","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"012031","DOI":"10.1088\/1742-6596\/2834\/1\/012031","article-title":"Preparation and performance evaluation of self-degrading temporary plugging agent for well workover of fractured reservoir","volume":"2834","author":"Ye","year":"2024","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1887","DOI":"10.1166\/mex.2021.2094","article-title":"Development and field application of downhole crosslinking plugging agent","volume":"11","author":"Feng","year":"2021","journal-title":"Mater. Express"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2150","DOI":"10.1016\/j.petsci.2022.07.006","article-title":"Double network self-healing hydrogel based on hydrophobic association and ionic bond for formation plugging","volume":"19","author":"Bai","year":"2022","journal-title":"Pet. Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"5677","DOI":"10.1007\/s10924-024-03334-1","article-title":"Preparation, evaluation and field application of thermally induced crosslinked polymer gel leakage plugging agent","volume":"32","author":"Chen","year":"2024","journal-title":"J. Polym. Environ."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Albonico, P., and Lockhart, T. (1993, January 2\u20135). Divalent ion-resistant polymer gels for high-temperature applications: Syneresis inhibiting additives. Proceedings of the SPE International Symposium on Oilfield Chemistry, Richardson, TX, USA.","DOI":"10.2118\/25220-MS"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0920-4105(00)00015-2","article-title":"A review of thermally stable gels for fluid diversion in petroleum production","volume":"26","year":"2000","journal-title":"J. Pet. Sci. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1016\/j.petrol.2011.12.016","article-title":"Gelation studies of an organically cross-linked polyacrylamide water shut-off gel system at different temperatures and pH","volume":"81","author":"Sengupta","year":"2012","journal-title":"J. Pet. Sci. Eng."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"106427","DOI":"10.1016\/j.cemconres.2021.106427","article-title":"A high-efficiency self-healing cementitious material based on supramolecular hydrogels impregnated with phosphate and ammonium","volume":"144","author":"Liu","year":"2021","journal-title":"Cem. Concr. Res."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Bai, Y., Liu, Y., Yang, K., and Lang, Y. (2023). Application and research prospect of functional polymer gels in oil and gas drilling and development engineering. Gels, 9.","DOI":"10.3390\/gels9050413"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Feng, X., Cao, X., Li, L., Li, Z., Zhang, Q., Sun, W., Hou, B., Liu, C., and Shi, Z. (2024). Study on performance and engineering application of novel expansive superfine cement slurry. Materials, 17.","DOI":"10.3390\/ma17225597"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"9283","DOI":"10.1021\/acs.energyfuels.7b01691","article-title":"Thermo-responsive temporary plugging agent based on multiple phase transition supramolecular gel","volume":"31","author":"Du","year":"2017","journal-title":"Energy Fuels"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"e55005","DOI":"10.1002\/app.55005","article-title":"Synthesis and properties of self-healing hydrogel plugging agent","volume":"141","author":"Bai","year":"2024","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"314","DOI":"10.1021\/acs.macromol.4c02598","article-title":"Molecular weight determination of Kuhn monomers from a dynamic property of polymers","volume":"58","author":"Degaki","year":"2025","journal-title":"Macromolecules"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"128572","DOI":"10.1016\/j.cej.2021.128572","article-title":"Reproducible and rapid synthesis of a conjugated polymer by Stille polycondensation in flow: Effects of reaction parameters on molecular weight","volume":"412","author":"Shin","year":"2021","journal-title":"Chem. Eng. J."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1186\/s10086-024-02131-7","article-title":"Applicability of enzymatic and phenol\u2013sulfuric acid methods for determination of cellulose nanofibers in ecotoxicity testing","volume":"70","author":"Matsuzawa","year":"2024","journal-title":"J. Wood Sci."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1151","DOI":"10.1016\/j.fuel.2018.10.089","article-title":"Effect of profile-control oil-displacement agent on increasing oil recovery and its mechanism","volume":"237","author":"Cao","year":"2019","journal-title":"Fuel"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"110760","DOI":"10.1016\/j.corsci.2022.110760","article-title":"Urea-formaldehyde resin covered etched basalt as durable composite coating with antibacterial activity and corrosion resistance","volume":"209","author":"Li","year":"2022","journal-title":"Corros. Sci."},{"key":"ref_32","unstructured":"Sydansk, R.D., and Argabright, P.A. (1987). Conformance Improvement in a Subterranean Hydrocarbon-Bearing Formation Using a Polymer Gel. (US4683949A), U.S. Patent."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"552","DOI":"10.1016\/j.petrol.2015.10.020","article-title":"Experimental study and application of gels formed by nonionic polyacrylamide and phenolic resin for in-depth profile control","volume":"135","author":"Zhao","year":"2015","journal-title":"J. Pet. Sci. Eng."}],"container-title":["Gels"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2310-2861\/11\/8\/578\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:16:36Z","timestamp":1760033796000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2310-2861\/11\/8\/578"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,26]]},"references-count":33,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2025,8]]}},"alternative-id":["gels11080578"],"URL":"https:\/\/doi.org\/10.3390\/gels11080578","relation":{},"ISSN":["2310-2861"],"issn-type":[{"type":"electronic","value":"2310-2861"}],"subject":[],"published":{"date-parts":[[2025,7,26]]}}}