Gunn M G Teige - Academia.edu (original) (raw)

Papers by Gunn M G Teige

Research paper thumbnail of Storage of CO2 in saline aquifers–Lessons learned from 10 years of injection into the Utsira Formation in the Sleipner area

Energy Procedia, 2009

The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reach... more The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reached the top of the Utsira Formation, but has instead migrated laterally below imperfect intra-reservoir seals. The CO2 trapping below the structural spill point in the Utsira Formation is due to local mini traps, capillary flow resistance, and the hydrodynamic drive of the injection.

Research paper thumbnail of Capillary resistance and trapping of hydrocarbons: a laboratory experiment

Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are ... more Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are sufficiently small to prevent a flux of oil into the cap rock. In order to investigate the influence of aquifer overpressures on oil retention, water pressure was applied to a water-wet, highly permeable (1988 mD) core sample, which was oil-saturated to irreducible water saturation S wi and mounted with a low-permeability and water-wet membrane at the outlet. A water pressure difference of 0.5 MPa was applied across the core. This pressure was high enough to ensure fluid flow through the sample. The experiment was designed to see whether the water pressure would force oil through the membrane or if capillary forces at the sandstone–membrane interface would retain the oil, in which case water flow might take place in the (residual) water in the core and through the membrane. The experiment showed that oil was kept in place by capillary forces while water flowed through the core and the membrane. Accordingly, residual water can move through sandstones that are saturated to S wi. The experiments also demonstrated that the permeability associated with this residual water is high enough to prevent overpressures in the aquifer below the oil–water contact from pushing oil through a membrane seal. Thus, even for this highly permeable sandstone, the overpressure in the aquifer will not cause capillary seal failure.

Research paper thumbnail of Seismic characteristics of fluid leakage from an underfilled and overpressured Jurassic fault trap in the Norwegian North Sea

Pre-drill estimates of hydrocarbon column heights are often uncertain, particularly where filling... more Pre-drill estimates of hydrocarbon column heights are often uncertain, particularly where filling to structural spill point is questioned. Identification of locations where vertical leakage is concentrated can allow more reliable hydrocarbon column height predictions. The locations of vertical leakage were sought on seismic data over an underfilled and overpressured trap (35/10-2) in the Norwegian North Sea. It was hoped that one single location or one single narrow leakage zone coinciding with the gas–water contact would be found. If such a location or zone existed, it was expected to be in or above a fault plane, as leakage in the 35/10-area is thought to mainly result from shear failure along faults. The investigation found a zone with pronounced dimming above a triple fault intersection bounding the 35/10-2 structure. This zone stretches further downdip and is positioned above a fault plane. The shallowest part of this zone intersects the top of the reservoir at the depth of the proven gas–water contact. These observations suggest that a discrete leakage zone, of which the shallowest part controls the column height of the structure, has been identified and that the column height is limited by leakage resulting from shear failure. The occurrence of similar seismic features over undrilled structures can lead to safer assessments of hydrocarbon column heights, especially if the observations are consistent with the general knowledge of stress state and leakage processes in the area.

Research paper thumbnail of Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring

… : an outgrowth of the …, 1998

Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Sh... more Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring, in Law, BE, GF ...

Research paper thumbnail of Storage of CO2 in saline aquifers–Lessons learned from 10 years of injection into the Utsira Formation in the Sleipner area

Energy Procedia, 2009

The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reach... more The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reached the top of the Utsira Formation, but has instead migrated laterally below imperfect intra-reservoir seals. The CO2 trapping below the structural spill point in the Utsira Formation is due to local mini traps, capillary flow resistance, and the hydrodynamic drive of the injection.

Research paper thumbnail of The Influence of Stress Regimes on Hydrocarbon Leakage

Evaluating Faults and Cap Rock Seals. …, 2005

ABSTRACT Hydrocarbon leakage through faults and fractures commonly limits in-place hydrocarbon re... more ABSTRACT Hydrocarbon leakage through faults and fractures commonly limits in-place hydrocarbon reserves. Faulting and fracturing are controlled by effective stress changes, and such changes may therefore alter hydrocarbon column heights. The predictive power of stress history analyses in seal evaluation depends on how accurately the stress history and relationships between effective stress changes and hydrocarbon leakage can be determined. Stress history and hydrocarbon occurrence were examined in four different overpressured provinces of offshore Norway in the search for such relationships. These provinces have experienced different geological histories and variable amounts of hydrocarbon leakage. Because all these areas received fairly recent hydrocarbon charge, the work focused on the identification of recent geological events that may subsequently have influenced recent stress history, including the present-day stresses. Areas of recent structuring were found to be characterized by more extensive hydrocarbon leakage than areas with less such structuring. This increased frequency of hydrocarbon leakage was interpreted to be the result of shear failure at the trap crests, induced by the combined effects of elevated pore pressures, stress anisotropy, and recent stress changes. These results suggest that identification of recent stress changes based on the geological history of the study area could aid the prediction of hydrocarbon occurrence. It is inferred that stress history analyses can also reduce the uncertainty involved in seal analyses elsewhere.

Research paper thumbnail of Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring

… : an outgrowth of the …, 1998

Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Sh... more Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring, in Law, BE, GF ...

Research paper thumbnail of Leakage observations from seismic data

Research paper thumbnail of Membrane seal leakage through establishment of oil-wet flow paths

Journal of Petroleum Geology

Leakage through non-fractured shaly caprock sequences is often envisioned as hydrocarbon percolat... more Leakage through non-fractured shaly caprock sequences is often envisioned as hydrocarbon percolation through water-wet pore networks. Leakage by this process requires that the buoyancy of the hydrocarbon column overcomes the capillary entry pressure of the caprock pores. If it does not, then leakage through caprocks that are not hydrofractured depends on diffusion of hydrocarbons, which is an extremely slow process. As a result, the hydrocarbon residence time would be almost endless. We suggest a novel model for leakage through non-fractured caprock shales. Two lines of laboratory-based research motivate our suggestion. One of these addresses wettability alterations, while the other addresses pore-scale fluid flow in the presence of capillary sealing. The latter approach has demonstrated that water can flow vertically through water-wet oil reservoirs and further through caprocks, whereas the oil remains in the reservoir. This recognition is a consequence of the observation that resi...

Research paper thumbnail of The lack of relationship between overpressure and porosity in North Sea and Haltenbanken shales

Marine and Petroleum Geology, 1999

Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explainin... more Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explaining overpressured formations. This mechanism relies on the hypothesis that overpressured shales have higher porosity than normally pressured shales for a given depth. Converted to porosity units, log response data from two Jurassic shales at Haltenbanken and nine Cretaceous and Tertiary shales in the Norwegian sector of the North Sea have been investigated to see whether such a relationship exists in these areas. The depth of the studied shale formations varies between 0.5-5 km. The degree of overpressuring within one formation typically varies by 20 MPa.

Research paper thumbnail of Storage of CO 2 in saline aquifers–Lessons learned from 10 years of injection into the Utsira Formation in the Sleipner area

Energy Procedia, 2009

The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reach... more The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reached the top of the Utsira Formation, but has instead migrated laterally below imperfect intra-reservoir seals. The CO2 trapping below the structural spill point in the Utsira Formation is due to local mini traps, capillary flow resistance, and the hydrodynamic drive of the injection.

Research paper thumbnail of New Sealing Analysis Strategies Based on Recent Progress in the Understanding of Compaction and Fluid Flow Processes

First EAGE International Conference on Fault and Top Seals - What do we know and where do we go?, 2003

Research paper thumbnail of History-matching of CO2 Flow at Sleipner – New Insight based on Analyses of Temperature and Seismic Data

Third EAGE CO2 Geological Storage Workshop, 2012

Research paper thumbnail of The Use of Internally Consistent Models in Seal Analysis

3rd EAGE International Conference on Fault and Top Seals, 2012

Research paper thumbnail of Regional CO2 Storage Capacity Estimation - Insight Gained from Local Volumetric Analyses

1st Sustainable Earth Sciences Conference and Exhibition (SES2011), 2011

Research paper thumbnail of Importance of Pressure Management in CO2 Storage

Offshore Technology Conference, 2013

Research paper thumbnail of Evaluation of caprock integrity in the western (high-pressured) haltenbanken area--a case history based on analyses of seismic signatures in overburden rocks

Norwegian Petroleum …, 2002

... based on analyses of seismic signatures in overburden rocks Gunn MG Teige, Christian Hermanru... more ... based on analyses of seismic signatures in overburden rocks Gunn MG Teige, Christian Hermanrud, Oddbj0rn S. Klovjan, Per Emil Eliassen, Helge ... In: AM Spencer, SO Johnsen, A. M0rk, E. Nysaether, P. Songstad and A. Spinnanger (Editors), Petroleum Geology of the North ...

Research paper thumbnail of Seismic characteristics of fluid leakage from an underfilled and overpressured Jurassic fault trap in the Norwegian North Sea

Petroleum Geoscience, 2004

... Previous analysis has suggested that shear failure, combined with high fluid pressures, was t... more ... Previous analysis has suggested that shear failure, combined with high fluid pressures, was the main mechanism for leakage in the study area (Nordgård Bolås & Hermanrud 2003). ... Lars Reistad is thanked for his graphical support. Received July 2, 2002. ...

Research paper thumbnail of Capillary resistance and trapping of hydrocarbons: a laboratory experiment

Petroleum Geoscience, 2005

Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are ... more Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are sufficiently small to prevent a flux of oil into the cap rock. In order to investigate the influence of aquifer overpressures on oil retention, water pressure was applied to a water-wet, ...

Research paper thumbnail of The lack of relationship between overpressure and porosity in North Sea and Haltenbanken shales

Marine and Petroleum Geology, 1999

Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explainin... more Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explaining overpressured formations. This mechanism relies on the hypothesis that overpressured shales have higher porosity than normally pressured shales for a given depth. Converted to porosity units, log response data from two Jurassic shales at Haltenbanken and nine Cretaceous and Tertiary shales in the Norwegian sector of the North Sea have been investigated to see whether such a relationship exists in these areas. The depth of the studied shale formations varies between 0.5-5 km. The degree of overpressuring within one formation typically varies by 20 MPa.

Research paper thumbnail of Storage of CO2 in saline aquifers–Lessons learned from 10 years of injection into the Utsira Formation in the Sleipner area

Energy Procedia, 2009

The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reach... more The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reached the top of the Utsira Formation, but has instead migrated laterally below imperfect intra-reservoir seals. The CO2 trapping below the structural spill point in the Utsira Formation is due to local mini traps, capillary flow resistance, and the hydrodynamic drive of the injection.

Research paper thumbnail of Capillary resistance and trapping of hydrocarbons: a laboratory experiment

Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are ... more Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are sufficiently small to prevent a flux of oil into the cap rock. In order to investigate the influence of aquifer overpressures on oil retention, water pressure was applied to a water-wet, highly permeable (1988 mD) core sample, which was oil-saturated to irreducible water saturation S wi and mounted with a low-permeability and water-wet membrane at the outlet. A water pressure difference of 0.5 MPa was applied across the core. This pressure was high enough to ensure fluid flow through the sample. The experiment was designed to see whether the water pressure would force oil through the membrane or if capillary forces at the sandstone–membrane interface would retain the oil, in which case water flow might take place in the (residual) water in the core and through the membrane. The experiment showed that oil was kept in place by capillary forces while water flowed through the core and the membrane. Accordingly, residual water can move through sandstones that are saturated to S wi. The experiments also demonstrated that the permeability associated with this residual water is high enough to prevent overpressures in the aquifer below the oil–water contact from pushing oil through a membrane seal. Thus, even for this highly permeable sandstone, the overpressure in the aquifer will not cause capillary seal failure.

Research paper thumbnail of Seismic characteristics of fluid leakage from an underfilled and overpressured Jurassic fault trap in the Norwegian North Sea

Pre-drill estimates of hydrocarbon column heights are often uncertain, particularly where filling... more Pre-drill estimates of hydrocarbon column heights are often uncertain, particularly where filling to structural spill point is questioned. Identification of locations where vertical leakage is concentrated can allow more reliable hydrocarbon column height predictions. The locations of vertical leakage were sought on seismic data over an underfilled and overpressured trap (35/10-2) in the Norwegian North Sea. It was hoped that one single location or one single narrow leakage zone coinciding with the gas–water contact would be found. If such a location or zone existed, it was expected to be in or above a fault plane, as leakage in the 35/10-area is thought to mainly result from shear failure along faults. The investigation found a zone with pronounced dimming above a triple fault intersection bounding the 35/10-2 structure. This zone stretches further downdip and is positioned above a fault plane. The shallowest part of this zone intersects the top of the reservoir at the depth of the proven gas–water contact. These observations suggest that a discrete leakage zone, of which the shallowest part controls the column height of the structure, has been identified and that the column height is limited by leakage resulting from shear failure. The occurrence of similar seismic features over undrilled structures can lead to safer assessments of hydrocarbon column heights, especially if the observations are consistent with the general knowledge of stress state and leakage processes in the area.

Research paper thumbnail of Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring

… : an outgrowth of the …, 1998

Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Sh... more Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring, in Law, BE, GF ...

Research paper thumbnail of Storage of CO2 in saline aquifers–Lessons learned from 10 years of injection into the Utsira Formation in the Sleipner area

Energy Procedia, 2009

The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reach... more The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reached the top of the Utsira Formation, but has instead migrated laterally below imperfect intra-reservoir seals. The CO2 trapping below the structural spill point in the Utsira Formation is due to local mini traps, capillary flow resistance, and the hydrodynamic drive of the injection.

Research paper thumbnail of The Influence of Stress Regimes on Hydrocarbon Leakage

Evaluating Faults and Cap Rock Seals. …, 2005

ABSTRACT Hydrocarbon leakage through faults and fractures commonly limits in-place hydrocarbon re... more ABSTRACT Hydrocarbon leakage through faults and fractures commonly limits in-place hydrocarbon reserves. Faulting and fracturing are controlled by effective stress changes, and such changes may therefore alter hydrocarbon column heights. The predictive power of stress history analyses in seal evaluation depends on how accurately the stress history and relationships between effective stress changes and hydrocarbon leakage can be determined. Stress history and hydrocarbon occurrence were examined in four different overpressured provinces of offshore Norway in the search for such relationships. These provinces have experienced different geological histories and variable amounts of hydrocarbon leakage. Because all these areas received fairly recent hydrocarbon charge, the work focused on the identification of recent geological events that may subsequently have influenced recent stress history, including the present-day stresses. Areas of recent structuring were found to be characterized by more extensive hydrocarbon leakage than areas with less such structuring. This increased frequency of hydrocarbon leakage was interpreted to be the result of shear failure at the trap crests, induced by the combined effects of elevated pore pressures, stress anisotropy, and recent stress changes. These results suggest that identification of recent stress changes based on the geological history of the study area could aid the prediction of hydrocarbon occurrence. It is inferred that stress history analyses can also reduce the uncertainty involved in seal analyses elsewhere.

Research paper thumbnail of Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring

… : an outgrowth of the …, 1998

Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Sh... more Page 71. Hermanrud, C., L. Wensaas, GMG Teige, E. Vik, HM Nordgård Bolås, and S. Hansen, 1998, Shale porosities from well logs on Haltenbanken (offshore mid-Norway) show no influence of overpressuring, in Law, BE, GF ...

Research paper thumbnail of Leakage observations from seismic data

Research paper thumbnail of Membrane seal leakage through establishment of oil-wet flow paths

Journal of Petroleum Geology

Leakage through non-fractured shaly caprock sequences is often envisioned as hydrocarbon percolat... more Leakage through non-fractured shaly caprock sequences is often envisioned as hydrocarbon percolation through water-wet pore networks. Leakage by this process requires that the buoyancy of the hydrocarbon column overcomes the capillary entry pressure of the caprock pores. If it does not, then leakage through caprocks that are not hydrofractured depends on diffusion of hydrocarbons, which is an extremely slow process. As a result, the hydrocarbon residence time would be almost endless. We suggest a novel model for leakage through non-fractured caprock shales. Two lines of laboratory-based research motivate our suggestion. One of these addresses wettability alterations, while the other addresses pore-scale fluid flow in the presence of capillary sealing. The latter approach has demonstrated that water can flow vertically through water-wet oil reservoirs and further through caprocks, whereas the oil remains in the reservoir. This recognition is a consequence of the observation that resi...

Research paper thumbnail of The lack of relationship between overpressure and porosity in North Sea and Haltenbanken shales

Marine and Petroleum Geology, 1999

Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explainin... more Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explaining overpressured formations. This mechanism relies on the hypothesis that overpressured shales have higher porosity than normally pressured shales for a given depth. Converted to porosity units, log response data from two Jurassic shales at Haltenbanken and nine Cretaceous and Tertiary shales in the Norwegian sector of the North Sea have been investigated to see whether such a relationship exists in these areas. The depth of the studied shale formations varies between 0.5-5 km. The degree of overpressuring within one formation typically varies by 20 MPa.

Research paper thumbnail of Storage of CO 2 in saline aquifers–Lessons learned from 10 years of injection into the Utsira Formation in the Sleipner area

Energy Procedia, 2009

The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reach... more The ongoing CO2 injection at Sleipner has demonstrated that 2/3 of the injected CO2 has not reached the top of the Utsira Formation, but has instead migrated laterally below imperfect intra-reservoir seals. The CO2 trapping below the structural spill point in the Utsira Formation is due to local mini traps, capillary flow resistance, and the hydrodynamic drive of the injection.

Research paper thumbnail of New Sealing Analysis Strategies Based on Recent Progress in the Understanding of Compaction and Fluid Flow Processes

First EAGE International Conference on Fault and Top Seals - What do we know and where do we go?, 2003

Research paper thumbnail of History-matching of CO2 Flow at Sleipner – New Insight based on Analyses of Temperature and Seismic Data

Third EAGE CO2 Geological Storage Workshop, 2012

Research paper thumbnail of The Use of Internally Consistent Models in Seal Analysis

3rd EAGE International Conference on Fault and Top Seals, 2012

Research paper thumbnail of Regional CO2 Storage Capacity Estimation - Insight Gained from Local Volumetric Analyses

1st Sustainable Earth Sciences Conference and Exhibition (SES2011), 2011

Research paper thumbnail of Importance of Pressure Management in CO2 Storage

Offshore Technology Conference, 2013

Research paper thumbnail of Evaluation of caprock integrity in the western (high-pressured) haltenbanken area--a case history based on analyses of seismic signatures in overburden rocks

Norwegian Petroleum …, 2002

... based on analyses of seismic signatures in overburden rocks Gunn MG Teige, Christian Hermanru... more ... based on analyses of seismic signatures in overburden rocks Gunn MG Teige, Christian Hermanrud, Oddbj0rn S. Klovjan, Per Emil Eliassen, Helge ... In: AM Spencer, SO Johnsen, A. M0rk, E. Nysaether, P. Songstad and A. Spinnanger (Editors), Petroleum Geology of the North ...

Research paper thumbnail of Seismic characteristics of fluid leakage from an underfilled and overpressured Jurassic fault trap in the Norwegian North Sea

Petroleum Geoscience, 2004

... Previous analysis has suggested that shear failure, combined with high fluid pressures, was t... more ... Previous analysis has suggested that shear failure, combined with high fluid pressures, was the main mechanism for leakage in the study area (Nordgård Bolås & Hermanrud 2003). ... Lars Reistad is thanked for his graphical support. Received July 2, 2002. ...

Research paper thumbnail of Capillary resistance and trapping of hydrocarbons: a laboratory experiment

Petroleum Geoscience, 2005

Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are ... more Low permeability cap rocks retain oil by capillary forces when the pore throats of the seals are sufficiently small to prevent a flux of oil into the cap rock. In order to investigate the influence of aquifer overpressures on oil retention, water pressure was applied to a water-wet, ...

Research paper thumbnail of The lack of relationship between overpressure and porosity in North Sea and Haltenbanken shales

Marine and Petroleum Geology, 1999

Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explainin... more Disequilibrium compaction (undercompaction) is probably the most accepted mechanism for explaining overpressured formations. This mechanism relies on the hypothesis that overpressured shales have higher porosity than normally pressured shales for a given depth. Converted to porosity units, log response data from two Jurassic shales at Haltenbanken and nine Cretaceous and Tertiary shales in the Norwegian sector of the North Sea have been investigated to see whether such a relationship exists in these areas. The depth of the studied shale formations varies between 0.5-5 km. The degree of overpressuring within one formation typically varies by 20 MPa.