GPN, the oil arm of top global gas producer Gazprom, agreed in April to start exclusive negotiations to purchase a 49 percent stake in Binh Son Refining and Petrochemical Company (BSR), the operator of Vietnam's Dung Quat oil refinery and a subsidiary of state-owned oil company PetroVietnam. The purchase was to cement energy ties between Vietnam and Russia and to advance Vietnam's policy of privatization of state-owned companies.

However, the negotiations officially halted after Vietnam could not offer GPN the preferences it sought, the report said. Vietnam's government invited GPN to invest in Binh Son as a strategic partner in the privatization of the refinery, said the PetroVietnam report.

GPN said it would "study the opportunity to buy stakes of BSR in the future," the PetroVietnam report said.

Dung Quat can process about 135,000 barrels a day of crude oil, according to Reuters data.

Spokesmen at Binh Son and PetroVietnam both declined to comment on the report when contacted by Reuters.

Gazprom Neft declined to immediately comment when contacted by Reuters.

Vietnam is currently considering about seven other oil refinery projects with the 200,000-barrel-a-day Nghi Son project slated to start up in 2017.

By Mai Nguyen & My Pham - Reuters - January 11, 2016