The leak that began 10 days ago at Total's Elgin site highlights weaknesses associated with the current 'plug and abandon' procedures used by the oil and gas industry, according to experts at BiSN Technologies Ltd.
When a well reaches its economic limit (when production no longer covers operating costs), it is 'plugged' and abandoned. But the method currently used by the industry to plug unprofitable wells has moved on very little since the 1950s, said Paul Carragher at BiSN Technologies.
"The problem of leaking oil and gas wells continues to grow, but we now have the technology to permanently seal even the most difficult of wells in a cost effective manner," he added.
BiSN have been at the forefront of developing tools for safe well abandonment. The BiSN Bridge PlugTM uses an alloy that is melted in situ, creating a solid metal to metal seal which expands as it solidifies. This new generation of bridge plugs are corrosion-resistant, and capable of holding back more than 50,000 PSI of pressure, which far exceeds anything else in the marketplace.
The tool has been developed with the help of the Virtual Engineering Centre; a University of Liverpool led partnership established to advance the use of Virtual Engineering techniques to provide innovative solutions to industry challenges. The Centre has been part-funded by the European Regional Development Fund (ERDF) and Northwest Development Agency (NWDA).
"The Virtual Engineering Centre has worked closely with BiSN Technologies Ltd to develop a numerical simulation of the installation process of the BiSN Bridge PlugTM. This simulation shows how the alloy melts and solidifies in the well and demonstrates the integrity of the seal. The simulation has been validated with experimental data and is adaptable to both oil and gas applications," said Executive Director at the Virtual Engineering Centre Dr. Anthony Robotham.
Worldwide, there are an estimated 20-30 million oil and gas wells that have been plugged and abandoned using old methods, but leaks could become a problem of the past if the industry embraces this new technology.