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A platform for research: civil engineering, architecture and urbanism
Composite confining systems: Rethinking geologic seals for permanent CO2 sequestration
https://orcid.org/0000-0002-7913-4305
https://orcid.org/0000-0003-0280-2982
https://orcid.org/0000-0002-2689-3113
https://orcid.org/0000-0002-3344-6274
https://orcid.org/0000-0001-8817-9065
Highlights Composite confining systems are multi-layer systems of discontinuous barriers. They work by drastically lowering effective Kv/Kh, creating long flow paths for CO2. Migration-assisted trapping effectively immobilizes CO2 with little vertical migration. Risks are familiar—legacy wells, permeable faults and high-relief structures. Composite confining systems are ideally suited to the goal of permanent sequestration.
Abstract Permanent containment is paramount for geologic carbon sequestration. Petroleum experience proves the possibility but also creates bias—to date, carbon storage projects have used seals similar to those of producing petroleum accumulations—thick, laterally extensive, effectively impermeable layers. These work for CO2, but may not be present where needed, nor optimal for sequestration. We introduce the concept of composite confining systems, defined here as multi-layer stratigraphic systems of discontinuous barriers with no a priori requirements for continuity or minimum capillary entry pressure. We explore the concept through physical analog modeling, geologic characterization and full-scale numerical modeling. We find that barriers need only offer enough capillary entry pressure contrast to divert the flow of CO2 and that barrier frequency and barrier area are the key variables in retarding vertical migration. Data from Southern Louisiana Miocene deltaic deposits shows ∼5–15 mudstone barriers/100 m of section, with average mudstone lengths of over 1 km and aspect ratios ∼2:1, giving effective ratios of vertical to horizontal permeability (kv/kh) of ∼0.0005. Full-scale reservoir models show that these systems can completely arrest vertical migration of industrial-scale volumes of CO2 (10's of megatons) within a few 10's of meters of stratigraphic section. Unlike more conventional petroleum seals and traps, which retain CO2 in a concentrated, mobile state, composite confining systems disperse and immobilize it via migration-assisted trapping. The greatest risks to performance of composite confining systems are the same as for conventional seals–the potential shortcuts across stratigraphic barriers, e.g., legacy wells, fluid escape pipes and permeable faults that focus flow.
Composite confining systems: Rethinking geologic seals for permanent CO2 sequestration
https://orcid.org/0000-0002-7913-4305
https://orcid.org/0000-0003-0280-2982
https://orcid.org/0000-0002-2689-3113
https://orcid.org/0000-0002-3344-6274
https://orcid.org/0000-0001-8817-9065
Highlights Composite confining systems are multi-layer systems of discontinuous barriers. They work by drastically lowering effective Kv/Kh, creating long flow paths for CO2. Migration-assisted trapping effectively immobilizes CO2 with little vertical migration. Risks are familiar—legacy wells, permeable faults and high-relief structures. Composite confining systems are ideally suited to the goal of permanent sequestration.
Abstract Permanent containment is paramount for geologic carbon sequestration. Petroleum experience proves the possibility but also creates bias—to date, carbon storage projects have used seals similar to those of producing petroleum accumulations—thick, laterally extensive, effectively impermeable layers. These work for CO2, but may not be present where needed, nor optimal for sequestration. We introduce the concept of composite confining systems, defined here as multi-layer stratigraphic systems of discontinuous barriers with no a priori requirements for continuity or minimum capillary entry pressure. We explore the concept through physical analog modeling, geologic characterization and full-scale numerical modeling. We find that barriers need only offer enough capillary entry pressure contrast to divert the flow of CO2 and that barrier frequency and barrier area are the key variables in retarding vertical migration. Data from Southern Louisiana Miocene deltaic deposits shows ∼5–15 mudstone barriers/100 m of section, with average mudstone lengths of over 1 km and aspect ratios ∼2:1, giving effective ratios of vertical to horizontal permeability (kv/kh) of ∼0.0005. Full-scale reservoir models show that these systems can completely arrest vertical migration of industrial-scale volumes of CO2 (10's of megatons) within a few 10's of meters of stratigraphic section. Unlike more conventional petroleum seals and traps, which retain CO2 in a concentrated, mobile state, composite confining systems disperse and immobilize it via migration-assisted trapping. The greatest risks to performance of composite confining systems are the same as for conventional seals–the potential shortcuts across stratigraphic barriers, e.g., legacy wells, fluid escape pipes and permeable faults that focus flow.
Composite confining systems: Rethinking geologic seals for permanent CO2 sequestration
https://orcid.org/0000-0002-7913-4305
https://orcid.org/0000-0003-0280-2982
https://orcid.org/0000-0002-2689-3113
https://orcid.org/0000-0002-3344-6274
https://orcid.org/0000-0001-8817-9065
Highlights Composite confining systems are multi-layer systems of discontinuous barriers. They work by drastically lowering effective Kv/Kh, creating long flow paths for CO2. Migration-assisted trapping effectively immobilizes CO2 with little vertical migration. Risks are familiar—legacy wells, permeable faults and high-relief structures. Composite confining systems are ideally suited to the goal of permanent sequestration.
Abstract Permanent containment is paramount for geologic carbon sequestration. Petroleum experience proves the possibility but also creates bias—to date, carbon storage projects have used seals similar to those of producing petroleum accumulations—thick, laterally extensive, effectively impermeable layers. These work for CO2, but may not be present where needed, nor optimal for sequestration. We introduce the concept of composite confining systems, defined here as multi-layer stratigraphic systems of discontinuous barriers with no a priori requirements for continuity or minimum capillary entry pressure. We explore the concept through physical analog modeling, geologic characterization and full-scale numerical modeling. We find that barriers need only offer enough capillary entry pressure contrast to divert the flow of CO2 and that barrier frequency and barrier area are the key variables in retarding vertical migration. Data from Southern Louisiana Miocene deltaic deposits shows ∼5–15 mudstone barriers/100 m of section, with average mudstone lengths of over 1 km and aspect ratios ∼2:1, giving effective ratios of vertical to horizontal permeability (kv/kh) of ∼0.0005. Full-scale reservoir models show that these systems can completely arrest vertical migration of industrial-scale volumes of CO2 (10's of megatons) within a few 10's of meters of stratigraphic section. Unlike more conventional petroleum seals and traps, which retain CO2 in a concentrated, mobile state, composite confining systems disperse and immobilize it via migration-assisted trapping. The greatest risks to performance of composite confining systems are the same as for conventional seals–the potential shortcuts across stratigraphic barriers, e.g., legacy wells, fluid escape pipes and permeable faults that focus flow.
Composite confining systems: Rethinking geologic seals for permanent CO2 sequestration
Bump, Alexander P. (author) / Bakhshian, Sahar (author) / Ni, Hailun (author) / Hovorka, Susan D. (author) / Olariu, Marianna I. (author) / Dunlap, Dallas (author) / Hosseini, Seyyed A. (author) / Meckel, Timothy A. (author)
2023-05-07
Article (Journal)
Electronic Resource
English
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