This book on the Petroleum Resources addresses the challenges of transforming hydrocarbons that exist in underground, to valuable products that can be sold and delivered. It is intended for readers who have a professional or student interest in the petroleum industry, and a basic level of prior knowledge in the technical and commercial aspects of the industry. The goal of the book is to increase the reader's general understanding of key work processes in the upstreamA" part of the petroleum industry; that is, the part of the industry that locates underground resources and converts them to valuable products. This book addresses many conditions currently facing the field of Petroleum Resources, including: * Much work in the petroleum industry is carried out in interdisciplinary project teams and work processes and involved personnel need to understand the wider context of petroleum resource development, and to share a terminology related to this. * Decision makers need to evaluate all aspects of the value chain to identify optimal field development solutions.*There is a need to recruit new graduates to the industry to work for oil companies and the engineering and service industry. Recruits to the industry will benefit from a general introduction to key topics related to developments of petroleum resources. * Scientists in different areas of the offshore oil and gas industry lack in many aspects the full understanding of the complexity of the industry.