Abstract:Aiming at those problems that plugging water agents are lower bonding strength, easily cracked in the progress of water plugging and difficultly degraded when agent has been cured, this paper offers a way to prepare a degradable and high-strength resin water plugging agent by using vegetable oil residue with epoxidation modification and methylhexahydrophthalic anhydride. Based on a combination of microstructure characterization, laboratory test and theoretical analysis, this paper evaluates thermal stability, compressive strength and water plugging performance of VOR, respectively, as well as explains curing mechanism and degradation mechanism of VOR. The rheological properties, stability, mechanical properties, plugging performance, curing mechanism and degradation mechanism of the plugging agent were investigated by means of theoretical analysis, microstructure characterization and indoor experimental evaluation. The results showed that the preparation mechanism of VOR gel was polyester crosslinking polymerization.The plugging agent has good injection performance and controllable curing time. The compressive strength of the plugging agent is more than 40 MPa, the thermal degradation temperature is 257.87 °C, and the mass retention rate of the plugging agent is more than 93 % under the condition of high temperature and high salinity ( curing temperature is 100 °C, salinity ≥ 8 × 104 mg / L ) for 90 days. The plugging agent has excellent stability. The distribution of spherical particles of plugging agent molecules endows the plugging agent with high strength and high adhesion characteristics, which makes the plugging agent have excellent plugging performance. When the temperature is 100 °C, the breakthrough pressure of water flooding is greater than 20 MPa. At 80 ~ 140 °C, the VOR gel can be completely degraded within 270 h, and the higher the reaction temperature, the faster the degradation rate. The infrared spectrum confirmed that the degradation mechanism of the plugging agent was the decomposition of the ester bond in the cross-linked structure. The development of this plugging agent not only realizes the resource utilization of plant residue, but also meets the needs of high-strength plugging agent for plugging and pressure integration, casing leakage treatment, horizontal well pipe external channeling and other operations.