HOUSTON, April 25 (Reuters) - Venezuelan crude oil sales to the United States declined in March for the third month in a row this year to 651,710 barrels per day due to falling exports of main grade Merey, according to Thomson Reuters trade flows data.
Venezuela's crude output fell in 2016 to its lowest level in 23 years. Analysts expect another decline in 2017 due to lack of investment and to cash flow problems affecting state-run oil firm PDVSA, which controls more than 40 joint ventures for exploration and production.
The volume of Venezuelan crude that PDVSA and its joint ventures exported in March was down by 2.3 percent from February and by 18 percent from a year earlier.
Exports of Merey blend crude to the United States, which started decreasing in February, averaged 165,320 bpd last month, their lowest since August, according to the data.
Merey is made with extra-heavy oil from Venezuela's main producing region, the Orinoco Belt, and lighter crudes. But as output from the member of the Organization of the Petroleum Exporting Countries becomes heavier, production and reserves of medium and light grades decline fast.
PDVSA's refining unit in the United States, Citgo Petroleum, was the largest receiver of Venezuelan crude in March, with 10 cargoes, followed by Valero Energy Corp and Chevron Corp .
This year Phillips 66 has received five or six monthly cargoes of 500,000 barrels each of Venezuelan Merey crude.
PDVSA announced a tender earlier this week to buy up to four 500,000-barrel cargoes of U.S. light crude, mainly to feed its 335,000-barrel-per-day Isla refinery in Curacao, which recently resumed operations after planned maintenance work. (Reporting by Marianna Parraga; Editing by Ernest Scheyder and Lisa Von Ahn)