Mechanics and Degradation Synergistic Modification of Polyglycolic Acid for Soluble Bridge Plug in Oil and Gas Fields

ABSTRACT To address the oil and gas industry’s need for soluble bridge plug materials with enhanced mechanical and degradation properties, this study investigates the reinforcement of polyglycolic acid (PGA) composites with glass fiber (GF). Experiments were conducted to assess the effects of GF content on the rheological behavior, thermal properties, and microstructure of PGA/GF composites, as well as on their mechanical and degradation properties. Results indicate that incorporating 35 wt% GF into PGA composites enhances tensile, flexural, and impact strengths to 170.82, 560.23 MPa, and 12.44 kJ/m ² , respectively—representing increases of 2.04, 3.15, and 4.73 times over pure PGA. However, GF addition slows the degradation rate of PGA/GF composites. To address this, zinc chloride (ZnCl ₂ ) was introduced as a catalyst to accelerate degradation. Analysis of varying ZnCl ₂ contents revealed that while ZnCl ₂ does increase the degradation rate, it also diminishes mechanical strength, particularly at higher concentrations. At an optimal ZnCl ₂ content of 0.1 wt%, PGA/GF/ZnCl ₂ composites achieve the highest degradation rate improvement with minimal mechanical strength reduction.