Methods for lost circulation control and water shutoff in oil and gas wells

Background: Improving technologies for lost circulation control and water shutoff remains a key priority in drilling oil and gas wells. In West Kazakhstan, which holds significant hydrocarbon reserves, various methods are applied, including cement slurries, lost circulation materials (LCM) of different particle sizes, and high-viscosity or polymer systems. Despite notable progress in cementing technologies, universal solutions that combine lost circulation control with water shutoff are still scarce. Their effectiveness is highly dependent on the geological and technical conditions of each field. Current research focuses on selective materials that adapt to reservoir heterogeneity and deliver reliable sealing. Aim: This study summarizes field experience with lost circulation and water shutoff technologies in wells drilled in West Kazakhstan. It also analyzes existing isolation materials and systems in terms of their effectiveness, limitations, and future potential. Materials and methods: The study used data from wells drilled in West Kazakhstan, results of field tests, and patent and technical literature on modern cementing and isolation materials. Results: This study reviews existing isolation systems, their mechanisms, and limitations, supported by field examples and patented technologies. A key focus is the concept of a universal sealing material able to address both lost circulation and water shutoff. This approach could enhance the efficiency of isolation treatments, lower operating costs, and reduce environmental risks. Conclusion: The effectiveness of isolation treatments depends on both the proper selection of materials and the technology of their application. The analysis of existing solutions indicates that, despite a variety of options, consistent performance is not always achieved under complex geological conditions. Therefore, further research is required to optimize formulations and adapt technologies to the specific characteristics of regional fields.