LONDON- OPEC oil output rose for a sixth month in December, a Reuters survey found, buoyed by further recovery in Libyan production and smaller rises elsewhere in the group.
The 13-member Organization of the Petroleum Exporting Countries pumped 25.59 million barrels per day (bpd) in December, the survey found, up 280,000 bpd from November and a further increase from a three-decade low reached in June.
Under a deal on February output agreed on Tuesday, most of OPEC+ will keep production steady while Saudi Arabia has offered to make a big voluntary cut.
"The additional production cut by Saudi Arabia will probably prevent the oil market from becoming oversupplied, which risked happening otherwise," said Carsten Fritsch, analyst at Commerzbank, referring to the first quarter.
In December, the biggest supply increase came from Libya, an OPEC member which is exempt from OPEC+ cuts, the survey found. Libyan output had been largely shut down for months due to unrest.
The OPEC producers bound by the supply deal also boosted output in December, the survey found, which meant their compliance with agreed output cuts slipped to 99% from 102% in November and hit their lowest level since August.
Libya, a nation politically split between east and west, has boosted production since eastern Libyan commander Khalifa Haftar said in September his forces would lift their eight-month blockade on oil exports.
The survey found Libya's output increased by 150,000 bpd in December to 1.25 million bpd, a faster rebound than some analysts and OPEC officials expected.
The United Arab Emirates raised supply by 70,000 bpd, the highest rise among those OPEC countries bound by quotas. However, it was still pumping below its target.
Smaller increases in Iraq, Nigeria and Angola added further to supply from the 10 members with quotas.
Iran, which is also exempt from OPEC cuts and hoping to raise exports this year if U.S. sanctions are eased, also boosted supply slightly.
No sizeable drop in output was seen in any OPEC country. Venezuela, also under U.S. sanctions and contending with a long-term drop in supply, pumped slightly less.
Top exporter Saudi Arabia kept output steady, as did Kuwait and smaller producers including Algeria, Congo and Gabon.
The Reuters survey aims to track supply to the market and is based on shipping data provided by external sources, Refinitiv Eikon flows data, information from tanker trackers such as Petro-Logistics and Kpler, and information provided by sources at oil companies, OPEC and consultants.
(Additional reporting by Rania El Gamal and Ahmad Ghaddar; editing by Jason Neely) ((firstname.lastname@example.org; +44 207 542 4087; Reuters Messaging: email@example.com))