Risk assessment for the entire CCS chain and its application to CO2Quest:

the specific case of impurities and real-scale experiments

R. Farret, Y. Flauw, J. Hebrard (INERIS) N. MacDowell, N. Shah (ICL)

An integrated method for risk analysis of the CCS chain Application in the CO2Quest project Impacts of impurities: real-scale experiments

What can go wrong ? How often (how likely) ? If it goes wrong, what consequences ? + How confident am I in the result ? RISK = combination of Likelyhood of an event and its Severity (consequence) (according to ISO 31000) Nota 1: If the likelihood can be estimated in a quantified way, it is generally called « probability » Nota 2: According to the same ISO 31000 (2009 version), the RISk has a more general definition :

« uncertainty in reaching the objectives »

L

Uncertainty

Risk analysis: the fundamental questions

S

Scenario

Scenario of « normal » evolution (no overpressure, homogeneous rocks…) Scenarios of « altered » evolution

Including Worst case / conservative options, especially in the underground, e.g. undetected heterogeneity, uncertain phenomena in the longer term.

Including accidental scenarios e.g. aleatory events , but predictable in terms of probability : accident on a

pipe, seismic event, …

Risk scenarios combining acute and long-term exposure

Transfer Scenario Exposure Scenario = Impacting Phenomenon

For CCS, there are 8 main families of « Impacting Phenomena »

Possible leakage pathways : pre-existing faults, well defects…

Concern both surface & underground instal- lations (pipe, well…) , but only accidental situations

1) E - Explosions (effect : overpressure & thermal), including burst of pipe/vessel, BLEVE 2) I – Fires (thermal effects) 3) SL - Sudden Leakage of gas at surface level (toxic effect)

4) LL - Low Leakage (diffuse emanation) of CO2 to air (toxic effect)

5) P - Pollution or aquifers by CO2 (effect on ecosystem, or on economic resource)

6) PS – Pollution by Substances : impurities, brine…

7) M – Mechanics and ground movement 7.1 slow effect : deformation at surface level (e.g. uplift) 7.2 dynamic effect : induced seism

8) H – Hydraulics : underground overpressure & perturbation of the fluid transfers

It is an organisational issues : how to seek for constant improvement Risk management involves such a PDCA constant improvement (see ISO 31000)

and interaction with authorities/stakeholders To be encouraged for pilots & projects on such a new technology, with public funding

Promote Knowledge sharing tools & Learning from experience

Promote an database for Accidents and incidents, including leakages To know what already happened & what works or not (e.g. Safety devices)

(see the state of the art in industrial safety) Examples for underground storage : Evans 2008 (HSE), Farret 2013 (INERIS)

Reinforce knowledge sharing for monitoring To promote the adequate monitoring tools To define how to measure the baseline To manage discrepancies between observations and

model results , whenever observed - see Sleipner as an example :

Initial Prediction (1996)

Plume Observation (2006)

Refined prediction (2006)

An integrated method for risk analysis of the CCS chain Application in the CO2Quest project Impacts of impurities: real-scale experiments

Objectives

Explore and define the incremental risks (additional safety and environmental impacts) associated with the presence of impurities in the CO2 stream on the CCS system performance (transportation and storage) : identify CO2 mixtures that have the most pronounced

impact on pipe and the most important effect of impurities on the performance of CO2 geological storage cover both safety and impact on the environment

Impact profiles of impurities In order to address the 8 « impacting phenomena » presented before, we identified 4 categories of mechanisms that are likely to be influenced by impurities:

• physical impacts; • chemical impacts; • toxic impacts (cloud dispersion, pollution of drinking water); • impacts on ecosystems (pollutants).

For each impurity identified in the CO2Quest project, these 4 categories were reviewed throughout the CCS chain.

Impurities especially non condensable

impurities (O2, N2, Ar, CH4, H2)

Mixture phase behavior modification

Supercritical CO2 volumetric properties modification

Mixture viscosity properties

modification

Mixture solubility in water

properties modification

Lower critical temperature & Higher critical pressure

More compression work needed

Higher pipe strength needed

2 phase flow inside pipeline

Lower stream density

Lower transported quantity for the same

pressure drop Tran

spor

t St

orag

e co

mpa

rtm

ent &

un

derg

roun

d

Better permeation

flux

Lower solubility trapping

Lower CO2 plume density

Greater CO2 plume volume

Higher plume buoyancy and migration velocity

Lower residual trapping efficiency

Reduced time of contact with brine

Accumulation and higher pressure underneath the caprock

Lower lateral spreading of the CO2 plume

Lower solubility trapping

Higher sensitivity to caprock porosity and discontinuity

Lower solubility trapping

Physical impacts and mechanisms

CO2 + Impurities Acidification of the milieu

Minerals dissolution

Ligands production

Dissolution of metallic elements : [Fe2+]aq

Successive effects:

• lower rock mechanical resistance • Higher rock porosity • Pore plugging by precipitation

Aqueous metallic species (scavenging)

Dissolved complexes (metal + ligand)

migrating with brine (water)

Organic element dissolution by

supercritical CO2

Higher Dissolved Organic Carbon (DOC)

Chemical impacts and mechanisms

Alteration of well cement

Toxic and ecotoxic impacts (see the « impacting phenomena » on ecosystems or human heath)

CO2 + Impurities

Internal failure Fault/well Shock Mechanical disorder

Long term leakage

Emission at surface Pollution of the aquifer

Global warming Drinking water

Accidental release (pipe)

Pollution

Toxic cloud Surface water

Impacts on human health

Ecotoxicity

Safety and impacts decision making method We chose a multicriteria scoring method for better flexibility Method based on a scoring according to qualitative arguments:

Propose a scoring scale for each component of each impact (we score the incremental risk with regards to pure CO2); For the case study (typical CO2 stream / for one given impurity ?) assess the scores for each mechanism; Within each impact category, aggregate these scores (weighted sum or maximum); Aggregate / compare the above scores.

Impurities especially non condensable

impurities (O2, N2, Ar, CH4, H2)

Mixture viscosity properties

modification

Mixture solubility in water properties

modification

Better permeation

flux

Lower solubility trapping

Safety and impacts decision making method We chose a multicriteria scoring method for better flexibility Method based on a scoring according to qualitative arguments:

Propose a scoring scale for each component of each impact (we score the incremental risk with regards to pure CO2); For the case study (typical CO2 stream / for one given impurity ?) assess the scores for each mechanism; Within each impact category, aggregate these scores (weighted sum or maximum); Aggregate / compare the above scores.

Impurities especially non condensable

impurities (O2, N2, Ar, CH4, H2)

Mixture viscosity properties

modification

Mixture solubility in water properties

modification

Better permeation

flux

Lower solubility trapping

Safety and impacts decision making method We chose a multicriteria scoring method for better flexibility Method based on a scoring according to qualitative arguments:

Propose a scoring scale for each component of each impact (we score the incremental risk with regards to pure CO2); For the case study (typical CO2 stream / for one given impurity ?) assess the scores for each mechanism; Within each impact category, aggregate these scores (weighted sum or maximum); Aggregate / compare the above scores.

Impurities especially non condensable

impurities (O2, N2, Ar, CH4, H2)

Mixture viscosity properties

modification

Mixture solubility in water properties

modification

Better permeation

flux

Lower solubility trapping

Safety and impacts decision making method We chose a multicriteria scoring method for better flexibility Method based on a scoring according to qualitative arguments:

Propose a scoring scale for each component of each impact (we score the incremental risk with regards to pure CO2); For the case study (typical CO2 stream / for one given impurity ?) assess the scores for each mechanism; Within each impact category, aggregate these scores (weighted sum or maximum); Aggregate / compare the above scores.

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Impuritiescomposition 1 Impurities

composition 2

Risk 3

Risk 2

Risk 1

An integrated method for risk analysis of the CCS chain Application in the CO2Quest project Impacts of impurities: real-scale experiments

Small scale experiments :

1liter vessel : •Weighed •Pressurised •Insulated •Pressure and Temperature measured inside

Thermo-dynamical properties of the mixing

70 cm pipeline: •Cooled •Pressure and temperature measured (inlet and outlet) Transport properties

of the mixing CO2+impurities

Middle scale experiments : 2m3 sphere

2m3 sphere + 6m long-2” pipe •Weighed •Pressurised (100 bar) •Insulated/Heated (100°C) •Pressure and temperature measured inside the vessel and the pipe •Calibrated orifice

Instrumentation of the cloud : •Concentrations •Temperatures •Special instrumentation of the very near field

Massive releases

Multi-scale experiments : Pipeline

40m -2” pipeline •Weighed •Pressurised (100 bar) •Insulated/Heated (50°C) •Special device to mix CO2 and impurities in the pipe •Transparent section •Pressure and temperature

Instrumentation of the cloud : •Concentrations •Temperatures •Special instrumentation of the very near field

Realistic releases