Analysis of methods for effective well plug and abandonment (P&A)
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This thesis will focus on plug and abandonment of wells, highlighting the requirements given to safely perform the operation, different procedures used to plug and abandon a well, tools used in the process of abandonment and the new technologies available. Steps to consider in an efficient abandonment of wells will be discussed.The huge costs related to plugging a well, and the great importance of safe solutions, are the background for this thesis. Plug and abandonment of no longer productive wells is the responsibility for the operating companies. Ensuring safety to the environment and population, are important. The fact that Norwegian companies have little experience in plugging wells emphasizes the need for reliable technology and good solutions.The operating companies' demand for new tools to make the operation more efficient and safe has been partly met by the industry, and makes the job easier. Figuring out the best tools to use is important; there are a large variety of tools available, and different technologies can be utilized approaching the same operation. The thesis will outline a variety of technologies used to establish efficient, permanent well barriers. A review has been made of conventional and new technology available, on removing pipe from the well. The thesis will highlight the pros. and cons. using the different tools. The work will also show that new technology can be applied for leaving the tubing in the well when performing plugging and abandonment.Further work for making P&A operations more efficient, are to prove the effectiveness of the different technologies, and to perform field-testing of different promising systems. New tools and improved systems for cost effective plugging of wells should be developed. Some examples to this are; logging tools able to log through multiple casings, well constructions prepared for abandonment and control lines prepared for plugging.