The development of the novel crosslinked polymer system was necessary to address operational inefficiency due to excess water production for offshore Peninsular Malaysia wells. The new crosslinked polymer system is developed with scientific advancement that offers water blocking at thief zones of high permeability reservoir. The reservoir characteristics were taken into account during the polymer development to ensure compatibility and to evaluate swelling and plugging capability of the novel polymer system. The novel polymer system is aimed to increase the well production performance.The inverse emulsion polymerisation was chosen as the polymer synthesis method as it is able to create polymer in microparticle form. The novel polymer system undergoes static and dynamic performance evaluation considering the reservoir characteristics in offshore Peninsular Malaysia that are known for their high-water production. The formulation of the polymer was made through rigorous water shut-off evaluation to ensure the polymer is suitable for implementation. Several core flooding runs are conducted to evaluate the performance on deploying the new polymer system at the reservoir setting.The polymer gel restricts flow by lodging into the pore throats of the high permeability thief zones. The novel polymer system showcased high performance in plugging and high swelling capacity which is demonstrated at clastic reservoir settings of 90 °C and 2000 psi. The polymer is further coated with an innovative coating system, that enhances the polymer characteristics. The results showed different concentrations of the coating significantly increase the swelling properties to a high degree. The unique state of this novel coated polymeric microparticles, in powder form, is comprised of formulation needed for swelling and plugging without the need to inject alternate slugs of chemicals, as practised for some cases of water-shut-off treatment. This new polymer formulation with coating system is synthesised to successfully plug high permeability thief zones in offshore Peninsular Malaysia. The significant reduction of unwanted water produced is expected to minimize operational inefficiency caused by limited infrastructure at offshore production platform to accommodate excess water. In addition, the innovative polymer system assists in minimizing concerns related to corrosion and the formation of scales due to produced water. Copyright © 2024, Offshore Technology Conference.