Plugging performance and mechanism of an OBDF oil-absorbing resin (MMA-SMA-St) plugging agent

To treat the issue of increased resource wastage due to the higher plugging tendencies of oil-based drilling fluids (OBDF) relative to water-based drilling fluids, this study synthesized a ternary composite oil-absorbing resin and optimized its synthesis parameters. The influence of temperature variations on the resin's oil absorption capacity was assessed. Techniques such as infrared spectroscopy, scanning electron microscopy, TGA-DSC measurements, crosslinking degree analysis, contact angle analysis, X-ray photoelectron spectrometry analysis and examination of the resin's plugging mechanism were employed to investigate its molecular structure, oil absorption properties, and plugging efficiency. Additionally, the impact of various synthesis conditions on the oil absorption expansion rate of the oil-absorbing resin was examined. The findings indicate that the resin developed in this research maintains robust oil absorption capabilities at 160 °C, exhibiting an oil absorption expansion rate of 12.5 g g^-1. At this temperature, the composite resin particles effectively sealed leaks of widths 0.25, 0.5, and 0.75 μm. Comparative analysis revealed that adding 3% of these resin particles to OBDF significantly enhanced the sealing of fractures. Remarkably, at 160 °C, OBDF amended with resin particles managed to completely seal fractures measuring 0.25 μm. The novelty of this study is attributed to the utilization of styrene for enhancing the resin's rigidity, coupled with the application of octadecyl methacrylate, which contains long-chain alkyl groups, to optimize the oil absorption and expansion characteristics of the oil-absorbing resin.