Oil firm Nexen today announced the immediate departure of its president and chief executive Marvin Romanow.
He will be replaced in the interim by Kevin Reinhart, executive vice president and chief financial officer, while the firm looks for a new chief executive.
It also said Gary Nieuwenburg, executive vice president of Canada, was also leaving the company with immediate effect.
Nexen employs about 1,200 full-time and contract staff in the UK, operating the Buzzard field and developing the Golden Eagle field.
Francis Saville, chairman of the board said: “Marvin has made a valuable contribution to Nexen during his 13 years with the company.
“The board thanks him for his contributions and wishes him well in his future endeavours.
“Kevin has been with the company for over 17 years and he has the full support of the board in his new role.”
Analysts have speculated that the departed pair’s links to the Canadian Long Lake oil sands project, which has been seen to have not met expectation, and a failure to renew a licence in Yemen could have played a role in their exit.
According to the firm’s website, Mr Romanow, 55, served as president and chief executive of Nexen from January 2009 through to today.
He was executive vice president and chief financial officer from June 1, 2001. Before this, he held a variety of finance positions at Nexen.
He was recognised as Canada’s CFO of the Year in 2007 and in September of the same year received the Petroleum Economist award for Energy Executive of the Year 2006.
Last year in the North Sea, Nexen had issues which hit production at its major Buzzard field, a large contributor to UK North Sea production.
It also got project sanction on its £2billion Golden Eagle development. The field is described as one of the largest in the North Sea and is expected to produce an estimated 140million barrels of oil equivalent – gross – of proved and probable reserves over 18 years.
Nexen also recently signed up to move to a new business park at Kingswells, near Aberdeen.