Plug and abandonment on the Norwegian continental shelf

Abstract

More and more wells all over the world are reaching the end of their productive life and will in near future be ready for Plug and Abandonment (P&A). How this operation is performed is dependent on many factors like the well condition, the cement status behind casing, the numbers of potential inflows etc. Where the P&A operation is carried out is also affecting this process. Different countries operate with different regulations and requirements and a company is by law obliged to make sure the P&A operation is completed according to regulations and requirements of the particular area. Different materials, placement techniques, cement evaluation tools and vessels are available for conducting the P&A operation today. The process of completing a successful P&A is a costly affair for the operator and the search for new methods to make this process more efficient and therefore less costly is an ongoing activity in the industry today. Most wells today, that are ready for P&A, have not been designed with this in mind and this leads to extra challenges when preparing the well for abandonment. New traditions, for including this already at the earliest stages of well designing, is needed and the industry is discussing what changes can be implemented to improve this process. This thesis has been written to give insight in to the process of plugging and abandoning a well. It is written for students on Master in Petroleum of Technology at the University of Stavanger and the focus is on P&A operations on the Norwegian Continental Shelf (NCS). It will give an insight into the regulations and requirements that a P&A operation needs to fulfill, different types of plugging material that are available for plugging operations, traditional methods used to complete a P&A operation today, the procedure of P&A and new techniques that might be used in the future.