Oil Search’s $21 billion merger with Santos is set to get the sign-off from shareholders in the Papua New Guinea oil and gas producer on Tuesday, with by far the majority of proxy votes understood to have been cast in favour of the deal to easily outweigh small pockets of resistance.

The approval expected from Oil Search investors at their decisive meeting on Tuesday will propel the enlarged Santos into the ranks of the top 20 global oil and gas producers and should arm it to better weather the challenges being thrown up by the transition to low-carbon energy.