UPDATE 1-Suncor says to cut 1,000 staff after takeover

* Suncor cutting 1,000 jobs following takeover

* Moving international operations from London

CALGARY, Alberta, Sept 3 (Reuters) - Suncor Energy Inc (SU.TO) said on Thursday it expects to cut 1,000 jobs by the middle of next month as it consolidates operations and reduces costs after its C$22.7 billion ($20.4 billion) acquisition of Petro-Canada last month.

The company, Canada's largest oil exploration and refining firm, said it will make the cuts by laying off staff, having some retire and ending contract positions.

The 1,000 jobs represent almost 7.8 percent of the 12,886 combined staff Suncor and Petro-Canada employed at the end of last year.

The cuts came as Suncor looks to make good on promises to chop operating expenses by C$300 million a year following its purchase of Petro-Canada.

"We are already seeing significant savings through integration of our product marketing logistics and economies of scale in our supply chain," Rick George, Suncor's chief executive, said in a statement. "Unfortunately, bringing two large businesses together has also meant that some of the efficiencies are necessarily through work force reductions."

Suncor also said it will shift management of the international and offshore operations to its Calgary, Alberta, headquarters from London following a 90-day consultation period mandated by U.K. laws.

It did not say how many staff would be cut because of that move.

Suncor shares rose 6 Canadian cents to C$33.05 on the Toronto Stock Exchange on Thursday. ($1=$1.10 Canadian) (Reporting by Scott Haggett; Editing by Jeffrey Jones)