Volume 62

Experimental Study of Elastic Lost Circulation Materials for Dynamic Fracture Losses in COâ‚‚ Storage Well Drilling Han Hu, Yongcun Feng, Ruixue Wang

Abstract

During drilling COâ‚‚ storage and monitoring wells, maintaining fracture stability is critical for preserving future injectivity and caprock sealing efficiency. Fluctuating bottom-hole pressure can induce cyclic deformation of natural fractures by transient drilling operations. This dynamic behavior destabilizes the plugging layer, making conventional lost circulation materials (LCMs) inadequate for sustained plugging performance. To address this problem, this study experimentally investigates the plugging behavior and formulation design criteria of three elastic LCMs including rubber particles, elastic graphite, and elastic mesh material under both static and dynamically deforming fracture conditions. The effects of particle size distribution, material proportion, pressure-bearing capacity, resealing behavior, and fracture-width adaptability were quantified. Experimental results demonstrate that appropriate coordination among three elastic materials enables controlled migration of the bridging zone within the fracture and significantly increases the fracture reopening pressure. When the particle size distribution of each elastic material is within its respective optimal range and the composite mass ratio satisfies filling: auxiliary bridging: secondary auxiliary bridging = 4:2:1, the optimized ternary formulation preferentially forms a tight, low-permeability, and extraction-resistant plugging layer. The plugging layer exhibits both higher reopen pressure and strong adaptability to dynamic changes in fracture width. These findings provide a scientific theoretical basis for mitigating drilling-induced losses and supporting wellbore stability management in COâ‚‚ storage well drilling.

Keywords CCS, Pressure Fluctuation, Plugging, Fracture Deformation