Abstract
Permanent Plug and Abandonment (P&A) of wells has been an inevitable part of hydrocarbon exploration and production; however, the methodology has not evolved with the same pace as the rest of the industry. Nonetheless, after the environmental impact of some recent events including the Deepwater Horizon oil spill, permanent P&A of hydrocarbon wells has been receiving more attention. Accordingly, regulatory authorities who oversee the P&A activities and operators have tried to improve the pre-existing P&A methodology by defining a modern P&A philosophy, zero leakage criterion. Although the legislated criterion, adapted by most authorities, has challenged the industry and it had a constructive impact on P&A operations, due to technology deficiencies, the associated cost of operation has significantly increased. In this work, most of the publicly available regulations and their recommended practices addressing P&A have been reviewed and discussed. The focus has been given to zero leakage acceptance policy, conventional versus risk-based approach, barrier verification, human factor in P&A, and technology deficiencies. Although Norway is not a major hydrocarbon producer based on the daily production rate, but because of its stricter requirement on P&A, its recommended practice (NORSOK D-010) for P&A has been used in different oil producing countries. As P&A and its impact on environment is a transnational subject, it is suggested to formulate an international guideline or standard on P&A, given the fact that every well is unique when considering P&A operation.
