Plug & abandonment of offshore wells: Ensuring long-term well integrity and cost-efficiency

摘要

There is an upcoming "P&A wave" of wells that need to be permanently plugged and abandoned, especially in mature, offshore areas such as the North Sea and Gulf of Mexico. It is important to ensure that plugged wells do not leak after abandonment, as there could be several potential leak paths such as microannuli in plugged wells. To ensure well integrity after abandonment, permanent well barriers must extend across the full cross section of the well. That includes establishing barriers in all annuli, which could however be quite time-consuming and thus costly.