Oil producer Neptune Energy has agreed to buy stakes in a number of North Sea fields from US firm Apache.
Neptune will acquire 35% of the Seagull development and 50% of the Isabella prospect.
Houston-headquartered Apache is the operator of both fields.
The transaction value was not disclosed.
Neptune said the deals would give it low cost, near-term development options near existing infrastructure in the central North Sea.
Seagull is being developed as a multi-well subsea tieback with first oil expected by the first quarter of 2022.
Neptune plans to start drilling operations on Isabella next year.
The firm is backed by investors CIC, The Carlyle Group and CVC Capital Partners and has been on a spending spree in recent times.
It completed a near-£4billion swoop for the oil and gas exploration and production interests of French energy giant Engie in February.
In June it struck a deal to buy Norwegian oil and gas producer VNG Norge.
Neptune’s chief executive is Jim House, who joined the company in January after working at Apache for more than 25 years.
In his time in the UK with Apache, the US business acquired the Forties field from BP and the Beryl area from Exxon Mobil.
He said: “In line with our strategy of expanding positions in key jurisdictions, Seagull and Isabella are both high quality opportunities which complement our existing assets within the broader North Sea theatre of operations.
“We are extremely pleased to announce our second acquisition since the completion of the Engie E&P transaction last February.
“The signing of the sale and purchase agreement with Apache, which follows the announcement in June of our agreement to acquire VNG Norge, underlines our determination to continue building a leading international independent exploration and production company.”
Deirdre Michie, Oil & Gas UK’s chief executive, said: “Neptune’s interest in the Seagull development and the Isabella prospect reflects its confidence in the continued potential of the UK Continental Shelf and the basin’s growing competitiveness.
“These transactions will help unlock future opportunities for industry, making optimum use of existing infrastructure in the Central North Sea and enabling the timely and economic development of new fields in a key hub.”
Neptune had production of 165,000 net barrels of oil equivalent (boe) per day during the first quarter 2018 and reserves of 542 million boe at the end of last year.
It has offices in various locations across the globe, including Aberdeen, London and Paris, and employs around 1,800 people.
Its executive chairman is Sam Laidlaw, a former boss at Scottish Gas owner Centrica.