Hydrate Plugging and Flow Remediation during CO2 Injection in Sediments

Energies

卷:13

Tanja Barth¹  Stian Almenningen²  Jarand Gauteplass²  Geir Ersland² 

[1] Department of Chemistry, University of Bergen, 5007 Bergen, Norway;

[2] Department of Physics and Technology, University of Bergen, 5007 Bergen, Norway;

关键词: CCS;    carbon storage;    injectivity;    hydrate formation;    flow remediation;    CO₂;   

DOI  :  10.3390/en13174511

来源: DOAJ

【 摘 要 】

Successful geological sequestration of carbon depends strongly on reservoir seal integrity and storage capacity, including CO₂ injection efficiency. Formation of solid hydrates in the near-wellbore area during CO₂ injection can cause permeability impairment and, eventually, injectivity loss. In this study, flow remediation in hydrate-plugged sandstone was assessed as function of hydrate morphology and saturation. CO₂ and CH₄ hydrates formed consistently at elevated pressures and low temperatures, reflecting gas-invaded zones containing residual brine near the injection well. Flow remediation by methanol injection benefited from miscibility with water; the methanol solution contacted and dissociated CO₂ hydrates via liquid water channels. Injection of N₂ gas did not result in flow remediation of non-porous CO₂ and CH₄ hydrates, likely due to insufficient gas permeability. In contrast, N₂ as a thermodynamic inhibitor dissociated porous CH₄ hydrates at lower hydrate saturations (<0.48 frac.). Core-scale thermal stimulation proved to be the most efficient remediation method for near-zero permeability conditions. However, once thermal stimulation ended and pure CO₂ injection recommenced at hydrate-forming conditions, secondary hydrate formation occurred aggressively due to the memory effect. Field-specific remediation methods must be included in the well design to avoid key operational challenges during carbon injection and storage.

【 授权许可】

Unknown