Hydro-dynamically controlled alteration of fractured Portland cements flowed by CO2-rich brine
MetadataShow full item record
Deficient sealing in the well cement plugs and annulus due to mechanical fracturing is an important risk of CO2 leakage from the reservoir to others permeable layers and the surface. Such situation was reproduced at laboratory scale in order to determine the hydro-chemical control on the fracture permeability. Specifically, we investigated the effect of CO2 rich-brine flowing through fractured Portland cements at T=60°C and P=10MPa and variable flow rates. We showed that carbonation process is dominant and induces permeability decrease and leakage mitigation for extremely low flow rate whereas for high flow rate injection the permeability remains constant due to the precipitation of a low density secondary Si-rich phase which maintains the initial fracture aperture. At intermediate flow rate the hydraulic aperture can increase due to the densification of the material triggered by the net precipitation of low porosity calcite. These results emphasize that more complex behaviors than those considered from batch experiments may take place in the vicinity of flowing fractures. Specifically, the redissolution of the neoformed calcite as well as the development of amorphous phases, both controlled by the CO2-rich brine renewing rate in the fracture may prevent the healing fracture. © 2013 Elsevier Ltd.
Showing items related by title, author, creator and subject.
Characterization and modeling of the alteration of fractured class-G Portland cement during flow of CO2-rich brineAbdoulghafour, Halidi; Gouze, P.; Luquot, L.; Leprovost, R. (2016)We investigate experimentally the alteration of fractured class-G cement flowed by CO2-rich brine. The experiment mimics a mechanically damaged rough-walled fractured cement annulus at temperature 60 °C and pressure 10 MPa. ...
Characterization of the mechanisms controlling the permeability changes of fractured cements flowed through by CO2-rich brineAbdoulghafour, Halidi; Luquot, L.; Gouze, P. (2013)Experiments were conducted to assess the potential impact of fractured well-cement degradation on leakage rate. Permeability was monitored while CO2-enriched reservoir-equilibrated brine was flowed at constant rate through ...
Stress Anisotropy, Long-Term Reservoir Flow Regimes and Production Performance in Tight Gas ReservoirsBahrami, H.; Rezaee, M. Reza; Asadi, Mohammad Sadegh (2010)Tight gas reservoirs normally have production problems due to very low matrix permeability and different damagemechanisms during drilling, completion and stimulation. Tight reservoirs need advanced drilling and completion ...