The location of the companies main HQ will also play a part.
Companies with a USA HQ (e.g. Halliburton, Schlumberger etc) generally get headcount reductions mandated down to them by HR in the USA with little or no input allowed from UK management/HR, irrespective of the impact on operations ("if there is an issue, we can handle any extra workload from the USA or UAE").
In my friends case, the UK operations were seen to be an easy hit for a number of reasons, including higher average base salary and a perceived better reception from the media and politicians back in the home country "USA first". On plus side, the UK employees got a much more generous redundancy package that their US equivalents - but most of that extra money was thanks to European Employment Law.
Bizarrely, the company did not mind the big layoff payoffs as they got a large tax benefit in the USA - bit like that story of Trump's losses being used to offset future profits.
Another factor that makes them layoff people without a whim is that one of the key metrics senior management performance in the USA is measured on is "revenue per head" - and they are measured on that on a monthly basis. So, in times of falling revenue, the only way those managers can keep their jobs is to get rid of people as fast as possible - irrespective of the problems it causes in the future with loss of experience etc.
Nothing like a redundancy consultation process to make you aware of how cynical the whole oil industry is - just remember there is no such thing as company loyalty in these big multinationals!