After the injection of CO2 into a subsurface formation, storage mechanisms help immobilize the CO2. Injection strategies that promote the movement of CO2 during the post-injection period can increase immobilization by mechanisms of dissolution and residual phase trapping. This book argues that the heterogeneity intrinsic to sedimentary rocks gives rise to another category of trapping called "local capillary trapping." The study presented in this book evaluates local capillary trapping, its effectiveness to add an element of increased capacity and containment security in CO2 storage, and assesses the amount and extent of local capillary trapping expected to occur in typical storage formations.