HOUSTON, April 1 (Reuters) - From Peru to Brazil, a rash of unplanned outages at ports and pipelines and necessary maintenance work at oilfields is taking a bite out of global production, unexpectedly curbing a historic supply glut.
Even though the disruptions are individually small, taken collectively they are helping slow an unprecedented global build-up of surplus crude stockpiles estimated at 1.5 million barrels per day (bpd) for the first half of 2016.
While likely short-lived, they could foreshadow a larger and longer-lasting output decline from a region that, because of its dependence on oil exports, is particularly vulnerable to the damaging effects of prices under $40 a barrel.
"Latin America is among the world's most vulnerable oil regions right now," said Robert Campbell from Energy Aspects. "We are expecting an exports decline of at least 100,000 barrels per day in the second quarter and possibly as much as 200,000 bpd compared with the same period of 2015."
Venezuela, the largest exporter in a region that pumps about a tenth of the world's oil, is suffering from selling its barrels at near break-even prices, even as equipment failures have hurt its crude upgrading and delayed loading and discharge at its main oil port.
In March, state-run PDVSA's crude exports from Venezuela and Curacao including oil and diluents re-exported as blends declined almost 300,000 bpd from a year earlier to 1.64 million bpd, according to preliminary data from Thomson Reuters Trade Flows.
"The situation at Jose port is starting to affect crude flows as some companies are not willing to bear demurrage costs. A largest effect of this delay could be seen in April," said a trader from a firm producing crude at Venezuela's Orinoco belt.
PDVSA, which has said its exports are at normal levels, did not respond to requests for comment.
Energy Aspects has forecast a production decline at some Brazilian fields, which would keep exports flat while more maintenance projects are done after state-run Petrobras and private operators postponed some in 2015.
In Latin America's smaller producing countries, where infrastructure disturbances are frequent, concerns have also emerged about oil shipments.
Colombia, whose production stopped increasing in 2014 after eight years of growth, has not been able to get rid of endemic violence afflicting transportation infrastructure.
A rebel attack shut the 200,000-bpd Caño Limon-Covenas pipeline, forcing state-run Ecopetrol to declare force majeure on three shipments in March.
In Peru, another out-of-service crude pipeline is preventing exports by one if its main private operators, Pacific Exploration & Production, which produces some 12,000 bpd of heavy crude in the Andean country.
The small line is scheduled to resume in two months. In the meantime, Pacific's output declined 55 percent in February from the previous month, and no production was reported in March.
In Panama, weather conditions have been limiting traffic at the Panama Canal, where most small to medium tankers pass to load and unload crude in the Americas. This could create a bottleneck, restricting Latin America's crude flows in the coming months.
Even as producers recover from these glitches, they face gloomy prospects. In real terms, Latin America has had the biggest decline in active oil drilling outside the United States, according to Baker Hughes monthly rig data RIG-OL-LAM-BHI.
The number of rigs has fallen 40 pct in two years to just 237 in February, its lowest since late 2005. Other regions like Europe and Africa have had declines too, but had far fewer rigs to begin with.
Latin America's output decreased to 9.52 million bpd last year, according to official figures from the six largest producing countries. Only Brazil showed a significant increase, offset by declines in the rest of the region, especially in Mexico.
Colombia's production has fallen 5 percent or 52,000 bpd day since September to 955,000 bpd in February, according to official data, due to a combination of budget cuts and frequent disturbances to transportation infrastructure.
Analysts expect the region's two largest exporters, Venezuelan and Mexico, to be particularly strained by worsening cash-flow woes, likely deepening the 250,000 bpd (4.5 percent) decline in output they registered last year.
Mexico's Pemex recently said an additional fall of 100,000 bpd will come due to more than $5 billion in budget cuts this year. But firms including Wood Mackenzie and Medley Global Advisors expect a bigger decrease as rig count is at historical lows and private operators do not expect to start drilling soon.
Mexican "President Peña Nieto wanted an output increase by the end of his term, but even though Pemex had originally forecasted a production of 3 million bpd for 2018, to reach that point in time with an output of 2 million bpd is now considered a good scenario," said Pablo Medina from Wood Mackenzie at a Platts conference this month in Houston.
Venezuela's rig situation is not as critical as its neighbors. Still, analysts expect PDVSA's output will be hit this year by cash flow problems, a shortage of spare parts, growing crime affecting the oil industry and a brain drain due to low salaries.
Reporting by Marianna Parraga in Houston, with additional reporting by Julia Symmes Cobb in Bogota, Alexandra Ulmer in Caracas, David Alire in Mexico City and Mitra Taj and Marco Aquino in Lima; editing by Jonathan Leff and