2025/04/26 by Eike Marie Thaysen, Ian B. Butler, Aliakbar Hassanpouryouzband +6 · 2 voices · 1 citation
Engineering · #Hydrocarbon exploration and reservoir analysis #Hydraulic Fracturing and Reservoir Analysis #Enhanced Oil Recovery Techniques
paper · doi:10.1016/j.jcis.2025.137704
• H 2 displacement of brine includes sudden pore-filling events known as Haines jumps. • Intermittent H 2 flow occurs in specific regions of the rock. • A higher H 2 fractional flow increased the H 2 saturation from 20–22% to 28%. • Phase connectivity appeared to have little control on H 2 saturation. Hydrogen (H 2 ) storage in porous geological formations offers a promising means to balance supply and demand in the renewable energy sector, supporting the energy transition. Important unknowns to this technology include the H 2 fluid flow dynamics through the porous medium which affect H 2 injectivity and recovery. We used time-resolved X-ray computed microtomography to image real-time unsteady and steady state injections of H 2 and brine (2 M KI) into a Clashach sandstone core at 5 MPa and ambient temperature. In steady state injections, H 2 entered the brine-saturated rock within seconds, dispersing over several discrete pores. Over time, some H 2 ganglia connected, disconnected and then reconnected from each other (intermittent flow), indicating that the current presumption of a constant connected flow pathway during multiphase fluid flow is an oversimplification. Pressure oscillations at the sample outlet were characterized as red noise, supporting observations of intermittent pore-filling. At higher H 2 fractional flow the H 2 saturation in the pore space increased from 20–22 % to 28 %. Average Euler characteristics were generally positive over time at all H 2 flow fractions, indicating poorly connected H 2 clusters and little control of connectivity on the H 2 saturation. In unsteady state injections, H 2 displaced brine in sudden pore-filling events termed Haines jumps, which are key to understanding fluid dynamics in porous media. Our results suggest a lower H 2 storage capacity in sandstone aquifers with higher injection-induced hydrodynamic flow and suggest a low H 2 recovery. For more accurate predictions of H 2 storage potential and recovery, geological models should incorporate energy-dissipating processes such as Haines jumps.