Modifications, Applications, and Challenges of Nano-SiO ₂ in Drilling Fluids: A Review

With the advancement of chemical modification techniques and the development of nanomicropores and microfractures in shale formations, the difficulties in drilling have skyrocketed since traditional drilling fluids fail to fulfill satisfactory sealing. In an attempt to tackle this issue, chemically modified nanosilicon dioxide, which is highly valued for its environmentally friendly nature, tunable surface properties, and low cost, has received extensive research and application. In this paper, the multirole application of modified nano-SiO 2 in drilling fluid is systematically reviewed for the first time from the perspective of “modification method-structure-performance.” We not only clarified its mechanism as a plugging agent, filtrate reducer, inhibitor, and lubricant but also critically compared the advantages and disadvantages of different modification strategies and finally constructed a future research and development framework for intelligent, green, and efficient drilling needs. It plays multiple crucial roles in drilling fluids, acting as a plugging agent. For instance, SNP-1(Nano-SiO 2 Plugging Agent-1) can effectively hinder liquid from infiltrating into pores; it also serves as an efficient fluid loss control agent and a reliable lubricant. By fulfilling these functions, we significantly enhance the overall performance of drilling fluids. Consequently, this not only furnishes theoretical underpinnings for the development of drilling fluid additives but also gives a strong impetus to the progression of drilling engineering.