Study on migration and plugging mechanism of knot temporary plugging agent in hydraulic fracturing
Weiqing Li, Yongsheng Liu, Qingsheng Meng, Jianjun Xue, Qiang Sun
Abstract
Horizontal well temporary plugging and diversion fracturing are critical for economical and efficient tight oil and gas reservoir development. Researchers have developed a novel degradable knot temporary plugging agent (TPA) to address the challenge of perforation plugging in wellbores. However, current research on this topic remains limited, and the understanding of the mechanism underlying the knot TPA temporary plugging is still inadequate. In this study, a computational fluid dynamics–discrete ball-chain coupled model was developed to investigate the flexible characteristics of the knot TPA. Numerical simulations analyzed the knot TPA's behavior near perforations, showing that it is primarily affected by eccentric drag and inertial forces. The rotational effect induced by the eccentric drag force facilitates the sealing of the knot TPA in the perforation. However, whether the knot TPA successfully seals depends on the resultant direction of the combined eccentric drag and inertial forces. Furthermore, during the numerical simulation process, the variations in flow rate, pressure in the fluid, and knot velocity confirm the knot TPA's temporary plugging effectiveness. A visualization-based experiment validated the numerical simulation feasibility and the rationality of the force analysis.