Experimental Study on Short-Term Fracture Conductivity Simulation of Hydraulic Fractures in Marine Combustible Ice Reservoirs

Marine combustible ice, as a potential clean energy resource, has attracted widespread attention in recent years. To enhance its production efficiency, hydraulic fracturing is considered a promising technique, in which fracture conductivity is one of the key parameters for evaluating stimulation performance. However, experimental investigations on low-strength sediments remain limited, and the evolution of fracture conductivity in hydrate-bearing sediments has not been systematically understood. Since ice and combustible ice share similar characteristics in terms of crystal structure, spectral features, mechanical behavior, and thermal expansion, and ice remains stable under low-temperature conditions, ice was employed as an experimental analog for combustible ice. This study systematically investigated the effects of proppant particle size, proppant concentration, and ice saturation on the short-term fracture conductivity. The results indicate that fracture conductivity increases with higher ice saturation and sand concentration. Larger proppant particles exhibit higher initial conductivity but experience greater conductivity loss. A multi-factor prediction model for the short-term fracture conductivity of fractured marine combustible ice reservoirs was established. The effects of properties of rock plates and sanding induced fracture clogging on conductivity are further discussed. These findings provide an experimental basis and theoretical reference for understanding the fracture conductivity characteristics and optimizing fracturing operations in marine combustible ice reservoirs.