Plugging pattern of different temporary plugging formulations in conglomerate reservoirs: A visualized experimental investigation

To enhance the complexity of fracture networks during hydraulic fracturing in unconventional oil and gas reservoirs, this study investigates the migration and plugging mechanisms of temporary plugging agents under dynamic fracture width conditions, using a self-developed visual dynamic fracture width plugging device. Experiments were conducted with temporary plugging agents of various particle sizes (1-2 mm, 3-4 mm, 5-6 mm), pump injection rates (60 ml/min, 100 ml/min), and particle shapes (cylindrical, irregular spherical), combined with real-time displacement sensors to monitor changes in fracture width. Key findings include that larger particle sizes (5-6 mm) form larger plugging bodies, exert greater compression on fracture surfaces, and result in a significant increase in fracture width (up to 5.5 mm). Low pump rates (60 ml/min) facilitate earlier and more stable settling of the plugging agent, leading to the formation of denser plugging bodies. Irregular spherical particles, due to their shape variability, create plugging bodies with more gaps, leading to frequent breakthroughs under fluid impact and significant fluctuations in fracture width. This research provides theoretical guidance for optimizing the selection of temporary plugging agents and field operation parameters in conglomerate reservoirs, advancing the development of dynamic fracture width-based plugging and diversion technologies.