London: Angola will ship the least crude oil in at least 11 years in April, suggesting structural issues afflicting the nation’s production are increasingly hurting its biggest source of export revenue.

Exports will drop to 1.31 million barrels a day in April, the smallest outflow since at least March 2008, according to copies of loading programs seen by Bloomberg.

Angola, Africa’s second-largest producer, is among members of the Organisation of Petroleum Exporting Countries participating in a global pact to trim production. Even if they’re not perfectly correlated, exports often offer clues about how much a country might be pumping. The nation pledged a curb of 47,000 barrels a day from October, but its April loadings will drop by far more than that.

The decrease in outflows from the country isn’t entirely unexpected. The International Energy Agency, an adviser to oil-producing nations, warned a year ago that a slump in output would only deepen due to ageing fields and a lack of interest from foreign investors.

“It does seem to reflect the issue of ageing fields for the Angolan oil industry,” said Warren Patterson, head of commodities strategy at ING Bank NV in Amsterdam. “If we cast our minds back to the previous Opec deal, Angola over-complied with the deal, and that certainly was not out of choice, but more an issue of maturing fields.”

Whether deliberate or involuntary, the decline from Angola would serve as a boost to the wider curbs by Opec and its allies as they attempt to avert a glut of crude. While Saudi Arabia has led the way with supply restrictions, conformity among some other participants in the pact has been less consistent.

Angola’s exports are down by almost 200,000 barrels a day compared with October, its starting point for curbs under the Opec+ accord.

Previously low oil prices discouraged investment in the country and are probably contributing to the reduced shipments, Patterson said.