HTC'S Risk Assessment Products And Services
Measuring the Risk
A Risk Assessment Scope of work would be used to establish and measure the risk associated with sequestering CO2 in any given geological formation.
Generally a Risk Assessment Check List would include the following:
General site information:
- Size of site
- Location with respect to population, construction and sites at risk
- Nature of sediments and accessibility to potable ground water
- Delivery route of CO2
Geological information - Injection zone:
- Depth
- Anticipated extent of plume
- Nature of trap
- Geological structure
- Lithology
- Mineralogy
- Gross and net thickness
- Porosity
- Permeability
- Water chemistry
- Stress fields and orientation
- Presence of fractures/faults and fault reactivation potential
- CO2 storage volume
- Bottom seal
Geological information - Caprock:
- Thickness
- Mineralogy
- Lithology
- Permeability
- Capillary entry pressure
- As above stress fields, faults, etc.
- Potential for thin spots in the caprock that might allow migration of the CO2 from one formation to another
Geological information - Overlying sediments:
- Number and nature of aquitards
- Number and nature of aquifers
- Deepest potable water zone
- Shallow sedimentary features - unconsolidated sediment, water filled, etc.
- Pressure temperature features in sediments that could lead to hydrate buildup (either the formation of CO2 hydrates or existing methane hydrates)
- Nature of potable water zones - particularly potential for CO2 to mobilize heavy metals, etc.
Monitoring:
- Techniques currently in use
- Issues with the sediments that preclude certain types of monitoring
- Regulations for monitoring and time frame
Surface information:
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Off shore we will take into consideration the presence of endangered species and impacts of leaks, acidification, potential for CO2 to build up in deep water, currents to dissipate CO2, etc.
Human information:
- Potential for other economic potential in the region
- Human activity (sea and land) that could impact pipeline
- Cultural features
- Capacity of government to retain records and share information
- Local regulations and potential for change (this is important for the pipeline, particularly if there is potential for the composition of the CO2 stream to change with time)
- Existing wells that impact the zone or overlying sediments within the plume (understanding plume shape and dimensions and risk of the plume breaching this limit)
- Type of well capping being used, concrete, etc.
Risk mitigation:
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Potential for dealing with leaks
Time:
- Injection phase (operational phase)
- Pressure equilibration phase
- Balance of time (out to 5,000 years or complete dissolution of the CO2 in reservoir fluids)