Multi phase fluids are common in energy-related geotechnical problems, including gaswater, gas-oil, ice-water, hydrate-water, and oil-water fluid conditions. The generalization of classical unsaturated soil mechanics concepts to energy geotechnology requires physical understanding of surface tension, contact angle, capillary pressure, solubility and nucleation. Eventually, these pore-level processes affect the granular skeleton. Together, pore and particle-scale interactions upscale through the sediment structure to affect its macroscale response. Possible emergent phenomena include fluid percolation, residual saturation and recovery efficiency; fluid driven fractures, lenses, fingering and pipe formation; bubble migration and bottom blow up.