Chinese energy giant CNOOC this week made a bid to buy the Canadian production firm Nexen for $15.1bn (£9.8bn).
Nexen is the second largest oil producer in the UK, outputting 114,000 barrels of oil equivalent per day (boepd).
In another deal, China’s Sinopec purchased a 49% share of Talisman’s oil-and-gas assets in the UK for $1.5bn (£970m).
A spokesperson from Talisman said its joint venture with Sinopec means it would “invest more in the UK than Talisman would have on its own”, according to reports.
Scottish Energy Minister Fergus Ewing said the deals demonstrate the confidence investors and the industry have in Scotland.
He added: “With more than half of the value of the North Sea’s oil & gas reserves yet to be extracted, 24 billion barrels with a wholesale value of 1.5 trillion pounds, oil and gas will remain an enormous economic resource for decades to come.”