Oil‐Soluble Temporary Plugging Agent Used for Drilling Reservoir Protection: Preparation, Characteristics and Mechanism

ABSTRACT This study engineered an innovative oil‐soluble temporary plugging agent (Poly‐zd‐1) through suspension dispersion blending method of polyethylene wax and coumarone resin; the optimum preparation process was determined based on single‐variable experimentation. Systematic characterization (FTIR, XRD, TGA, and SEM) confirmed the agent's structural integrity, thermal resilience, and spherical morphology, and then its physical, chemical properties, and compatibility with drilling fluid were further explored. As a result, the key functional attributes include: (1) Tunable thermo‐responsiveness: softening point modulation (100°C–120°C) via wax/resin compositional control, (2) enhanced dissolution kinetics: 99% hydrocarbon solubility within 24 h across 60°C–90°C operational window, (3) precision‐engineered gradation: the particle sizes ( D 10 , D 50 , and D 90 ) of oil‐soluble temporary plugging agent Poly‐zd‐1 are 83.08, 241, and 405.2 μm, respectively. Further, the Poly‐zd‐1 has a good size matching relationship with other components of drilling fluid, with no obvious influence on the pH (ΔpH ≤ 0.35) and density (density variance < 0.016 g/cm 3 ). Moreover, the Poly‐zd‐1 was introduced into drilling fluids by 2.0 wt%; as a result, the filtration, rheology, and plugging performance of drilling fluids were improved. Finally, the reservoir protection characteristics and mechanism of Poly‐zd‐1 in drilling operations were studied by quantitative and qualitative research.