SINGAPORE  - Abu Dhabi National Oil Company (ADNOC) will likely ship more crude in April by cutting term crude supply nominations by 5% versus cuts of 10%-15% in March, sources familiar with the matter said on Tuesday.

Two Asian refiners said the 5% volume cut applies to all four crude grades while two others said they were notified of a 5% volume cut for the medium sour grade Upper Zakum. ADNOC also sells Murban, Das and Umm Lulu crude.

ADNOC's decision to ease allocation cuts comes ahead of a March 4 meeting at which the Organization of the Petroleum Exporting Countries and its allies, a grouping known as OPEC+, are expected to discuss a modest easing of oil supply curbs from April.

Three OPEC+ sources said an output increase of 500,000 barrels per day from April looked possible without building up inventories, although updated supply and demand balances that ministers will consider at their March 4 meeting will determine their decision.  

One of the sources said ADNOC's smaller allocation cut would provide relief for refiners as Middle East supplies tightened this year after top exporter Saudi Arabia made additional supply cuts of 1 million bpd in February and March.

Last month, ADNOC notified clients that March term supplies for Upper Zakum crude would be cut by 15%, sources said. Term supplies for other grades were reduced by 10%. 

ADNOC did not immediately respond to a request for comment.

(Reporting by Shu Zhang and Florence Tan in Singapore, Rania El Gamal in Dubai, Nidhi Verma in New Delhi; Editing by Christian Schmollinger and Tom Hogue) ((shu.zhang@thomsonreuters.com; +65-6870-3549; Reuters Messaging: Twitter @shuzhang4))