| Description |
xi, 108 leaves : illustrations (some color) ; 29 cm |
| Summary |
"Geological sequestration of CO₂ has been identified as one method to reduce global emissions of CO₂ and achieve lower levels of CO₂ concentrations in the atmosphere. Geological formations have to be assessed in terms of their capacity, sealing capabilities and economic feasibility before CO₂ sequestration can commence. Potential leakage of injected CO₂ from the reservoir formation could occur due to natural or injection induced faults or fractures in the reservoir or sealing formations. As part of a potential leakage investigation a geomechanical characterization which refers to the assessment of the in-situ stress conditions, rock strength and stiffness properties of the formations of interest helps to determine the seal integrity before, during and after injection of CO₂ into the formation. In this study a rock mechanical testing apparatus was designed and commissioned, and the geological formations of interest were analyzed by conducting rock mechanical testing including Brazilian tensile tests, uniaxial tests and single stage triaxial tests accompanied by sonic velocity tests. Mohr Coulomb and Hoek Brown criteria were used to determine failure characteristics. The study helps establish the safe injection pressure. It was found that the formations had a greater likelihood of undergoing tensile failure than shear failure. Although laboratory tests revealed that the capping rock has a higher tensile strength than the reservoir rock, the combination of in-situ stress and pore pressure conditions makes the cap rock susceptible to failure very close to the tensile failure value of the reservoir rock and hence the injection pressures have to be maintained just below that of the tensile failure value of the reservoir rock"--Abstract, leaf iii. |
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