Efficient early-time plugging of wide fractures was aimed to investigate by considering granular lost circulation material (LCM) sizes, its concentrations, and geometries as the essential parameters. Fracture sealing time was experimentally investigated using sepiolite based mud prepared considering API standards. Steady shear flow, thixotropy loop and oscillatory dynamic shear tests were conducted using Discovery Hybrid Rheometer (DHR-II) to evaluate gel structure and particle suspension ability of sepiolite based mud as carrier fluid. The set of seventeen sieves 75-3360 mu m was used for analyzing grain sizes of calcium carbonate (CaCO3) as LCM. The effect of sixteen different LCM size ranges on the fracture sealing time was investigated through six slotted discs having different fracture widths (apertures) (508 mu m-3048 mu m) and lengths. Using wide range of sieve set allows providing uniform, bi-modal, and tri-modal particle size distribution of CaCO3 pills as the fundamentals to investigate fracture sealing time. Upward flow direction was provided using Pore Plugging Apparatus (PPA) under 1000 psi of pressure differential. Fracture sealing time values were measured using precise pressure transmitter connected between experimental setup and computer. Sealing performance of LCM sizes and concentrations was visually evaluated using optical microscope.