Petroleum reservoir engineering is a branch of petroleum engineering that studies the application of scientific principles to maximize the economic recovery of crude oil from reservoirs. Numerous drainage problems arise in production processes. Petroleum reservoir engineering builds on the tools developed from subsurface geology, applied mathematics and basic physics and chemistry. It strives to understand phase behavior of crude oil and natural gas to develop working tools of reservoir engineering. The key functionalities of surveillance, analysis, production and simulation modeling are also explored in the domain of reservoir engineering. Reservoir engineering is also significant for field development planning and framing cost-effective reservoir depletion schemes in order to optimize recovery of petroleum from deposits. The various advancements in petroleum reservoir engineering are glanced at in this book and their applications as well as ramifications are looked at in detail. Different approaches, evaluations, methodologies and advanced studies in this domain have been included in this book. It is aimed at engineers, geologists, students and other professionals involved in this field.