Improved Integrity of Primary Cemented Wells

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Canada is a top-10 producer of oil and natural gas globally and this industry is the largest single private sector investor in Canada. Despite alternate energy growth, ~70% of primary and secondary energy consumption comes from oil and natural gas. This project addresses technological aspects of the upstream petroleum industry that impact the environment and/or production efficiency: specifically well cementing. Before hydrocarbons are produced every well undergoes primary cementing. This operation seals the outside of the well, increasing production and preventing subsurface fluids from percolating to surface. Conventional oil recovery rates typically are 20-40%, losing even a few % of productivity is significant. Gas recovery rates are higher, but gas leakage to surface is also more common. Well leakage rates and severity vary worldwide. A common perception is that 10-20% of wellbores leak, which has both health & safety consequences and environmental/ecological impact. Further consequences come at well abandonment: where a poor primary cementing seal necessitates repair/remediation before eventual abandonment. This project targets research in 4 areas related to primary cementing of wells, with a view to improving the process for both production and later abandonment. We study the processes of fluid displacement/mud removal, irregular wellbores and cement hydration. This build on our previous research. New results will be made public via published papers & theses, industry presentations and through engineering software available for design purposes.Over 0.5 million wells have been drilled in Canada, with about 1/3 abandoned, which includes many that are shut-in with pressure at surface. Despite strong evidence that primary cementing is not effective in many cases, it remains a process that is relatively under-researched. Even with the recent industry downturn, over 4800 wells were completed in Canada in 2015. The incentive to improve is ever present.