Geology, Uncertainty and Performance Assesment

• CO2SINK• CO2ReMoVe• CO2GeoNet Association• BIGCCS

Presenter:Peter Frykman (GEUS)

EU

N

CO2GeoNet Association

CO2REMOVE – Research, monitoring, verification

CO2GeoNet Association

Ketzin pilot site

Norway-DK-UK storage research

Geology, Uncertainty and Performance Assesment

GEUS engaged in:• Consequences of the site geology for:

– Capacity, injectivity, migration pattern– Containment & Risk– Long-term processes and safety– Regional pressure propagation

• Site specific modelling– Depositional model and sequence stratigraphy as

prediction tools– Flow simulation (migration path, filling efficiency,

capacity)

Triassic geology:Regional conceptual model

Floodplain with incised valleyswith fluvial deposits

Fluvial system type unknown:Meandering/anastomosing?

Scandinavian highlandssource area for clastic material

Berlin

Marine influence

From Nietsch (1995)

Geology:Ketzin: How to build a

version-1 model?

CO2SINK Project

CO2SINK Project

UncertaintyReflected by geostatistical modelling

Porosity variability and internal heterogeneity in the channel belts assuming patchy point-bar systems

Channel belt model

5x5 km model, 76 m thick

Performance assessmentFlow simulation of plume migration

CO2REMOVE Project

Regional pressure propagation - performance100 x 100 km regional model – site model 12x16 km20 years injection 3 Mt/year, Overpressure above hydrostatic shown

SP3 – CO2 StorageProcesses, methods and resolution

GEUS interests:• Case-studies and simulations of pressure evolution in regional models

• Preparation of guidelines for new CCS databases

• Test case building– Model scenarios from different geological settings and at different scales– Heterogeneity effects on injection filling efficiency

• Geomechanical issues– analyses and tests on caprock material– access to core material and outcrop material

• Basic mechanisms for CO2 behaviour– Halite precipitation experiments, permeability development

• Thin-layered reservoirs and their seismic response– geological structure and depositional patterns for thin-layered reservoirs– Sensitivity studies of seismic recognition

Host Instituition: SINTEF Energy Research ASSP3 Partners:BGS - Natural Environment Research CouncilGEUS - Geological Survey of Denmark and GreenlandGeological Survey of Norway (NGU) Norwegian University of Science and Technology (NTNU) University of Oslo

Funding:

The ”Benson-plot”How to make it site-specific?

IPCC 2005

Claim:“Convection will never happen in

most real storage sites”

The amount of solubility trapping is closely linked to brine convection stripping of the free CO2

Dissolution of CO2 in the Utsira Brine

Year 2021 Year 2412

Year 2621 Year 5019

Year 7018

Source: Gemini No. 1, 2004 (NTNU and Sintef)

The convection-added “safety”

• CO2 dissolution into the underlying brine leads to a local density increase that results in a gravitational instability that causes convective vertical current to form

• However, the instability depends on permeability and bed thickness

Will convection start?

• Penetration depth at onset of instability

• And we must haveH= bed thickness

= mixing zone thickness

• (Riaz et al. 2006)

Riaz et al. (2006) fig. 15

2.5 m

100 mD effective vertical permeability

Will convection start?• Penetration depth at onset of instability

• And we must have

(Riaz et al. 2006)

• So, is that << equal to a factor 10?• If so, bed thickness must be > 25 m for

instability to arise and start convection in a 100 mD formation

Case study of 320 m thick reservoir with multiple sandlayers separated by intraformational sealing layersVery common form for reservoir

Top_Gassum_A

Top_Gassum_B

Top_Gassum_C

Bot_Gassum_C

1750

1800

1850

1900

1950

2000

2050

(2089)

MD-0.03 0.50lay_PHIE_lim34 [U] (From property)-0.03 0.50PHIE_lim34

Top_Gassum_A

Top_Gassum_B

Top_Gassum_C

Bot_Gassum_C

VEDSTED-1 [MD]

Top_Gassum_A

Top_Gassum_B

Top_Gassum_C

Bot_Gassum_C

Top_Gassum_C

Bot_Gassum_C

1900

1920

1940

1960

1980

2000

2020

2040

2060

2076

MD-0.03 0.50lay_PHIE_lim34 [U] (From property)-0.03 0.50PHIE_lim34

Top_Gassum_C

Bot_Gassum_C

VEDSTED-1 [MD]

Top_Gassum_C

Bot_Gassum_C

25 m

• Bed thickness rarely reaches more than 25 m

• So, convection will probably never start in this type of sequence

• This reservoir geometry with intraformational sealing layers might be the most common type of reservoir

Lower part of reservoir only

Welcome to reality!The ”Benson-plot”IPCC and numerous references

Could this be the new viewLots of mobile CO2!

Mineral

Dissolution

Residual

Structural & stratigraphic trapping