Intentional salt clogging: A novel concept for long-term CO2 sealing

Intentional salt clogging: A novel concept for long-term CO2 sealing

Wasch, L.J.
Wollenweber, J.
Tambach, T.J.

2013

Well abandonment in the context of CO2 storage operations demands a mitigation strategy for CO2 leakage along the wellbore. To prevent possible CO2 transport toward the surface and to protect the wellbore material from contact with acid brine, we propose forming a salt seal around the wellbore at reservoir level, after CO2 injection into a depleted gas field. The mechanism of water evaporation into dry gas and subsequent salting-out of the dissolved halite is a well-known issue in hydrocarbon production. We propose alternating injection of brine and CO 2 to facilitate intentional salt clogging of the reservoir. Salt clogging was studied with TOUGH2, simu-lating multiple cycles of brine and CO2 injection. We developed two near-well reservoir models - a homogeneous 2D model and a more complex heterogeneous 2D model - using certain characteristics of the K12-B depleted gas field. The homogeneous 2D model yields a 50-cm thick salt bank around the well and complete permeability impairment after eight cycles of brine-CO2 injection. Addition of vertical permeability heterogeneities causes variation in the lateral extent of salt precipitation and hence vertical discontinuities in the salt bank. A carefully designed injection strategy - with more injection cycles and lower injection rates - improves the vertical sealing. Predictions of the amount of required clogging for effective sealing would benefit from more accurate porosity-permeability relationships and insights in the long-term stability of the salt bank regarding re-dissolution. We conclude that alternating brine-CO2 injection could be a promising method for intentional salt-clogging of the near-wellbore area. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd.

Earth & Environment
SGE - Sustainable Geo Energy
EELS - Earth, Environmental and Life Sciences
Geological Survey Netherlands
Geosciences
Energy / Geological Survey Netherlands
CO2 storage
depleted gas field
drying out
intentional salt clogging
salt precipitation
well abandonment
Alternating injection
Gas fields
Hydrocarbon production
intentional salt clogging
Permeability impairments
Salt precipitation
Vertical permeabilities
Well abandonment
Abandoned wells
Boreholes
Gas industry
Oil field equipment
Precipitation (chemical)
Water injection
Carbon dioxide

http://resolver.tudelft.nl/uuid:c9f9bc22-f5d8-4805-8fd0-6721b63a06f4

https://doi.org/10.1002/ghg.1373

485647

2152-3878

Greenhouse Gases: Science and Technology, 3 (6), 491-502

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