The Role of Capillary Hysteresis and Pore-Scale Heterogeneity in Limiting the Migration of Buoyant Immiscible Fluids in Porous Media
Abstract Understanding the main mechanisms affecting long‐term migration and redistribution of injected CO 2 in geological carbon storage is needed for developing predictive models to assess environmental risks and designing monitoring schemes. Preparation of a postinjection site care plan is required for CO 2 injection wells, including monitoring of pressure changes and injected CO 2 plume. Knowledge gaps exist regarding assessment of postinjection monitoring timeframes for the CO 2 plume because the processes driving long‐term CO 2 plume migration and trapping are not fully understood. In the postinjection stage of geological carbon storage, redistribution of CO 2 occurs mainly due to buoyancy and capillary forces. This work presents experimental and modeling studies to investigate processes contributing to postinjection plume distribution and stabilization. We conducted a flow cell experiments (0.5 m × 0.05 m × 0.01 m) with two immiscible fluid phases in a glass bead porous medium to study postinjection plume behavior. We employed a hysteretic macroscopic two‐phase flow model to interpret the experimental results and to understand main processes leading to plume stabilization. Our findings show that capillary pressure hysteresis explains the experimentally observed plume shape and redistribution at early postinjection stages; however, the long‐term plume migration and eventual plume stabilization can only be represented when in addition microscale heterogeneity is accounted for. Results also show that plume stabilization can be extremely slow and that the migration of the plume front can occur through multiple intermittent bursts over long times. Further studies are needed to understand implications of the results for more realistic porous media and large‐scale storage reservoirs.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE)
- Grant/Contract Number:
- AC02-05CH11231; DE‐AC02‐05CH11231
- OSTI ID:
- 1477335
- Alternate ID(s):
- OSTI ID: 1458804
- Journal Information:
- Water Resources Research, Vol. 54, Issue 7; ISSN 0043-1397
- Publisher:
- American Geophysical Union (AGU)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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