Thief-zone plugging mechanism and application of calcite particles in fractured formations

Abstract Lost circulation in fractured strata during drilling incurs additional costs and leads to difficulties promoting safety efficiency. Plugging-while-drilling is a feasible means address lost formations. The particle size distribution (PSD) of plugging particles determined empirically; therefore, it often not matched with the fracture sealing requirement. This study investigates mechanism identifies calcite particle-based material as preferred agent. design PSD concentration are demonstrated. Based on concentration, plugging-while-drilling technique was developed for strata. results show that tend form filling layer at inlet, which cuts off leakage fluid into fracture, eliminating pressure applied surface. Thus, stable formation achieved, pressure-bearing capacity borehole wall increased. result also reveals optimal mixing models various diameters. based formations field experiment. confirm can improve chance prevention thief-zone remarkably reduce both event quantity volume loss. findings this research lay theoretical basis and, thus, have important practical significance.