Human civilization and global economy are dominated by energy and it is seen to be the foundation of human refinement. Evaluating the performance of the unconventional reservoirs through statistical tools is essential in making management decisions and allocations of energy resources for the future, on the other hand the consequences of climate change due to carbon dioxide emissions from oil and gas industries need to be reduced by storing in a deep geological formations. This book describes the usage of two different statistical tools such as Data Envelopment Analysis-Frontier (DEAF) and Multiple Linear Regression to evaluate the performance of the Bakken shale oil and Eagle Ford gas condensate reservoirs in the northern and southern United States. Critical reviews and analysis were made on the unconventional reservoirs and also on using carbon dioxide huff-n-puff and flooding processes for enhanced oil recovery (EOR), and geological sequestration in these unconventional petroleum reservoirs.