Oil prices eased on Tuesday as investors appeared to shrug off earlier supply concerns following a force majeure declared by Libya on two major oilfields amid a military blockade.A document sent to oil traders and seen by Reuters on Monday said the NOC had declared force majeure – a waiver on contractual obligations – on crude loadings from El Sharara and El Feel oilfields in Libya’s southwest. Adding to supply, Guyana exported its first-ever shipment of crude on Monday, marking the tiny South American nation’s debut as an oil exporter.Any supply disruptions could be offset by increased output from the Organization of the Petroleum Exporting Countries (OPEC), which could limit the impact on global oil markets, the head of Japan’s petroleum industry body said.