Norwegian oilfield services company Interwell has developed a technique wherein artificial lava composed of molten metal is used to plug and seal abandoned oil and gas wells.

According to Interwell, the approach involves making a metal plug, including a bismuth alloy, at depth in the well casing. The Interwell team explained that artificial lava was created in the subsurface, thereby melting all the manufactured components and materials, which then solidify, forming a permanent seal barrier.

Source: InterwellSource: Interwell

The technology, dubbed “RockSolid,” features a solid barrier composed of several phases that are created during a thermite reaction, which entails ignition of a metal when exposed to the oxide of another metal that is less reactive than the first metal — for example, the same chemical reaction employed for welding rail tracks together.

Amid the thermite reaction, oxygen reportedly ‘jumped’ from the oxide to the unoxidized metal, thereby releasing heat of more than 3,500° C that melted both the well casing and the cement surrounding it. The end result of the reaction, according to Interwell, was an elongated plug that fills all of the available space, molding itself to the irregular shape of the borehole.

So far, testing of the technique has been successfully conducted by the Norwegian lab the Foundation for Scientific and Industrial Research with simulated downhole conditions — including elevated temperatures, pressures and the presence of carbon dioxide, hydrogen sulfide and chlorides — exhibiting no signs of corrosion on the bismuth alloy layer.

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