Plug & abandon strategies for Canada's oil & gas wells

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With the increasing public scrutiny of the oil and gas industry in the past 10-20 years, the attention of the industry, regulatory authorities and all levels of government is driven towards tackling serious questions of environmental stewardship that afflict the industry. High amongst the list is the question of safe long-term abandonment of oil and gas wells. By 2013, more than 550,000 oil & gas well had been drilled in Canada, most of which were in the Western Canada Sedimentary Basin. In Alberta alone, 35% of total wells are abandoned: this number adds up to around 151,000 abandoned wellbores in the province. Much of the current well stock is 30-40 years old or more. Canada is entering an era of P&A (Plug and Abandonment) in which 1000's of wells will be abandoned annually for the foreseeable future. Environmental & public safety concerns abound. Long term sealing of wellbores requires proper placement of sealing materials (cement), avoidance of contamination/mixing and ensuring a good bond of the cement to the surrounding rock. This 4-year project is about the engineering design of P&A operations. The project has 2 key objectives. First we will assess the status of typical Canadian P&A operations, well architectures and regulatory practices, within a more global context. We will conduct a detailed review of the scientific and engineering literature as it pertains to longevity/sealing, clarify knowledge gaps and expose technological issues. Second, through a network of collaborative Canadian researchers and targeted complementary sub-projects we will provide physical and engineering rationale for regulatory and operational decisions that concern fluid mechanical issues (placement, cleaning, mixing, and thus potential bonding). Our team will conduct 7 complementary and interlinked studies addressing P&A knowledge gaps while providing fundamental advances, using a combination of experimental, analytical and computational methodologies, combined with field survey work with industrial partners.