Tianze Liu: Seismic and borehole-acoustic observations of free-gas migration

Dr. Tianze Liu, Research Associate at Woods Hole Oceanographic Institute, presents “Seismic and borehole-acoustic observations of free-gas migration and tensile fracture growth during low-temperature peridotite alteration” at the MIT Earth Resources Laboratory on February 13, 2026. "The dual capacity of peridotite formations to produce hydrogen and absorb CO2 through low-temperature alteration is attracting increasing interest from the energy industry. However, key questions regarding the alteration processes remain, including: (1) How does the hydrogen produced by serpentinization migrate in the formation, and (2) Can the alteration-induced volume expansions fracture the rock, promoting further alteration by creating new reaction surfaces? In this talk, I will synthesize observations from a unique seismic and borehole-acoustic experiment at the Oman Drilling Project Multi-Borehole Observatory, which detected a variety of signals associated with active peridotite alteration. We find that free gas migrates through the subsurface fracture network in a highly dynamic manner and that active alteration likely maintains near-critical stress at the tensile fracture tips in the borehole, such that small pore-pressure perturbations can trigger fracture growth. Our results indicate that: (1) Free gas may be more prevalent in peridotite formations than previously estimated, (2) Seismological techniques can effectively monitor free-gas migration in peridotite formations, and (3) Active alteration may facilitate fracture growth during stimulated geological hydrogen production and carbon mineralization."