I would like to acknowledge the financial support provided by the the Research Council of Norway through the PETROMAKS program. I also gratefully acknowledge Uni CIPR and Uni Research for providing me the opportunity to participate in the PhD program in the period 2010-2013, and furthermore, offering me a permanent position as a senior researcher, thereafter. Thanks also to the administration staff, to make CIPR a social environment and a friendly working place. Many thanks to my fellow students and colleagues at CIPR and EOR Group, especially Anita Torabi, and fellow PhDs Reza Alikarami, Nematollah Zamani, Jonas Solbakken, Annette Meland Johannessen, and my office-mate Abduljelil Kedir for their support, discussions and friendship. I heartily send my thanks and appreciation to my beloved mother and father and dear brothers for their love, enthusiastic support and encouragement. I would also like to send my gratitude to my parent in-law for their supports and care throughout these years. Last, but not least I wish to express my sincere appreciation and recognition to my lovely wife, Enciyeh, and my precious son, Sahand, for having them with me, for their true love and patience, and their unconditional support during the course of this work.