SINGAPORE - Buyers of Oman crude oil have completed 2020 supply deals with premiums mostly unchanged from this year's prices, despite deeper output cuts planned by OPEC+ producers and U.S. sanctions on Iran and Venezuela, trade sources told Reuters on Monday.

Oman cargoes with an operational tolerance limit of 5% were sold at premiums of about 15-20 cents a barrel above the official selling price (OSP), with the majority of contracts done at a premium of 15-16 cents, sources said.

For 2019, the 5% term cargoes were sold at premiums of around 15 cents, they said.

Oman cargoes with an operational tolerance limit of 0.2% were sold at premiums of around 5 cents a barrel above the OSP for 2020, the same as for this year, the sources said.

The 5% term cargoes offer greater flexibility as buyers can use operational tolerance to adjust loading volumes for demand and logistical reasons.

DME Oman crude oil contracts' operational tolerance is plus/minus 0.2%, which caps the premiums for the 0.2% term cargoes.

The stable premiums for Oman crude were indicative of expectations of decent demand against the interplay of complex supply-side factors including deeper output cuts from OPEC+, U.S. sanctions on Iran and Venezuela, and expected output increases next year by non-OPEC+ producers, notably the United States.

Discussions for Oman crude term contracts had started before OPEC+ producers, which together pump over 40% of the world's oil, agreed last week to cut output from January through March by as much as 2.1 million barrels per day (bpd).

A report released in October by international credit rating agency Standard & Poor's put Oman's output at about 0.97 million bpd this year, and projected a gradual increase to close to 1.1 million bpd by 2022.

Oman is trying to raise funds from asset sales because lower oil prices have led it to pile up debt over the past few years.

State-owned Oman Oil Co expects to list 20%-25% of its shares in an initial public offering by the end of 2020, Oman's Oil Minister Mohammed al-Rumhi has said earlier this month.

(Reporting By Shu Zhang; Editing by Tom Hogue & Simon Cameron-Moore) ((shu.zhang@thomsonreuters.com; +65-6870-3549; Reuters Messaging: Twitter @shuzhang4))