Lignin-based plugging hydrogel with high-temperature resistance and adjustable gelation

Lost circulation is a prevalent and intricate phenomenon in the domain of oil and gas drilling, which has resulted in significant economic losses for the global oil industry. Common gel lost circulation materials have been observed to exhibit deficiencies in temperature resistance and gel strength. In this study, a lignin-based plugging hydrogel (Lig-plugel) was prepared for lost circulation plugging using a simple method. The hydrogel employed the self-cross-linking mechanism of lignin in a high-temperature environment, which reduced the quantity of cross-linker, achieved the objective of regulating gelation time, and enhanced its mechanical properties. The maximum compressive strain of Lig-plugel synthesized at 200 °C with a 25 wt% cross-linker amount reached 76.83%, and the compressive strength and compressive toughness reached 1.85 MPa and 276.13 kJ/m³, respectively. Furthermore, Lig-plugel exhibits excellent heat resistance. It demonstrates minimal mass loss during thermal decomposition in high-temperature environments below 220 °C, which is sufficient for high-temperature applications. Additionally, the simulated plugging experiments indicate that Lig-plugel has an effective plugging effect and is adaptable. This study presents an environmentally friendly and sustainable solution to the lost circulation problem and has a broad application prospect in the field of oil and gas drilling.