A novel preparation method for nondestructive multivoid structure core: Use thermosensitive phase-change material

Before developing energy minerals, core physical simulation experiments are essential to evaluate the effectiveness of development methods. This study proposes a nondestructive method for preparing multivoid structure cores using a thermosensitive phase-change material. Natural camphor powder, evenly mixed with quartz sand, volatilized to form secondary pores, with key volatilization factors determined experimentally. The effects of various parameters on core matrix porosity and permeability were systematically analyzed, and predictive equations were established using statistical methods. Additionally, camphor blocks of specific shapes and sizes, compressed under high pressure, volatilized within the cores to create fractures and caves. Nuclear magnetic resonance imaging (NMRI) reconstruction and three-dimensional core modeling confirmed that this method allowed precise control over the location and size of fractures/caves while maintaining core integrity. This work provides a cost-effective approach to fabricating artificial multivoid structure cores with controllable parameters, offering a valuable foundation for future oilfield development research.