Advanced Trends in Shale Mechanical Inhibitors for Enhanced Wellbore Stability in Water-Based Drilling Fluids

Abstract

Wellbore instability, particularly in shale formations, presents a great challenge to modern drilling operations. Although conventional chemical inhibitors are frequently employed in water-based drilling fluids, they may not always function in highly reactive or naturally fractured shale formations. In recent years, mechanical inhibitors have attracted attention as a complementary solution to chemical methods. These inhibitors, which include carbon-based, silicon-based, metal-based, and mineral-based particle materials, provide structural support to the wellbore by physically plugging fractures and sealing microfractures. This paper presents a comprehensive review of the mineral types associated with shale wellbore instability as well as a critical analysis of the mechanisms, categories, and effectiveness of mechanical inhibitors in enhancing wellbore stability. The development challenges and prospects of mechanical inhibitors in water-based drilling fluids are also discussed. This review emphasizes the potential of mechanical inhibitors in reducing fluid invasion, preventing wellbore collapse, and improving overall drilling efficiency, which will help facilitate the development and large-scale application of mechanical inhibitors in drilling fluids.