Modelling Of C02 Leakage in Cement Plug in Abandoned Well

Greenhouse gasses emission is serious problem to the environment. Carbon
capture and storage is one of the methods to control and reduce the number of gasses
release. There is a significant amount of CO2 stored in the well bore that suffered
from leakage. The potential leakage paths of C02 can be identified thorough the
cement plug in the abandoned wellbore due to the exposure of high CO2
concentration after years of operation. The permeability and integrity of the cement
will determine how effective it is in preventing leakage. This research is to discover
the effects of permeability of the cement plug which is made by Portland cement'
with the risk of CO2 leakage from abandoned well in Carbon Capture and Storage
projects.
A computational fluid dynamics tools, ANSYS FLUENT will be employed
where the solution of K-epsilon Model and Eddy Dissipation model in the wellbore
geometry is sought. However, the reaction of Portland cement has to be defined
earlier before the permeability of cement plug can be determined using Darcy Law
equation. The flow will be modelled and simulated in which the effect of
permeability will be studied.
The results show the mass fraction of calcium bicarbonate has been increased
after the iteration is completed and the value of the density at different cement length
is obtained from the simulation. The density is found to be decreased by the
increment of cement plug length, thus it given high value of permeability at face
sizing of 200000umand 2135 numbersof mesh elementsis applied in the model.