A novel temperature-sensitive expandable lost circulation material based on shape memory epoxy foams to prevent losses in geothermal drilling

•The applications of shape memory polymer in petroleum industry were reviewed.•Lost circulation materials based on shape memory epoxy foams (SMP-LCM) with temperature response and expandable properties were designed and synthesized.•The shape memory mechanism of shape memory epoxy foams used to prepare SMP-LCMs was revealed.•The plugging experiment demonstrated that the SMP-LCMs were effective in loss control. Lost circulation will inevitably increase non-productive time (NPT) and well cost. The application of high-efficiency lost circulation materials (LCMs) plays an indispensable role in preventing and mitigating loss. The development of new LCMs based on stimuli-responsive materials is an important research direction and it is expected to realize the revolutionary development of LCMs. In recent years, the temperature-responsive plugging agent based on shape memory polymers has caused a lot of attention. In this paper, based on the shape memory epoxy polymer (SMEP) and hollow glass beads (HGBs), a shape memory epoxy foam (SMEF) was successfully synthesized. The results show that the shape memory temperature (51.6 °C - 97.5 °C) of the SMEPs has a good linear relationship with the content of curing agent 4, 4′-diaminodiphenyl methane (DDM) (12% - 20%), and the expansion ratio (0% - 120.2%) of the SMEFs has a good linear relationship with the content of HGBs (0% - 50%). The mechanism of the SMEFs was proposed. A novel temperature-sensitive and expandable plugging agent (SMP-LCM) has been developed. The plugging experiment shows that SMP-LCM has a good plugging effect on high permeability loss zone simulated by sand beds. Compared with conventional LCMs (e.g., nutshells or fibers), SMP-LCMs can eliminate the risk of plugging of downhole drilling tools and enhance the plugging effect. [Display omitted]