This project seeks to achieve a clear insight into the abandonment process of oil and gas wells of the North Sea by reviewing the current state of practice in the sector of the United Kingdom. Most important legislations, regulations, and their impact on the well abandonment process are mentioned as well as an overview of standards and guidelines of the well abandonment operation in the North Sea area. Most important features of guidelines/standards for operating companies regarding well abandonment process are highlighted. The author will discuss the topic how to achieve perfect sealed formations and permanent durable barriers in the abandonment operation. How to repair leaks and some examples of it will round off this subject. Some actual production technology methods and their influence on the well abandonment process will be mentioned. Further a case study of redevelopment of a field will support the argument of the author. A review of the well abandonment cost of the last 15 years and details of the cost structure can help to minimise or avoid costs. Future predictions about possible well abandonment costs and the amount of wells, that are to abandon in the next years, shall outline the increasing importance of this topic. The author recommends all regulatory institutions of the oil and gas producing countries of the North Sea to agree to a uniform definition of terms used in Guidelines/Standards.