Oilfield thermite plug

In the North Sea approximately 2000 wells are planned to be permanently plugged and abandoned in the upcoming decade.[1] The industry is already closing more sites than it is opening, and by the 2050s much of it is expected to be gone.[2] Estimates for the decommissioning of the North Sea range from £50bn to £100bn.[3] Plugging and abandoning (P&A) account for approximately 49% of the total decommissioning projects.[4]

Cement is still the dominant product used to seal oil and gas wells. It is challenged in a number of areas, and many players in the oil industry are looking for more flexible and environmentally friendly alternatives.[5] In the North Sea area, cement plugs fail in more than 25% of the cases.[6] Most worrying of all, they are never 100% safe, with the wells regularly leaking.[7]

When ignited, thermite burns at around 2,500°C, enough to melt through the tubing, casing and cement. It is also hot enough to melt the surrounding rock, bonding the materials together and forming an ideal barrier with which to plug the well.[8] Thermite can provide environmental benefits, and reduce the cost of decommissioning by 35%.[9] In cases where there are vent flow and gas migration, in the long run, thermite could potentially reduce the cost by at least 50%.[7]

When will plugging sub-sea oil fields with thermite become an accepted practice?

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References:
[1] Vrålstad, T., Saasen, A., Fjær, E., Øia, T., Ytrehus, J. D., & Khalifeh, M. (2019). Plug & abandonment of offshore wells: Ensuring long-term well integrity and cost-efficiency. Journal of Petroleum Science and Engineering, 173, 478-491.
[2] Kaminski, I. (2017).Tackling old oil and gas platforms
[3] Offshore-technology (2017). Can decommissioning cause more harm than good?
[4] Oil & Gas UK (2018). Decommissioning Insight 2018
[5] Wellcem (2017).Effective Alternatives to Cement in Oil and Gas Wells
[6] Harestad,K., Herigstad,T., Torsvoll, A., Nodland,N., Saasen, A. (1997). Optimization of Balanced-Plug Cementing
[7] Offshore Technology, (2018) Artificial magma: Could it work for sealing offshore wells?
[8] Hauan, T. (2016). Thermite makes P&A right
[9] Dunkley, P. (2017). BiSN Seals Deal with Significant Investment
More information:
Patwardhan, H. (2018) Offshore Decommissioning Market to Grow at 5.05% CAGR to 2025
Patent: E21B33/1208 Packers; Plugs characterised by the construction of the sealing or packing means

 

 

 

By Matthew J. Spaniol