Venezuela’s state-run oil firm, PDVSA, is increasingly delivering poor quality crude oil to major refiners in the United States, India and China, causing repeated complaints, canceled orders and demands for discounts, according to internal PDVSA documents and interviews with a dozen oil executives, workers, traders and inspectors.

The disputes involve cargoes soiled with high levels of water, salt or metals that can cause problems for refineries, according to the sources and internal PDVSA trade documents seen by Reuters.

The quality issues stem from shortages of chemicals and equipment to properly treat and store the oil, resulting in shutdowns and slowdowns at PDVSA production facilities, along with hurried transporting to avoid late deliveries, the sources said.

U.S. refiner Phillips 66 (PSX.N) canceled at least eight crude cargoes because of poor oil quality in the first half of the year and demanded discounts on other deliveries, according to the PDVSA documents and employees from both firms. The canceled shipments - amounting to 4.4 million barrels of oil - had a market value of nearly $200 million....