MICROSEISMIC• Detection and localization from a surface network

• Implementation of the slant stack algorithm

EMSAPCO2: Geophysical methods for CO2

reservoirs monitoring

ELECTROMAGNETISMModeling of the time-lapse electric response of a 2 km×2 km×70 m CO2 bubble, of 10 ohm.m resistivity in a deep saline

aquifer

a) for a short-electrode injection at the surface

b) for a LEMAM injection via a pair of vertical casings (1900 m long).

Communication to the Hedberg conference on “Geological Carbon Sequestration: Prediction and Verification ”,

16-19 Août 2009, Vancouver, Canada. « Numerical modelling of the time-lapse EM response of a CO2 injection

in a deep saline aquifer using metallic casings for the current injection »

Goal : Propose an integrated and adaptative panel of

geophysical solutions to monitor CO2 geological storages

•Development of permanent acquisition methods

•Better understanding of wave propagation in CO2 reservoirs

0 100 200 300

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Electric field in the vertical plane Y=0

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Electric field in the horizontal plane Z=0

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Electric field in the vertical plane Y=0

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Electric field in the horizontal plane Z=0

Insulated electric wire driving the source current to the electrodes

Contour of the CO2 response normalized to the primary field (relative time-lapse anomaly [%])

a) b)

SEISMIC

Wave velocities and impedances in porous media

saturated with liquid and gas

Left plots: Pwave velocity as a function of saturation for a porous rock equivalent to Utsira formation saturated with

water/CO2 mixture. The Gassmann-Landau&Lifshitz method takes into account the phases transfers when acoustic

wave is occurring.Available in low frequency domain (f<fc).

Right plots: Pwave velocity, impedance and reflectivity curves for a 100 m-thick low gas-saturated (Sg(CO2) = 1%)

reservoir sandwiched between shales, calculated according to the two methods, Wood and Landau-Lifshitz.

Communication: EAGE Amsterdam June 8-10th 2009, Congrès Français de Mécanique, Marseille, August

2009

Impact of fractures on CO2 geological storage seismic

monitoring

Pwave anisotropy parameter , i.e. the normalized difference between horizontal and vertical Pwave velocities as

function of the difference between the azimuth of the seismic profile and the azimuth of the fracture for different

porosities (Phi=5% and Phi=15%) and for different saturating fluids (gas and water).

Communication: Impact of fractures on CO2 storage monitoring, 1st EAGE CO2 geological storage

workshop Budapest, 29-30 septembre 2008

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VP (km/s)

water/CH4 (fizz water)

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ZI (km/s.g/cc) RPP-0.2 0.0 0.2

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Liquid saturation

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water/CO2

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Wood Landau-Lifshitz

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Thermodynamic approach:

Gassmann – Landau&Lifshitz

Classical approach:

Gassmann – Wood

to the electrodes

Metal casing used as long injection electrode (pink)or for CO2 injection (blue)

the primary field (relative time-lapse anomaly [%])

1.0%

3.0%

5.0%

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10.0%

Influence of the interfacesThe spatial region in the vicinity of a curved homogeneous interface, which actually affects the interface response has been investigated .The maximum vertical extent of the Fresnel volume may

be greater than the seismic wavelength for near-critical incidence angles. Although the region of influence below the interface is less than indicated by earlier studies, the total vertical extent

is larger than previously reported.

Communication in Geophysics, Jannuary 2009, « What is a seismic reflector like? »