Kazakhstan journal for oil & gas industryKazakhstan journal for oil & gas industry2707-42262957-806XKMG Engineering10884210.54859/kjogi108842Research ArticleSuccessful application of PROMILL technology for oil well isolation in KazakhstanYermekovM.<p>Doct. Sc. (Engineering)</p>milbor090@gmail.comhttps://orcid.org/0009-0003-1106-2514MustafinT.timur.mustafin@wellboreintegrity.comhttps://orcid.org/0009-0003-4105-3328Wellbore Integrity Solutions240620257251601803202514042025Copyright © 2025, Yermekov M., Mustafin T.2025<p style="font-weight: 400;">The article presents the known technological causes of the overflow of the water-gas mixture and reservoir fluid in the behind-the-casing space of a cemented oil and gas well and through a cement plug, and the complications to which they can lead.</p> <p style="font-weight: 400;">Continuous work to improve well abandonment technology allowed Wellbore Integrity Solutions to create a highly efficient ProMILL™ system in 2016. The ProMILL system combines a Bridge Plug assembly, a Section Mill, and a high-ratio Underreamer to prepare the foundation for a cement barrier in a single run. During the milling and expansion process, it eradicates all leak paths from the cement fill, while achieving continuous, reliable rock-to-rock zonal isolation.</p> <p><span style="font-weight: 400;">Was presented the results of the successful execution of the First ProMILL Job in Kazakhstan onshore - successful deployment of the 5500 ProMILL for high-grade section milling and outer casing ID scraping in one trip.</span></p>water-gas mixturebehind-the-casing flowcement barrierannulusmillingwell abandonmentrepair and isolation workssustained casing pressureсу-газ қоспасыбағана артындағы ағынбетон тосқауылыайналма кеңістікфрезерлеуұңғыманы жоюжөндеу және оқшаулау жұмыстарытұрақты бағанаралық қысымводогазовая смесьзаколонный перетокбетонный барьеркольцевое пространствофрезерованиеликвидация скважиныремонтно-изоляционные работыустойчивое межколонное давление1.Chukwuemeka AO, Oluyemia G, Mohammed AI, Njuguna J. Plug and abandonment of oil and gas wells – A comprehensive review of regulations, practices, and related impact of materials selection. Geoenergy Science and Engineering. 2023;226:211718. doi: 10.1016/j.geoen.2023.211718.2.wellboreintegrity.com [Internet]. ProMILL™ Milling and Underreaming System WIS [cited 2025 Feb 12]. Available from: https://www.wellboreintegrity.com.3.wellboreintegrity.com [Internet]. Well Abandonment & Slot Recovery Systems, 2024 [cited 2025 Feb 12]. Available from: https://www.wellboreintegrity.com/RedBaron.4.blog.wellcem.com [Internet]. Plug and abandonment of oil and gas wells: Different materials, 2017 [cited 2025 Feb 17]. Available from: https://www.blog.wellcem.com.5.wellboreintegrity.com [Internet]. Sustained Casing Pressure Brochure [cited 2025 Feb 17]. Available from: https://www.wellboreintegrity.com/RedBaron.6.wellboreintegrity.com [Internet]. Expanding into New Regions: Successful Execution of the First ProMILL™ Job in Central Asia – Kazakhstan Onshore [cited 2025 Feb 20]. Available from: https://www.wellboreintegrity.com.