CO2 Transport and Storage

Photo: Mark Person

Controls on CO2 Flow and Transport

Must understand in order to understand CO2 storage CO2 gas is miscible in other gasses

Supercritical CO2 is immiscible in water

Fluid flow Pressure gradients from injection Natural hydraulic gradients

Buoyancy Strong in saline formations Weaker in oil and gas reservoirs CO2 will descend in gas reservoirs

Controls on CO2 Flow and Transport (Continued…)

Diffusion Dispersion Dissolution into formation fluid

Significant amount (>30%) can go into solution

Moves with formation water at very slow rates (mm/yr) compared to separate phase flow

Water saturated with CO2 slightly denser

Mineralization

Controls on CO2 Flow and Transport (Continued…)

Pore space (relative permeability) trapping Important when multiphase Depends on fluid viscosities Wetting versus non-wetting phases (CO2 gas

and supercritical are non-wetting)

Adsorption onto organic matter

Residual Saturation

Wetting fluid at residual saturation Non-wetting fluid at

residual saturation

Which do you expect for CO2/water? What questions do you have to ask to answer this?

Storage Mechanisms

Structural stratigraphic trapping Hydrodynamic (residual) trapping Geochemical trapping

Storage Mechanisms

IPCC

IPCC

Structural and Stratigraphic Trapping

Traps created by: Deformation (faults, folds) Depositional characteristics (grain size

changes)

The most expensive dry hole in history

Mukluk well Thought to contain 1.5 to 10 billion

barrels of oil. Mukluk structure leased in 1982 for $1.5

billionDrilled in 1983 from a man-made island

350 feet in diameter, 69 ft above seafloor and required 1.25 million cubic yards of mined gravel

Cost of drilling $120 million