It's no different to people who meet the requirements for family visa having their family visas rejected. It's discretionary. You don't have a RIGHT to change your job. You are an expat in a foreign country,and if Immigration doesn't want to approve your transfer, then they won't, and there's nothing you can do about it.
Be realistic, the job cuts in the oil and gas companies are to make expats leave the country, not make them find another job in the country.