* First well in Agar-Plantain field due in Q3
* First oil likely early 2022
* Azinor plans further stake sales in 2019
* Azinor IPO "certainly a possibility" - managing director (Adds comment from Azinor Managing Director)
By Shadia Nasralla
LONDON, June 14 (Reuters) - Cairn Energy has bought a 50 percent stake in the Agar-Plantain oilfields in the British North Sea from Azinor Catalyst, the companies said on Thursday, amid renewed interest in North Sea assets.
Oil producers are returning to the North Sea having sold many assets in the past few years, often to private equity investors, after oil prices collapsed.
"There has clearly been a sentiment change in the North Sea. Certainly from our perspective since the beginning of the year. The oil price is up, costs remain low and it's a really exciting window of opportunity to invest in the North Sea," Azinor Managing Director Nick Terrell said.
Azinor, which is backed by private equity firm Seacrest Capital and owns a portfolio of North Sea assets, discovered the Agar-Plantain fields in 2014 and said on Thursday that it expected to start drilling in the third quarter, pending regulatory approval.
First oil is expected in early 2022 from Agar and Plantain which have "estimated combined mid-case resources of 60 million barrels oil equivalent, with an upside case of 98 million barrels oil equivalent", Azinor said.
The companies did not say how much Cairn Energy paid.
Azinor currently has nine licences in the British North Sea and plans to take part in the upcoming 31st offshore licensing round. Terrell said the company was open to a possible stock market listing.
"Yes, that's certainly a possiblity. We're aggressively growing, increasing the value of our company and we will be pursuing a range of sources of capital... Seacrest have been a great investor for us and will continue to be so no doubt but clearly the capital markets are opening."
Renewed interest in North Sea assets was highlighted last month when Royal Dutch Shell , BP and Norway's Equinor as well as smaller independent oil producers including Siccar Point, Chrysaor and Premier Oil were awarded 229 blocks in the British North Sea.
Azinor is planning to sell further stakes next year as it prepares to drill more wells across its portfolio. (Editing by Susan Fenton; Editing by Elaine Hardcastle)