TY - JOUR
T1 - Scaling analysis of hydrogen flow with carbon dioxide cushion gas in subsurface heterogeneous porous media
AU - Wang, G.
AU - Pickup, G.
AU - Sorbie, K.
AU - Mackay, E.
N1 - Funding Information:
Leverhulme Trust is thanked for supporting the Early-Career fellowship held by Dr. Gang Wang. Energi Simulation is thanked for funding the chair in CCUS and Reactive Flow Simulation at Heriot-Watt University held by Prof. Eric Mackay. Dr Gillian Pickup is part-funded by HyStorPor EPSRC EP/S027815/1. The authors would also like to appreciate the support by CMG for the use of CMG/GEM and Schlumberger for the use of Petrel.
Funding Information:
Leverhulme Trust is thanked for supporting the Early-Career fellowship held by Dr. Gang Wang. Energi Simulation is thanked for funding the chair in CCUS and Reactive Flow Simulation at Heriot-Watt University held by Prof. Eric Mackay. The authors would also like to appreciate the support by CMG for the use of CMG/GEM and Schlumberger for the use of Petrel.
Publisher Copyright:
© 2021 Hydrogen Energy Publications LLC
PY - 2022/1/8
Y1 - 2022/1/8
N2 - Subsurface hydrogen (H2) storage in geological formations is of growing interest for decarbonization. However, there is a knowledge gap in understanding the multiphase flow involved in this process, which can have a significant impact on the recovery performance of H2. Therefore, a full-compositional modeling study was conducted to analyze potential issues and to understand the fundamental hydrodynamic mechanisms of H2 storage. We performed a range of 2D vertical simulations at the decametre scale with a very fine cell size (0.1 m) to observe the detailed flow behaviour of H2 with carbon dioxide (CO2) as cushion gas in various flow regimes. Issues such as viscous instability, capillary bypassing, gas trapping and gravity segregation are analysed here. To generalize our calculations, we have validated and applied the scaling theory in the context of subsurface H2 storage. Since this study is focused on the hydrodynamic behaviour, three dimensionless groups, including aspect factor, capillary/viscous ratio and gravity/viscous ratio were identified to correlate recovery performance between various scales in a fixed heterogeneous system. It was found that H2 could infiltrate the cushion gas in the proximity of the injectors, meaning that CO2 is not displaced away from the injectors in a piston-like fashion. As a result, the purity of the back produced H2 is much degraded, particularly in a viscous-dominated scenario. On the other hand, the injected H2 mostly accumulates at the top forming a highly restricted mixing zone with CO2 in the gravity-dominated case. The recovery performance is therefore much improved in this case. Although the gas distribution can be significantly altered by capillary forces leading to bypassed zones, the recovery performance of H2 is hardly influenced. This is because the back-produced H2 recovery is not dependent on the sweep efficiency of the gas. H2 can be back produced following the same paths which were formed during injection.
AB - Subsurface hydrogen (H2) storage in geological formations is of growing interest for decarbonization. However, there is a knowledge gap in understanding the multiphase flow involved in this process, which can have a significant impact on the recovery performance of H2. Therefore, a full-compositional modeling study was conducted to analyze potential issues and to understand the fundamental hydrodynamic mechanisms of H2 storage. We performed a range of 2D vertical simulations at the decametre scale with a very fine cell size (0.1 m) to observe the detailed flow behaviour of H2 with carbon dioxide (CO2) as cushion gas in various flow regimes. Issues such as viscous instability, capillary bypassing, gas trapping and gravity segregation are analysed here. To generalize our calculations, we have validated and applied the scaling theory in the context of subsurface H2 storage. Since this study is focused on the hydrodynamic behaviour, three dimensionless groups, including aspect factor, capillary/viscous ratio and gravity/viscous ratio were identified to correlate recovery performance between various scales in a fixed heterogeneous system. It was found that H2 could infiltrate the cushion gas in the proximity of the injectors, meaning that CO2 is not displaced away from the injectors in a piston-like fashion. As a result, the purity of the back produced H2 is much degraded, particularly in a viscous-dominated scenario. On the other hand, the injected H2 mostly accumulates at the top forming a highly restricted mixing zone with CO2 in the gravity-dominated case. The recovery performance is therefore much improved in this case. Although the gas distribution can be significantly altered by capillary forces leading to bypassed zones, the recovery performance of H2 is hardly influenced. This is because the back-produced H2 recovery is not dependent on the sweep efficiency of the gas. H2 can be back produced following the same paths which were formed during injection.
KW - CO cushion gas
KW - Fine-scale flow simulation
KW - Flow regimes
KW - H purity
KW - Scaling theory
KW - Underground gas storage
UR - http://www.scopus.com/inward/record.url?scp=85119451360&partnerID=8YFLogxK
U2 - 10.1016/j.ijhydene.2021.10.224
DO - 10.1016/j.ijhydene.2021.10.224
M3 - Article
AN - SCOPUS:85119451360
VL - 47
SP - 1752
EP - 1764
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
SN - 0360-3199
IS - 3
ER -
