Adds figures, context

By Kemol King

GEORGETOWN, April 24 (Reuters) - Oil output in Guyana fell about 3% to 627,000 barrels per day (bpd) in March from the previous month, but the 631,000 bpd produced in the first quarter was 3% higher year-on-year, data from the country's energy ministry showed on Thursday.

Guyana last year became Latin America's fifth largest oil exporter after Brazil, Mexico, Venezuela and Colombia. The new producer is expected to gain even more market share this year once a fourth floating facility that arrived in the country this month is installed for the Yellowtail project, raising output capacity to some 940,000 bpd.

The small South American nation, where all oil and gas output is controlled by a consortium led by U.S. major Exxon Mobil XOM.N, produced some 613,000 bpd of oil in the first quarter last year, according to the ministry's figures.

The government has said it expects production in the last quarter this year to jump to an average of 786,000 bpd, boosted by the start-up of Yellowtail, Exxon's fourth project.

The Exxon group is in final talks with the government for the relinquishment of a portion of its massive Stabroek offshore block that was not explored or where commercial reserves were not found.

The parties agreed that a minimum of 2,534 square kilometers (253,400 hectares) has to be returned, the government said on Thursday in a release, without providing further details.

The finance ministry earlier this month reported a $605.46 million oil revenue from royalties and sales made by the government in the last quarter last year, which included a total of seven cargoes exported from its share of crude produced in the country.

(Reporting by Kemol King, writing by Marianna ParragaEditing by Marguerita Choy)

((marianna.parraga@thomsonreuters.com; +1 713 371 7559; Reuters Messaging: @mariannaparraga))