According to the quarterly industry survey from jobs board, oilandgaspeople.com, 44% of the workforce is already aged over 45.
The survey found that while tax breaks for the industry were promoting record investment, it was also creating an even greater demand for already scarce skilled professionals.
Last month bank of England governor, Mervyn King, claimed that North Sea oil will boost economic recovery, however the survey found 70% of employers are "struggling" to recruit quality candidates and the recruitment crisis is "set to get worse".
The survey also revealed mass skills shortages across the industry, with 25% of companies failing to find enough engineers. There was also shortages in: drilling specialists (38%), subsea specialists (75%), HSE specialists (37%), project engineers (65%) and geoscientists (25%).
Kevin Forbes, CEO of oilandgaspeople.com, said: "North Sea investment is at record levels and production will help boost the economy but there is one dark cloud on the horizon and it is a fast reducing qualified work force.
"It's one thing having record levels of investment but if you don't have enough people to do the jobs, then the growth will grind to a halt.
"As our survey found, the industry specialisms that are most hard to fill are those with an ageing workforce. It's no surprise that geoscientists and drilling specialists are hard to recruit as these key workers are retiring in large numbers."
He added: "The oil industry shed thousands of specialists 20 years ago and now they are waking up to a big retirement headache. Over the next 10 years they will have to find 125,000 new staff otherwise there won't be enough qualified engineers to do the work."